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Commit 53a0ef89 authored by Imre Deak's avatar Imre Deak Committed by Dmitry Torokhov
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Input: ads7846 - power down ADC a bit later 



Submit a seperate request for powering down the ADC in ads7846,
doing it after the last read request.  Otherwise some of the read
values are incorrect.

Signed-off-by: default avatarImre Deak <imre.deak@nokia.com>
Signed-off-by: default avatarJuha Yrjola <juha.yrjola@nokia.com>
Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent 438f2a74

drivers/input/touchscreen/ads7846.c

+18 −3
Original line number Diff line number Diff line
@@ -72,10 +72,11 @@ struct ads7846 { 
	u16			vref_delay_usecs;

	u16			x_plate_ohms;



	u8			read_x, read_y, read_z1, read_z2;

	u8			read_x, read_y, read_z1, read_z2, pwrdown;

	u16			dummy;		/* for the pwrdown read */

	struct ts_event		tc;



	struct spi_transfer	xfer[8];

	struct spi_transfer	xfer[10];

	struct spi_message	msg;



	spinlock_t		lock;
@@ -125,7 +126,9 @@ struct ads7846 { 
#define	READ_Y	(READ_12BIT_DFR(y)  | ADS_PD10_ADC_ON)

#define	READ_Z1	(READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON)

#define	READ_Z2	(READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON)

#define	READ_X	(READ_12BIT_DFR(x)  | ADS_PD10_PDOWN)	/* LAST */



#define	READ_X	(READ_12BIT_DFR(x)  | ADS_PD10_ADC_ON)

#define	PWRDOWN	(READ_12BIT_DFR(y)  | ADS_PD10_PDOWN)	/* LAST */



/* single-ended samples need to first power up reference voltage;

 * we leave both ADC and VREF powered
@@ -541,6 +544,18 @@ static int __devinit ads7846_probe(struct spi_device *spi) 
	x++;

	x->rx_buf = &ts->tc.x;

	x->len = 2;

	spi_message_add_tail(x, &ts->msg);



	/* power down */

	x++;

	ts->pwrdown = PWRDOWN;

	x->tx_buf = &ts->pwrdown;

	x->len = 1;

	spi_message_add_tail(x, &ts->msg);



	x++;

	x->rx_buf = &ts->dummy;

	x->len = 2;

	CS_CHANGE(*x);

	spi_message_add_tail(x, &ts->msg);