2009-11-04 13:23:36

by Aaro Koskinen

[permalink] [raw]
Subject: [PATCH v2 1/2] input: touchscreen: introduce tsc2005 driver

From: Lauri Leukkunen <[email protected]>

Introduce a driver for the Texas Instruments TSC2005 touchscreen
controller.

Includes additional modifications by David Brownell, Phil Carmody,
Imre Deak, Hiroshi DOYU, Ari Kauppi, Tony Lindgren, Jarkko Nikula,
Eero Nurkkala and Roman Tereshonkov.

Signed-off-by: Lauri Leukkunen <[email protected]>
[[email protected]: patch description, rebasing & cleanup]
Signed-off-by: Aaro Koskinen <[email protected]>
CC: David Brownell <[email protected]>
CC: Phil Carmody <[email protected]>
CC: Imre Deak <[email protected]>
CC: Hiroshi DOYU <[email protected]>
CC: Ari Kauppi <[email protected]>
CC: Tony Lindgren <[email protected]>
CC: Jarkko Nikula <[email protected]>
CC: Eero Nurkkala <[email protected]>
CC: Roman Tereshonkov <[email protected]>
---

The patch is for 2.6.32-rc6.

v2:
- Move RX-51 specific stuff to a separate patch
- Change year in the comments

drivers/input/touchscreen/Kconfig | 11 +
drivers/input/touchscreen/Makefile | 1 +
drivers/input/touchscreen/tsc2005.c | 958 +++++++++++++++++++++++++++++++++++
include/linux/spi/tsc2005.h | 30 ++
4 files changed, 1000 insertions(+), 0 deletions(-)
create mode 100644 drivers/input/touchscreen/tsc2005.c
create mode 100644 include/linux/spi/tsc2005.h

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 8cc453c..b758ba8 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -501,6 +501,17 @@ config TOUCHSCREEN_TOUCHIT213
To compile this driver as a module, choose M here: the
module will be called touchit213.

