| Message ID | 1526975559-18966-7-git-send-email-eugen.hristev@microchip.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, 22 May 2018 10:52:36 +0300 Eugen Hristev <eugen.hristev@microchip.com> wrote: > This adds a generic resistive touchscreen (GRTS) driver, which is based > on an IIO device (an ADC). It must be connected to the channels of an ADC > to receive touch data. Then it will feed the data into the input subsystem > where it registers an input device. > It uses an IIO callback buffer to register to the IIO device > > Some parts of this patch are based on initial original work by > Mohamed Jamsheeth Hajanajubudeen and Bandaru Venkateswara Swamy > > Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com> > Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Applied to the togreg branch of iio.git and pushed out as testing for the autobuilders to play with it. Thanks, Jonathan > --- > Changes in v7: > - cosmetic fixes as suggested by Dmitry: moved min pressure > property lookup below and only if pressure channel is available. > used the error variable in probe at some point, removed it at > different point. > > Changes in v6: > - changed a dev_err to dev_dbg which was forgotten in v5. > > Changes in v5: > - return error on probe if failed add_action_or_reset > - renamed property touchscreen-threshold-pressure to > touchscreen-min-pressure, changed variables accordingly > > Changes in v4: > - added a small description in file header > - changed MAX_POS_MASK to GRTS_MAX_POS_MASK > - initialized press with 0, as this value means no touch. > press has to be initialized because compiler/checkpatch complains > that can be used uninitialized. > - changed of_property_read_u32 to device_* > - set_abs_params for pressure will have range according to threshold > - changed evbit and keybit with set_capability call > - changed variable names to error instead of ret > - checked errors for add_action_or_reset > - cosmetic cleaning > > Changes in v3: > - pressure now reported naturally growing down-up > - using helpers from touchscreen.h to parse DT properties > - added devm_add_action_or_reset to handle callback buffer clean on exit > - changed compatible and threshold property to adapt to changed bindings > > Changes in v2: > - this is now a generic resistive adc touchscreen driver > > drivers/input/touchscreen/Kconfig | 13 ++ > drivers/input/touchscreen/Makefile | 1 + > drivers/input/touchscreen/resistive-adc-touch.c | 204 ++++++++++++++++++++++++ > 3 files changed, 218 insertions(+) > create mode 100644 drivers/input/touchscreen/resistive-adc-touch.c > > diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig > index 4f15496..8f85d3a 100644 > --- a/drivers/input/touchscreen/Kconfig > +++ b/drivers/input/touchscreen/Kconfig > @@ -92,6 +92,19 @@ config TOUCHSCREEN_AD7879_SPI > To compile this driver as a module, choose M here: the > module will be called ad7879-spi. > > +config TOUCHSCREEN_ADC > + tristate "Generic ADC based resistive touchscreen" > + depends on IIO > + select IIO_BUFFER_CB > + help > + Say Y here if you want to use the generic ADC > + resistive touchscreen driver. > + > + If unsure, say N (but it's safe to say "Y"). > + > + To compile this driver as a module, choose M here: the > + module will be called resistive-adc-touch.ko. > + > config TOUCHSCREEN_AR1021_I2C > tristate "Microchip AR1020/1021 i2c touchscreen" > depends on I2C && OF > diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile > index dddae79..843c7f9 100644 > --- a/drivers/input/touchscreen/Makefile > +++ b/drivers/input/touchscreen/Makefile > @@ -13,6 +13,7 @@ obj-$(CONFIG_TOUCHSCREEN_AD7877) += ad7877.o > obj-$(CONFIG_TOUCHSCREEN_AD7879) += ad7879.o > obj-$(CONFIG_TOUCHSCREEN_AD7879_I2C) += ad7879-i2c.o > obj-$(CONFIG_TOUCHSCREEN_AD7879_SPI) += ad7879-spi.o > +obj-$(CONFIG_TOUCHSCREEN_ADC) += resistive-adc-touch.o > obj-$(CONFIG_TOUCHSCREEN_ADS7846) += ads7846.o > obj-$(CONFIG_TOUCHSCREEN_AR1021_I2C) += ar1021_i2c.o > obj-$(CONFIG_TOUCHSCREEN_ATMEL_MXT) += atmel_mxt_ts.o > diff --git a/drivers/input/touchscreen/resistive-adc-touch.c b/drivers/input/touchscreen/resistive-adc-touch.c > new file mode 100644 > index 0000000..cfc8bb4 > --- /dev/null > +++ b/drivers/input/touchscreen/resistive-adc-touch.c > @@ -0,0 +1,204 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * ADC generic resistive touchscreen (GRTS) > + * This is a generic input driver that connects to an ADC > + * given the channels in device tree, and reports events to the input > + * subsystem. > + * > + * Copyright (C) 2017,2018 Microchip Technology, > + * Author: Eugen Hristev <eugen.hristev@microchip.com> > + * > + */ > +#include <linux/input.h> > +#include <linux/input/touchscreen.h> > +#include <linux/iio/consumer.h> > +#include <linux/iio/iio.