The following functionalities are supported:
- write, read from volatile memory
Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22060b.pdf
Signed-off-by: Slawomir Stepien <[email protected]>
---
Changes since v3:
- Added 'potentiometer' to subject
- Replaced mcp4131_exec with spi_write and mcp4131_read
- Narrowed mutex locking and unlocking places
Changes since v2:
- Removed unnecessary parentheses in MCP4131_WIPER_SHIFT macro
- Replaced the rx and tx SPI buffers with one buf that is ____cacheline_aligned
- Changed mutex locking position
- Replaced the devid with pointer to model configuration
- Removed positive ("Registered" & "Unregistered") dev_info prints
- Removed the mcp4131_remove callback
Changes since v1:
- One line summary changed
- Fixed module name and OF compatible
- Based code on Peter Rosin's code from mcp4531.c
- No additional sysfs attributes
- Deleted not used devid struct memeber
- Changed mcp4131_exec function arguments:
- write value is now u16
- no need to pass return buffer array - rx array from mcp4131_data is used
- Added missing new line characters to dev_info
---
.../bindings/iio/potentiometer/mcp4131.txt | 84 ++++
drivers/iio/potentiometer/Kconfig | 18 +
drivers/iio/potentiometer/Makefile | 1 +
drivers/iio/potentiometer/mcp4131.c | 492 +++++++++++++++++++++
4 files changed, 595 insertions(+)
create mode 100644 Documentation/devicetree/bindings/iio/potentiometer/mcp4131.txt
create mode 100644 drivers/iio/potentiometer/mcp4131.c
diff --git a/Documentation/devicetree/bindings/iio/potentiometer/mcp4131.txt b/Documentation/devicetree/bindings/iio/potentiometer/mcp4131.txt
new file mode 100644
index 0000000..3ccba16
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/potentiometer/mcp4131.txt
@@ -0,0 +1,84 @@
+* Microchip MCP413X/414X/415X/416X/423X/424X/425X/426X Digital Potentiometer
+ driver
+
+The node for this driver must be a child node of a SPI controller, hence
+all mandatory properties described in
+
+ Documentation/devicetree/bindings/spi/spi-bus.txt
+
+must be specified.
+
+Required properties:
+ - compatible: Must be one of the following, depending on the
+ model:
+ "microchip,mcp4131-502"
+ "microchip,mcp4131-103"
+ "microchip,mcp4131-503"
+ "microchip,mcp4131-104"
+ "microchip,mcp4132-502"
+ "microchip,mcp4132-103"
+ "microchip,mcp4132-503"
+ "microchip,mcp4132-104"
+ "microchip,mcp4141-502"
+ "microchip,mcp4141-103"
+ "microchip,mcp4141-503"
+ "microchip,mcp4141-104"
+ "microchip,mcp4142-502"
+ "microchip,mcp4142-103"
+ "microchip,mcp4142-503"
+ "microchip,mcp4142-104"
+ "microchip,mcp4151-502"
+ "microchip,mcp4151-103"
+ "microchip,mcp4151-503"
+ "microchip,mcp4151-104"
+ "microchip,mcp4152-502"
+ "microchip,mcp4152-103"
+ "microchip,mcp4152-503"
+ "microchip,mcp4152-104"
+ "microchip,mcp4161-502"
+ "microchip,mcp4161-103"
+ "microchip,mcp4161-503"
+ "microchip,mcp4161-104"
+ "microchip,mcp4162-502"
+ "microchip,mcp4162-103"
+ "microchip,mcp4162-503"
+ "microchip,mcp4162-104"
+ "microchip,mcp4231-502"
+ "microchip,mcp4231-103"
+ "microchip,mcp4231-503"
+ "microchip,mcp4231-104"
+ "microchip,mcp4232-502"