+config TOUCHSCREEN_TSC2005
+ tristate "TSC2005 based touchscreens"
+ depends on SPI_MASTER
+ help
+ Say Y here if you have a TSC2005 based touchscreen.
+
+ If unsure, say N.
+
+ To compile this driver as a module, choose M here: the
+ module will be called tsc2005.
+
config TOUCHSCREEN_TSC2007
tristate "TSC2007 based touchscreens"
depends on I2C
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 15fa62c..0626f9f 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_TOUCHSCREEN_PENMOUNT) += penmount.o
obj-$(CONFIG_TOUCHSCREEN_TOUCHIT213) += touchit213.o
obj-$(CONFIG_TOUCHSCREEN_TOUCHRIGHT) += touchright.o
obj-$(CONFIG_TOUCHSCREEN_TOUCHWIN) += touchwin.o
+obj-$(CONFIG_TOUCHSCREEN_TSC2005) += tsc2005.o
obj-$(CONFIG_TOUCHSCREEN_TSC2007) += tsc2007.o
obj-$(CONFIG_TOUCHSCREEN_UCB1400) += ucb1400_ts.o
obj-$(CONFIG_TOUCHSCREEN_WACOM_W8001) += wacom_w8001.o
diff --git a/drivers/input/touchscreen/tsc2005.c b/drivers/input/touchscreen/tsc2005.c
new file mode 100644
index 0000000..abc0548
--- /dev/null
+++ b/drivers/input/touchscreen/tsc2005.c
@@ -0,0 +1,958 @@
+/*
+ * TSC2005 touchscreen driver
+ *
+ * Copyright (C) 2006-2009 Nokia Corporation
+ *
+ * Author: Lauri Leukkunen <[email protected]>
+ * based on TSC2301 driver by Klaus K. Pedersen <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/spi/spi.h>
+
+#include <linux/spi/tsc2005.h>
+
+/**
+ * The touchscreen interface operates as follows:
+ *
+ * Initialize:
+ * Request access to GPIO103 (DAV)
+ * tsc2005_ts_irq_handler will trigger when DAV line goes down
+ *
+ * 1) Pen is pressed against touchscreeen
+ * 2) TSC2005 performs AD conversion
+ * 3) After the conversion is done TSC2005 drives DAV line down
+ * 4) GPIO IRQ is received and tsc2005_ts_irq_handler is called
+ * 5) tsc2005_ts_irq_handler queues up an spi transfer to fetch
+ * the x, y, z1, z2 values
+ * 6) tsc2005_ts_rx() reports coordinates to input layer and
+ * sets up tsc2005_ts_timer() to be called after TSC2005_TS_SCAN_TIME
+ * 7) When the penup_timer expires, there have not been DAV interrupts
+ * during the last 20ms which means the pen has been lifted.
+ */
+
+#define TSC2005_VDD_LOWER_27
+
+#ifdef TSC2005_VDD_LOWER_27
+#define TSC2005_HZ (10000000)
+#else
+#define TSC2005_HZ (25000000)
+#endif
+
+#define TSC2005_CMD (0x80)
+#define TSC2005_REG (0x00)
+
+#define TSC2005_CMD_STOP (1)
+#define TSC2005_CMD_10BIT (0 << 2)
+#define TSC2005_CMD_12BIT (1 << 2)
+
+#define TSC2005_CMD_SCAN_XYZZ (0 << 3)
+#define TSC2005_CMD_SCAN_XY (1 << 3)
+#define TSC2005_CMD_SCAN_X (2 << 3)
+#define TSC2005_CMD_SCAN_Y (3 << 3)
+#define TSC2005_CMD_SCAN_ZZ (4 << 3)
+#define TSC2005_CMD_AUX_SINGLE (5 << 3)
+#define TSC2005_CMD_TEMP1 (6 << 3)
+#define TSC2005_CMD_TEMP2 (7 << 3)
+#define TSC2005_CMD_AUX_CONT (8 << 3)
+#define TSC2005_CMD_TEST_X_CONN (9 << 3)
+#define TSC2005_CMD_TEST_Y_CONN (10 << 3)
+#define TSC2005_CMD_TEST_SHORT (11 << 3)
+/* command 12 reserved, according to 2008-03 erratum */
+#define TSC2005_CMD_DRIVE_XX (13 << 3)
+#define TSC2005_CMD_DRIVE_YY (14 << 3)
+#define TSC2005_CMD_DRIVE_YX (15 << 3)
+
+#define TSC2005_REG_X (0 << 3)
+#define TSC2005_REG_Y (1 << 3)
+#define TSC2005_REG_Z1 (2 << 3)
+#define TSC2005_REG_Z2 (3 << 3)
+#define TSC2005_REG_AUX (4 << 3)
+#define TSC2005_REG_TEMP1 (5 << 3)
+#define TSC2005_REG_TEMP2 (6 << 3)
+#define TSC2005_REG_STATUS (7 << 3)
+#define TSC2005_REG_AUX_HIGH (8 << 3)
+#define TSC2005_REG_AUX_LOW (9 << 3)
+#define TSC2005_REG_TEMP_HIGH (10 << 3)
+#define TSC2005_REG_TEMP_LOW (11 << 3)
+#define TSC2005_REG_CFR0 (12 << 3)
+#define TSC2005_REG_CFR1 (13 << 3)
+#define TSC2005_REG_CFR2 (14 << 3)
+#define TSC2005_REG_FUNCTION (15 << 3)
+
+#define TSC2005_REG_PND0 (1 << 1)
+#define TSC2005_REG_READ (0x01)
+#define TSC2005_REG_WRITE (0x00)
+
+
+#define TSC2005_CFR0_LONGSAMPLING (1)
+#define TSC2005_CFR0_DETECTINWAIT (1 << 1)
+#define TSC2005_CFR0_SENSETIME_32US (0)
+#define TSC2005_CFR0_SENSETIME_96US (1 << 2)
+#define TSC2005_CFR0_SENSETIME_544US (1 << 3)
+#define TSC2005_CFR0_SENSETIME_2080US (1 << 4)
+#define TSC2005_CFR0_SENSETIME_2656US (0x001C)
+#define TSC2005_CFR0_PRECHARGE_20US (0x0000)
+#define TSC2005_CFR0_PRECHARGE_84US (0x0020)
+#define TSC2005_CFR0_PRECHARGE_276US (0x0040)
+#define TSC2005_CFR0_PRECHARGE_1044US (0x0080)
+#define TSC2005_CFR0_PRECHARGE_1364US (0x00E0)
+#define TSC2005_CFR0_STABTIME_0US (0x0000)
+#define TSC2005_CFR0_STABTIME_100US (0x0100)
+#define TSC2005_CFR0_STABTIME_500US (0x0200)
+#define TSC2005_CFR0_STABTIME_1MS (0x0300)
+#define TSC2005_CFR0_STABTIME_5MS (0x0400)
+#define TSC2005_CFR0_STABTIME_100MS (0x0700)
+#define TSC2005_CFR0_CLOCK_4MHZ (0x0000)
+#define TSC2005_CFR0_CLOCK_2MHZ (0x0800)
+#define TSC2005_CFR0_CLOCK_1MHZ (0x1000)
+#define TSC2005_CFR0_RESOLUTION12 (0x2000)
+#define TSC2005_CFR0_STATUS (0x4000)
+#define TSC2005_CFR0_PENMODE (0x8000)
+
+#define TSC2005_CFR0_INITVALUE (TSC2005_CFR0_STABTIME_1MS | \
+ TSC2005_CFR0_CLOCK_1MHZ | \
+ TSC2005_CFR0_RESOLUTION12 | \
+ TSC2005_CFR0_PRECHARGE_276US | \
+ TSC2005_CFR0_PENMODE)
+
+/* Bits common to both read and write of config register 0 */
+#define TSC2005_CFR0_RW_MASK 0x3fff
+
+#define TSC2005_CFR1_BATCHDELAY_0MS (0x0000)
+#define TSC2005_CFR1_BATCHDELAY_1MS (0x0001)
+#define TSC2005_CFR1_BATCHDELAY_2MS (0x0002)
+#define TSC2005_CFR1_BATCHDELAY_4MS (0x0003)
+#define TSC2005_CFR1_BATCHDELAY_10MS (0x0004)
+#define TSC2005_CFR1_BATCHDELAY_20MS (0x0005)
+#define TSC2005_CFR1_BATCHDELAY_40MS (0x0006)
+#define TSC2005_CFR1_BATCHDELAY_100MS (0x0007)
+
+#define TSC2005_CFR1_INITVALUE (TSC2005_CFR1_BATCHDELAY_4MS)
+
+#define TSC2005_CFR2_MAVE_TEMP (0x0001)
+#define TSC2005_CFR2_MAVE_AUX (0x0002)
+#define TSC2005_CFR2_MAVE_Z (0x0004)
+#define TSC2005_CFR2_MAVE_Y (0x0008)
+#define TSC2005_CFR2_MAVE_X (0x0010)
+#define TSC2005_CFR2_AVG_1 (0x0000)
+#define TSC2005_CFR2_AVG_3 (0x0400)
+#define TSC2005_CFR2_AVG_7 (0x0800)
+#define TSC2005_CFR2_MEDIUM_1 (0x0000)
+#define TSC2005_CFR2_MEDIUM_3 (0x1000)
+#define TSC2005_CFR2_MEDIUM_7 (0x2000)
+#define TSC2005_CFR2_MEDIUM_15 (0x3000)
+
+#define TSC2005_CFR2_IRQ_MASK (0xC000)
+#define TSC2005_CFR2_IRQ_DAV (0x4000)
+#define TSC2005_CFR2_IRQ_PEN (0x8000)
+#define TSC2005_CFR2_IRQ_PENDAV (0x0000)
+
+#define TSC2005_CFR2_INITVALUE (TSC2005_CFR2_IRQ_PENDAV | \
+ TSC2005_CFR2_MAVE_X | \
+ TSC2005_CFR2_MAVE_Y | \
+ TSC2005_CFR2_MAVE_Z | \
+ TSC2005_CFR2_MEDIUM_15 | \
+ TSC2005_CFR2_AVG_7)
+
+#define MAX_12BIT ((1 << 12) - 1)
+#define TS_SAMPLES 4
+#define TSC2005_TS_PENUP_TIME 40
+
+static const u32 tsc2005_read_reg[] = {
+ (TSC2005_REG | TSC2005_REG_X | TSC2005_REG_READ) << 16,
+ (TSC2005_REG | TSC2005_REG_Y | TSC2005_REG_READ) << 16,
+ (TSC2005_REG | TSC2005_REG_Z1 | TSC2005_REG_READ) << 16,
+ (TSC2005_REG | TSC2005_REG_Z2 | TSC2005_REG_READ) << 16,
+};
+#define NUM_READ_REGS (sizeof(tsc2005_read_reg)/sizeof(tsc2005_read_reg[0]))
+
+struct tsc2005 {
+ struct spi_device *spi;
+
+ struct input_dev *idev;
+ char phys[32];
+ struct timer_list penup_timer;
+
+ /* ESD recovery via a hardware reset if the tsc2005
+ * doesn't respond after a configurable period (in ms) of
+ * IRQ/SPI inactivity. If esd_timeout is 0, timer and work
+ * fields are used.
+ */
+ u32 esd_timeout;
+ struct timer_list esd_timer;
+ struct work_struct esd_work;
+
+ spinlock_t lock;
+ struct mutex mutex;
+
+ struct spi_message read_msg;
+ struct spi_transfer read_xfer[NUM_READ_REGS];
+ u32 data[NUM_READ_REGS];
+
+ /* previously reported x,y,p (if pen_down) */
+ int out_x;
+ int out_y;
+ int out_p;
+ /* fudge parameters - changes must exceed one of these. */
+ int fudge_x;
+ int fudge_y;
+ int fudge_p;
+ /* raw copy of previous x,y,z */
+ int in_x;
+ int in_y;
+ int in_z1;
+ int in_z2;
+ /* average accumulators for each component */
+ int sample_cnt;
+ int avg_x;
+ int avg_y;
+ int avg_z1;
+ int avg_z2;
+ /* configuration */
+ int x_plate_ohm;
+ int hw_avg_max;
+ int stab_time;
+ int p_max;
+ int touch_pressure;
+ /* status */
+ u8 sample_sent;
+ u8 pen_down;
+ u8 disabled;
+ u8 disable_depth;
+ u8 spi_pending;
+
+ void (*set_reset)(bool enable);
+};
+
+static void tsc2005_cmd(struct tsc2005 *ts, u8 cmd)
+{
+ u8 data = TSC2005_CMD | TSC2005_CMD_12BIT | cmd;
+ struct spi_message msg;
+ struct spi_transfer xfer = { 0 };
+
+ xfer.tx_buf = &data;
+ xfer.rx_buf = NULL;
+ xfer.len = 1;
+ xfer.bits_per_word = 8;
+
+ spi_message_init(&msg);
+ spi_message_add_tail(&xfer, &msg);
+ spi_sync(ts->spi, &msg);
+}
+
+static void tsc2005_write(struct tsc2005 *ts, u8 reg, u16 value)
+{
+ u32 tx;
+ struct spi_message msg;
+ struct spi_transfer xfer = { 0 };
+
+ tx = (TSC2005_REG | reg | TSC2005_REG_PND0 |
+ TSC2005_REG_WRITE) << 16;
+ tx |= value;
+
+ xfer.tx_buf = &tx;
+ xfer.rx_buf = NULL;
+ xfer.len = 4;
+ xfer.bits_per_word = 24;
+
+ spi_message_init(&msg);
+ spi_message_add_tail(&xfer, &msg);
+ spi_sync(ts->spi, &msg);
+}
+
+static void tsc2005_read(struct tsc2005 *ts, u8 reg, u16 *value)
+{
+ u32 tx;
+ u32 rx = 0;
+ struct spi_message msg;
+ struct spi_transfer xfer = { 0 };
+
+ tx = (TSC2005_REG | reg | TSC2005_REG_READ) << 16;
+
+ xfer.tx_buf = &tx;
+ xfer.rx_buf = &rx;
+ xfer.len = 4;
+ xfer.bits_per_word = 24;
+
+ spi_message_init(&msg);
+ spi_message_add_tail(&xfer, &msg);
+ spi_sync(ts->spi, &msg);
+ *value = rx;
+}
+
+static void tsc2005_ts_update_pen_state(struct tsc2005 *ts,
+ int x, int y, int pressure)
+{
+ if (pressure) {
+ input_report_abs(ts->idev, ABS_X, x);
+ input_report_abs(ts->idev, ABS_Y, y);
+ input_report_abs(ts->idev, ABS_PRESSURE, pressure);
+ if (!ts->pen_down) {
+ input_report_key(ts->idev, BTN_TOUCH, 1);
+ ts->pen_down = 1;
+ }
+ } else {
+ input_report_abs(ts->idev, ABS_PRESSURE, 0);
+ if (ts->pen_down) {
+ input_report_key(ts->idev, BTN_TOUCH, 0);
+ ts->pen_down = 0;
+ }
+ }
+
+ input_sync(ts->idev);
+}
+
+/*
+ * This function is called by the SPI framework after the coordinates
+ * have been read from TSC2005
+ */
+static void tsc2005_ts_rx(void *arg)
+{
+ struct tsc2005 *ts = arg;
+ unsigned long flags;
+ int inside_rect, pressure_limit;
+ int x, y, z1, z2, pressure;
+
+ spin_lock_irqsave(&ts->lock, flags);
+
+ if (ts->disable_depth) {
+ ts->spi_pending = 0;
+ goto out;
+ }
+
+ x = ts->data[0];
+ y = ts->data[1];
+ z1 = ts->data[2];
+ z2 = ts->data[3];
+
+ /* validate pressure and position */
+ if (x > MAX_12BIT || y > MAX_12BIT)
+ goto out;
+
+ /* skip coords if the pressure-components are out of range */
+ if (z1 < 100 || z2 > MAX_12BIT || z1 >= z2)
+ goto out;
+
+ /* skip point if this is a pen down with the exact same values as
+ * the value before pen-up - that implies SPI fed us stale data
+ */
+ if (!ts->pen_down &&
+ ts->in_x == x &&
+ ts->in_y == y &&
+ ts->in_z1 == z1 &&
+ ts->in_z2 == z2)
+ goto out;
+
+ /* At this point we are happy we have a valid and useful reading.
+ * Remember it for later comparisons. We may now begin downsampling
+ */
+ ts->in_x = x;
+ ts->in_y = y;
+ ts->in_z1 = z1;
+ ts->in_z2 = z2;
+
+ /* don't run average on the "pen down" event */
+ if (ts->sample_sent) {
+ ts->avg_x += x;
+ ts->avg_y += y;
+ ts->avg_z1 += z1;
+ ts->avg_z2 += z2;
+
+ if (++ts->sample_cnt < TS_SAMPLES)
+ goto out;
+
+ x = ts->avg_x / TS_SAMPLES;
+ y = ts->avg_y / TS_SAMPLES;
+ z1 = ts->avg_z1 / TS_SAMPLES;
+ z2 = ts->avg_z2 / TS_SAMPLES;
+ }
+
+ ts->sample_cnt = 0;
+ ts->avg_x = 0;
+ ts->avg_y = 0;
+ ts->avg_z1 = 0;
+ ts->avg_z2 = 0;
+
+ pressure = x * (z2 - z1) / z1;
+ pressure = pressure * ts->x_plate_ohm / 4096;
+
+ pressure_limit = ts->sample_sent ? ts->p_max : ts->touch_pressure;
+ if (pressure > pressure_limit)
+ goto out;
+
+ /* Discard the event if it still is within the previous rect -
+ * unless the pressure is clearly harder, but then use previous
+ * x,y position. If any coordinate deviates enough, fudging
+ * of all three will still take place in the input layer.
+ */
+ inside_rect = (ts->sample_sent &&
+ x > (int)ts->out_x - ts->fudge_x &&
+ x < (int)ts->out_x + ts->fudge_x &&
+ y > (int)ts->out_y - ts->fudge_y &&
+ y < (int)ts->out_y + ts->fudge_y);
+ if (inside_rect)
+ x = ts->out_x, y = ts->out_y;
+
+ if (!inside_rect || pressure < (ts->out_p - ts->fudge_p)) {
+ tsc2005_ts_update_pen_state(ts, x, y, pressure);
+ ts->sample_sent = 1;
+ ts->out_x = x;
+ ts->out_y = y;
+ ts->out_p = pressure;
+ }
+out:
+ if (ts->spi_pending > 1) {
+ /* One or more interrupts (sometimes several dozens)
+ * occured while waiting for the SPI read - get
+ * another read going.
+ */
+ ts->spi_pending = 1;
+ if (spi_async(ts->spi, &ts->read_msg)) {
+ dev_err(&ts->spi->dev, "ts: spi_async() failed");
+ ts->spi_pending = 0;
+ }
+ } else
+ ts->spi_pending = 0;
+
+ /* kick pen up timer - to make sure it expires again(!) */
+ if (ts->sample_sent) {
+ mod_timer(&ts->penup_timer,
+ jiffies + msecs_to_jiffies(TSC2005_TS_PENUP_TIME));
+ /* Also kick the watchdog, as we still think we're alive */
+ if (ts->esd_timeout && ts->disable_depth == 0) {
+ unsigned long wdj = msecs_to_jiffies(ts->esd_timeout);
+ mod_timer(&ts->esd_timer, round_jiffies(jiffies+wdj));
+ }
+ }
+ spin_unlock_irqrestore(&ts->lock, flags);
+}
+
+/* This penup timer is very forgiving of delayed SPI reads. The
+ * (ESD) watchdog will rescue us if spi_pending remains set, unless
+ * we are enterring the disabled state. In that case we must just
+ * handle the pen up, and let disabling complete.
+ */
+static void tsc2005_ts_penup_timer_handler(unsigned long data)
+{
+ struct tsc2005 *ts = (struct tsc2005 *)data;
