Re: [PATCH] Add touch screen input driver for TPS6507x family of multi-function chips.

[Kevin Hilman <khilman@deeprootsystems.com>]

Todd Fischer <todd.fischer@ridgerun.com> writes:

> The TPS6507x family of Texas Instruments power management ICs (pmic)
> are multi-function chips that include voltage regulation and touch
> screen controller capabilities.  This patch adds a touch screen
> input driver for the TPS6507x pmic.  There was an existing regulator
> driver.  Before the touch screen driver could be added, a multi-function
> device (MFD) driver was needed and the regulator driver modified to
> use the MDF driver.  Patches for these changes have been posted and
> reviewed.  The TPS6507x touch screen driver applies cleanly to the
> MFD GIT repo after the above referenced patches are applied.  If I
> should use a different approach for the touch screen driver, please
> let me know.
>
> Signed-off-by: Todd Fischer <todd.fischer@ridgerun.com>
> ---
>  arch/arm/mach-davinci/board-da850-evm.c |   12 +

Could you separate out the da850 board support from the driver please?

To avoid convlicts with other arch code, I will merge the board
support via davinci git after the driver is merged via the appropriate
subsystem tree.

Kevin

>  drivers/input/touchscreen/Kconfig       |   13 +
>  drivers/input/touchscreen/Makefile      |    1 +
>  drivers/input/touchscreen/tps6507x-ts.c |  400 +++++++++++++++++++++++++++++++
>  drivers/mfd/tps6507x.c                  |    3 +
>  include/linux/input/tps6507x-ts.h       |   24 ++
>  include/linux/mfd/tps6507x.h            |    2 +
>  7 files changed, 455 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/input/touchscreen/tps6507x-ts.c
>  create mode 100644 include/linux/input/tps6507x-ts.h
>
> diff --git a/arch/arm/mach-davinci/board-da850-evm.c b/arch/arm/mach-davinci/board-da850-evm.c
> index d059924..b3cbb32 100644
> --- a/arch/arm/mach-davinci/board-da850-evm.c
> +++ b/arch/arm/mach-davinci/board-da850-evm.c
> @@ -25,6 +25,8 @@
>  #include <linux/mtd/partitions.h>
>  #include <linux/mtd/physmap.h>
>  #include <linux/regulator/machine.h>
> +#include <linux/mfd/tps6507x.h>
> +#include <linux/input/tps6507x-ts.h>
>  
>  #include <asm/mach-types.h>
>  #include <asm/mach/arch.h>
> @@ -534,8 +536,18 @@ struct regulator_init_data tps65070_regulator_data[] = {
>  	},
>  };
>  
> +static struct touchscreen_init_data tps6507x_touchscreen_data = {
> +	.poll_period =  30,	/* ms between touch samples */
> +	.min_pressure = 0x30,	/* minimum pressure to trigger touch */
> +	.vref = 0,		/* turn off vref when not using A/D */
> +	.vendor = 0,		/* /sys/class/input/input?/id/vendor */
> +	.product = 65070,	/* /sys/class/input/input?/id/product */
> +	.version = 0x100,	/* /sys/class/input/input?/id/version */
> +};
> +
>  static struct tps6507x_board tps_board = {
>  	.tps6507x_pmic_init_data = &tps65070_regulator_data[0],
> +	.tps6507x_ts_init_data = &tps6507x_touchscreen_data,
>  };
>  
>  static struct i2c_board_info __initdata da850evm_tps65070_info[] = {
> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> index 8a8fa4d..6166aa8 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -594,4 +594,17 @@ config TOUCHSCREEN_PCAP
>  
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called pcap_ts.
> +
> +config TOUCHSCREEN_TPS6507X
> +	tristate "TPS6507x based touchscreens"
> +	depends on I2C
> +	help
> +	  Say Y here if you have a TPS6507x based touchscreen
> +	  controller.
> +
> +	  If unsure, say N.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called tps6507x_ts.