+ "microchip,mcp4232-103"
+ "microchip,mcp4232-503"
+ "microchip,mcp4232-104"
+ "microchip,mcp4241-502"
+ "microchip,mcp4241-103"
+ "microchip,mcp4241-503"
+ "microchip,mcp4241-104"
+ "microchip,mcp4242-502"
+ "microchip,mcp4242-103"
+ "microchip,mcp4242-503"
+ "microchip,mcp4242-104"
+ "microchip,mcp4251-502"
+ "microchip,mcp4251-103"
+ "microchip,mcp4251-503"
+ "microchip,mcp4251-104"
+ "microchip,mcp4252-502"
+ "microchip,mcp4252-103"
+ "microchip,mcp4252-503"
+ "microchip,mcp4252-104"
+ "microchip,mcp4261-502"
+ "microchip,mcp4261-103"
+ "microchip,mcp4261-503"
+ "microchip,mcp4261-104"
+ "microchip,mcp4262-502"
+ "microchip,mcp4262-103"
+ "microchip,mcp4262-503"
+ "microchip,mcp4262-104"
+
+Example:
+mcp4131: mcp4131@0 {
+ compatible = "mcp4131-502";
+ reg = <0>;
+ spi-max-frequency = <500000>;
+};
diff --git a/drivers/iio/potentiometer/Kconfig b/drivers/iio/potentiometer/Kconfig
index fd75db7..5ef181a 100644
--- a/drivers/iio/potentiometer/Kconfig
+++ b/drivers/iio/potentiometer/Kconfig
@@ -5,6 +5,24 @@
menu "Digital potentiometers"
+config MCP4131
+ tristate "Microchip MCP413X/414X/415X/416X/423X/424X/425X/426X Digital Potentiometer driver"
+ depends on SPI
+ help
+ Say yes here to build support for the Microchip
+ MCP4131, MCP4132,
+ MCP4141, MCP4142,
+ MCP4151, MCP4152,
+ MCP4161, MCP4162,
+ MCP4231, MCP4232,
+ MCP4241, MCP4242,
+ MCP4251, MCP4252,
+ MCP4261, MCP4262,
+ digital potentiomenter chips.
+
+ To compile this driver as a module, choose M here: the
+ module will be called mcp4131.
+
config MCP4531
tristate "Microchip MCP45xx/MCP46xx Digital Potentiometer driver"
depends on I2C
diff --git a/drivers/iio/potentiometer/Makefile b/drivers/iio/potentiometer/Makefile
index 8afe492..cd5c80b 100644
--- a/drivers/iio/potentiometer/Makefile
+++ b/drivers/iio/potentiometer/Makefile
@@ -3,4 +3,5 @@
#
# When adding new entries keep the list in alphabetical order
+obj-$(CONFIG_MCP4131) += mcp4131.o
obj-$(CONFIG_MCP4531) += mcp4531.o
diff --git a/drivers/iio/potentiometer/mcp4131.c b/drivers/iio/potentiometer/mcp4131.c
new file mode 100644
index 0000000..53546e8
--- /dev/null
+++ b/drivers/iio/potentiometer/mcp4131.c
@@ -0,0 +1,492 @@
+/*
+ * Industrial I/O driver for Microchip digital potentiometers
+ *
+ * Copyright (c) 2016 Slawomir Stepien
+ * Based on: Peter Rosin's code from mcp4531.c
+ *
+ * Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22060b.pdf
+ *
+ * DEVID #Wipers #Positions Resistor Opts (kOhm)
+ * mcp4131 1 129 5, 10, 50, 100
+ * mcp4132 1 129 5, 10, 50, 100
+ * mcp4141 1 129 5, 10, 50, 100
+ * mcp4142 1 129 5, 10, 50, 100
+ * mcp4151 1 257 5, 10, 50, 100
+ * mcp4152 1 257 5, 10, 50, 100
+ * mcp4161 1 257 5, 10, 50, 100
+ * mcp4162 1 257 5, 10, 50, 100
+ * mcp4231 2 129 5, 10, 50, 100
+ * mcp4232 2 129 5, 10, 50, 100
+ * mcp4241 2 129 5, 10, 50, 100
+ * mcp4242 2 129 5, 10, 50, 100
+ * mcp4251 2 257 5, 10, 50, 100
+ * mcp4252 2 257 5, 10, 50, 100
+ * mcp4261 2 257 5, 10, 50, 100
+ * mcp4262 2 257 5, 10, 50, 100
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+/*
+ * TODO:
+ * 1. Write wiper setting to EEPROM for EEPROM capable models.
