Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752223AbbGRMkh (ORCPT ); Sat, 18 Jul 2015 08:40:37 -0400 Received: from mail-pd0-f176.google.com ([209.85.192.176]:32931 "EHLO mail-pd0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750809AbbGRMke (ORCPT ); Sat, 18 Jul 2015 08:40:34 -0400 Date: Sat, 18 Jul 2015 18:07:33 +0530 From: maitysanchayan@gmail.com To: Dmitry Torokhov Cc: linux-input@vger.kernel.org, devicetree@vger.kernel.org, mark.rutland@arm.com, pawel.moll@arm.com, ijc+devicetree@hellion.org.uk, linux-kernel@vger.kernel.org, stefan@agner.ch, robh+dt@kernel.org, kernel@pengutronix.de, galak@codeaurora.org, shawn.guo@linaro.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2 3/4] touchscreen: colibri-vf50-ts: Add touchscreen support for Colibri VF50 Message-ID: <20150718123732.GB1833@Sanchayan-Arch> References: <26748bd9a7bde7c2304b6b971f1150bb575e4938.1437058481.git.maitysanchayan@gmail.com> <20150717234242.GJ39282@dtor-ws> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20150717234242.GJ39282@dtor-ws> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 17514 Lines: 594 Hello Dmitry, On 15-07-17 16:42:42, Dmitry Torokhov wrote: > Hi Sanchayan, > > > On Thu, Jul 16, 2015 at 08:43:21PM +0530, Sanchayan Maity wrote: > > The Colibri Vybrid VF50 module supports 4-wire touchscreens using > > FETs and ADC inputs. This driver uses the IIO consumer interface > > and relies on the vf610_adc driver based on the IIO framework. > > This looks pretty good, thank you. Just a few comments below. > > > > > Signed-off-by: Sanchayan Maity > > --- > > drivers/input/touchscreen/Kconfig | 12 + > > drivers/input/touchscreen/Makefile | 1 + > > drivers/input/touchscreen/colibri-vf50-ts.c | 451 ++++++++++++++++++++++++++++ > > 3 files changed, 464 insertions(+) > > create mode 100644 drivers/input/touchscreen/colibri-vf50-ts.c > > > > diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig > > index 80f6386..28948ca 100644 > > --- a/drivers/input/touchscreen/Kconfig > > +++ b/drivers/input/touchscreen/Kconfig > > @@ -1027,4 +1027,16 @@ config TOUCHSCREEN_ZFORCE > > To compile this driver as a module, choose M here: the > > module will be called zforce_ts. > > > > +config TOUCHSCREEN_COLIBRI_VF50 > > + tristate "Toradex Colibri on board touchscreen driver" > > + depends on GPIOLIB && IIO && VF610_ADC > > + help > > + Say Y here if you have a Colibri VF50 and plan to use > > + the on-board provided 4-wire touchscreen driver. > > + > > + If unsure, say N. > > + > > + To compile this driver as a module, choose M here: the > > + module will be called colibri_vf50_ts. > > + > > endif > > diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile > > index 44deea7..93746a0 100644 > > --- a/drivers/input/touchscreen/Makefile > > +++ b/drivers/input/touchscreen/Makefile > > @@ -84,3 +84,4 @@ obj-$(CONFIG_TOUCHSCREEN_W90X900) += w90p910_ts.o > > obj-$(CONFIG_TOUCHSCREEN_SX8654) += sx8654.o > > obj-$(CONFIG_TOUCHSCREEN_TPS6507X) += tps6507x-ts.o > > obj-$(CONFIG_TOUCHSCREEN_ZFORCE) += zforce_ts.o > > +obj-$(CONFIG_TOUCHSCREEN_COLIBRI_VF50) += colibri-vf50-ts.o > > diff --git a/drivers/input/touchscreen/colibri-vf50-ts.c b/drivers/input/touchscreen/colibri-vf50-ts.c > > new file mode 100644 > > index 0000000..eb16bdc > > --- /dev/null > > +++ b/drivers/input/touchscreen/colibri-vf50-ts.c > > @@ -0,0 +1,451 @@ > > +/* Copyright 2015 Toradex AG > > + * > > + * Toradex Colibri VF50 Touchscreen driver > > + * > > + * Originally authored by Stefan