diff options
author | Imre Deak <imre.deak@solidboot.com> | 2007-01-18 00:45:21 -0500 |
---|---|---|
committer | Dmitry Torokhov <dtor@insightbb.com> | 2007-01-18 00:45:21 -0500 |
commit | de2defd96d7d92fe8b5f9cf2bfd385d8d4819923 (patch) | |
tree | 191349b9480dca988f6d776db0a0b00ff10bffca /drivers/input | |
parent | da970e69efb9fd0be0c23ace5bde42d4caf17b40 (diff) |
Input: ads7846 - optionally leave Vref on during differential measurements
On some LCDs leaving the Vref on provides much better readings.
Signed-off-by: Jarkko Oikarinen <jarkko.oikarinen@nokia.com>
Signed-off-by: Imre Deak <imre.deak@solidboot.com>
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Diffstat (limited to 'drivers/input')
-rw-r--r-- | drivers/input/touchscreen/ads7846.c | 30 |
1 files changed, 17 insertions, 13 deletions
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c index 03e527c16c23..c34e59b720a6 100644 --- a/drivers/input/touchscreen/ads7846.c +++ b/drivers/input/touchscreen/ads7846.c | |||
@@ -145,15 +145,16 @@ struct ads7846 { | |||
145 | #define MAX_12BIT ((1<<12)-1) | 145 | #define MAX_12BIT ((1<<12)-1) |
146 | 146 | ||
147 | /* leave ADC powered up (disables penirq) between differential samples */ | 147 | /* leave ADC powered up (disables penirq) between differential samples */ |
148 | #define READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \ | 148 | #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \ |
149 | | ADS_12_BIT | ADS_DFR) | 149 | | ADS_12_BIT | ADS_DFR | \ |
150 | (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0)) | ||
150 | 151 | ||
151 | #define READ_Y (READ_12BIT_DFR(y) | ADS_PD10_ADC_ON) | 152 | #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref)) |
152 | #define READ_Z1 (READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON) | 153 | #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref)) |
153 | #define READ_Z2 (READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON) | 154 | #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref)) |
154 | 155 | ||
155 | #define READ_X (READ_12BIT_DFR(x) | ADS_PD10_ADC_ON) | 156 | #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref)) |
156 | #define PWRDOWN (READ_12BIT_DFR(y) | ADS_PD10_PDOWN) /* LAST */ | 157 | #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */ |
157 | 158 | ||
158 | /* single-ended samples need to first power up reference voltage; | 159 | /* single-ended samples need to first power up reference voltage; |
159 | * we leave both ADC and VREF powered | 160 | * we leave both ADC and VREF powered |
@@ -161,8 +162,8 @@ struct ads7846 { | |||
161 | #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \ | 162 | #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \ |
162 | | ADS_12_BIT | ADS_SER) | 163 | | ADS_12_BIT | ADS_SER) |
163 | 164 | ||
164 | #define REF_ON (READ_12BIT_DFR(x) | ADS_PD10_ALL_ON) | 165 | #define REF_ON (READ_12BIT_DFR(x, 1, 1)) |
165 | #define REF_OFF (READ_12BIT_DFR(y) | ADS_PD10_PDOWN) | 166 | #define REF_OFF (READ_12BIT_DFR(y, 0, 0)) |
166 | 167 | ||
167 | /*--------------------------------------------------------------------------*/ | 168 | /*--------------------------------------------------------------------------*/ |
168 | 169 | ||
@@ -670,6 +671,7 @@ static int __devinit ads7846_probe(struct spi_device *spi) | |||
670 | struct ads7846_platform_data *pdata = spi->dev.platform_data; | 671 | struct ads7846_platform_data *pdata = spi->dev.platform_data; |
671 | struct spi_message *m; | 672 | struct spi_message *m; |
672 | struct spi_transfer *x; | 673 | struct spi_transfer *x; |
674 | int vref; | ||
673 | int err; | 675 | int err; |
674 | 676 | ||
675 | if (!spi->irq) { | 677 | if (!spi->irq) { |
@@ -767,6 +769,8 @@ static int __devinit ads7846_probe(struct spi_device *spi) | |||
767 | input_set_abs_params(input_dev, ABS_PRESSURE, | 769 | input_set_abs_params(input_dev, ABS_PRESSURE, |
768 | pdata->pressure_min, pdata->pressure_max, 0, 0); | 770 | pdata->pressure_min, pdata->pressure_max, 0, 0); |
769 | 771 | ||
772 | vref = pdata->keep_vref_on; | ||
773 | |||
770 | /* set up the transfers to read touchscreen state; this assumes we | 774 | /* set up the transfers to read touchscreen state; this assumes we |
771 | * use formula #2 for pressure, not #3. | 775 | * use formula #2 for pressure, not #3. |
772 | */ | 776 | */ |
@@ -776,7 +780,7 @@ static int __devinit ads7846_probe(struct spi_device *spi) | |||
776 | spi_message_init(m); | 780 | spi_message_init(m); |
777 | 781 | ||
778 | /* y- still on; turn on only y+ (and ADC) */ | 782 | /* y- still on; turn on only y+ (and ADC) */ |
779 | ts->read_y = READ_Y; | 783 | ts->read_y = READ_Y(vref); |
780 | x->tx_buf = &ts->read_y; | 784 | x->tx_buf = &ts->read_y; |
781 | x->len = 1; | 785 | x->len = 1; |
782 | spi_message_add_tail(x, m); | 786 | spi_message_add_tail(x, m); |
@@ -794,7 +798,7 @@ static int __devinit ads7846_probe(struct spi_device *spi) | |||
794 | 798 | ||
795 | /* turn y- off, x+ on, then leave in lowpower */ | 799 | /* turn y- off, x+ on, then leave in lowpower */ |
796 | x++; | 800 | x++; |
797 | ts->read_x = READ_X; | 801 | ts->read_x = READ_X(vref); |
798 | x->tx_buf = &ts->read_x; | 802 | x->tx_buf = &ts->read_x; |
799 | x->len = 1; | 803 | x->len = 1; |
800 | spi_message_add_tail(x, m); | 804 | spi_message_add_tail(x, m); |
@@ -813,7 +817,7 @@ static int __devinit ads7846_probe(struct spi_device *spi) | |||
813 | spi_message_init(m); | 817 | spi_message_init(m); |
814 | 818 | ||
815 | x++; | 819 | x++; |
816 | ts->read_z1 = READ_Z1; | 820 | ts->read_z1 = READ_Z1(vref); |
817 | x->tx_buf = &ts->read_z1; | 821 | x->tx_buf = &ts->read_z1; |
818 | x->len = 1; | 822 | x->len = 1; |
819 | spi_message_add_tail(x, m); | 823 | spi_message_add_tail(x, m); |
@@ -830,7 +834,7 @@ static int __devinit ads7846_probe(struct spi_device *spi) | |||
830 | spi_message_init(m); | 834 | spi_message_init(m); |
831 | 835 | ||
832 | x++; | 836 | x++; |
833 | ts->read_z2 = READ_Z2; | 837 | ts->read_z2 = READ_Z2(vref); |
834 | x->tx_buf = &ts->read_z2; | 838 | x->tx_buf = &ts->read_z2; |
835 | x->len = 1; | 839 | x->len = 1; |
836 | spi_message_add_tail(x, m); | 840 | spi_message_add_tail(x, m); |