+ if ((!ts->spi_pending || ts->disable_depth) &&
+ ts->sample_sent) {
+ tsc2005_ts_update_pen_state(ts, 0, 0, 0);
+ ts->sample_sent = 0;
+ }
+}
+
+/*
+ * This interrupt is called when pen is down and coordinates are
+ * available. That is indicated by a either:
+ * a) a rising edge on PINTDAV or (PENDAV mode)
+ * b) a falling edge on DAV line (DAV mode)
+ * depending on the setting of the IRQ bits in the CFR2 setting above.
+ */
+static irqreturn_t tsc2005_ts_irq_handler(int irq, void *dev_id)
+{
+ struct tsc2005 *ts = dev_id;
+ if (ts->disable_depth)
+ goto out;
+
+ if (!ts->spi_pending) {
+ if (spi_async(ts->spi, &ts->read_msg)) {
+ dev_err(&ts->spi->dev, "ts: spi_async() failed");
+ goto out;
+ }
+ }
+ /* By shifting in 1s we can never wrap */
+ ts->spi_pending = (ts->spi_pending<<1)+1;
+
+ /* Kick pen up timer only if it's not been started yet. Strictly,
+ * it isn't even necessary to start it at all here, but doing so
+ * keeps an equivalence between pen state and timer state.
+ * The SPI read loop will keep pushing it into the future.
+ * If it times out with an SPI pending, it's ignored anyway.
+ */
+ if (!timer_pending(&ts->penup_timer)) {
+ unsigned long pu = msecs_to_jiffies(TSC2005_TS_PENUP_TIME);
+ ts->penup_timer.expires = jiffies + pu;
+ add_timer(&ts->penup_timer);
+ }
+out:
+ return IRQ_HANDLED;
+}
+
+static void tsc2005_ts_setup_spi_xfer(struct tsc2005 *ts)
+{
+ struct spi_message *m = &ts->read_msg;
+ struct spi_transfer *x = &ts->read_xfer[0];
+ int i;
+
+ spi_message_init(m);
+
+ for (i = 0; i < NUM_READ_REGS; i++, x++) {
+ x->tx_buf = &tsc2005_read_reg[i];
+ x->rx_buf = &ts->data[i];
+ x->len = 4;
+ x->bits_per_word = 24;
+ x->cs_change = i < (NUM_READ_REGS - 1);
+ spi_message_add_tail(x, m);
+ }
+
+ m->complete = tsc2005_ts_rx;
+ m->context = ts;
+}
+
+static ssize_t tsc2005_ts_pen_down_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct tsc2005 *ts = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%u\n", ts->pen_down);
+}
+
+static DEVICE_ATTR(pen_down, S_IRUGO, tsc2005_ts_pen_down_show, NULL);
+
+static int tsc2005_configure(struct tsc2005 *ts, int flags)
+{
+ tsc2005_write(ts, TSC2005_REG_CFR0, TSC2005_CFR0_INITVALUE);
+ tsc2005_write(ts, TSC2005_REG_CFR1, TSC2005_CFR1_INITVALUE);
+ tsc2005_write(ts, TSC2005_REG_CFR2, TSC2005_CFR2_INITVALUE);
+ tsc2005_cmd(ts, flags);
+
+ return 0;
+}
+
+static void tsc2005_start_scan(struct tsc2005 *ts)
+{
+ tsc2005_configure(ts, TSC2005_CMD_SCAN_XYZZ);
+}
+
+static void tsc2005_stop_scan(struct tsc2005 *ts)
+{
+ tsc2005_cmd(ts, TSC2005_CMD_STOP);
+}
+
+/* Must be called with mutex held */
+static void tsc2005_disable(struct tsc2005 *ts)
+{
+ if (ts->disable_depth++ != 0)
+ return;
+
+ disable_irq(ts->spi->irq);
+ if (ts->esd_timeout)
+ del_timer(&ts->esd_timer);
+
+ /* wait until penup timer expire normally */
+ do {
+ msleep(4);
+ } while (ts->sample_sent);
+
+ tsc2005_stop_scan(ts);
+}
+
+static void tsc2005_enable(struct tsc2005 *ts)
+{
+ if (ts->disable_depth != 1)
+ goto out;
+
+ if (ts->esd_timeout) {
+ unsigned long wdj = msecs_to_jiffies(ts->esd_timeout);
+ ts->esd_timer.expires = round_jiffies(jiffies+wdj);
+ add_timer(&ts->esd_timer);
+ }
+ tsc2005_start_scan(ts);
+ enable_irq(ts->spi->irq);
+out:
+ --ts->disable_depth;
+}
+
+static ssize_t tsc2005_disable_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct tsc2005 *ts = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%u\n", ts->disabled);
+}
+
+static ssize_t tsc2005_disable_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct tsc2005 *ts = dev_get_drvdata(dev);
+ unsigned long res;
+ int i;
+
+ if (strict_strtoul(buf, 10, &res) < 0)
+ return -EINVAL;
+ i = res ? 1 : 0;
+
+ mutex_lock(&ts->mutex);
+ if (i == ts->disabled)
+ goto out;
+ ts->disabled = i;
+
+ if (i)
+ tsc2005_disable(ts);
+ else
+ tsc2005_enable(ts);
+out:
+ mutex_unlock(&ts->mutex);
+ return count;
+}
+
+static DEVICE_ATTR(disable_ts, 0664, tsc2005_disable_show,
+ tsc2005_disable_store);
+
+static ssize_t tsc2005_ctrl_selftest_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ u16 temp_high_orig, temp_high_test, temp_high;
+ unsigned int result = 1;
+ struct tsc2005 *ts = dev_get_drvdata(dev);
+
+ if (!ts->set_reset) {
+ dev_warn(&ts->spi->dev,
+ "unable to selftest: reset not configured\n");
+ result = 0;
+ goto out;
+ }
+
+ mutex_lock(&ts->mutex);
+ tsc2005_disable(ts);
+
+ /* Test ctrl communications via temp high / low registers */
+ tsc2005_read(ts, TSC2005_REG_TEMP_HIGH, &temp_high_orig);
+
+ temp_high_test = (temp_high_orig - 1) & 0x0FFF;
+
+ tsc2005_write(ts, TSC2005_REG_TEMP_HIGH, temp_high_test);
+
+ tsc2005_read(ts, TSC2005_REG_TEMP_HIGH, &temp_high);
+
+ if (temp_high != temp_high_test) {
+ result = 0;
+ dev_warn(dev, "selftest failed: %d != %d\n",
+ temp_high, temp_high_test);
+ }
+
+ /* HW Reset */
+ ts->set_reset(0);
+ msleep(1); /* only 10us required */
+ ts->set_reset(1);
+
+ tsc2005_enable(ts);
+
+ /* Test that reset really happened */
+ tsc2005_read(ts, TSC2005_REG_TEMP_HIGH, &temp_high);
+
+ if (temp_high != temp_high_orig) {
+ result = 0;
+ dev_warn(dev, "selftest failed after reset: "
+ "%d != %d\n",
+ temp_high, temp_high_orig);
+ }
+
+ mutex_unlock(&ts->mutex);
+
+out:
+ return sprintf(buf, "%u\n", result);
+}
+
+static DEVICE_ATTR(ts_ctrl_selftest, S_IRUGO, tsc2005_ctrl_selftest_show, NULL);
+
+static void tsc2005_esd_timer_handler(unsigned long data)
+{
+ struct tsc2005 *ts = (struct tsc2005 *)data;
+ if (!ts->disable_depth)
+ schedule_work(&ts->esd_work);
+}
+
+static void tsc2005_rst_handler(struct work_struct *work)
+{
+ u16 reg_val;
+ struct tsc2005 *ts = container_of(work, struct tsc2005, esd_work);
+ unsigned long wdj;
+
+ mutex_lock(&ts->mutex);
+
+ /* If we are disabled, or the a touch has been detected,
+ * then ignore this timeout. The enable will restart the
+ * watchdog, as it restarts scanning
+ */
+ if (ts->disable_depth)
+ goto out;
+
+ /* If we cannot read our known value from configuration register 0
+ * then reset the controller as if from power-up and start
+ * scanning again. Always re-arm the watchdog.
+ */
+ tsc2005_read(ts, TSC2005_REG_CFR0, &reg_val);
+ if ((reg_val ^ TSC2005_CFR0_INITVALUE) & TSC2005_CFR0_RW_MASK) {
+ dev_info(&ts->spi->dev, "TSC not responding, resetting.\n");
+ /* If this timer kicked in, the penup timer, if ever active
+ * at all, must have expired ages ago, so no need to del it.
+ */
+ ts->set_reset(0);
+ if (ts->sample_sent) {
+ tsc2005_ts_update_pen_state(ts, 0, 0, 0);
+ ts->sample_sent = 0;
+ }
+ ts->spi_pending = 0;
+ msleep(1); /* only 10us required */
+ ts->set_reset(1);
+ tsc2005_start_scan(ts);
+ }
+ wdj = msecs_to_jiffies(ts->esd_timeout);
+ mod_timer(&ts->esd_timer, round_jiffies(jiffies+wdj));
+
+out:
+ mutex_unlock(&ts->mutex);
+}
+
+static int __devinit tsc2005_ts_init(struct tsc2005 *ts,
+ struct tsc2005_platform_data *pdata)
+{
+ struct input_dev *idev;
+ int r;
+ int x_max, y_max;
+
+ init_timer(&ts->penup_timer);
+ setup_timer(&ts->penup_timer, tsc2005_ts_penup_timer_handler,
+ (unsigned long)ts);
+
+ spin_lock_init(&ts->lock);
+ mutex_init(&ts->mutex);
+
+ ts->x_plate_ohm = pdata->ts_x_plate_ohm ? : 280;
+ ts->hw_avg_max = pdata->ts_hw_avg;
+ ts->stab_time = pdata->ts_stab_time;
+ x_max = pdata->ts_x_max ? : 4096;
+ ts->fudge_x = pdata->ts_x_fudge ? : 4;
+ y_max = pdata->ts_y_max ? : 4096;
+ ts->fudge_y = pdata->ts_y_fudge ? : 8;
+ ts->p_max = pdata->ts_pressure_max ? : MAX_12BIT;
+ ts->touch_pressure = pdata->ts_touch_pressure ? : ts->p_max;
+ ts->fudge_p = pdata->ts_pressure_fudge ? : 2;
+
+ ts->set_reset = pdata->set_reset;
+
+ idev = input_allocate_device();
+ if (idev == NULL) {
+ r = -ENOMEM;
+ goto err1;
+ }
+
+ idev->name = "TSC2005 touchscreen";
+ snprintf(ts->phys, sizeof(ts->phys), "%s/input-ts",
+ dev_name(&ts->spi->dev));
+ idev->phys = ts->phys;
+
+ idev->evbit[0] = BIT(EV_ABS) | BIT(EV_KEY);
+ idev->absbit[0] = BIT(ABS_X) | BIT(ABS_Y) | BIT(ABS_PRESSURE);
+ idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
+ ts->idev = idev;
+
+ tsc2005_ts_setup_spi_xfer(ts);
+
+ input_set_abs_params(idev, ABS_X, 0, x_max, ts->fudge_x, 0);
+ input_set_abs_params(idev, ABS_Y, 0, y_max, ts->fudge_y, 0);
+ input_set_abs_params(idev, ABS_PRESSURE, 0, ts->p_max, ts->fudge_p, 0);
+
+ tsc2005_start_scan(ts);
+
+ r = request_irq(ts->spi->irq, tsc2005_ts_irq_handler,
+ (((TSC2005_CFR2_INITVALUE & TSC2005_CFR2_IRQ_MASK) ==
+ TSC2005_CFR2_IRQ_PENDAV)
+ ? IRQF_TRIGGER_RISING
+ : IRQF_TRIGGER_FALLING) |
+ IRQF_DISABLED, "tsc2005", ts);
+ if (r < 0) {
+ dev_err(&ts->spi->dev, "unable to get DAV IRQ");
+ goto err2;
+ }
+
+ set_irq_wake(ts->spi->irq, 1);
+
+ r = input_register_device(idev);
+ if (r < 0) {
+ dev_err(&ts->spi->dev, "can't register touchscreen device\n");
+ goto err3;
+ }
+
+ /* We can tolerate these failing */
+ r = device_create_file(&ts->spi->dev, &dev_attr_ts_ctrl_selftest);
+ if (r < 0)
+ dev_warn(&ts->spi->dev, "can't create sysfs file for %s: %d\n",
+ dev_attr_ts_ctrl_selftest.attr.name, r);
+
+ r = device_create_file(&ts->spi->dev, &dev_attr_pen_down);
+ if (r < 0)
+ dev_warn(&ts->spi->dev, "can't create sysfs file for %s: %d\n",
+ dev_attr_pen_down.attr.name, r);
+
+ r = device_create_file(&ts->spi->dev, &dev_attr_disable_ts);
+ if (r < 0)
+ dev_warn(&ts->spi->dev, "can't create sysfs file for %s: %d\n",
+ dev_attr_disable_ts.attr.name, r);
+
+ /* Finally, configure and start the optional EDD watchdog. */
+ ts->esd_timeout = pdata->esd_timeout;
+ if (ts->esd_timeout && ts->set_reset) {
+ unsigned long wdj;
+ setup_timer(&ts->esd_timer, tsc2005_esd_timer_handler,
+ (unsigned long)ts);
+ INIT_WORK(&ts->esd_work, tsc2005_rst_handler);
+ wdj = msecs_to_jiffies(ts->esd_timeout);
+ ts->esd_timer.expires = round_jiffies(jiffies+wdj);
+ add_timer(&ts->esd_timer);
+ }
+
+ return 0;
+err3:
+ free_irq(ts->spi->irq, ts);
+err2:
+ tsc2005_stop_scan(ts);
+ input_free_device(idev);
+err1:
+ return r;
+}
+
+static int __devinit tsc2005_probe(struct spi_device *spi)
+{
+ struct tsc2005 *ts;
+ struct tsc2005_platform_data *pdata = spi->dev.platform_data;
+ int r;
+
+ if (spi->irq < 0) {
+ dev_dbg(&spi->dev, "no irq?\n");
+ return -ENODEV;
+ }
+ if (!pdata) {
+ dev_dbg(&spi->dev, "no platform data?\n");
+ return -ENODEV;
+ }
+
+ ts = kzalloc(sizeof(*ts), GFP_KERNEL);
+ if (ts == NULL)
+ return -ENOMEM;
+
+ dev_set_drvdata(&spi->dev, ts);
+ ts->spi = spi;
+ spi->dev.power.power_state = PMSG_ON;
+
+ spi->mode = SPI_MODE_0;
+ spi->bits_per_word = 8;
+ /* The max speed might've been defined by the board-specific
+ * struct */
+ if (!spi->max_speed_hz)
+ spi->max_speed_hz = TSC2005_HZ;
+
+ spi_setup(spi);
+
+ r = tsc2005_ts_init(ts, pdata);
+ if (r)
+ goto err1;
+
+ return 0;
+
+err1:
+ kfree(ts);
+ return r;
+}
+
+static int __devexit tsc2005_remove(struct spi_device *spi)
+{
+ struct tsc2005 *ts = dev_get_drvdata(&spi->dev);
+
+ mutex_lock(&ts->mutex);
+ tsc2005_disable(ts);
+ mutex_unlock(&ts->mutex);
+
+ device_remove_file(&ts->spi->dev, &dev_attr_disable_ts);
+ device_remove_file(&ts->spi->dev, &dev_attr_pen_down);
+ device_remove_file(&ts->spi->dev, &dev_attr_ts_ctrl_selftest);
+
+ free_irq(ts->spi->irq, ts);
+ input_unregister_device(ts->idev);
+
+ if (ts->esd_timeout)
+ del_timer(&ts->esd_timer);
+ kfree(ts);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int tsc2005_suspend(struct spi_device *spi, pm_message_t mesg)
+{
+ struct tsc2005 *ts = dev_get_drvdata(&spi->dev);
+
+ mutex_lock(&ts->mutex);
+ tsc2005_disable(ts);
+ mutex_unlock(&ts->mutex);
+
+ return 0;
+}
+
+static int tsc2005_resume(struct spi_device *spi)
+{
+ struct tsc2005 *ts = dev_get_drvdata(&spi->dev);
+
+ mutex_lock(&ts->mutex);
+ tsc2005_enable(ts);
+ mutex_unlock(&ts->mutex);
+
+ return 0;
+}
+#endif
+
+static struct spi_driver tsc2005_driver = {
+ .driver = {
+ .name = "tsc2005",
+ .owner = THIS_MODULE,
+ },
+#ifdef CONFIG_PM
+ .suspend = tsc2005_suspend,
+ .resume = tsc2005_resume,
+#endif
+ .probe = tsc2005_probe,
+ .remove = __devexit_p(tsc2005_remove),
+};
+
+static int __init tsc2005_init(void)
+{
+ printk(KERN_INFO "TSC2005 driver initializing\n");
+
+ return spi_register_driver(&tsc2005_driver);
+}
+module_init(tsc2005_init);
+
+static void __exit tsc2005_exit(void)
+{
+ spi_unregister_driver(&tsc2005_driver);
+}
+module_exit(tsc2005_exit);
+
+MODULE_AUTHOR("Lauri Leukkunen <[email protected]>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:tsc2005");
diff --git a/include/linux/spi/tsc2005.h b/include/linux/spi/tsc2005.h
new file mode 100644
index 0000000..1a60c90
--- /dev/null
+++ b/include/linux/spi/tsc2005.h
@@ -0,0 +1,30 @@
+#ifndef _LINUX_SPI_TSC2005_H
+#define _LINUX_SPI_TSC2005_H
+
+#include <linux/types.h>
+
+struct tsc2005_platform_data {
+ u16 ts_x_plate_ohm;
+ u32 ts_stab_time; /* voltage settling time */
+ u8 ts_hw_avg; /* HW assiseted averaging. Can be
+ 0, 4, 8, 16 samples per reading */
+ u32 ts_touch_pressure; /* Pressure limit until we report a
+ touch event. After that we switch
+ to ts_max_pressure. */
+ u32 ts_pressure_max;/* Samples with bigger pressure value will
+ be ignored, since the corresponding X, Y
+ values are unreliable */
+ u32 ts_pressure_fudge;
+ u32 ts_x_max;
+ u32 ts_x_fudge;
+ u32 ts_y_max;
+ u32 ts_y_fudge;
+
+ u32 esd_timeout; /* msec of inactivity before we check */
+
+ unsigned ts_ignore_last:1;
+
+ void (*set_reset)(bool enable);
+};
+
+#endif
--
1.6.0.4