Agner for 3.0 kernel > > + * > > + * 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. > > + */ > > + > > +#include > > Why? Remnant of old usage. Will fix. > > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > Is not used as far as I can see. Right. Crept in from old usage of extracting gpio information from DT. Should have removed when I switched to using gpiod_* and removal of legacy gpio API. Will fix. > > > +#include > > +#include > > +#include > > +#include > > + > > +#define DRIVER_NAME "colibri-vf50-ts" > > +#define DRV_VERSION "1.0" > > + > > +#define VF_ADC_MAX ((1 << 12) - 1) > > + > > +#define COLI_TOUCH_MIN_DELAY_US 1000 > > +#define COLI_TOUCH_MAX_DELAY_US 2000 > > + > > +static int min_pressure = 200; > > + > > +struct vf50_touch_device { > > + struct platform_device *pdev; > > + struct input_dev *ts_input; > > + struct workqueue_struct *ts_workqueue; > > + struct work_struct ts_work; > > + struct iio_channel *channels; > > + struct gpio_desc *gpio_xp; > > + struct gpio_desc *gpio_xm; > > + struct gpio_desc *gpio_yp; > > + struct gpio_desc *gpio_ym; > > + struct gpio_desc *gpio_pen_detect; > > + struct gpio_desc *gpio_pen_detect_pullup; > > + int pen_irq; > > + bool stop_touchscreen; > > +}; > > + > > +/* > > + * Enables given plates and measures touch parameters using ADC > > + */ > > +static int adc_ts_measure(struct iio_channel *channel, > > + struct gpio_desc *plate_p, struct gpio_desc *plate_m) > > +{ > > + int i, value = 0, val = 0; > > + int ret; > > + > > + gpiod_set_value(plate_p, 1); > > + gpiod_set_value(plate_m, 1); > > + > > + usleep_range(COLI_TOUCH_MIN_DELAY_US, COLI_TOUCH_MAX_DELAY_US); > > + > > + for (i = 0; i < 5; i++) { > > + ret = iio_read_channel_raw(channel, &val); > > + if (ret < 0) > > + return -EINVAL; > > + > > + value += val; > > + } > > + > > + value /= 5; > > + > > + gpiod_set_value(plate_p, 0); > > + gpiod_set_value(plate_m, 0); > > + > > + return value; > > +} > > + > > +/* > > + * Enable touch detection using falling edge detection on XM > > + */ > > +static void vf50_ts_enable_touch_detection(struct vf50_touch_device *vf50_ts) > > +{ > > + /* Enable plate YM (needs to be strong GND, high active) */ > > + gpiod_set_value(vf50_ts->gpio_ym, 1); > > + > > + /* > > + * Let the platform mux to idle state in order to enable > > + * Pull-Up on GPIO > > + */ > > + pinctrl_pm_select_idle_state(&vf50_ts->pdev->dev); > > +} > > + > > +/* > > + * ADC touch screen sampling worker function > > + */ > > +static void vf50_ts_work(struct work_struct *ts_work) > > +{ > > + struct vf50_touch_device *vf50_ts = container_of(ts_work, > > + struct vf50_touch_device, ts_work); > > + struct device *dev = &vf50_ts->pdev->dev; > > + int val_x, val_y, val_z1, val_z2, val_p = 0; > > + bool discard_val_on_start = true; > > + > > + while (!vf50_ts->stop_touchscreen) { > > + /* X-Direction */ > > + val_x = adc_ts_measure(&vf50_ts->channels[0], > > + vf50_ts->gpio_xp, vf50_ts->gpio_xm); > > + if (val_x < 0) > > + continue; > > + > > + /* Y-Direction */ > > + val_y = adc_ts_measure(&vf50_ts->channels[1], > > + vf50_ts->gpio_yp, vf50_ts->gpio_ym); > > + if (val_y < 0) > > + continue; > > + > > + /* > > + * Touch pressure > > + * Measure on XP/YM > > + */ > > + val_z1 = adc_ts_measure(&vf50_ts->channels[2], > > + vf50_ts->gpio_yp, vf50_ts->gpio_xm); > > + if (val_z1 < 0) > > + continue; > > + val_z2 = adc_ts_measure(&vf50_ts->channels[3], > > + vf50_ts->gpio_yp, vf50_ts->gpio_xm); > > + if (val_z2 < 