> +
>  endif
> diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
> index 7fef7d5..cfa83d0 100644
> --- a/drivers/input/touchscreen/Makefile
> +++ b/drivers/input/touchscreen/Makefile
> @@ -46,3 +46,4 @@ obj-$(CONFIG_TOUCHSCREEN_WM97XX_ATMEL)	+= atmel-wm97xx.o
>  obj-$(CONFIG_TOUCHSCREEN_WM97XX_MAINSTONE)	+= mainstone-wm97xx.o
>  obj-$(CONFIG_TOUCHSCREEN_WM97XX_ZYLONITE)	+= zylonite-wm97xx.o
>  obj-$(CONFIG_TOUCHSCREEN_W90X900)	+= w90p910_ts.o
> +obj-$(CONFIG_TOUCHSCREEN_TPS6507X)	+= tps6507x-ts.o
> diff --git a/drivers/input/touchscreen/tps6507x-ts.c b/drivers/input/touchscreen/tps6507x-ts.c
> new file mode 100644
> index 0000000..5de80a1
> --- /dev/null
> +++ b/drivers/input/touchscreen/tps6507x-ts.c
> @@ -0,0 +1,400 @@
> +/*
> + * drivers/input/touchscreen/tps6507x_ts.c
> + *
> + * Touchscreen driver for the tps6507x chip.
> + *
> + * Copyright (c) 2009 RidgeRun (todd.fischer@ridgerun.com)
> + *
> + * Credits:
> + *
> + *    Using code from tsc2007, MtekVision Co., Ltd.
> + *
> + * For licencing details see kernel-base/COPYING
> + *
> + * TPS65070, TPS65073, TPS650731, and TPS650732 support
> + * 10 bit touch screen interface.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/workqueue.h>
> +#include <linux/slab.h>
> +#include <linux/input.h>
> +#include <linux/platform_device.h>
> +#include <linux/mfd/tps6507x.h>
> +#include <linux/input/tps6507x-ts.h>
> +#include <linux/delay.h>
> +
> +#define TSC_DEFAULT_POLL_PERIOD 30 /* ms */
> +#define TPS_DEFAULT_MIN_PRESSURE 0x30
> +#define MAX_10BIT ((1 << 10) - 1)
> +
> +#define	TPS6507X_ADCONFIG_CONVERT_TS (TPS6507X_ADCONFIG_AD_ENABLE | \
> +					 TPS6507X_ADCONFIG_START_CONVERSION | \
> +					 TPS6507X_ADCONFIG_INPUT_REAL_TSC)
> +#define	TPS6507X_ADCONFIG_POWER_DOWN_TS (TPS6507X_ADCONFIG_INPUT_REAL_TSC)
> +
> +struct ts_event {
> +	u16	x;
> +	u16	y;
> +	u16	pressure;
> +};
> +
> +struct tps6507x_ts {
> +	struct input_dev	*input_dev;
> +	struct device		*dev;
> +	char			phys[32];
> +	struct workqueue_struct *wq;
> +	struct delayed_work	work;
> +	unsigned		polling;	/* polling is active */
> +	struct ts_event		tc;
> +	struct tps6507x_dev	*mfd;
> +	u16			model;
> +	unsigned		pendown;
> +	int			irq;
> +	void			(*clear_penirq)(void);
> +	unsigned long		poll_period;	/* ms */
> +	u16			min_pressure;
> +	int			vref;		/* non-zero to leave vref on */
> +};
> +
> +static int tps6507x_read_u8(struct tps6507x_ts *tsc, u8 reg, u8 *data)
> +{
> +	int err;
> +
> +	err = tsc->mfd->read_dev(tsc->mfd, reg, 1, data);
> +
> +	if (err)
> +		return err;
> +
> +	return 0;
> +}
> +
> +static int tps6507x_write_u8(struct tps6507x_ts *tsc, u8 reg, u8 data)
> +{
> +	return tsc->mfd->write_dev(tsc->mfd, reg, 1, &data);
> +}
> +
> +static s32 tps6507x_adc_conversion(struct tps6507x_ts *tsc,
> +				   u8 tsc_mode, u16 *value)
> +{
> +	s32 ret;
> +	u8 adc_status;
> +	u8 result;
> +
> +	/* Route input signal to A/D converter */
> +
> +	ret = tps6507x_write_u8(tsc, TPS6507X_REG_TSCMODE, tsc_mode);
> +	if (ret) {
> +		dev_err(tsc->dev, "TSC mode read failed\n");
> +		goto err;
> +	}
> +
> +	/* Start A/D conversion */
> +
> +	ret = tps6507x_write_u8(tsc, TPS6507X_REG_ADCONFIG,
> +				TPS6507X_ADCONFIG_CONVERT_TS);
> +	if (ret) {
> +		dev_err(tsc->dev, "ADC config write failed\n");
> +		return ret;
> +	}
> +
> +	do {
> +		ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADCONFIG,
> +				       &adc_status);
> +		if (ret) {
> +			dev_err(tsc->dev, "ADC config read failed\n");
> +			goto err;
> +		}
> +	} while (adc_status & TPS6507X_ADCONFIG_START_CONVERSION);
> +
> +	ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADRESULT_2, &result);
> +	if (ret) {
> +		dev_err(tsc->dev, "ADC result 2 read failed\n");
> +		goto err;
> +	}
> +
> +	*value = (result & TPS6507X_REG_ADRESULT_2_MASK) << 8;
> +
> +	ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADRESULT_1, &result);
> +	if (ret) {
> +		dev_err(tsc->dev, "ADC result 1 read failed\n");
> +		goto err;
> +	}
> +
> +	*value |= result;
> +
> +	dev_dbg(tsc->dev, "TSC channel %d = 0x%X\n", tsc_mode, *value);
> +
> +err:
> +	return ret;
> +}
> +
> +/* Need to call tps6507x_adc_standby() after using A/D converter for the
> + * touch screen interrupt to work properly.
