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| author | Imre Deak <imre.deak@nokia.com> | 2006-04-11 23:41:49 -0400 |
|---|---|---|
| committer | Dmitry Torokhov <dtor_core@ameritech.net> | 2006-04-11 23:41:49 -0400 |
| commit | 53a0ef89e95c725f3faab98573770aeb7429c1a3 (patch) | |
| tree | 66d9258d53621f86ac686f768d17885404edced6 /drivers/input/touchscreen/ads7846.c | |
| parent | 438f2a7401ec5d8f85923a7c3e6da444f097a3a1 (diff) | |
| download | lwn-53a0ef89e95c725f3faab98573770aeb7429c1a3.tar.gz lwn-53a0ef89e95c725f3faab98573770aeb7429c1a3.zip | |
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>
Diffstat (limited to 'drivers/input/touchscreen/ads7846.c')
| -rw-r--r-- | drivers/input/touchscreen/ads7846.c | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c index 7f384a694d80..54d433477860 100644 --- a/drivers/input/touchscreen/ads7846.c +++ b/drivers/input/touchscreen/ads7846.c @@ -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); |