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Commit ebcaaad9 authored by Alexander Stein's avatar Alexander Stein Committed by Dmitry Torokhov
Browse files

Input: ads7846 - add possibility to use external vref on ads7846 



Just set vref_mv in your platform config to use external vref. Otherwise
the internal one is used.

Signed-off-by: default avatarAlexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent e70bdd41

drivers/input/touchscreen/ads7846.c

+11 −8
Original line number Diff line number Diff line
@@ -109,6 +109,7 @@ struct ads7846 { 
	u16			pressure_max;



	bool			swap_xy;

	bool			use_internal;



	struct ads7846_packet	*packet;
@@ -300,7 +301,6 @@ static int ads7846_read12_ser(struct device *dev, unsigned command) 
	struct ads7846 *ts = dev_get_drvdata(dev);

	struct ser_req *req;

	int status;

	int use_internal;



	req = kzalloc(sizeof *req, GFP_KERNEL);

	if (!req)
@@ -308,11 +308,8 @@ static int ads7846_read12_ser(struct device *dev, unsigned command) 


	spi_message_init(&req->msg);



	/* FIXME boards with ads7846 might use external vref instead ... */

	use_internal = (ts->model == 7846);



	/* maybe turn on internal vREF, and let it settle */

	if (use_internal) {

	if (ts->use_internal) {

		req->ref_on = REF_ON;

		req->xfer[0].tx_buf = &req->ref_on;

		req->xfer[0].len = 1;
@@ -324,8 +321,14 @@ static int ads7846_read12_ser(struct device *dev, unsigned command) 
		/* for 1uF, settle for 800 usec; no cap, 100 usec.  */

		req->xfer[1].delay_usecs = ts->vref_delay_usecs;

		spi_message_add_tail(&req->xfer[1], &req->msg);



		/* Enable reference voltage */

		command |= ADS_PD10_REF_ON;

	}



	/* Enable ADC in every case */

	command |= ADS_PD10_ADC_ON;



	/* take sample */

	req->command = (u8) command;

	req->xfer[2].tx_buf = &req->command;
@@ -409,7 +412,7 @@ name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \ 
{ \

	struct ads7846 *ts = dev_get_drvdata(dev); \

	ssize_t v = ads7846_read12_ser(dev, \

			READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \

			READ_12BIT_SER(var)); \

	if (v < 0) \

		return v; \

	return sprintf(buf, "%u\n", adjust(ts, v)); \
@@ -502,6 +505,7 @@ static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts) 
		if (!ts->vref_mv) {

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

			ts->vref_mv = 2500;

			ts->use_internal = true;

		}

		break;

	case 7845:
@@ -1333,8 +1337,7 @@ static int __devinit ads7846_probe(struct spi_device *spi) 
	if (ts->model == 7845)

		ads7845_read12_ser(&spi->dev, PWRDOWN);

	else

		(void) ads7846_read12_ser(&spi->dev,

				READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);

		(void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));



	err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);

	if (err)

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, 7873. */

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

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

	u16	vref_mv;		/* external vref value, milliVolts

					 * ads7846: if 0, use internal vref */

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

					 * measurements as well */

	bool	swap_xy;		/* swap x and y axes */