> + */
> +
> +static s32 tps6507x_adc_standby(struct tps6507x_ts *tsc)
> +{
> +	s32 ret;
> +	s32 loops = 0;
> +	u8 val;
> +
> +	ret = tps6507x_write_u8(tsc,  TPS6507X_REG_ADCONFIG,
> +				TPS6507X_ADCONFIG_INPUT_TSC);
> +	if (ret)
> +		return ret;
> +
> +	ret = tps6507x_write_u8(tsc, TPS6507X_REG_TSCMODE,
> +				TPS6507X_TSCMODE_STANDBY);
> +	if (ret)
> +		return ret;
> +
> +	ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
> +	if (ret)
> +		return ret;
> +
> +	while (val & TPS6507X_REG_TSC_INT) {
> +		mdelay(10);
> +		ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
> +		if (ret)
> +			return ret;
> +		loops++;
> +	}
> +
> +	return ret;
> +}
> +
> +static void tps6507x_ts_handler(struct work_struct *work)
> +{
> +	struct tps6507x_ts *tsc =  container_of(work,
> +				struct tps6507x_ts, work.work);
> +	struct input_dev *input_dev = tsc->input_dev;
> +	int pendown;
> +	int schd;
> +	int poll = 0;
> +	s32 ret;
> +
> +	ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_PRESSURE,
> +				       &tsc->tc.pressure);
> +	if (ret)
> +		goto done;
> +
> +	pendown = tsc->tc.pressure > tsc->min_pressure;
> +
> +	if (unlikely(!pendown && tsc->pendown)) {
> +		dev_dbg(tsc->dev, "UP\n");
> +		input_report_key(input_dev, BTN_TOUCH, 0);
> +		input_report_abs(input_dev, ABS_PRESSURE, 0);
> +		input_sync(input_dev);
> +		tsc->pendown = 0;
> +	}
> +
> +	if (pendown) {
> +
> +		if (!tsc->pendown) {
> +			dev_dbg(tsc->dev, "DOWN\n");
> +			input_report_key(input_dev, BTN_TOUCH, 1);
> +		} else
> +			dev_dbg(tsc->dev, "still down\n");
> +
> +		ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_X_POSITION,
> +					       &tsc->tc.x);
> +		if (ret)
> +			goto done;
> +
> +		ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_Y_POSITION,
> +					       &tsc->tc.y);
> +		if (ret)
> +			goto done;
> +
> +		input_report_abs(input_dev, ABS_X, tsc->tc.x);
> +		input_report_abs(input_dev, ABS_Y, tsc->tc.y);
> +		input_report_abs(input_dev, ABS_PRESSURE, tsc->tc.pressure);
> +		input_sync(input_dev);
> +		tsc->pendown = 1;
> +		poll = 1;
> +	}
> +
> +done:
> +	/* always poll if not using interrupts */
> +	poll = 1;
> +
> +	if (poll) {
> +		schd = queue_delayed_work(tsc->wq, &tsc->work,
> +					  tsc->poll_period * HZ / 1000);
> +		if (schd)
> +			tsc->polling = 1;
> +		else {
> +			tsc->polling = 0;
> +			dev_err(tsc->dev, "re-schedule failed");
> +		}
> +	} else
> +		tsc->polling = 0;
> +
> +	ret = tps6507x_adc_standby(tsc);
> +}
> +
> +static int tps6507x_ts_probe(struct platform_device *pdev)
> +{
> +	int error;
> +	struct tps6507x_ts *tsc;
> +	struct tps6507x_dev *tps6507x_dev = dev_get_drvdata(pdev->dev.parent);
> +	struct touchscreen_init_data *init_data;
> +	struct input_dev *input_dev;
> +	struct tps6507x_board *tps_board;
> +	int schd;
> +
> +	/**
> +	 * tps_board points to pmic related constants
> +	 * coming from the board-evm file.