+ */
+
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+#include <linux/err.h>
+
+#include <linux/iio/iio.h>
+
+#define MCP4131_WRITE (0x00 << 2)
+#define MCP4131_READ (0x03 << 2)
+
+#define MCP4131_WIPER_SHIFT 4
+#define MCP4131_CMDERR(r) ((r[0]) & 0x02)
+#define MCP4131_RAW(r) ((r[0]) == 0xff ? 0x100 : (r[1]))
+
+struct mcp4131_cfg {
+ int wipers;
+ int max_pos;
+ int kohms;
+};
+
+enum mcp4131_type {
+ MCP413x_502 = 0,
+ MCP413x_103,
+ MCP413x_503,
+ MCP413x_104,
+ MCP414x_502,
+ MCP414x_103,
+ MCP414x_503,
+ MCP414x_104,
+ MCP415x_502,
+ MCP415x_103,
+ MCP415x_503,
+ MCP415x_104,
+ MCP416x_502,
+ MCP416x_103,
+ MCP416x_503,
+ MCP416x_104,
+ MCP423x_502,
+ MCP423x_103,
+ MCP423x_503,
+ MCP423x_104,
+ MCP424x_502,
+ MCP424x_103,
+ MCP424x_503,
+ MCP424x_104,
+ MCP425x_502,
+ MCP425x_103,
+ MCP425x_503,
+ MCP425x_104,
+ MCP426x_502,
+ MCP426x_103,
+ MCP426x_503,
+ MCP426x_104,
+};
+
+static const struct mcp4131_cfg mcp4131_cfg[] = {
+ [MCP413x_502] = { .wipers = 1, .max_pos = 128, .kohms = 5, },
+ [MCP413x_103] = { .wipers = 1, .max_pos = 128, .kohms = 10, },
+ [MCP413x_503] = { .wipers = 1, .max_pos = 128, .kohms = 50, },
+ [MCP413x_104] = { .wipers = 1, .max_pos = 128, .kohms = 100, },
+ [MCP414x_502] = { .wipers = 1, .max_pos = 128, .kohms = 5, },
+ [MCP414x_103] = { .wipers = 1, .max_pos = 128, .kohms = 10, },
+ [MCP414x_503] = { .wipers = 1, .max_pos = 128, .kohms = 50, },
+ [MCP414x_104] = { .wipers = 1, .max_pos = 128, .kohms = 100, },
+ [MCP415x_502] = { .wipers = 1, .max_pos = 256, .kohms = 5, },
+ [MCP415x_103] = { .wipers = 1, .max_pos = 256, .kohms = 10, },
+ [MCP415x_503] = { .wipers = 1, .max_pos = 256, .kohms = 50, },
+ [MCP415x_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, },
+ [MCP416x_502] = { .wipers = 1, .max_pos = 256, .kohms = 5, },
+ [MCP416x_103] = { .wipers = 1, .max_pos = 256, .kohms = 10, },
+ [MCP416x_503] = { .wipers = 1, .max_pos = 256, .kohms = 50, },
+ [MCP416x_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, },
+ [MCP423x_502] = { .wipers = 2, .max_pos = 128, .kohms = 5, },
+ [MCP423x_103] = { .wipers = 2, .max_pos = 128, .kohms = 10, },
+ [MCP423x_503] = { .wipers = 2, .max_pos = 128, .kohms = 50, },
+ [MCP423x_104] = { .wipers = 2, .max_pos = 128, .kohms = 100, },
+ [MCP424x_502] = { .wipers = 2, .max_pos = 128, .kohms = 5, },
+ [MCP424x_103] = { .wipers = 2, .max_pos = 128, .kohms = 10, },
+ [MCP424x_503] = { .wipers = 2, .max_pos = 128, .kohms = 50, },
+ [MCP424x_104] = { .wipers = 2, .max_pos = 128, .kohms = 100, },
+ [MCP425x_502] = { .wipers = 2, .max_pos = 256, .kohms = 5, },
+ [MCP425x_103] = { .wipers = 2, .max_pos = 256, .kohms = 10, },
+ [MCP425x_503] = { .wipers = 2, .max_pos = 256, .kohms = 50, },
+ [MCP425x_104] = { .wipers = 2, .max_pos = 256, .kohms = 100, },
+ [MCP426x_502] = { .wipers = 2, .max_pos = 256, .kohms = 5, },
+ [MCP426x_103] = { .wipers = 2, .max_pos = 256, .kohms = 10, },
+ [MCP426x_503] = { .wipers = 2, .max_pos = 256, .kohms = 50, },
+ [MCP426x_104] = { .wipers = 2, .max_pos = 256, .kohms = 100, },
+};
+
+struct mcp4131_data {
+ struct spi_device *spi;
+ const struct mcp4131_cfg *cfg;
+ struct mutex lock;
+ u8 buf[2] ____cacheline_aligned;
+};
+
+#define MCP4131_CHANNEL(ch) { \
+ .type = IIO_RESISTANCE, \
+ .indexed = 1, \
+ .output = 1, \
+ .channel = (ch), \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+}