2009-11-04 13:23:22

by Aaro Koskinen

[permalink] [raw]
Subject: [PATCH v2 2/2] omap: RX-51: enable tsc2005

Enable tsc2005 touchscreen driver on the RX-51 board.

Signed-off-by: Aaro Koskinen <[email protected]>
---

The patch is for 2.6.32-rc6.

arch/arm/configs/rx51_defconfig | 1 +
arch/arm/mach-omap2/board-rx51-peripherals.c | 66 ++++++++++++++++++++++++++
2 files changed, 67 insertions(+), 0 deletions(-)

diff --git a/arch/arm/configs/rx51_defconfig b/arch/arm/configs/rx51_defconfig
index e7e3133..b10de8f 100644
--- a/arch/arm/configs/rx51_defconfig
+++ b/arch/arm/configs/rx51_defconfig
@@ -802,6 +802,7 @@ CONFIG_INPUT_TOUCHSCREEN=y
# CONFIG_TOUCHSCREEN_TOUCHWIN is not set
# CONFIG_TOUCHSCREEN_USB_COMPOSITE is not set
# CONFIG_TOUCHSCREEN_TOUCHIT213 is not set
+CONFIG_TOUCHSCREEN_TSC2005=m
# CONFIG_TOUCHSCREEN_TSC2007 is not set
CONFIG_INPUT_MISC=y
# CONFIG_INPUT_ATI_REMOTE is not set
diff --git a/arch/arm/mach-omap2/board-rx51-peripherals.c b/arch/arm/mach-omap2/board-rx51-peripherals.c
index e34d96a..ff3869a 100644
--- a/arch/arm/mach-omap2/board-rx51-peripherals.c
+++ b/arch/arm/mach-omap2/board-rx51-peripherals.c
@@ -14,6 +14,7 @@
#include <linux/input.h>
#include <linux/input/matrix_keypad.h>
#include <linux/spi/spi.h>
+#include <linux/spi/tsc2005.h>
#include <linux/i2c.h>
#include <linux/i2c/twl4030.h>
#include <linux/clk.h>
@@ -509,6 +510,68 @@ static inline void board_onenand_init(void)

#endif

+#define RX51_TSC2005_RESET_GPIO 104
+#define RX51_TSC2005_IRQ_GPIO 100
+
+static struct omap2_mcspi_device_config tsc2005_mcspi_config = {
+ .turbo_mode = 0,
+ .single_channel = 1,
+};
+
+static struct tsc2005_platform_data tsc2005_config = {
+ .ts_x_plate_ohm = 280,
+ .ts_hw_avg = 0,
+ .ts_touch_pressure = 1500,
+ .ts_stab_time = 1000,
+ .ts_pressure_max = 2048,
+ .ts_pressure_fudge = 2,
+ .ts_x_max = 4096,
+ .ts_x_fudge = 4,
+ .ts_y_max = 4096,
+ .ts_y_fudge = 7,
+
+ .esd_timeout = 8*1000, /* ms of inactivity before we check */
+
+ .set_reset = NULL,
+};
+
+static void rx51_tsc2005_set_reset(bool enable)
+{
+ gpio_set_value(RX51_TSC2005_RESET_GPIO, enable);
+}
+
+static void __init rx51_init_tsc2005(void)
+{
+ int r;
+
+ r = gpio_request(RX51_TSC2005_IRQ_GPIO, "tsc2005 DAV IRQ");
+ if (r >= 0)
+ gpio_direction_input(RX51_TSC2005_IRQ_GPIO);
+ else
+ printk(KERN_ERR "unable to get %s GPIO\n", "tsc2005 DAV IRQ");
+
+ r = gpio_request(RX51_TSC2005_RESET_GPIO, "tsc2005 reset");
+ if (r >= 0) {
+ gpio_direction_output(RX51_TSC2005_RESET_GPIO, 1);
+ tsc2005_config.set_reset = rx51_tsc2005_set_reset;
+ } else {
+ printk(KERN_ERR "unable to get %s GPIO\n", "tsc2005 reset");
+ tsc2005_config.esd_timeout = 0;
+ }
+}
+
+static struct spi_board_info rx51_peripherals_spi_board_info[] = {
+ [0] = {
+ .modalias = "tsc2005",
+ .bus_num = 1,
+ .chip_select = 0,
+ .irq = OMAP_GPIO_IRQ(RX51_TSC2005_IRQ_GPIO),
+ .max_speed_hz = 6000000,
+ .controller_data = &tsc2005_mcspi_config,
+ .platform_data = &tsc2005_config,
+ },
+};
+
#if defined(CONFIG_SMC91X) || defined(CONFIG_SMC91X_MODULE)

static struct omap_smc91x_platform_data board_smc91x_data = {
@@ -538,6 +601,9 @@ static inline void board_smc91x_init(void)

void __init rx51_peripherals_init(void)
{
+ spi_register_board_info(rx51_peripherals_spi_board_info,
+ ARRAY_SIZE(rx51_peripherals_spi_board_info));
+ rx51_init_tsc2005();
rx51_i2c_init();
board_onenand_init();
board_smc91x_init();
--
1.6.0.4

2009-11-04 15:06:14

by Tommi Rantala

[permalink] [raw]
Subject: Re: [PATCH v2 2/2] omap: RX-51: enable tsc2005

Aaro Koskinen wrote:
> +static struct spi_board_info rx51_peripherals_spi_board_info[] = {

This can be marked with __initdata.

BR,
Tommi Rantala

2009-11-07 15:43:55

by Kalle Valo

[permalink] [raw]
Subject: Re: [PATCH v2 2/2] omap: RX-51: enable tsc2005

Aaro Koskinen <[email protected]> writes:

> Enable tsc2005 touchscreen driver on the RX-51 board.
>
> Signed-off-by: Aaro Koskinen <[email protected]>
> ---
>
> The patch is for 2.6.32-rc6.

[...]

> +static struct spi_board_info rx51_peripherals_spi_board_info[] = {
> + [0] = {
> + .modalias = "tsc2005",
> + .bus_num = 1,
> + .chip_select = 0,
> + .irq = OMAP_GPIO_IRQ(RX51_TSC2005_IRQ_GPIO),
> + .max_speed_hz = 6000000,
> + .controller_data = &tsc2005_mcspi_config,
> + .platform_data = &tsc2005_config,
> + },
> +};

I sent a wl1251 patch which adds spi_board_info and conflicts with
this patch:

http://www.mail-archive.com/[email protected]/msg17604.html

How do we handle this?

--
Kalle Valo

2009-11-09 13:29:43

by Aaro Koskinen

[permalink] [raw]
Subject: Re: [PATCH v2 2/2] omap: RX-51: enable tsc2005

Hi,

ext Kalle Valo wrote:
> Aaro Koskinen <[email protected]> writes:
>
>> Enable tsc2005 touchscreen driver on the RX-51 board.
>>
>> Signed-off-by: Aaro Koskinen <[email protected]>
>> ---
>>
>> The patch is for 2.6.32-rc6.
>
> [...]
>
>> +static struct spi_board_info rx51_peripherals_spi_board_info[] = {
>> + [0] = {
>> + .modalias = "tsc2005",
>> + .bus_num = 1,
>> + .chip_select = 0,
>> + .irq = OMAP_GPIO_IRQ(RX51_TSC2005_IRQ_GPIO),
>> + .max_speed_hz = 6000000,
>> + .controller_data = &tsc2005_mcspi_config,
>> + .platform_data = &tsc2005_config,
>> + },
>> +};
>
> I sent a wl1251 patch which adds spi_board_info and conflicts with
> this patch:
>
> http://www.mail-archive.com/[email protected]/msg17604.html
>
> How do we handle this?

I can resend/rebase this patch once the wl1251 patch is integrated.

BTW, check the comment from Tommi Rantala - spi_board_info can be marked
with __initdata.

A.

2009-11-10 10:30:37

by Kalle Valo

[permalink] [raw]
Subject: Re: [PATCH v2 2/2] omap: RX-51: enable tsc2005

Aaro Koskinen <[email protected]> writes:

>> I sent a wl1251 patch which adds spi_board_info and conflicts with
>> this patch:
>>
>> http://www.mail-archive.com/[email protected]/msg17604.html
>>
>> How do we handle this?
>
> I can resend/rebase this patch once the wl1251 patch is integrated.

Ok, thanks. I'll resend the wl1251 patch just to be sure that it
doesn't get lost.

> BTW, check the comment from Tommi Rantala - spi_board_info can be marked
> with __initdata.

I'll add it to my patch.