> +	 */
> +
> +	tps_board = (struct tps6507x_board *)tps6507x_dev->dev->platform_data;
> +
> +	if (!tps_board) {
> +		dev_err(tps6507x_dev->dev,
> +			"Could not find tps6507x platform data\n");
> +		return -EIO;
> +	}
> +
> +	/**
> +	 * init_data points to array of regulator_init structures
> +	 * coming from the board-evm file.
> +	 */
> +
> +	init_data = tps_board->tps6507x_ts_init_data;
> +
> +	tsc = kzalloc(sizeof(struct tps6507x_ts), GFP_KERNEL);
> +	if (!tsc) {
> +		dev_err(tps6507x_dev->dev, "failed to allocate driver data\n");
> +		error = -ENOMEM;
> +		goto err0;
> +	}
> +
> +	tps6507x_dev->ts = tsc;
> +	tsc->mfd = tps6507x_dev;
> +	tsc->dev = tps6507x_dev->dev;
> +	input_dev = input_allocate_device();
> +	if (!input_dev) {
> +		dev_err(tsc->dev, "Failed to allocate input device.\n");
> +		error = -ENOMEM;
> +		goto err1;
> +	}
> +
> +	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
> +	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
> +
> +	input_set_abs_params(input_dev, ABS_X, 0, MAX_10BIT, 0, 0);
> +	input_set_abs_params(input_dev, ABS_Y, 0, MAX_10BIT, 0, 0);
> +	input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_10BIT, 0, 0);
> +
> +	input_dev->name = "TPS6507x Touchscreen";
> +	input_dev->id.bustype = BUS_I2C;
> +	input_dev->dev.parent = tsc->dev;
> +
> +	snprintf(tsc->phys, sizeof(tsc->phys),
> +		 "%s/input0", dev_name(tsc->dev));
> +	input_dev->phys = tsc->phys;
> +
> +	dev_dbg(tsc->dev, "device: %s\n", input_dev->phys);
> +
> +	input_set_drvdata(input_dev, tsc);
> +
> +	tsc->input_dev = input_dev;
> +
> +	INIT_DELAYED_WORK(&tsc->work, tps6507x_ts_handler);
> +	tsc->wq = create_workqueue("TPS6507x Touchscreen");
> +
> +	if (init_data) {
> +		tsc->poll_period = init_data->poll_period;
> +		tsc->vref = init_data->vref;
> +		tsc->min_pressure = init_data->min_pressure;
> +		input_dev->id.vendor = init_data->vendor;
> +		input_dev->id.product = init_data->product;
> +		input_dev->id.version = init_data->version;
> +	} else {
> +		tsc->poll_period = TSC_DEFAULT_POLL_PERIOD;
> +		tsc->min_pressure = TPS_DEFAULT_MIN_PRESSURE;
> +	}
> +
> +	error = tps6507x_adc_standby(tsc);
> +	if (error)
> +		goto err2;
> +
> +	error = input_register_device(input_dev);
> +	if (error)
> +		goto err2;
> +
> +	schd = queue_delayed_work(tsc->wq, &tsc->work,
> +				  tsc->poll_period * HZ / 1000);
> +
> +	if (schd)
> +		tsc->polling = 1;
> +	else {
> +		tsc->polling = 0;
> +		dev_err(tsc->dev, "schedule failed");
> +		goto err2;
> +	 }
> +
> +	return 0;
> +
> +err2:
> +	cancel_delayed_work(&tsc->work);
> +	flush_workqueue(tsc->wq);
> +	destroy_workqueue(tsc->wq);
> +	tsc->wq = 0;
> +	input_free_device(input_dev);
> +err1:
> +	kfree(tsc);
> +	tps6507x_dev->ts = NULL;
> +err0:
> +	return error;
> +}
> +
> +static int __devexit tps6507x_ts_remove(struct platform_device *pdev)
> +{
> +	struct tps6507x_dev *tps6507x_dev = platform_get_drvdata(pdev);