0) > > + continue; > > + > > + /* Validate signal (avoid calculation using noise) */ > > + if (val_z1 > 64 && val_x > 64) { > > + /* > > + * Calculate resistance between the plates > > + * lower resistance means higher pressure > > + */ > > + int r_x = (1000 * val_x) / VF_ADC_MAX; > > + > > + val_p = (r_x * val_z2) / val_z1 - r_x; > > + > > + } else { > > + val_p = 2000; > > + } > > + > > + val_p = 2000 - val_p; > > + dev_dbg(dev, "Measured values: x: %d, y: %d, z1: %d, z2: %d, " > > + "p: %d\n", val_x, val_y, val_z1, val_z2, val_p); > > + > > + /* > > + * If touch pressure is too low, stop measuring and reenable > > + * touch detection > > + */ > > + if (val_p < min_pressure || val_p > 2000) > > + break; > > + > > + /* > > + * The pressure may not be enough for the first x and the > > + * second y measurement, but, the pressure is ok when the > > + * driver is doing the third and fourth measurement. To > > + * take care of this, we drop the first measurement always. > > + */ > > + if (discard_val_on_start) { > > + discard_val_on_start = false; > > + } else { > > + /* > > + * Report touch position and sleep for > > + * next measurement > > + */ > > + input_report_abs(vf50_ts->ts_input, > > + ABS_X, VF_ADC_MAX - val_x); > > + input_report_abs(vf50_ts->ts_input, > > + ABS_Y, VF_ADC_MAX - val_y); > > + input_report_abs(vf50_ts->ts_input, > > + ABS_PRESSURE, val_p); > > + input_report_key(vf50_ts->ts_input, BTN_TOUCH, 1); > > + input_sync(vf50_ts->ts_input); > > + } > > + > > + msleep(10); > > + } > > + > > + /* Report no more touch, reenable touch detection */ > > + input_report_abs(vf50_ts->ts_input, ABS_PRESSURE, 0); > > + input_report_key(vf50_ts->ts_input, BTN_TOUCH, 0); > > + input_sync(vf50_ts->ts_input); > > + > > + vf50_ts_enable_touch_detection(vf50_ts); > > + > > + /* Wait for the pull-up to be stable on high */ > > + msleep(10); > > + > > + /* Reenable IRQ to detect touch */ > > + enable_irq(vf50_ts->pen_irq); > > + > > + dev_dbg(dev, "Reenabled touch detection interrupt\n"); > > +} > > + > > +static irqreturn_t vf50_ts_touched(int irq, void *dev_id) > > +{ > > + struct vf50_touch_device *vf50_ts = (struct vf50_touch_device *)dev_id; > > + struct device *dev = &vf50_ts->pdev->dev; > > + > > + dev_dbg(dev, "Touch detected, start worker thread\n"); > > + > > + disable_irq_nosync(irq); > > + > > + /* Disable the touch detection plates */ > > + gpiod_set_value(vf50_ts->gpio_ym, 0); > > + > > + /* Let the platform mux to default state in order to mux as ADC */ > > + pinctrl_pm_select_default_state(dev); > > + > > + queue_work(vf50_ts->ts_workqueue, &vf50_ts->ts_work); > > If you convert this to a threaded interrupt you won't need to > disable/reenable interrupt or queue work. You should also be able to use > gpiod_set_value_cansleep() extending the range of ways the controller > could be connected to systems. I must accept I have never used threaded IRQ's. Will take a look and respin the patch accordingly. > > > + > > + return IRQ_HANDLED; > > +} > > + > > +static int vf50_ts_open(struct input_dev *dev_input) > > +{ > > + int ret; > > + struct vf50_touch_device *touchdev = input_get_drvdata(dev_input); > > + struct device *dev = &touchdev->pdev->dev; > > + > > + dev_dbg(dev, "Input device %s opened, starting touch detection\n", > > + dev_input->name); > > + > > + touchdev->stop_touchscreen = false; > > + > > + ret = gpiod_direction_output(touchdev->gpio_xp, 0); > > + if (ret) { > > + dev_err(dev, "Could not set gpio xp as output %d\n", ret); > > + return ret; > > + } > > + > > + ret = gpiod_direction_output(touchdev->gpio_xm, 0); > > + if (ret) { > > + dev_err(dev, "Could not set gpio xm as output %d\n", ret); > > + return ret; > > + } > > + > > + ret = gpiod_direction_output(touchdev->gpio_yp, 0); > > + if (ret) { > > + dev_err(dev, "Could not set gpio yp as output %d\n", ret); > > + return ret; > > + } > > + > > + ret = gpiod_direction_output(touchdev->gpio_ym, 0); > > + if (ret) { > > + dev_err(dev, "Could not set gpio ym as output %d\n", ret); > > + return ret; > > + } > > + > > + ret = gpiod_direction_input(touchdev->gpio_pen_detect); > > + if (ret) { > > + dev_err(dev, > > + "Could not set gpio pen detect as input %d\n", ret); > > + return ret; > > + } > > + > > + ret = gpiod_direction_input(touchdev->gpio_pen_detect_pullup); > > + if (ret) { > > + dev_err(dev, > > + "Could not set pen detect pullup as input %d\n", ret); > > + return ret; > > + } > > I do not see this GPIO being actually used... Correct. Will remove. > > > + > > + /* Mux detection before request IRQ, wait for pull-up to settle */ > > + vf50_ts_enable_touch_detection(touchdev); > > + msleep(10); > > + > > + touchdev->pen_irq = gpiod_to_irq(touchdev->gpio_pen_detect); > > + if (touchdev->pen_irq < 0) { > > + dev_err(dev, "Unable to get IRQ for GPIO\n"); > > + return touchdev->pen_irq; > > + } > > + > > + ret = request_irq(touchdev->pen_irq, vf50_ts_touched, > > + IRQF_TRIGGER_FALLING, "touch detected", touchdev); > > + if (ret < 0) { > > + dev_err(dev, "Unable to request IRQ %d\n", touchdev->pen_irq); > > + return ret; > > + } > > I'd rather we did most initialization in probe() so that -EPROBE_DEFER > would get handled properly. Ok. > > > + > > + return 0; > > +} > > + > > +static void vf50_ts_close(struct input_dev *dev_input) > > +{ > > + struct vf50_touch_device *touchdev = input_get_drvdata(dev_input); > > + struct device *dev = &touchdev->pdev->dev; > > + > > + free_irq(touchdev->pen_irq, touchdev); > > + > > + touchdev->stop_touchscreen = true; > > + > > + /* Wait until touchscreen thread finishes any possible remnants. */ > > + cancel_work_sync(&touchdev->ts_work); > > + > > + dev_dbg(dev, "Input device %s closed, disable touch detection\n", > > + dev_input->name); > > +} > > + > > +static inline int vf50_ts_get_gpiod(struct device *dev, > > + struct gpio_desc **gpio_d, const char *con_id) > > +{ > > + int ret; > > + > > + *gpio_d = devm_gpiod_get(dev, con_id); > > + if (IS_ERR(*gpio_d)) { > > + ret = PTR_ERR(*gpio_d); > > + dev_err(dev, "Could not get gpio_%s %d\n", con_id, ret); > > + return ret; > > + } > > + > > + return 0; > > +} > > + > > +static int vf50_ts_probe(struct platform_device *pdev) > > +{ > > + struct device *dev = &pdev->dev; > > + struct device_node *node = dev->of_node; > > + struct vf50_touch_device *touchdev; > > + struct input_dev *input; > > + int ret = 0; > > Personal preference: can we call this "error"? Also no need to > gratuitously initialize it to 0. Ok. > > > + > > + if (!node) { > > + dev_err(dev, "Device does not have associated DT data\n"); > > + return -EINVAL; > > So what? I do not see you using of_node anywhere. Not required. Will fix. > > > + } > > + > > + touchdev = devm_kzalloc(dev, sizeof(*touchdev), GFP_KERNEL); > > + if (touchdev == NULL) > > + return -ENOMEM; > > + > > + input = devm_input_allocate_device(dev); > > + if (!input) { > > + dev_err(dev, "Failed to allocate TS input device\n"); > > + ret = -ENOMEM; > > + return