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/of_device.h> > +#include <linux/platform_device.h> > + > +#define DRIVER_NAME "resistive-adc-touch" > +#define GRTS_DEFAULT_PRESSURE_MIN 50000 > +#define GRTS_MAX_POS_MASK GENMASK(11, 0) > + > +/** > + * grts_state - generic resistive touch screen information struct > + * @pressure_min: number representing the minimum for the pressure > + * @pressure: are we getting pressure info or not > + * @iio_chans: list of channels acquired > + * @iio_cb: iio_callback buffer for the data > + * @input: the input device structure that we register > + * @prop: touchscreen properties struct > + */ > +struct grts_state { > + u32 pressure_min; > + bool pressure; > + struct iio_channel *iio_chans; > + struct iio_cb_buffer *iio_cb; > + struct input_dev *input; > + struct touchscreen_properties prop; > +}; > + > +static int grts_cb(const void *data, void *private) > +{ > + const u16 *touch_info = data; > + struct grts_state *st = private; > + unsigned int x, y, press = 0x0; > + > + /* channel data coming in buffer in the order below */ > + x = touch_info[0]; > + y = touch_info[1]; > + if (st->pressure) > + press = touch_info[2]; > + > + if ((!x && !y) || (st->pressure && (press < st->pressure_min))) { > + /* report end of touch */ > + input_report_key(st->input, BTN_TOUCH, 0); > + input_sync(st->input); > + return 0; > + } > + > + /* report proper touch to subsystem*/ > + touchscreen_report_pos(st->input, &st->prop, x, y, false); > + if (st->pressure) > + input_report_abs(st->input, ABS_PRESSURE, press); > + input_report_key(st->input, BTN_TOUCH, 1); > + input_sync(st->input); > + > + return 0; > +} > + > +static int grts_open(struct input_dev *dev) > +{ > + int error; > + struct grts_state *st = input_get_drvdata(dev); > + > + error = iio_channel_start_all_cb(st->iio_cb); > + if (error) { > + dev_err(dev->dev.parent, "failed to start callback buffer.\n"); > + return error; > + } > + return 0; > +} > + > +static void grts_close(struct input_dev *dev) > +{ > + struct grts_state *st = input_get_drvdata(dev); > + > + iio_channel_stop_all_cb(st->iio_cb); > +} > + > +static void grts_disable(void *data) > +{ > + iio_channel_release_all_cb(data); > +} > + > +static int grts_probe(struct platform_device *pdev) > +{ > + struct grts_state *st; > + struct input_dev *input; > + struct device *dev = &pdev->dev; > + struct iio_channel *chan; > + int error; > + > + st = devm_kzalloc(dev, sizeof(struct grts_state), GFP_KERNEL); > + if (!st) > + return -ENOMEM; > + > + /* get the channels from IIO device */ > + st->iio_chans = devm_iio_channel_get_all(dev); > + if (IS_ERR(st->iio_chans)) { > + error = PTR_ERR(st->iio_chans); > + if (error != -EPROBE_DEFER) > + dev_err(dev, "can't get iio channels.\n"); > + return error; > + } > + > + chan = &st->iio_chans[0]; > + st->pressure = false; > + while (chan && chan->indio_dev) { > + if (!strcmp(chan->channel->datasheet_name, "pressure")) > + st->pressure = true; > + chan++; > + } > + > + if (st->pressure) { > + error = device_property_read_u32(dev, > + "touchscreen-min-pressure", > + &st->pressure_min); > + if (error) { > + dev_dbg(dev, "can't get touchscreen-min-pressure property.\n"); > + st->pressure_min = GRTS_DEFAULT_PRESSURE_MIN; > + } > + } > + > + input = devm_input_allocate_device(dev); > + if (!input) { > + dev_err(dev, "failed to allocate input device.