+
+static const struct iio_chan_spec mcp4131_channels[] = {
+ MCP4131_CHANNEL(0),
+ MCP4131_CHANNEL(1),
+};
+
+static int mcp4131_read(struct spi_device *spi, void *buf, size_t len)
+{
+ struct spi_transfer t = {
+ .tx_buf = buf, /* We need to send addr, cmd and 12 bits */
+ .rx_buf = buf,
+ .len = len,
+ };
+ struct spi_message m;
+
+ spi_message_init(&m);
+ spi_message_add_tail(&t, &m);
+
+ return spi_sync(spi, &m);
+}
+
+static int mcp4131_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ int err;
+ struct mcp4131_data *data = iio_priv(indio_dev);
+ int address = chan->channel;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&data->lock);
+
+ data->buf[0] = (address << MCP4131_WIPER_SHIFT) | MCP4131_READ;
+ data->buf[1] = 0;
+
+ err = mcp4131_read(data->spi, data->buf, 2);
+ if (err) {
+ mutex_unlock(&data->lock);
+ return err;
+ }
+
+ /* Error, bad address/command combination */
+ if (!MCP4131_CMDERR(data->buf))
+ return -EIO;
+
+ *val = MCP4131_RAW(data->buf);
+ mutex_unlock(&data->lock);
+
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_SCALE:
+ *val = 1000 * data->cfg->kohms;
+ *val2 = data->cfg->max_pos;
+ return IIO_VAL_FRACTIONAL;
+ }
+
+ return -EINVAL;
+}
+
+static int mcp4131_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ int err;
+ struct mcp4131_data *data = iio_priv(indio_dev);
+ int address = chan->channel << MCP4131_WIPER_SHIFT;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ if (val > data->cfg->max_pos || val < 0)
+ return -EINVAL;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ mutex_lock(&data->lock);
+
+ data->buf[0] = address << MCP4131_WIPER_SHIFT;
+ data->buf[0] |= MCP4131_WRITE | (val >> 8);
+ data->buf[1] = val & 0xFF; /* 8 bits here */
+
+ err = spi_write(data->spi, data->buf, 2);
+ if (err) {
+ mutex_unlock(&data->lock);
+ return err;
+ }
+ mutex_unlock(&data->lock);
+
+ return 0;
+}
+
+static const struct iio_info mcp4131_info = {
+ .read_raw = mcp4131_read_raw,
+ .write_raw = mcp4131_write_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static int mcp4131_probe(struct spi_device *spi)
+{
+ int err;
+ struct device *dev = &spi->dev;
+ unsigned long devid = spi_get_device_id(spi)->driver_data;
+ struct mcp4131_data *data;
+ struct iio_dev *indio_dev;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ data = iio_priv(indio_dev);
+ spi_set_drvdata(spi, indio_dev);
+ data->spi = spi;
+ data->cfg = &mcp4131_cfg[devid];
+
+ mutex_init(&data->lock);
+
+ indio_dev->dev.parent = dev;
+ indio_dev->info = &mcp4131_info;
+ indio_dev->channels = mcp4131_channels;
+ indio_dev->num_channels = data->cfg->wipers;
+ indio_dev->name = spi_get_device_id(spi)->name;
+
+ err = devm_iio_device_register(dev, indio_dev);
+ if (err) {
+ dev_info(&spi->dev, "Unable to register %s\n", indio_dev->name);
+ return err;
+ }
+
+ return 0;
+}
+
+#if defined(CONFIG_OF)
+static const struct of_device_id mcp4131_dt_ids[] = {
+ { .compatible = "microchip,mcp4131-502",
+ .data = &mcp4131_cfg[MCP413x_502] },
+ { .compatible = "microchip,mcp4131-103",
+ .data = &mcp4131_cfg[MCP413x_103] },
+ { .compatible = "microchip,mcp4131-503",
+ .data = &mcp4131_cfg[MCP413x_503] },
+ { .compatible = "microchip,mcp4131-104",
+ .data = &mcp4131_cfg[MCP413x_104] },
+ { .compatible = "microchip,mcp4132-502",
+ .data = &mcp4131_cfg[MCP413x_502] },
+ { .compatible = "microchip,mcp4132-103",