> +	struct tps6507x_ts *tsc = tps6507x_dev->ts;
> +	struct input_dev *input_dev = tsc->input_dev;
> +
> +	if (!tsc)
> +		return 0;
> +
> +	cancel_delayed_work(&tsc->work);
> +	flush_workqueue(tsc->wq);
> +	destroy_workqueue(tsc->wq);
> +	tsc->wq = 0;
> +
> +	input_free_device(input_dev);
> +
> +	tps6507x_dev->ts = NULL;
> +	kfree(tsc);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver tps6507x_ts_driver = {
> +	.driver = {
> +		.name = "tps6507x-ts",
> +		.owner = THIS_MODULE,
> +	},
> +	.probe = tps6507x_ts_probe,
> +	.remove = __devexit_p(tps6507x_ts_remove),
> +};
> +
> +static int __init tps6507x_ts_init(void)
> +{
> +	return platform_driver_register(&tps6507x_ts_driver);
> +}
> +module_init(tps6507x_ts_init);
> +
> +static void __exit tps6507x_ts_exit(void)
> +{
> +	platform_driver_unregister(&tps6507x_ts_driver);
> +}
> +module_exit(tps6507x_ts_exit);
> +
> +MODULE_AUTHOR("Todd Fischer <todd.fischer@ridgerun.com>");
> +MODULE_DESCRIPTION("TPS6507x - TouchScreen driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:tps6507x-tsc");
> diff --git a/drivers/mfd/tps6507x.c b/drivers/mfd/tps6507x.c
> index edda9ff..d05c52d 100644
> --- a/drivers/mfd/tps6507x.c
> +++ b/drivers/mfd/tps6507x.c
> @@ -25,6 +25,9 @@ static struct mfd_cell tps6507x_devs[] = {
>  	{
>  		.name = "tps6507x-pmic",
>  	},
> +	{
> +		.name = "tps6507x-ts",
> +	},
>  };
>  
>  
> diff --git a/include/linux/input/tps6507x-ts.h b/include/linux/input/tps6507x-ts.h
> new file mode 100644
> index 0000000..ab14403
> --- /dev/null
> +++ b/include/linux/input/tps6507x-ts.h
> @@ -0,0 +1,24 @@
> +/* linux/i2c/tps6507x-ts.h
> + *
> + * Functions to access TPS65070 touch screen chip.
> + *
> + * Copyright (c) 2009 RidgeRun (todd.fischer@ridgerun.com)
> + *
> + *
> + *  For licencing details see kernel-base/COPYING
> + */
> +
> +#ifndef __LINUX_I2C_TPS6507X_TS_H
> +#define __LINUX_I2C_TPS6507X_TS_H
> +
> +/* Board specific touch screen initial values */
> +struct touchscreen_init_data {
> +	int	poll_period;	/* ms */
> +	int	vref;		/* non-zero to leave vref on */
> +	__u16	min_pressure;	/* min reading to be treated as a touch */
> +	__u16	vendor;
> +	__u16	product;
> +	__u16	version;
> +};
> +
> +#endif /*  __LINUX_I2C_TPS6507X_TS_H */
> diff --git a/include/linux/mfd/tps6507x.h b/include/linux/mfd/tps6507x.h
> index 9543cb7..c923e48 100644
> --- a/include/linux/mfd/tps6507x.h
> +++ b/include/linux/mfd/tps6507x.h
> @@ -142,6 +142,7 @@
>  
>  struct tps6507x_board {
>  	struct regulator_init_data *tps6507x_pmic_init_data;
> +	struct touchscreen_init_data *tps6507x_ts_init_data;
>  };
>  
>  /**
> @@ -162,6 +163,7 @@ struct tps6507x_dev {
>  
>  	/* Client devices */
>  	struct tps6507x_pmic *pmic;
> +	struct tps6507x_ts *ts;
>  };
>  
>  #endif /*  __LINUX_MFD_TPS6507X_H */
> -- 
> 1.6.0.4
>
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