\n"); > + return -ENOMEM; > + } > + > + input->name = DRIVER_NAME; > + input->id.bustype = BUS_HOST; > + input->open = grts_open; > + input->close = grts_close; > + > + input_set_abs_params(input, ABS_X, 0, GRTS_MAX_POS_MASK - 1, 0, 0); > + input_set_abs_params(input, ABS_Y, 0, GRTS_MAX_POS_MASK - 1, 0, 0); > + if (st->pressure) > + input_set_abs_params(input, ABS_PRESSURE, st->pressure_min, > + 0xffff, 0, 0); > + > + input_set_capability(input, EV_KEY, BTN_TOUCH); > + > + /* parse optional device tree properties */ > + touchscreen_parse_properties(input, false, &st->prop); > + > + st->input = input; > + input_set_drvdata(input, st); > + > + error = input_register_device(input); > + if (error) { > + dev_err(dev, "failed to register input device."); > + return error; > + } > + > + st->iio_cb = iio_channel_get_all_cb(dev, grts_cb, st); > + if (IS_ERR(st->iio_cb)) { > + dev_err(dev, "failed to allocate callback buffer.\n"); > + return PTR_ERR(st->iio_cb); > + } > + > + error = devm_add_action_or_reset(dev, grts_disable, st->iio_cb); > + if (error) { > + dev_err(dev, "failed to add disable action.\n"); > + return error; > + } > + > + return 0; > +} > + > +static const struct of_device_id grts_of_match[] = { > + { > + .compatible = "resistive-adc-touch", > + }, { > + /* sentinel */ > + }, > +}; > + > +MODULE_DEVICE_TABLE(of, grts_of_match); > + > +static struct platform_driver grts_driver = { > + .probe = grts_probe, > + .driver = { > + .name = DRIVER_NAME, > + .of_match_table = of_match_ptr(grts_of_match), > + }, > +}; > + > +module_platform_driver(grts_driver); > + > +MODULE_AUTHOR("Eugen Hristev <eugen.hristev@microchip.com>"); > +MODULE_DESCRIPTION("Generic ADC Resistive Touch Driver"); > +MODULE_LICENSE("GPL v2"); -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig index 4f15496..8f85d3a 100644 --- a/drivers/input/touchscreen/Kconfig +++ b/drivers/input/touchscreen/Kconfig @@ -92,6 +92,19 @@ config TOUCHSCREEN_AD7879_SPI To compile this driver as a module, choose M here: the module will be called ad7879-spi. +config TOUCHSCREEN_ADC + tristate "Generic ADC based resistive touchscreen" + depends on IIO + select IIO_BUFFER_CB + help + Say Y here if you want to use the generic ADC + resistive touchscreen driver. + + If unsure, say N (but it's safe to say "Y"). + + To compile this driver as a module, choose M here: the + module will be called resistive-adc-touch.ko. + config TOUCHSCREEN_AR1021_I2C tristate "Microchip AR1020/1021 i2c touchscreen" depends on I2C && OF diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile index dddae79..843c7f9 100644 --- a/drivers/input/touchscreen/Makefile +++ b/drivers/input/touchscreen/Makefile @@ -13,6 +13,7 @@ obj-$(CONFIG_TOUCHSCREEN_AD7877) += ad7877.o obj-$(CONFIG_TOUCHSCREEN_AD7879) += ad7879.o obj-$(CONFIG_TOUCHSCREEN_AD7879_I2C) += ad7879-i2c.o obj-$(CONFIG_TOUCHSCREEN_AD7879_SPI) += ad7879-spi.o +obj-$(CONFIG_TOUCHSCREEN_ADC) += resistive-adc-touch.o obj-$(CONFIG_TOUCHSCREEN_ADS7846) += ads7846.o obj-$(CONFIG_TOUCHSCREEN_AR1021_I2C) += ar1021_i2c.o obj-$(CONFIG_TOUCHSCREEN_ATMEL_MXT) += atmel_mxt_ts.o diff --git a/drivers/input/touchscreen/resistive-adc-touch.c b/drivers/input/touchscreen/resistive-adc-touch.c new file mode 100644 index 0000000..cfc8bb4 --- /dev/null +++ b/drivers/input/touchscreen/resistive-adc-touch.c @@ -0,0 +1,204 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * ADC generic resistive touchscreen (GRTS) + * This is a generic input driver that connects to an ADC + * given the channels in device tree, and reports events to the input + * subsystem. + * + * Copyright (C) 2017,2018 Microchip Technology, + * Author: Eugen Hristev <eugen.hristev@microchip.com> + * + */ +#include <linux/input.h> +#include <linux/input/touchscreen.h> +#include <linux/iio/consumer.h> +#include <linux/iio/iio.