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: Imre Deak <imre.deak@nokia.com>
Signed-off-by: Juha Yrjola <juha.yrjola@nokia.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index 7f384a6..54d4334 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -72,10 +72,11 @@
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 @@
#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 @@
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);