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Commit 7c6d0ee1 authored by David Brownell's avatar David Brownell Committed by Dmitry Torokhov
Browse files

Input: ads7846 - simplify support of external vREF (and ads7843) 



This updates the ads7846 driver to handle external vREF (required
on boards using ads7843 chips) without module parameters, and also
removes a needless variable with its associated bogus gcc warning.

Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent e6cdd156

drivers/input/touchscreen/ads7846.c

+10 −12
Original line number Diff line number Diff line
@@ -87,6 +87,7 @@ struct ads7846 { 
#endif



	u16			model;

	u16			vref_mv;

	u16			vref_delay_usecs;

	u16			x_plate_ohms;

	u16			pressure_max;
@@ -184,9 +185,6 @@ struct ads7846 { 
 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;

 * ads7846 lets that pin be unconnected, to use internal vREF.

 */

static unsigned vREF_mV;

module_param(vREF_mV, uint, 0);

MODULE_PARM_DESC(vREF_mV, "external vREF voltage, in milliVolts");



struct ser_req {

	u8			ref_on;
@@ -213,7 +211,6 @@ static int ads7846_read12_ser(struct device *dev, unsigned command) 
	struct ads7846		*ts = dev_get_drvdata(dev);

	struct ser_req		*req = kzalloc(sizeof *req, GFP_KERNEL);

	int			status;

	int			uninitialized_var(sample);

	int			use_internal;



	if (!req)
@@ -270,13 +267,13 @@ static int ads7846_read12_ser(struct device *dev, unsigned command) 


	if (status == 0) {

		/* on-wire is a must-ignore bit, a BE12 value, then padding */

		sample = be16_to_cpu(req->sample);

		sample = sample >> 3;

		sample &= 0x0fff;

		status = be16_to_cpu(req->sample);

		status = status >> 3;

		status &= 0x0fff;

	}



	kfree(req);

	return status ? status : sample;

	return status;

}



#if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
@@ -317,7 +314,7 @@ static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v) 
	unsigned retval = v;



	/* external resistors may scale vAUX into 0..vREF */

	retval *= vREF_mV;

	retval *= ts->vref_mv;

	retval = retval >> 12;

	return retval;

}
@@ -375,14 +372,14 @@ static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts) 
	/* hwmon sensors need a reference voltage */

	switch (ts->model) {

	case 7846:

		if (!vREF_mV) {

		if (!ts->vref_mv) {

			dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");

			vREF_mV = 2500;

			ts->vref_mv = 2500;

		}

		break;

	case 7845:

	case 7843:

		if (!vREF_mV) {

		if (!ts->vref_mv) {

			dev_warn(&spi->dev,

				"external vREF for ADS%d not specified\n",

				ts->model);
@@ -875,6 +872,7 @@ static int __devinit ads7846_probe(struct spi_device *spi) 


	ts->spi = spi;

	ts->input = input_dev;

	ts->vref_mv = pdata->vref_mv;



	hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);

	ts->timer.function = ads7846_timer;

include/linux/spi/ads7846.h

+2 −1
Original line number Diff line number Diff line
@@ -14,7 +14,8 @@ enum ads7846_filter { 
struct ads7846_platform_data {

	u16	model;			/* 7843, 7845, 7846. */

	u16	vref_delay_usecs;	/* 0 for external vref; etc */

	int	keep_vref_on:1;		/* set to keep vref on for differential

	u16	vref_mv;		/* external vref value, milliVolts */

	bool	keep_vref_on;		/* set to keep vref on for differential

					 * measurements as well */



	/* Settling time of the analog signals; a function of Vcc and the