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> + +#define DRIVER_NAME "resistive-adc-touch" +#define GRTS_DEFAULT_PRESSURE_MIN 50000 +#define GRTS_MAX_POS_MASK GENMASK(11, 0) + +/** + * grts_state - generic resistive touch screen information struct + * @pressure_min: number representing the minimum for the pressure + * @pressure: are we getting pressure info or not + * @iio_chans: list of channels acquired + * @iio_cb: iio_callback buffer for the data + * @input: the input device structure that we register + * @prop: touchscreen properties struct + */ +struct grts_state { + u32 pressure_min; + bool pressure; + struct iio_channel *iio_chans; + struct iio_cb_buffer *iio_cb; + struct input_dev *input; + struct touchscreen_properties prop; +}; + +static int grts_cb(const void *data, void *private) +{ + const u16 *touch_info = data; + struct grts_state *st = private; + unsigned int x, y, press = 0x0; + + /* channel data coming in buffer in the order below */ + x = touch_info[0]; + y = touch_info[1]; + if (st->pressure) + press = touch_info[2]; + + if ((!x && !y) || (st->pressure && (press < st->pressure_min))) { + /* report end of touch */ + input_report_key(st->input, BTN_TOUCH, 0); + input_sync(st->input); + return 0; + } + + /* report proper touch to subsystem*/ + touchscreen_report_pos(st->input, &st->prop, x, y, false); + if (st->pressure) + input_report_abs(st->input, ABS_PRESSURE, press); + input_report_key(st->input, BTN_TOUCH, 1); + input_sync(st->input); + + return 0; +} + +static int grts_open(struct input_dev *dev) +{ + int error; + struct grts_state *st = input_get_drvdata(dev); + + error = iio_channel_start_all_cb(st->iio_cb); + if (error) { + dev_err(dev->dev.parent, "failed to start callback buffer.\n"); + return error; + } + return 0; +} + +static void grts_close(struct input_dev *dev) +{ + struct grts_state *st = input_get_drvdata(dev); + + iio_channel_stop_all_cb(st->iio_cb); +} + +static void grts_disable(void *data) +{ + iio_channel_release_all_cb(data); +} + +static int grts_probe(struct platform_device *pdev) +{ + struct grts_state *st; + struct input_dev *input; + struct device *dev = &pdev->dev; + struct iio_channel *chan; + int error; + + st = devm_kzalloc(dev, sizeof(struct grts_state), GFP_KERNEL); + if (!st) + return -ENOMEM; + + /* get the channels from IIO device */ + st->iio_chans = devm_iio_channel_get_all(dev); + if (IS_ERR(st->iio_chans)) { + error = PTR_ERR(st->iio_chans); + if (error != -EPROBE_DEFER) + dev_err(dev, "can't get iio channels.\n"); + return error; + } + + chan = &st->iio_chans[0]; + st->pressure = false; + while (chan && chan->indio_dev) { + if (!strcmp(chan->channel->datasheet_name, "pressure")) + st->pressure = true; + chan++; + } + + if (st->pressure) { + error = device_property_read_u32(dev, + "touchscreen-min-pressure", + &st->pressure_min); + if (error) { + dev_dbg(dev, "can't get touchscreen-min-pressure property.\n"); + st->pressure_min = GRTS_DEFAULT_PRESSURE_MIN; + } + } + + input = devm_input_allocate_device(dev); + if (!input) { + dev_err(dev, "failed to allocate input device.\n"); + return -ENOMEM; + } + + input->name = DRIVER_NAME; + input->id.bustype = BUS_HOST; + input->open = grts_open; + input->close = grts_close; + + input_set_abs_params(input, ABS_X, 0, GRTS_MAX_POS_MASK - 1, 0, 0); + input_set_abs_params(input, ABS_Y, 0, GRTS_MAX_POS_MASK - 1, 0, 0); + if (st->pressure) + input_set_abs_params(input, ABS_PRESSURE, st->pressure_min, + 0xffff, 0, 0); + + input_set_capability(input, EV_KEY, BTN_TOUCH); + + /* parse optional device tree properties */ + touchscreen_parse_properties(input, false, &st->prop); + + st->input = input; + input_set_drvdata(input, st); + + error = input_register_device(input); + if (error) { + dev_err(dev, "failed to register input device."); + return error; + } + + st->iio_cb = iio_channel_get_all_cb(dev, grts_cb, st); + if (IS_ERR(st->iio_cb)) { + dev_err(dev, "failed to allocate callback buffer.\n"); + return PTR_ERR(st->iio_cb); + } + + error = devm_add_action_or_reset(dev, grts_disable, st->iio_cb); + if (error) { + dev_err(dev, "failed to add disable action.\n"); + return error; + } + + return 0; +} + +static const struct of_device_id grts_of_match[] = { + { + .compatible = "resistive-adc-touch", + }, { + /* sentinel */ + }, +}; + +MODULE_DEVICE_TABLE(of, grts_of_match); + +static struct platform_driver grts_driver = { + .probe = grts_probe, + .driver = { + .name = DRIVER_NAME, + .of_match_table = of_match_ptr(grts_of_match), + }, +}; + +module_platform_driver(grts_driver); + +MODULE_AUTHOR("Eugen Hristev <eugen.hristev@microchip.com>"); +MODULE_DESCRIPTION("Generic ADC Resistive Touch Driver"); +MODULE_LICENSE("GPL v2");