diff options
| -rw-r--r-- | drivers/input/touchscreen/ads7846.c | 30 | ||||
| -rw-r--r-- | include/linux/spi/ads7846.h | 2 |
2 files changed, 19 insertions, 13 deletions
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c index 03e527c16c2..c34e59b720a 100644 --- a/drivers/input/touchscreen/ads7846.c +++ b/drivers/input/touchscreen/ads7846.c @@ -145,15 +145,16 @@ struct ads7846 { #define MAX_12BIT ((1<<12)-1) /* leave ADC powered up (disables penirq) between differential samples */ -#define READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \ - | ADS_12_BIT | ADS_DFR) +#define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \ + | ADS_12_BIT | ADS_DFR | \ + (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0)) -#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_Y(vref) (READ_12BIT_DFR(y, 1, vref)) +#define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref)) +#define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref)) -#define READ_X (READ_12BIT_DFR(x) | ADS_PD10_ADC_ON) -#define PWRDOWN (READ_12BIT_DFR(y) | ADS_PD10_PDOWN) /* LAST */ +#define READ_X(vref) (READ_12BIT_DFR(x, 1, vref)) +#define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */ /* single-ended samples need to first power up reference voltage; * we leave both ADC and VREF powered @@ -161,8 +162,8 @@ struct ads7846 { #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \ | ADS_12_BIT | ADS_SER) -#define REF_ON (READ_12BIT_DFR(x) | ADS_PD10_ALL_ON) -#define REF_OFF (READ_12BIT_DFR(y) | ADS_PD10_PDOWN) +#define REF_ON (READ_12BIT_DFR(x, 1, 1)) +#define REF_OFF (READ_12BIT_DFR(y, 0, 0)) /*--------------------------------------------------------------------------*/ @@ -670,6 +671,7 @@ static int __devinit ads7846_probe(struct spi_device *spi) struct ads7846_platform_data *pdata = spi->dev.platform_data; struct spi_message *m; struct spi_transfer *x; + int vref; int err; if (!spi->irq) { @@ -767,6 +769,8 @@ static int __devinit ads7846_probe(struct spi_device *spi) input_set_abs_params(input_dev, ABS_PRESSURE, pdata->pressure_min, pdata->pressure_max, 0, 0); + vref = pdata->keep_vref_on; + /* set up the transfers to read touchscreen state; this assumes we * use formula #2 for pressure, not #3. */ @@ -776,7 +780,7 @@ static int __devinit ads7846_probe(struct spi_device *spi) spi_message_init(m); /* y- still on; turn on only y+ (and ADC) */ - ts->read_y = READ_Y; + ts->read_y = READ_Y(vref); x->tx_buf = &ts->read_y; x->len = 1; spi_message_add_tail(x, m); @@ -794,7 +798,7 @@ static int __devinit ads7846_probe(struct spi_device *spi) /* turn y- off, x+ on, then leave in lowpower */ x++; - ts->read_x = READ_X; + ts->read_x = READ_X(vref); x->tx_buf = &ts->read_x; x->len = 1; spi_message_add_tail(x, m); @@ -813,7 +817,7 @@ static int __devinit ads7846_probe(struct spi_device *spi) spi_message_init(m); x++; - ts->read_z1 = READ_Z1; + ts->read_z1 = READ_Z1(vref); x->tx_buf = &ts->read_z1; x->len = 1; spi_message_add_tail(x, m); @@ -830,7 +834,7 @@ static int __devinit ads7846_probe(struct spi_device *spi) spi_message_init(m); x++; - ts->read_z2 = READ_Z2; + ts->read_z2 = READ_Z2(vref); x->tx_buf = &ts->read_z2; x->len = 1; spi_message_add_tail(x, m); diff --git a/include/linux/spi/ads7846.h b/include/linux/spi/ads7846.h index 1663f940ca1..3387e44dfd1 100644 --- a/include/linux/spi/ads7846.h +++ b/include/linux/spi/ads7846.h @@ -14,6 +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 + * measurements as well */ u16 x_plate_ohms; u16 y_plate_ohms; |