--
Kalle Valo

2009-11-14 06:03:39

by Dmitry Torokhov

[permalink] [raw]
Subject: Re: [PATCH v2 1/2] input: touchscreen: introduce tsc2005 driver

Hi Aaro,

On Wed, Nov 04, 2009 at 03:23:01PM +0200, Aaro Koskinen wrote:
> +
> +static void tsc2005_ts_update_pen_state(struct tsc2005 *ts,
> + int x, int y, int pressure)
> +{
> + if (pressure) {
> + input_report_abs(ts->idev, ABS_X, x);
> + input_report_abs(ts->idev, ABS_Y, y);
> + input_report_abs(ts->idev, ABS_PRESSURE, pressure);
> + if (!ts->pen_down) {
> + input_report_key(ts->idev, BTN_TOUCH, 1);
> + ts->pen_down = 1;
> + }

Just report BTN_TOUCH always, input core will filter duplicates.

> + } else {
> + input_report_abs(ts->idev, ABS_PRESSURE, 0);
> + if (ts->pen_down) {
> + input_report_key(ts->idev, BTN_TOUCH, 0);
> + ts->pen_down = 0;
> + }
> + }
> +
> + input_sync(ts->idev);
> +}
> +
> +/*
> + * This function is called by the SPI framework after the coordinates
> + * have been read from TSC2005
> + */
> +static void tsc2005_ts_rx(void *arg)
> +{
> + struct tsc2005 *ts = arg;
> + unsigned long flags;
> + int inside_rect, pressure_limit;
> + int x, y, z1, z2, pressure;
> +
> + spin_lock_irqsave(&ts->lock, flags);
> +
> + if (ts->disable_depth) {
> + ts->spi_pending = 0;
> + goto out;
> + }
> +
> + x = ts->data[0];
> + y = ts->data[1];
> + z1 = ts->data[2];
> + z2 = ts->data[3];
> +
> + /* validate pressure and position */
> + if (x > MAX_12BIT || y > MAX_12BIT)
> + goto out;
> +
> + /* skip coords if the pressure-components are out of range */
> + if (z1 < 100 || z2 > MAX_12BIT || z1 >= z2)
> + goto out;
> +
> + /* skip point if this is a pen down with the exact same values as
> + * the value before pen-up - that implies SPI fed us stale data
> + */
> + if (!ts->pen_down &&
> + ts->in_x == x &&
> + ts->in_y == y &&
> + ts->in_z1 == z1 &&
> + ts->in_z2 == z2)
> + goto out;
> +
> + /* At this point we are happy we have a valid and useful reading.
> + * Remember it for later comparisons. We may now begin downsampling
> + */
> + ts->in_x = x;
> + ts->in_y = y;
> + ts->in_z1 = z1;
> + ts->in_z2 = z2;
> +
> + /* don't run average on the "pen down" event */
> + if (ts->sample_sent) {
> + ts->avg_x += x;
> + ts->avg_y += y;
> + ts->avg_z1 += z1;
> + ts->avg_z2 += z2;
> +
> + if (++ts->sample_cnt < TS_SAMPLES)
> + goto out;
> +
> + x = ts->avg_x / TS_SAMPLES;
> + y = ts->avg_y / TS_SAMPLES;
> + z1 = ts->avg_z1 / TS_SAMPLES;
> + z2 = ts->avg_z2 / TS_SAMPLES;
> + }
>

Do we really need to do filtering and averaging in kernel? What about
tslib?

> + ts->sample_cnt = 0;
> + ts->avg_x = 0;
> + ts->avg_y = 0;
> + ts->avg_z1 = 0;
> + ts->avg_z2 = 0;
> +
> + pressure = x * (z2 - z1) / z1;
> + pressure = pressure * ts->x_plate_ohm / 4096;
> +
> + pressure_limit = ts->sample_sent ? ts->p_max : ts->touch_pressure;
> + if (pressure > pressure_limit)
> + goto out;
> +
> + /* Discard the event if it still is within the previous rect -
> + * unless the pressure is clearly harder, but then use previous
> + * x,y position. If any coordinate deviates enough, fudging
> + * of all three will still take place in the input layer.
> + */
> + inside_rect = (ts->sample_sent &&
> + x > (int)ts->out_x - ts->fudge_x &&
> + x < (int)ts->out_x + ts->fudge_x &&
> + y > (int)ts->out_y - ts->fudge_y &&
> + y < (int)ts->out_y + ts->fudge_y);
> + if (inside_rect)
> + x = ts->out_x, y = ts->out_y;
> +
> + if (!inside_rect || pressure < (ts->out_p - ts->fudge_p)) {
> + tsc2005_ts_update_pen_state(ts, x, y, pressure);
> + ts->sample_sent = 1;
> + ts->out_x = x;
> + ts->out_y = y;
> + ts->out_p = pressure;
> + }
> +out:
> + if (ts->spi_pending > 1) {
> + /* One or more interrupts (sometimes several dozens)
> + * occured while waiting for the SPI read - get
> + * another read going.
> + */
> + ts->spi_pending = 1;
> + if (spi_async(ts->spi, &ts->read_msg)) {
> + dev_err(&ts->spi->dev, "ts: spi_async() failed");
> + ts->spi_pending = 0;
> + }
> + } else
> + ts->spi_pending = 0;
> +
> + /* kick pen up timer - to make sure it expires again(!) */
> + if (ts->sample_sent) {
> + mod_timer(&ts->penup_timer,
> + jiffies + msecs_to_jiffies(TSC2005_TS_PENUP_TIME));
> + /* Also kick the watchdog, as we still think we're alive */
> + if (ts->esd_timeout && ts->disable_depth == 0) {
> + unsigned long wdj = msecs_to_jiffies(ts->esd_timeout);
> + mod_timer(&ts->esd_timer, round_jiffies(jiffies+wdj));
> + }
> + }
> + spin_unlock_irqrestore(&ts->lock, flags);
> +}
> +
> +/* This penup timer is very forgiving of delayed SPI reads. The
> + * (ESD) watchdog will rescue us if spi_pending remains set, unless
> + * we are enterring the disabled state. In that case we must just
> + * handle the pen up, and let disabling complete.
> + */
> +static void tsc2005_ts_penup_timer_handler(unsigned long data)
> +{
> + struct tsc2005 *ts = (struct tsc2005 *)data;
> + if ((!ts->spi_pending || ts->disable_depth) &&
> + ts->sample_sent) {
> + tsc2005_ts_update_pen_state(ts, 0, 0, 0);
> + ts->sample_sent = 0;
> + }
> +}
> +
> +/*
> + * This interrupt is called when pen is down and coordinates are
> + * available. That is indicated by a either:
> + * a) a rising edge on PINTDAV or (PENDAV mode)
> + * b) a falling edge on DAV line (DAV mode)
> + * depending on the setting of the IRQ bits in the CFR2 setting above.
> + */
> +static irqreturn_t tsc2005_ts_irq_handler(int irq, void *dev_id)
> +{
> + struct tsc2005 *ts = dev_id;
> + if (ts->disable_depth)
> + goto out;
> +
> + if (!ts->spi_pending) {
> + if (spi_async(ts->spi, &ts->read_msg)) {
> + dev_err(&ts->spi->dev, "ts: spi_async() failed");
> + goto out;
> + }
> + }
> + /* By shifting in 1s we can never wrap */
> + ts->spi_pending = (ts->spi_pending<<1)+1;
> +
> + /* Kick pen up timer only if it's not been started yet. Strictly,
> + * it isn't even necessary to start it at all here, but doing so
> + * keeps an equivalence between pen state and timer state.
> + * The SPI read loop will keep pushing it into the future.
> + * If it times out with an SPI pending, it's ignored anyway.
> + */
> + if (!timer_pending(&ts->penup_timer)) {
> + unsigned long pu = msecs_to_jiffies(TSC2005_TS_PENUP_TIME);
> + ts->penup_timer.expires = jiffies + pu;
> + add_timer(&ts->penup_timer);
> + }
> +out:
> + return IRQ_HANDLED;
> +}
> +
> +static void tsc2005_ts_setup_spi_xfer(struct tsc2005 *ts)
> +{
> + struct spi_message *m = &ts->read_msg;
> + struct spi_transfer *x = &ts->read_xfer[0];
> + int i;
> +
> + spi_message_init(m);
> +
> + for (i = 0; i < NUM_READ_REGS; i++, x++) {
> + x->tx_buf = &tsc2005_read_reg[i];
> + x->rx_buf = &ts->data[i];
> + x->len = 4;
> + x->bits_per_word = 24;
> + x->cs_change = i < (NUM_READ_REGS - 1);
> + spi_message_add_tail(x, m);
> + }
> +
> + m->complete = tsc2005_ts_rx;
> + m->context = ts;
> +}
> +
> +static ssize_t tsc2005_ts_pen_down_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct tsc2005 *ts = dev_get_drvdata(dev);
> +
> + return sprintf(buf, "%u\n", ts->pen_down);
> +}
> +
> +static DEVICE_ATTR(pen_down, S_IRUGO, tsc2005_ts_pen_down_show, NULL);

What is the point of exporting this through sysfs?
> +
> +static int tsc2005_configure(struct tsc2005 *ts, int flags)
> +{
> + tsc2005_write(ts, TSC2005_REG_CFR0, TSC2005_CFR0_INITVALUE);
> + tsc2005_write(ts, TSC2005_REG_CFR1, TSC2005_CFR1_INITVALUE);
> + tsc2005_write(ts, TSC2005_REG_CFR2, TSC2005_CFR2_INITVALUE);
> + tsc2005_cmd(ts, flags);
> +
> + return 0;
> +}
> +
> +static void tsc2005_start_scan(struct tsc2005 *ts)
> +{
> + tsc2005_configure(ts, TSC2005_CMD_SCAN_XYZZ);
> +}
> +
> +static void tsc2005_stop_scan(struct tsc2005 *ts)
> +{
> + tsc2005_cmd(ts, TSC2005_CMD_STOP);
> +}
> +
> +/* Must be called with mutex held */
> +static void tsc2005_disable(struct tsc2005 *ts)
> +{
> + if (ts->disable_depth++ != 0)
> + return;
> +
> + disable_irq(ts->spi->irq);
> + if (ts->esd_timeout)
> + del_timer(&ts->esd_timer);

del_timer_sync()?

> +
> + /* wait until penup timer expire normally */
> + do {
> + msleep(4);
> + } while (ts->sample_sent);
> +
> + tsc2005_stop_scan(ts);
> +}
> +
> +static void tsc2005_enable(struct tsc2005 *ts)
> +{
> + if (ts->disable_depth != 1)
> + goto out;
> +
> + if (ts->esd_timeout) {
> + unsigned long wdj = msecs_to_jiffies(ts->esd_timeout);
> + ts->esd_timer.expires = round_jiffies(jiffies+wdj);
> + add_timer(&ts->esd_timer);

just use mod_timer().