+ .data = &mcp4131_cfg[MCP413x_103] },
+ { .compatible = "microchip,mcp4132-503",
+ .data = &mcp4131_cfg[MCP413x_503] },
+ { .compatible = "microchip,mcp4132-104",
+ .data = &mcp4131_cfg[MCP413x_104] },
+ { .compatible = "microchip,mcp4141-502",
+ .data = &mcp4131_cfg[MCP414x_502] },
+ { .compatible = "microchip,mcp4141-103",
+ .data = &mcp4131_cfg[MCP414x_103] },
+ { .compatible = "microchip,mcp4141-503",
+ .data = &mcp4131_cfg[MCP414x_503] },
+ { .compatible = "microchip,mcp4141-104",
+ .data = &mcp4131_cfg[MCP414x_104] },
+ { .compatible = "microchip,mcp4142-502",
+ .data = &mcp4131_cfg[MCP414x_502] },
+ { .compatible = "microchip,mcp4142-103",
+ .data = &mcp4131_cfg[MCP414x_103] },
+ { .compatible = "microchip,mcp4142-503",
+ .data = &mcp4131_cfg[MCP414x_503] },
+ { .compatible = "microchip,mcp4142-104",
+ .data = &mcp4131_cfg[MCP414x_104] },
+ { .compatible = "microchip,mcp4151-502",
+ .data = &mcp4131_cfg[MCP415x_502] },
+ { .compatible = "microchip,mcp4151-103",
+ .data = &mcp4131_cfg[MCP415x_103] },
+ { .compatible = "microchip,mcp4151-503",
+ .data = &mcp4131_cfg[MCP415x_503] },
+ { .compatible = "microchip,mcp4151-104",
+ .data = &mcp4131_cfg[MCP415x_104] },
+ { .compatible = "microchip,mcp4152-502",
+ .data = &mcp4131_cfg[MCP415x_502] },
+ { .compatible = "microchip,mcp4152-103",
+ .data = &mcp4131_cfg[MCP415x_103] },
+ { .compatible = "microchip,mcp4152-503",
+ .data = &mcp4131_cfg[MCP415x_503] },
+ { .compatible = "microchip,mcp4152-104",
+ .data = &mcp4131_cfg[MCP415x_104] },
+ { .compatible = "microchip,mcp4161-502",
+ .data = &mcp4131_cfg[MCP416x_502] },
+ { .compatible = "microchip,mcp4161-103",
+ .data = &mcp4131_cfg[MCP416x_103] },
+ { .compatible = "microchip,mcp4161-503",
+ .data = &mcp4131_cfg[MCP416x_503] },
+ { .compatible = "microchip,mcp4161-104",
+ .data = &mcp4131_cfg[MCP416x_104] },
+ { .compatible = "microchip,mcp4162-502",
+ .data = &mcp4131_cfg[MCP416x_502] },
+ { .compatible = "microchip,mcp4162-103",
+ .data = &mcp4131_cfg[MCP416x_103] },
+ { .compatible = "microchip,mcp4162-503",
+ .data = &mcp4131_cfg[MCP416x_503] },
+ { .compatible = "microchip,mcp4162-104",
+ .data = &mcp4131_cfg[MCP416x_104] },
+ { .compatible = "microchip,mcp4231-502",
+ .data = &mcp4131_cfg[MCP423x_502] },
+ { .compatible = "microchip,mcp4231-103",
+ .data = &mcp4131_cfg[MCP423x_103] },
+ { .compatible = "microchip,mcp4231-503",
+ .data = &mcp4131_cfg[MCP423x_503] },
+ { .compatible = "microchip,mcp4231-104",
+ .data = &mcp4131_cfg[MCP423x_104] },
+ { .compatible = "microchip,mcp4232-502",
+ .data = &mcp4131_cfg[MCP423x_502] },
+ { .compatible = "microchip,mcp4232-103",
+ .data = &mcp4131_cfg[MCP423x_103] },
+ { .compatible = "microchip,mcp4232-503",
+ .data = &mcp4131_cfg[MCP423x_503] },
+ { .compatible = "microchip,mcp4232-104",
+ .data = &mcp4131_cfg[MCP423x_104] },
+ { .compatible = "microchip,mcp4241-502",
+ .data = &mcp4131_cfg[MCP424x_502] },
+ { .compatible = "microchip,mcp4241-103",
+ .data = &mcp4131_cfg[MCP424x_103] },
+ { .compatible = "microchip,mcp4241-503",
+ .data = &mcp4131_cfg[MCP424x_503] },
+ { .compatible = "microchip,mcp4241-104",
+ .data = &mcp4131_cfg[MCP424x_104] },
+ { .compatible = "microchip,mcp4242-502",
+ .data = &mcp4131_cfg[MCP424x_502] },
+ { .compatible = "microchip,mcp4242-103",
+ .data = &mcp4131_cfg[MCP424x_103] },
+ { .compatible = "microchip,mcp4242-503",
