| Message ID | 1526898477-9952-7-git-send-email-eugen.hristev@microchip.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, May 21, 2018 at 01:27:54PM +0300, Eugen Hristev 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> I assume this will go through IIO tree? Just a couple of comsmetic comments below, feel free to ignore. > --- > 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 | 201 ++++++++++++++++++++++++ > 3 files changed, 215 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..05d629b > --- /dev/null > +++ b/drivers/input/touchscreen/resistive-adc-touch.c > @@ -0,0 +1,201 @@ > +// 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; > + > + 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; > + } I do not think it makes sense to complain about missing property if there is no "pressure" channel. Probably move down? > + > + /* get the channels from IIO device */ > + st->iio_chans = devm_iio_channel_get_all(dev); > + if (IS_ERR(st->iio_chans)) { > + if (PTR_ERR(st->iio_chans) != -EPROBE_DEFER) > + dev_err(dev, "can't get iio channels.\n"); > + return PTR_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++; > + } > + > + 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"); > + error = PTR_ERR(st->iio_cb); > + return error; Simply: return PTR_ERR(st->iio_cb); since you opted out of printing error codes in error messages. > + } > + > + 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"); > -- > 2.7.4 > Thanks.
On 22.05.2018 00:06, Dmitry Torokhov wrote: > On Mon, May 21, 2018 at 01:27:54PM +0300, Eugen Hristev 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> > > I assume this will go through IIO tree? Just a couple of comsmetic > comments below, feel free to ignore. Thank you, I modified as you suggested and sent out v7. Jonathan said in an earlier e-mail that he will take them through IIO tree. Waiting on his feedback. Eugen > >> --- >> 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 | 201 ++++++++++++++++++++++++ >> 3 files changed, 215 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..05d629b >> --- /dev/null >> +++ b/drivers/input/touchscreen/resistive-adc-touch.c >> @@ -0,0 +1,201 @@ >> +// 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; >> + >> + 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; >> + } > > I do not think it makes sense to complain about missing property if > there is no "pressure" channel. Probably move down? > >> + >> + /* get the channels from IIO device */ >> + st->iio_chans = devm_iio_channel_get_all(dev); >> + if (IS_ERR(st->iio_chans)) { >> + if (PTR_ERR(st->iio_chans) != -EPROBE_DEFER) >> + dev_err(dev, "can't get iio channels.\n"); >> + return PTR_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++; >> + } >> + >> + 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"); >> + error = PTR_ERR(st->iio_cb); >> + return error; > > Simply: > > return PTR_ERR(st->iio_cb); > > since you opted out of printing error codes in error messages. > >> + } >> + >> + 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"); >> -- >> 2.7.4 >> > > Thanks. > -- To unsubscribe from this list: send the line "unsubscribe linux-input" 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..05d629b --- /dev/null +++ b/drivers/input/touchscreen/resistive-adc-touch.c @@ -0,0 +1,201 @@ +// 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; + + 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; + } + + /* get the channels from IIO device */ + st->iio_chans = devm_iio_channel_get_all(dev); + if (IS_ERR(st->iio_chans)) { + if (PTR_ERR(st->iio_chans) != -EPROBE_DEFER) + dev_err(dev, "can't get iio channels.\n"); + return PTR_ERR(st->iio_chans); + } + + chan = &st->iio_chans[0]; + st->pressure = false; + while (chan && chan->indio_dev) { + if (!strcmp(chan->channel->datasheet_name, "pressure")) + st->pressure = true; + chan++; + } + + 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"); + error = PTR_ERR(st->iio_cb); + return error; + } + + 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");
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> --- 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 | 201 ++++++++++++++++++++++++ 3 files changed, 215 insertions(+) create mode 100644 drivers/input/touchscreen/resistive-adc-touch.c