ret; > > + } > > + > > + platform_set_drvdata(pdev, touchdev); > > + > > + touchdev->pdev = pdev; > > + > > + input->name = DRIVER_NAME; > > + input->id.bustype = BUS_HOST; > > + input->dev.parent = dev; > > + input->open = vf50_ts_open; > > + input->close = vf50_ts_close; > > + > > + _set_bit(EV_ABS, input->evbit); > > + _set_bit(EV_KEY, input->evbit); > > + _set_bit(BTN_TOUCH, input->keybit); > > + input_set_abs_params(input, ABS_X, 0, VF_ADC_MAX, 0, 0); > > + input_set_abs_params(input, ABS_Y, 0, VF_ADC_MAX, 0, 0); > > + input_set_abs_params(input, ABS_PRESSURE, 0, VF_ADC_MAX, 0, 0); > > + > > + touchdev->ts_input = input; > > + input_set_drvdata(input, touchdev); > > + ret = input_register_device(input); > > + if (ret) { > > + dev_err(dev, "Failed to register input device\n"); > > + return ret; > > + } > > + > > + ret = vf50_ts_get_gpiod(dev, &touchdev->gpio_xp, "xp"); > > + if (ret) > > + return ret; > > + > > + ret = vf50_ts_get_gpiod(dev, &touchdev->gpio_xm, "xm"); > > + if (ret) > > + return ret; > > + > > + ret = vf50_ts_get_gpiod(dev, &touchdev->gpio_yp, "yp"); > > + if (ret) > > + return ret; > > + > > + ret = vf50_ts_get_gpiod(dev, &touchdev->gpio_ym, "ym"); > > + if (ret) > > + return ret; > > + > > + ret = vf50_ts_get_gpiod(dev, &touchdev->gpio_pen_detect, > > + "pen-detect"); > > + if (ret) > > + return ret; > > + > > + ret = vf50_ts_get_gpiod(dev, &touchdev->gpio_pen_detect_pullup, > > + "pen-pullup"); > > + if (ret) > > + return ret; > > + > > + INIT_WORK(&touchdev->ts_work, vf50_ts_work); > > + touchdev->ts_workqueue = create_singlethread_workqueue("vf50-ts-touch"); > > + > > + if (!touchdev->ts_workqueue) { > > + ret = PTR_ERR(touchdev->ts_workqueue); > > + dev_err(dev, > > + "Failed creating vf50-ts-touch workqueue %d\n", ret); > > + return ret; > > + } > > This should go away with the threaded IRQ. Ok. > > > + > > + touchdev->channels = iio_channel_get_all(dev); > > + if (IS_ERR(touchdev->channels)) > > + return PTR_ERR(touchdev->channels); > > + > > + dev_info(dev, "Attached colibri-vf50-ts driver successfully\n"); > > Please drop, you should see message from input core about the new device > already. Ok. > > > + > > + return 0; > > +} > > + > > +static int vf50_ts_remove(struct platform_device *pdev) > > +{ > > + struct vf50_touch_device *touchdev = platform_get_drvdata(pdev); > > + > > + destroy_workqueue(touchdev->ts_workqueue); > > + iio_channel_release_all(touchdev->channels); > > + > > + return 0; > > +} > > + > > +static const struct of_device_id vf50_touch_of_match[] = { > > + { .compatible = "toradex,vf50-touchctrl", }, > > + { } > > +}; > > +MODULE_DEVICE_TABLE(of, vf50_touch_of_match); > > + > > +static struct platform_driver __refdata vf50_touch_driver = { > > Why do you need __refdata? Crept in from the old implementation. Will purge. > > > + .driver = { > > + .name = "toradex,vf50_touchctrl", > > + .of_match_table = vf50_touch_of_match, > > + }, > > + .probe = vf50_ts_probe, > > + .remove = vf50_ts_remove, > > + .prevent_deferred_probe = false, > > Deferrals are enabled by default. Ok. > > > +}; > > + > > +module_platform_driver(vf50_touch_driver); > > + > > +module_param(min_pressure, int, 0600); > > +MODULE_PARM_DESC(min_pressure, "Minimum pressure for touch detection"); > > I'd rather let userspace figure out what it recognizes as valid touch. Will rethink this. Thanks for the feedback Dmitry. Will take care of all comments in the next version. - Sanchayan. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/