+ .data = &mcp4131_cfg[MCP424x_503] },
+ { .compatible = "microchip,mcp4242-104",
+ .data = &mcp4131_cfg[MCP424x_104] },
+ { .compatible = "microchip,mcp4251-502",
+ .data = &mcp4131_cfg[MCP425x_502] },
+ { .compatible = "microchip,mcp4251-103",
+ .data = &mcp4131_cfg[MCP425x_103] },
+ { .compatible = "microchip,mcp4251-503",
+ .data = &mcp4131_cfg[MCP425x_503] },
+ { .compatible = "microchip,mcp4251-104",
+ .data = &mcp4131_cfg[MCP425x_104] },
+ { .compatible = "microchip,mcp4252-502",
+ .data = &mcp4131_cfg[MCP425x_502] },
+ { .compatible = "microchip,mcp4252-103",
+ .data = &mcp4131_cfg[MCP425x_103] },
+ { .compatible = "microchip,mcp4252-503",
+ .data = &mcp4131_cfg[MCP425x_503] },
+ { .compatible = "microchip,mcp4252-104",
+ .data = &mcp4131_cfg[MCP425x_104] },
+ { .compatible = "microchip,mcp4261-502",
+ .data = &mcp4131_cfg[MCP426x_502] },
+ { .compatible = "microchip,mcp4261-103",
+ .data = &mcp4131_cfg[MCP426x_103] },
+ { .compatible = "microchip,mcp4261-503",
+ .data = &mcp4131_cfg[MCP426x_503] },
+ { .compatible = "microchip,mcp4261-104",
+ .data = &mcp4131_cfg[MCP426x_104] },
+ { .compatible = "microchip,mcp4262-502",
+ .data = &mcp4131_cfg[MCP426x_502] },
+ { .compatible = "microchip,mcp4262-103",
+ .data = &mcp4131_cfg[MCP426x_103] },
+ { .compatible = "microchip,mcp4262-503",
+ .data = &mcp4131_cfg[MCP426x_503] },
+ { .compatible = "microchip,mcp4262-104",
+ .data = &mcp4131_cfg[MCP426x_104] },
+ {}
+};
+MODULE_DEVICE_TABLE(of, mcp4131_dt_ids);
+#endif /* CONFIG_OF */
+
+static const struct spi_device_id mcp4131_id[] = {
+ { "mcp4131-502", MCP413x_502 },
+ { "mcp4131-103", MCP413x_103 },
+ { "mcp4131-503", MCP413x_503 },
+ { "mcp4131-104", MCP413x_104 },
+ { "mcp4132-502", MCP413x_502 },
+ { "mcp4132-103", MCP413x_103 },
+ { "mcp4132-503", MCP413x_503 },
+ { "mcp4132-104", MCP413x_104 },
+ { "mcp4141-502", MCP414x_502 },
+ { "mcp4141-103", MCP414x_103 },
+ { "mcp4141-503", MCP414x_503 },
+ { "mcp4141-104", MCP414x_104 },
+ { "mcp4142-502", MCP414x_502 },
+ { "mcp4142-103", MCP414x_103 },
+ { "mcp4142-503", MCP414x_503 },
+ { "mcp4142-104", MCP414x_104 },
+ { "mcp4151-502", MCP415x_502 },
+ { "mcp4151-103", MCP415x_103 },
+ { "mcp4151-503", MCP415x_503 },
+ { "mcp4151-104", MCP415x_104 },
+ { "mcp4152-502", MCP415x_502 },
+ { "mcp4152-103", MCP415x_103 },
+ { "mcp4152-503", MCP415x_503 },
+ { "mcp4152-104", MCP415x_104 },
+ { "mcp4161-502", MCP416x_502 },
+ { "mcp4161-103", MCP416x_103 },
+ { "mcp4161-503", MCP416x_503 },
+ { "mcp4161-104", MCP416x_104 },
+ { "mcp4162-502", MCP416x_502 },
+ { "mcp4162-103", MCP416x_103 },
+ { "mcp4162-503", MCP416x_503 },
+ { "mcp4162-104", MCP416x_104 },
+ { "mcp4231-502", MCP423x_502 },
+ { "mcp4231-103", MCP423x_103 },
+ { "mcp4231-503", MCP423x_503 },
+ { "mcp4231-104", MCP423x_104 },
+ { "mcp4232-502", MCP423x_502 },
+ { "mcp4232-103", MCP423x_103 },
+ { "mcp4232-503", MCP423x_503 },
+ { "mcp4232-104", MCP423x_104 },
+ { "mcp4241-502", MCP424x_502 },
+ { "mcp4241-103", MCP424x_103 },
+ { "mcp4241-503", MCP424x_503 },
+ { "mcp4241-104", MCP424x_104 },
+ { "mcp4242-502", MCP424x_502 },
+ { "mcp4242-103", MCP424x_103 },
+ { "mcp4242-503", MCP424x_503 },
+ { "mcp4242-104", MCP424x_104 },
+ { "mcp4251-502", MCP425x_502 },
+ { "mcp4251-103", MCP425x_103 },
+ { "mcp4251-503", MCP425x_503 },
+ { "mcp4251-104", MCP425x_104 },