> + }
> + tsc2005_start_scan(ts);
> + enable_irq(ts->spi->irq);
> +out:
> + --ts->disable_depth;
> +}
> +
> +static ssize_t tsc2005_disable_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct tsc2005 *ts = dev_get_drvdata(dev);
> +
> + return sprintf(buf, "%u\n", ts->disabled);
> +}
> +
> +static ssize_t tsc2005_disable_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct tsc2005 *ts = dev_get_drvdata(dev);
> + unsigned long res;
> + int i;
> +
> + if (strict_strtoul(buf, 10, &res) < 0)
> + return -EINVAL;
> + i = res ? 1 : 0;
> +
> + mutex_lock(&ts->mutex);
> + if (i == ts->disabled)
> + goto out;
> + ts->disabled = i;
> +
> + if (i)
> + tsc2005_disable(ts);
> + else
> + tsc2005_enable(ts);
> +out:
> + mutex_unlock(&ts->mutex);
> + return count;
> +}
> +
> +static DEVICE_ATTR(disable_ts, 0664, tsc2005_disable_show,
> + tsc2005_disable_store);
> +
> +static ssize_t tsc2005_ctrl_selftest_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + u16 temp_high_orig, temp_high_test, temp_high;
> + unsigned int result = 1;
> + struct tsc2005 *ts = dev_get_drvdata(dev);
> +
> + if (!ts->set_reset) {
> + dev_warn(&ts->spi->dev,
> + "unable to selftest: reset not configured\n");
> + result = 0;
> + goto out;
> + }
> +
> + mutex_lock(&ts->mutex);
> + tsc2005_disable(ts);
> +
> + /* Test ctrl communications via temp high / low registers */
> + tsc2005_read(ts, TSC2005_REG_TEMP_HIGH, &temp_high_orig);
> +
> + temp_high_test = (temp_high_orig - 1) & 0x0FFF;
> +
> + tsc2005_write(ts, TSC2005_REG_TEMP_HIGH, temp_high_test);
> +
> + tsc2005_read(ts, TSC2005_REG_TEMP_HIGH, &temp_high);
> +
> + if (temp_high != temp_high_test) {
> + result = 0;
> + dev_warn(dev, "selftest failed: %d != %d\n",
> + temp_high, temp_high_test);
> + }
> +
> + /* HW Reset */
> + ts->set_reset(0);
> + msleep(1); /* only 10us required */
> + ts->set_reset(1);
> +
> + tsc2005_enable(ts);
> +
> + /* Test that reset really happened */
> + tsc2005_read(ts, TSC2005_REG_TEMP_HIGH, &temp_high);
> +
> + if (temp_high != temp_high_orig) {
> + result = 0;
> + dev_warn(dev, "selftest failed after reset: "
> + "%d != %d\n",
> + temp_high, temp_high_orig);
> + }
> +
> + mutex_unlock(&ts->mutex);
> +
> +out:
> + return sprintf(buf, "%u\n", result);
> +}
> +
> +static DEVICE_ATTR(ts_ctrl_selftest, S_IRUGO, tsc2005_ctrl_selftest_show, NULL);
> +
> +static void tsc2005_esd_timer_handler(unsigned long data)
> +{
> + struct tsc2005 *ts = (struct tsc2005 *)data;
> + if (!ts->disable_depth)
> + schedule_work(&ts->esd_work);
> +}
> +
> +static void tsc2005_rst_handler(struct work_struct *work)
> +{
> + u16 reg_val;
> + struct tsc2005 *ts = container_of(work, struct tsc2005, esd_work);
> + unsigned long wdj;
> +
> + mutex_lock(&ts->mutex);
> +
> + /* If we are disabled, or the a touch has been detected,
> + * then ignore this timeout. The enable will restart the
> + * watchdog, as it restarts scanning
> + */
> + if (ts->disable_depth)
> + goto out;
> +
> + /* If we cannot read our known value from configuration register 0
> + * then reset the controller as if from power-up and start
> + * scanning again. Always re-arm the watchdog.
> + */
> + tsc2005_read(ts, TSC2005_REG_CFR0, &reg_val);
> + if ((reg_val ^ TSC2005_CFR0_INITVALUE) & TSC2005_CFR0_RW_MASK) {
> + dev_info(&ts->spi->dev, "TSC not responding, resetting.\n");
> + /* If this timer kicked in, the penup timer, if ever active
> + * at all, must have expired ages ago, so no need to del it.
> + */
> + ts->set_reset(0);
> + if (ts->sample_sent) {
> + tsc2005_ts_update_pen_state(ts, 0, 0, 0);
> + ts->sample_sent = 0;
> + }
> + ts->spi_pending = 0;
> + msleep(1); /* only 10us required */
> + ts->set_reset(1);
> + tsc2005_start_scan(ts);
> + }
> + wdj = msecs_to_jiffies(ts->esd_timeout);
> + mod_timer(&ts->esd_timer, round_jiffies(jiffies+wdj));
> +
> +out:
> + mutex_unlock(&ts->mutex);
> +}
> +
> +static int __devinit tsc2005_ts_init(struct tsc2005 *ts,
> + struct tsc2005_platform_data *pdata)
> +{
> + struct input_dev *idev;
> + int r;
> + int x_max, y_max;
> +
> + init_timer(&ts->penup_timer);
> + setup_timer(&ts->penup_timer, tsc2005_ts_penup_timer_handler,
> + (unsigned long)ts);
> +
> + spin_lock_init(&ts->lock);
> + mutex_init(&ts->mutex);
> +
> + ts->x_plate_ohm = pdata->ts_x_plate_ohm ? : 280;
> + ts->hw_avg_max = pdata->ts_hw_avg;
> + ts->stab_time = pdata->ts_stab_time;
> + x_max = pdata->ts_x_max ? : 4096;
> + ts->fudge_x = pdata->ts_x_fudge ? : 4;
> + y_max = pdata->ts_y_max ? : 4096;
> + ts->fudge_y = pdata->ts_y_fudge ? : 8;
> + ts->p_max = pdata->ts_pressure_max ? : MAX_12BIT;
> + ts->touch_pressure = pdata->ts_touch_pressure ? : ts->p_max;
> + ts->fudge_p = pdata->ts_pressure_fudge ? : 2;
> +
> + ts->set_reset = pdata->set_reset;
> +
> + idev = input_allocate_device();
> + if (idev == NULL) {
> + r = -ENOMEM;
> + goto err1;
> + }
> +
> + idev->name = "TSC2005 touchscreen";
> + snprintf(ts->phys, sizeof(ts->phys), "%s/input-ts",
> + dev_name(&ts->spi->dev));
> + idev->phys = ts->phys;
> +
> + idev->evbit[0] = BIT(EV_ABS) | BIT(EV_KEY);
> + idev->absbit[0] = BIT(ABS_X) | BIT(ABS_Y) | BIT(ABS_PRESSURE);
> + idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
> + ts->idev = idev;
> +
> + tsc2005_ts_setup_spi_xfer(ts);
> +
> + input_set_abs_params(idev, ABS_X, 0, x_max, ts->fudge_x, 0);
> + input_set_abs_params(idev, ABS_Y, 0, y_max, ts->fudge_y, 0);
> + input_set_abs_params(idev, ABS_PRESSURE, 0, ts->p_max, ts->fudge_p, 0);
> +
> + tsc2005_start_scan(ts);
> +
> + r = request_irq(ts->spi->irq, tsc2005_ts_irq_handler,
> + (((TSC2005_CFR2_INITVALUE & TSC2005_CFR2_IRQ_MASK) ==
> + TSC2005_CFR2_IRQ_PENDAV)
> + ? IRQF_TRIGGER_RISING
> + : IRQF_TRIGGER_FALLING) |
> + IRQF_DISABLED, "tsc2005", ts);
> + if (r < 0) {
> + dev_err(&ts->spi->dev, "unable to get DAV IRQ");
> + goto err2;
> + }
> +
> + set_irq_wake(ts->spi->irq, 1);
> +
> + r = input_register_device(idev);
> + if (r < 0) {
> + dev_err(&ts->spi->dev, "can't register touchscreen device\n");
> + goto err3;
> + }
> +
> + /* We can tolerate these failing */

Should we though?

> + r = device_create_file(&ts->spi->dev, &dev_attr_ts_ctrl_selftest);
> + if (r < 0)
> + dev_warn(&ts->spi->dev, "can't create sysfs file for %s: %d\n",
> + dev_attr_ts_ctrl_selftest.attr.name, r);
> +
> + r = device_create_file(&ts->spi->dev, &dev_attr_pen_down);
> + if (r < 0)
> + dev_warn(&ts->spi->dev, "can't create sysfs file for %s: %d\n",
> + dev_attr_pen_down.attr.name, r);
> +
> + r = device_create_file(&ts->spi->dev, &dev_attr_disable_ts);
> + if (r < 0)
> + dev_warn(&ts->spi->dev, "can't create sysfs file for %s: %d\n",
> + dev_attr_disable_ts.attr.name, r);
> +

attribute_group is more compact by the way.

> + /* Finally, configure and start the optional EDD watchdog. */
> + ts->esd_timeout = pdata->esd_timeout;
> + if (ts->esd_timeout && ts->set_reset) {
> + unsigned long wdj;
> + setup_timer(&ts->esd_timer, tsc2005_esd_timer_handler,
> + (unsigned long)ts);
> + INIT_WORK(&ts->esd_work, tsc2005_rst_handler);
> + wdj = msecs_to_jiffies(ts->esd_timeout);
> + ts->esd_timer.expires = round_jiffies(jiffies+wdj);
> + add_timer(&ts->esd_timer);
> + }
> +
> + return 0;
> +err3:
> + free_irq(ts->spi->irq, ts);
> +err2:
> + tsc2005_stop_scan(ts);
> + input_free_device(idev);
> +err1:
> + return r;
> +}
> +
> +static int __devinit tsc2005_probe(struct spi_device *spi)
> +{
> + struct tsc2005 *ts;
> + struct tsc2005_platform_data *pdata = spi->dev.platform_data;
> + int r;
> +
> + if (spi->irq < 0) {
> + dev_dbg(&spi->dev, "no irq?\n");
> + return -ENODEV;
> + }
> + if (!pdata) {
> + dev_dbg(&spi->dev, "no platform data?\n");
> + return -ENODEV;
> + }
> +
> + ts = kzalloc(sizeof(*ts), GFP_KERNEL);
> + if (ts == NULL)
> + return -ENOMEM;
> +
> + dev_set_drvdata(&spi->dev, ts);
> + ts->spi = spi;
> + spi->dev.power.power_state = PMSG_ON;
> +
> + spi->mode = SPI_MODE_0;
> + spi->bits_per_word = 8;
> + /* The max speed might've been defined by the board-specific
> + * struct */
> + if (!spi->max_speed_hz)
> + spi->max_speed_hz = TSC2005_HZ;
> +
> + spi_setup(spi);
> +
> + r = tsc2005_ts_init(ts, pdata);
> + if (r)
> + goto err1;
> +
> + return 0;
> +
> +err1:
> + kfree(ts);
> + return r;
> +}
> +
> +static int __devexit tsc2005_remove(struct spi_device *spi)
> +{
> + struct tsc2005 *ts = dev_get_drvdata(&spi->dev);
> +
> + mutex_lock(&ts->mutex);
> + tsc2005_disable(ts);
> + mutex_unlock(&ts->mutex);
> +
> + device_remove_file(&ts->spi->dev, &dev_attr_disable_ts);
> + device_remove_file(&ts->spi->dev, &dev_attr_pen_down);
> + device_remove_file(&ts->spi->dev, &dev_attr_ts_ctrl_selftest);
> +
> + free_irq(ts->spi->irq, ts);
> + input_unregister_device(ts->idev);
> +
> + if (ts->esd_timeout)
> + del_timer(&ts->esd_timer);

del_timer_sync().


--
Dmitry

2009-11-16 12:34:36

by Phil Carmody

[permalink] [raw]
Subject: Re: [PATCH v2 1/2] input: touchscreen: introduce tsc2005 driver


Many thanks for your reply, Dmitry. Some comments follow yours.

On 14/11/09 07:03 +0100, ext Dmitry Torokhov wrote:
> Hi Aaro,
>
> On Wed, Nov 04, 2009 at 03:23:01PM +0200, Aaro Koskinen wrote:
> > +
> > +static void tsc2005_ts_update_pen_state(struct tsc2005 *ts,
> > + int x, int y, int pressure)
> > +{
> > + if (pressure) {
> > + input_report_abs(ts->idev, ABS_X, x);
> > + input_report_abs(ts->idev, ABS_Y, y);
> > + input_report_abs(ts->idev, ABS_PRESSURE, pressure);
> > + if (!ts->pen_down) {
> > + input_report_key(ts->idev, BTN_TOUCH, 1);
> > + ts->pen_down = 1;
> > + }
>
> Just report BTN_TOUCH always, input core will filter duplicates.

Because there are several places where a check will be made whether
we need to do anything or not. We'll grab a spinlock, decide to add
no entropy, decide to toggle no status bits, and decide to not do
anything more after that. Sounds like waste.