+ { "mcp4252-502", MCP425x_502 },
+ { "mcp4252-103", MCP425x_103 },
+ { "mcp4252-503", MCP425x_503 },
+ { "mcp4252-104", MCP425x_104 },
+ { "mcp4261-502", MCP426x_502 },
+ { "mcp4261-103", MCP426x_103 },
+ { "mcp4261-503", MCP426x_503 },
+ { "mcp4261-104", MCP426x_104 },
+ { "mcp4262-502", MCP426x_502 },
+ { "mcp4262-103", MCP426x_103 },
+ { "mcp4262-503", MCP426x_503 },
+ { "mcp4262-104", MCP426x_104 },
+ {}
+};
+MODULE_DEVICE_TABLE(spi, mcp4131_id);
+
+static struct spi_driver mcp4131_driver = {
+ .driver = {
+ .name = "mcp4131",
+ .of_match_table = of_match_ptr(mcp4131_dt_ids),
+ },
+ .probe = mcp4131_probe,
+ .id_table = mcp4131_id,
+};
+
+module_spi_driver(mcp4131_driver);
+
+MODULE_AUTHOR("Slawomir Stepien <[email protected]>");
+MODULE_DESCRIPTION("MCP4131 digital potentiometer");
+MODULE_LICENSE("GPL v2");
--
2.7.4
Hi Slawomir,
On 22 March 2016 at 16:44, Slawomir Stepien <[email protected]> wrote:
> The following functionalities are supported:
> - write, read from volatile memory
>
> Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22060b.pdf
>
> Signed-off-by: Slawomir Stepien <[email protected]>
> ---
> +#include <linux/module.h>
> +#include <linux/spi/spi.h>
> +#include <linux/err.h>
> +
> +#include <linux/iio/iio.h>
Give that you use that you have a some OF stuff in your driver you
should also include <linux/of.h>. Same goes for <linux/mutex.h>.
I am sure this builds fine without those includes, but you should
explicitly include stuff that you use.
While you're at it you could also put the includes in alphabetic order.
> +static int mcp4131_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long mask)
> +{
> + int err;
> + struct mcp4131_data *data = iio_priv(indio_dev);
> + int address = chan->channel;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + mutex_lock(&data->lock);
> +
> + data->buf[0] = (address << MCP4131_WIPER_SHIFT) | MCP4131_READ;
> + data->buf[1] = 0;
> +
> + err = mcp4131_read(data->spi, data->buf, 2);
> + if (err) {
> + mutex_unlock(&data->lock);
> + return err;
> + }
> +
> + /* Error, bad address/command combination */
> + if (!MCP4131_CMDERR(data->buf))
> + return -EIO;
Missing mutex unlock here.
> +
> + *val = MCP4131_RAW(data->buf);
> + mutex_unlock(&data->lock);
> +
> + return IIO_VAL_INT;
> +
> + case IIO_CHAN_INFO_SCALE:
> + *val = 1000 * data->cfg->kohms;
> + *val2 = data->cfg->max_pos;
> + return IIO_VAL_FRACTIONAL;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int mcp4131_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int val, int val2, long mask)
> +{
> + int err;
> + struct mcp4131_data *data = iio_priv(indio_dev);
> + int address = chan->channel << MCP4131_WIPER_SHIFT;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + if (val > data->cfg->max_pos || val < 0)
> + return -EINVAL;
> + break;
> +
> + default:
> + return -EINVAL;
> + }
> +
> + mutex_lock(&data->lock);
> +
> + data->buf[0] = address << MCP4131_WIPER_SHIFT;
> + data->buf[0] |= MCP4131_WRITE | (val >> 8);
> + data->buf[1] = val & 0xFF; /* 8 bits here */
> +
> + err = spi_write(data->spi, data->buf, 2);
> + if (err) {
> + mutex_unlock(&data->lock);
> + return err;
> + }
> + mutex_unlock(&data->lock);
> +
> + return 0;
This last part could be written as:
err = spi_write(data->spi, data->buf, 2);
mutex_unlock(&data->lock);
return err;
Other than the things I noted driver looks good to me.
regards,
Joachim Eastwood
On Mar 22, 2016 17:10, Joachim Eastwood wrote:
> Hi Slawomir,
>
> On 22 March 2016 at 16:44, Slawomir Stepien <[email protected]> wrote:
> > The following functionalities are supported:
> > - write, read from volatile memory
> >
> > Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22060b.pdf
> >
> > Signed-off-by: Slawomir Stepien <[email protected]>
> > ---
>
> > +#include <linux/module.h>
> > +#include <linux/spi/spi.h>
> > +#include <linux/err.h>
> > +
> > +#include <linux/iio/iio.h>
>
> Give that you use that you have a some OF stuff in your driver you
> should also include <linux/of.h>. Same goes for <linux/mutex.h>.
> I am sure this builds fine without those includes, but you should
> explicitly include stuff that you use.
Oh yes that's true.
> While you're at it you could also put the includes in alphabetic order.
OK
> > +static int mcp4131_read_raw(struct iio_dev *indio_dev,
> > + struct iio_chan_spec const *chan,
> > + int *val, int *val2, long mask)
> > +{
> > + int err;
> > + struct mcp4131_data *data = iio_priv(indio_dev);
> > + int address = chan->channel;
> > +
> > + switch (mask) {
> > + case IIO_CHAN_INFO_RAW:
> > + mutex_lock(&data->lock);
> > +
> > + data->buf[0] = (address << MCP4131_WIPER_SHIFT) | MCP4131_READ;
> > + data->buf[1] = 0;
> > +
> > + err = mcp4131_read(data->spi, data->buf, 2);
> > + if (err) {
> > + mutex_unlock(&data->lock);
> > + return err;
> > + }
> > +
> > + /* Error, bad address/command combination */
> > + if (!MCP4131_CMDERR(data->buf))
> > + return -EIO;
>
> Missing mutex unlock here.
Oh ;) I'll fix that.
> > +
> > + *val = MCP4131_RAW(data->buf);
> > + mutex_unlock(&data->lock);
> > +
> > + return IIO_VAL_INT;
> > +
> > + case IIO_CHAN_INFO_SCALE:
> > + *val = 1000 * data->cfg->kohms;
> > + *val2 = data->cfg->max_pos;
> > + return IIO_VAL_FRACTIONAL;
> > + }
> > +
> > + return -EINVAL;
> > +}
> > +
> > +static int mcp4131_write_raw(struct iio_dev *indio_dev,
> > + struct iio_chan_spec const *chan,
> > + int val, int val2, long mask)
> > +{
> > + int err;
> > + struct mcp4131_data *data = iio_priv(indio_dev);
> > + int address = chan->channel << MCP4131_WIPER_SHIFT;
> > +
> > + switch (mask) {
> > + case IIO_CHAN_INFO_RAW:
> > + if (val > data->cfg->max_pos || val < 0)
> > + return -EINVAL;
> > + break;
> > +
> > + default:
> > + return -EINVAL;
> > + }
> > +
> > + mutex_lock(&data->lock);
> > +
> > + data->buf[0] = address << MCP4131_WIPER_SHIFT;
> > + data->buf[0] |= MCP4131_WRITE | (val >> 8);
> > + data->buf[1] = val & 0xFF; /* 8 bits here */
> > +
> > + err = spi_write(data->spi, data->buf, 2);
> > + if (err) {
> > + mutex_unlock(&data->lock);
> > + return err;
> > + }
> > + mutex_unlock(&data->lock);
> > +
> > + return 0;
>
> This last part could be written as:
> err = spi_write(data->spi, data->buf, 2);
> mutex_unlock(&data->lock);
>
> return err;
OK
> Other than the things I noted driver looks good to me.
>
>
> regards,
> Joachim Eastwood
--
Slawomir Stepien