> > + } else {
> > + input_report_abs(ts->idev, ABS_PRESSURE, 0);
> > + if (ts->pen_down) {
> > + input_report_key(ts->idev, BTN_TOUCH, 0);
> > + ts->pen_down = 0;
> > + }
> > + }
> > +
> > + input_sync(ts->idev);
> > +}
> > +
> > +/*
> > + * This function is called by the SPI framework after the coordinates
> > + * have been read from TSC2005
> > + */
> > +static void tsc2005_ts_rx(void *arg)
> > +{
> > + struct tsc2005 *ts = arg;
> > + unsigned long flags;
> > + int inside_rect, pressure_limit;
> > + int x, y, z1, z2, pressure;
> > +
> > + spin_lock_irqsave(&ts->lock, flags);
> > +
> > + if (ts->disable_depth) {
> > + ts->spi_pending = 0;
> > + goto out;
> > + }
> > +
> > + x = ts->data[0];
> > + y = ts->data[1];
> > + z1 = ts->data[2];
> > + z2 = ts->data[3];
> > +
> > + /* validate pressure and position */
> > + if (x > MAX_12BIT || y > MAX_12BIT)
> > + goto out;
> > +
> > + /* skip coords if the pressure-components are out of range */
> > + if (z1 < 100 || z2 > MAX_12BIT || z1 >= z2)
> > + goto out;
> > +
> > + /* skip point if this is a pen down with the exact same values as
> > + * the value before pen-up - that implies SPI fed us stale data
> > + */
> > + if (!ts->pen_down &&
> > + ts->in_x == x &&
> > + ts->in_y == y &&
> > + ts->in_z1 == z1 &&
> > + ts->in_z2 == z2)
> > + goto out;
> > +
> > + /* At this point we are happy we have a valid and useful reading.
> > + * Remember it for later comparisons. We may now begin downsampling
> > + */
> > + ts->in_x = x;
> > + ts->in_y = y;
> > + ts->in_z1 = z1;
> > + ts->in_z2 = z2;
> > +
> > + /* don't run average on the "pen down" event */
> > + if (ts->sample_sent) {
> > + ts->avg_x += x;
> > + ts->avg_y += y;
> > + ts->avg_z1 += z1;
> > + ts->avg_z2 += z2;
> > +
> > + if (++ts->sample_cnt < TS_SAMPLES)
> > + goto out;
> > +
> > + x = ts->avg_x / TS_SAMPLES;
> > + y = ts->avg_y / TS_SAMPLES;
> > + z1 = ts->avg_z1 / TS_SAMPLES;
> > + z2 = ts->avg_z2 / TS_SAMPLES;
> > + }
> >
>
> Do we really need to do filtering and averaging in kernel? What about
> tslib?

Not everyone uses tslib. There's already some filtering in the tsc2005
already, but it's not really enough. This averaging also has the
pleasant side-effect of reducing the number of input events. The
fudging that takes place later has slightly different smoothing
behaviour, and isn't a substitute.

> > + ts->sample_cnt = 0;
> > + ts->avg_x = 0;
> > + ts->avg_y = 0;
> > + ts->avg_z1 = 0;
> > + ts->avg_z2 = 0;
> > +
> > + pressure = x * (z2 - z1) / z1;
> > + pressure = pressure * ts->x_plate_ohm / 4096;
> > +
> > + pressure_limit = ts->sample_sent ? ts->p_max : ts->touch_pressure;
> > + if (pressure > pressure_limit)
> > + goto out;
> > +
> > + /* Discard the event if it still is within the previous rect -
> > + * unless the pressure is clearly harder, but then use previous
> > + * x,y position. If any coordinate deviates enough, fudging
> > + * of all three will still take place in the input layer.
> > + */
> > + inside_rect = (ts->sample_sent &&
> > + x > (int)ts->out_x - ts->fudge_x &&
> > + x < (int)ts->out_x + ts->fudge_x &&
> > + y > (int)ts->out_y - ts->fudge_y &&
> > + y < (int)ts->out_y + ts->fudge_y);
> > + if (inside_rect)
> > + x = ts->out_x, y = ts->out_y;
> > +
> > + if (!inside_rect || pressure < (ts->out_p - ts->fudge_p)) {
> > + tsc2005_ts_update_pen_state(ts, x, y, pressure);
> > + ts->sample_sent = 1;
> > + ts->out_x = x;
> > + ts->out_y = y;
> > + ts->out_p = pressure;
> > + }
> > +out:
> > + if (ts->spi_pending > 1) {
> > + /* One or more interrupts (sometimes several dozens)
> > + * occured while waiting for the SPI read - get
> > + * another read going.
> > + */
> > + ts->spi_pending = 1;
> > + if (spi_async(ts->spi, &ts->read_msg)) {
> > + dev_err(&ts->spi->dev, "ts: spi_async() failed");
> > + ts->spi_pending = 0;
> > + }
> > + } else
> > + ts->spi_pending = 0;
> > +
> > + /* kick pen up timer - to make sure it expires again(!) */
> > + if (ts->sample_sent) {
> > + mod_timer(&ts->penup_timer,
> > + jiffies + msecs_to_jiffies(TSC2005_TS_PENUP_TIME));
> > + /* Also kick the watchdog, as we still think we're alive */
> > + if (ts->esd_timeout && ts->disable_depth == 0) {
> > + unsigned long wdj = msecs_to_jiffies(ts->esd_timeout);
> > + mod_timer(&ts->esd_timer, round_jiffies(jiffies+wdj));
> > + }
> > + }
> > + spin_unlock_irqrestore(&ts->lock, flags);
> > +}
> > +
> > +/* This penup timer is very forgiving of delayed SPI reads. The
> > + * (ESD) watchdog will rescue us if spi_pending remains set, unless
> > + * we are enterring the disabled state. In that case we must just
> > + * handle the pen up, and let disabling complete.
> > + */
> > +static void tsc2005_ts_penup_timer_handler(unsigned long data)
> > +{
> > + struct tsc2005 *ts = (struct tsc2005 *)data;
> > + if ((!ts->spi_pending || ts->disable_depth) &&
> > + ts->sample_sent) {
> > + tsc2005_ts_update_pen_state(ts, 0, 0, 0);
> > + ts->sample_sent = 0;
> > + }
> > +}
> > +
> > +/*
> > + * This interrupt is called when pen is down and coordinates are
> > + * available. That is indicated by a either:
> > + * a) a rising edge on PINTDAV or (PENDAV mode)
> > + * b) a falling edge on DAV line (DAV mode)
> > + * depending on the setting of the IRQ bits in the CFR2 setting above.
> > + */
> > +static irqreturn_t tsc2005_ts_irq_handler(int irq, void *dev_id)
> > +{
> > + struct tsc2005 *ts = dev_id;
> > + if (ts->disable_depth)
> > + goto out;
> > +
> > + if (!ts->spi_pending) {
> > + if (spi_async(ts->spi, &ts->read_msg)) {
> > + dev_err(&ts->spi->dev, "ts: spi_async() failed");
> > + goto out;
> > + }
> > + }
> > + /* By shifting in 1s we can never wrap */
> > + ts->spi_pending = (ts->spi_pending<<1)+1;
> > +
> > + /* Kick pen up timer only if it's not been started yet. Strictly,
> > + * it isn't even necessary to start it at all here, but doing so
> > + * keeps an equivalence between pen state and timer state.
> > + * The SPI read loop will keep pushing it into the future.
> > + * If it times out with an SPI pending, it's ignored anyway.
> > + */
> > + if (!timer_pending(&ts->penup_timer)) {
> > + unsigned long pu = msecs_to_jiffies(TSC2005_TS_PENUP_TIME);
> > + ts->penup_timer.expires = jiffies + pu;
> > + add_timer(&ts->penup_timer);
> > + }
> > +out:
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static void tsc2005_ts_setup_spi_xfer(struct tsc2005 *ts)
> > +{
> > + struct spi_message *m = &ts->read_msg;
> > + struct spi_transfer *x = &ts->read_xfer[0];
> > + int i;
> > +
> > + spi_message_init(m);
> > +
> > + for (i = 0; i < NUM_READ_REGS; i++, x++) {
> > + x->tx_buf = &tsc2005_read_reg[i];
> > + x->rx_buf = &ts->data[i];
> > + x->len = 4;
> > + x->bits_per_word = 24;
> > + x->cs_change = i < (NUM_READ_REGS - 1);
> > + spi_message_add_tail(x, m);
> > + }
> > +
> > + m->complete = tsc2005_ts_rx;
> > + m->context = ts;
> > +}
> > +
> > +static ssize_t tsc2005_ts_pen_down_show(struct device *dev,
> > + struct device_attribute *attr,
> > + char *buf)
> > +{
> > + struct tsc2005 *ts = dev_get_drvdata(dev);
> > +
> > + return sprintf(buf, "%u\n", ts->pen_down);
> > +}
> > +
> > +static DEVICE_ATTR(pen_down, S_IRUGO, tsc2005_ts_pen_down_show, NULL);
>
> What is the point of exporting this through sysfs?

It's a quick and simple way for any user-space app to know if the
screen is currently being touched without having to subscribe to the
stream of input events. OK, that wasn't a great reason, I admit.

> > +static int tsc2005_configure(struct tsc2005 *ts, int flags)
> > +{
> > + tsc2005_write(ts, TSC2005_REG_CFR0, TSC2005_CFR0_INITVALUE);
> > + tsc2005_write(ts, TSC2005_REG_CFR1, TSC2005_CFR1_INITVALUE);
> > + tsc2005_write(ts, TSC2005_REG_CFR2, TSC2005_CFR2_INITVALUE);
> > + tsc2005_cmd(ts, flags);
> > +
> > + return 0;
> > +}
> > +
> > +static void tsc2005_start_scan(struct tsc2005 *ts)
> > +{
> > + tsc2005_configure(ts, TSC2005_CMD_SCAN_XYZZ);
> > +}
> > +
> > +static void tsc2005_stop_scan(struct tsc2005 *ts)
> > +{
> > + tsc2005_cmd(ts, TSC2005_CMD_STOP);
> > +}
> > +
> > +/* Must be called with mutex held */
> > +static void tsc2005_disable(struct tsc2005 *ts)
> > +{
> > + if (ts->disable_depth++ != 0)
> > + return;
> > +
> > + disable_irq(ts->spi->irq);
> > + if (ts->esd_timeout)
> > + del_timer(&ts->esd_timer);
>
> del_timer_sync()?

Yup.

> > +
> > + /* wait until penup timer expire normally */
> > + do {
> > + msleep(4);
> > + } while (ts->sample_sent);
> > +
> > + tsc2005_stop_scan(ts);
> > +}
> > +
> > +static void tsc2005_enable(struct tsc2005 *ts)
> > +{
> > + if (ts->disable_depth != 1)
> > + goto out;
> > +
> > + if (ts->esd_timeout) {
> > + unsigned long wdj = msecs_to_jiffies(ts->esd_timeout);
> > + ts->esd_timer.expires = round_jiffies(jiffies+wdj);
> > + add_timer(&ts->esd_timer);
>
> just use mod_timer().

There are, or at least should be, no situations where the timer can be
active at that point. So mod_timer()'s not necessary. My preference is
for add_timer(), but I won't cling to that religiously.

> > + }
> > + tsc2005_start_scan(ts);
> > + enable_irq(ts->spi->irq);
> > +out:
> > + --ts->disable_depth;
> > +}
> > +
> > +static ssize_t tsc2005_disable_show(struct device *dev,
> > + struct device_attribute *attr, char *buf)
> > +{
> > + struct tsc2005 *ts = dev_get_drvdata(dev);
> > +
> > + return sprintf(buf, "%u\n", ts->disabled);
> > +}
> > +
> > +static ssize_t tsc2005_disable_store(struct device *dev,
> > + struct device_attribute *attr,
> > + const char *buf, size_t count)
> > +{
> > + struct tsc2005 *ts = dev_get_drvdata(dev);
> > + unsigned long res;
> > + int i;
> > +
> > + if (strict_strtoul(buf, 10, &res) < 0)
> > + return -EINVAL;
> > + i = res ? 1 : 0;
> > +
> > + mutex_lock(&ts->mutex);
> > + if (i == ts->disabled)
> > + goto out;
> > + ts->disabled = i;
> > +
> > + if (i)
> > + tsc2005_disable(ts);
> > + else
> > + tsc2005_enable(ts);
> > +out:
> > + mutex_unlock(&ts->mutex);
> > + return count;
> > +}
> > +
> > +static DEVICE_ATTR(disable_ts, 0664, tsc2005_disable_show,
> > + tsc2005_disable_store);
> > +
> > +static ssize_t tsc2005_ctrl_selftest_show(struct device *dev,
> > + struct device_attribute *attr,
> > + char *buf)
> > +{
> > + u16 temp_high_orig, temp_high_test, temp_high;
> > + unsigned int result = 1;
> > + struct tsc2005 *ts = dev_get_drvdata(dev);
> > +
> > + if (!ts->set_reset) {
> > + dev_warn(&ts->spi->dev,
> > + "unable to selftest: reset not configured\n");
> > + result = 0;
> > + goto out;
> > + }
> > +
> > + mutex_lock(&ts->mutex);
> > + tsc2005_disable(ts);
> > +
> > + /* Test ctrl communications via temp high / low registers */
> > + tsc2005_read(ts, TSC2005_REG_TEMP_HIGH, &temp_high_orig);
> > +
> > + temp_high_test = (temp_high_orig - 1) & 0x0FFF;
> > +
> > + tsc2005_write(ts, TSC2005_REG_TEMP_HIGH, temp_high_test);
> > +
> > + tsc2005_read(ts, TSC2005_REG_TEMP_HIGH, &temp_high);
> > +
> > + if (temp_high != temp_high_test) {
> > + result = 0;
> > + dev_warn(dev, "selftest failed: %d != %d\n",
> > + temp_high, temp_high_test);
> > + }
> > +
> > + /* HW Reset */
> > + ts->set_reset(0);
> > + msleep(1); /* only 10us required */
> > + ts->set_reset(1);
> > +
> > + tsc2005_enable(ts);
> > +
> > + /* Test that reset really happened */
> > + tsc2005_read(ts, TSC2005_REG_TEMP_HIGH, &temp_high);
> > +
> > + if (temp_high != temp_high_orig) {
> > + result = 0;
> > + dev_warn(dev, "selftest failed after reset: "
> > + "%d != %d\n",
> > + temp_high, temp_high_orig);
> > + }
> > +
> > + mutex_unlock(&ts->mutex);
> > +
> > +out:
> > + return sprintf(buf, "%u\n", result);
> > +}
> > +
> > +static DEVICE_ATTR(ts_ctrl_selftest, S_IRUGO, tsc2005_ctrl_selftest_show, NULL);
> > +
> > +static void tsc2005_esd_timer_handler(unsigned long data)
> > +{
> > + struct tsc2005 *ts = (struct tsc2005 *)data;
> > + if (!ts->disable_depth)
> > + schedule_work(&ts->esd_work);
> > +}
> > +
> > +static void tsc2005_rst_handler(struct work_struct *work)
> > +{
> > + u16 reg_val;
> > + struct tsc2005 *ts = container_of(work, struct tsc2005, esd_work);
> > + unsigned long wdj;
> > +
> > + mutex_lock(&ts->mutex);
> > +
> > + /* If we are disabled, or the a touch has been detected,
> > + * then ignore this timeout. The enable will restart the
> > + * watchdog, as it restarts scanning
> > + */
> > + if (ts->disable_depth)
> > + goto out;
> > +
> > + /* If we cannot read our known value from configuration register 0
> > + * then reset the controller as if from power-up and start
> > + * scanning again. Always re-arm the watchdog.
> > + */
> > + tsc2005_read(ts, TSC2005_REG_CFR0, &reg_val);
> > + if ((reg_val ^ TSC2005_CFR0_INITVALUE) & TSC2005_CFR0_RW_MASK) {
> > + dev_info(&ts->spi->dev, "TSC not responding, resetting.\n");
> > + /* If this timer kicked in, the penup timer, if ever active
> > + * at all, must have expired ages ago, so no need to del it.
> > + */
> > + ts->set_reset(0);
> > + if (ts->sample_sent) {
> > + tsc2005_ts_update_pen_state(ts, 0, 0, 0);
> > + ts->sample_sent = 0;
> > + }
> > + ts->spi_pending = 0;
> > + msleep(1); /* only 10us required */
> > + ts->set_reset(1);
> > + tsc2005_start_scan(ts);
> > + }
> > + wdj = msecs_to_jiffies(ts->esd_timeout);
> > + mod_timer(&ts->esd_timer, round_jiffies(jiffies+wdj));
> > +
> > +out:
> > + mutex_unlock(&ts->mutex);
> > +}
> > +
> > +static int __devinit tsc2005_ts_init(struct tsc2005 *ts,
> > + struct tsc2005_platform_data *pdata)
> > +{
> > + struct input_dev *idev;
> > + int r;
> > + int x_max, y_max;
> > +
> > + init_timer(&ts->penup_timer);
> > + setup_timer(&ts->penup_timer, tsc2005_ts_penup_timer_handler,
> > + (unsigned long)ts);
> > +
> > + spin_lock_init(&ts->lock);
> > + mutex_init(&ts->mutex);
> > +
> > + ts->x_plate_ohm = pdata->ts_x_plate_ohm ? : 280;
> > + ts->hw_avg_max = pdata->ts_hw_avg;
> > + ts->stab_time = pdata->ts_stab_time;
> > + x_max = pdata->ts_x_max ? : 4096;
> > + ts->fudge_x = pdata->ts_x_fudge ? : 4;
> > + y_max = pdata->ts_y_max ? : 4096;
> > + ts->fudge_y = pdata->ts_y_fudge ? : 8;
> > + ts->p_max = pdata->ts_pressure_max ? : MAX_12BIT;
> > + ts->touch_pressure = pdata->ts_touch_pressure ? : ts->p_max;
> > + ts->fudge_p = pdata->ts_pressure_fudge ? : 2;
> > +
> > + ts->set_reset = pdata->set_reset;
> > +
> > + idev = input_allocate_device();
> > + if (idev == NULL) {
> > + r = -ENOMEM;
> > + goto err1;
> > + }
> > +
> > + idev->name = "TSC2005 touchscreen";
> > + snprintf(ts->phys, sizeof(ts->phys), "%s/input-ts",
> > + dev_name(&ts->spi->dev));
> > + idev->phys = ts->phys;
> > +
> > + idev->evbit[0] = BIT(EV_ABS) | BIT(EV_KEY);
> > + idev->absbit[0] = BIT(ABS_X) | BIT(ABS_Y) | BIT(ABS_PRESSURE);
> > + idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
> > + ts->idev = idev;
> > +
> > + tsc2005_ts_setup_spi_xfer(ts);
> > +
> > + input_set_abs_params(idev, ABS_X, 0, x_max, ts->fudge_x, 0);
> > + input_set_abs_params(idev, ABS_Y, 0, y_max, ts->fudge_y, 0);
> > + input_set_abs_params(idev, ABS_PRESSURE, 0, ts->p_max, ts->fudge_p, 0);
> > +
> > + tsc2005_start_scan(ts);
> > +
> > + r = request_irq(ts->spi->irq, tsc2005_ts_irq_handler,
> > + (((TSC2005_CFR2_INITVALUE & TSC2005_CFR2_IRQ_MASK) ==
> > + TSC2005_CFR2_IRQ_PENDAV)
> > + ? IRQF_TRIGGER_RISING
> > + : IRQF_TRIGGER_FALLING) |
> > + IRQF_DISABLED, "tsc2005", ts);
> > + if (r < 0) {
> > + dev_err(&ts->spi->dev, "unable to get DAV IRQ");
> > + goto err2;
> > + }
> > +
> > + set_irq_wake(ts->spi->irq, 1);
> > +
> > + r = input_register_device(idev);
> > + if (r < 0) {
> > + dev_err(&ts->spi->dev, "can't register touchscreen device\n");
> > + goto err3;
> > + }
> > +
> > + /* We can tolerate these failing */
>
> Should we though?

For graceful degradation of functionality, yes. The core interface is
the touchscreen event stream, without that we make no sense at all.
We can function as such without the following.

> > + r = device_create_file(&ts->spi->dev, &dev_attr_ts_ctrl_selftest);
> > + if (r < 0)
> > + dev_warn(&ts->spi->dev, "can't create sysfs file for %s: %d\n",
> > + dev_attr_ts_ctrl_selftest.attr.name, r);
> > +
> > + r = device_create_file(&ts->spi->dev, &dev_attr_pen_down);
> > + if (r < 0)
> > + dev_warn(&ts->spi->dev, "can't create sysfs file for %s: %d\n",
> > + dev_attr_pen_down.attr.name, r);
> > +
> > + r = device_create_file(&ts->spi->dev, &dev_attr_disable_ts);
> > + if (r < 0)
> > + dev_warn(&ts->spi->dev, "can't create sysfs file for %s: %d\n",
> > + dev_attr_disable_ts.attr.name, r);
> > +
>
> attribute_group is more compact by the way.

I promise I won't add to that list in the future, and will instead
move it over to an attribute_group.

> > + /* Finally, configure and start the optional EDD watchdog. */
> > + ts->esd_timeout = pdata->esd_timeout;
> > + if (ts->esd_timeout && ts->set_reset) {
> > + unsigned long wdj;
> > + setup_timer(&ts->esd_timer, tsc2005_esd_timer_handler,
> > + (unsigned long)ts);
> > + INIT_WORK(&ts->esd_work, tsc2005_rst_handler);
> > + wdj = msecs_to_jiffies(ts->esd_timeout);
> > + ts->esd_timer.expires = round_jiffies(jiffies+wdj);
> > + add_timer(&ts->esd_timer);
> > + }
> > +
> > + return 0;
> > +err3:
> > + free_irq(ts->spi->irq, ts);
> > +err2:
> > + tsc2005_stop_scan(ts);
> > + input_free_device(idev);
> > +err1:
> > + return r;
> > +}
> > +
> > +static int __devinit tsc2005_probe(struct spi_device *spi)
> > +{
> > + struct tsc2005 *ts;
> > + struct tsc2005_platform_data *pdata = spi->dev.platform_data;
> > + int r;
> > +
> > + if (spi->irq < 0) {
> > + dev_dbg(&spi->dev, "no irq?\n");
> > + return -ENODEV;
> > + }
> > + if (!pdata) {
> > + dev_dbg(&spi->dev, "no platform data?\n");
> > + return -ENODEV;
> > + }
> > +
> > + ts = kzalloc(sizeof(*ts), GFP_KERNEL);
> > + if (ts == NULL)
> > + return -ENOMEM;
> > +
> > + dev_set_drvdata(&spi->dev, ts);
> > + ts->spi = spi;
> > + spi->dev.power.power_state = PMSG_ON;
> > +
> > + spi->mode = SPI_MODE_0;
> > + spi->bits_per_word = 8;
> > + /* The max speed might've been defined by the board-specific
> > + * struct */
> > + if (!spi->max_speed_hz)
> > + spi->max_speed_hz = TSC2005_HZ;
> > +
> > + spi_setup(spi);
> > +
> > + r = tsc2005_ts_init(ts, pdata);
> > + if (r)
> > + goto err1;
> > +
> > + return 0;
> > +
> > +err1:
> > + kfree(ts);
> > + return r;
> > +}
> > +
> > +static int __devexit tsc2005_remove(struct spi_device *spi)
> > +{
> > + struct tsc2005 *ts = dev_get_drvdata(&spi->dev);
> > +
> > + mutex_lock(&ts->mutex);
> > + tsc2005_disable(ts);
> > + mutex_unlock(&ts->mutex);
> > +
> > + device_remove_file(&ts->spi->dev, &dev_attr_disable_ts);
> > + device_remove_file(&ts->spi->dev, &dev_attr_pen_down);
> > + device_remove_file(&ts->spi->dev, &dev_attr_ts_ctrl_selftest);
> > +
> > + free_irq(ts->spi->irq, ts);
> > + input_unregister_device(ts->idev);
> > +
> > + if (ts->esd_timeout)
> > + del_timer(&ts->esd_timer);
>
> del_timer_sync().

Yup.

Phil

2009-11-16 15:23:53

by Mark Brown

[permalink] [raw]
Subject: Re: [PATCH v2 1/2] input: touchscreen: introduce tsc2005 driver

On Mon, Nov 16, 2009 at 02:37:48PM +0200, Phil Carmody wrote:
> On 14/11/09 07:03 +0100, ext Dmitry Torokhov wrote:

> > Do we really need to do filtering and averaging in kernel? What about
> > tslib?

> Not everyone uses tslib. There's already some filtering in the tsc2005
> already, but it's not really enough. This averaging also has the
> pleasant side-effect of reducing the number of input events. The
> fudging that takes place later has slightly different smoothing
> behaviour, and isn't a substitute.

If we do want to be doing filtering and averaging in kernel then it
really ought to be some sort of generic framework rather than driver
specific code since otherwise there will be duplication of effort. The
OpenMoko guys were pushing a framework for doing that, I'm not sure what
the current status is.