diff options
Diffstat (limited to 'drivers/iio/adc/at91_adc.c')
| -rw-r--r-- | drivers/iio/adc/at91_adc.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c index 0438c68015e8..bbdac07f4aaa 100644 --- a/drivers/iio/adc/at91_adc.c +++ b/drivers/iio/adc/at91_adc.c @@ -113,6 +113,7 @@ #define AT91_ADC_TSMR_TSAV (3 << 4) /* Averages samples */ #define AT91_ADC_TSMR_TSAV_(x) ((x) << 4) #define AT91_ADC_TSMR_SCTIM (0x0f << 16) /* Switch closure time */ +#define AT91_ADC_TSMR_SCTIM_(x) ((x) << 16) #define AT91_ADC_TSMR_PENDBC (0x0f << 28) /* Pen Debounce time */ #define AT91_ADC_TSMR_PENDBC_(x) ((x) << 28) #define AT91_ADC_TSMR_NOTSDMA (1 << 22) /* No Touchscreen DMA */ @@ -150,6 +151,7 @@ #define MAX_RLPOS_BITS 10 #define TOUCH_SAMPLE_PERIOD_US_RL 10000 /* 10ms, the SoC can't keep up with 2ms */ #define TOUCH_SHTIM 0xa +#define TOUCH_SCTIM_US 10 /* 10us for the Touchscreen Switches Closure Time */ /** * struct at91_adc_reg_desc - Various informations relative to registers @@ -1001,7 +1003,9 @@ static void atmel_ts_close(struct input_dev *dev) static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz) { + struct iio_dev *idev = iio_priv_to_dev(st); u32 reg = 0; + u32 tssctim = 0; int i = 0; /* a Pen Detect Debounce Time is necessary for the ADC Touch to avoid @@ -1034,11 +1038,20 @@ static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz) return 0; } + /* Touchscreen Switches Closure time needed for allowing the value to + * stabilize. + * Switch Closure Time = (TSSCTIM * 4) ADCClock periods + */ + tssctim = DIV_ROUND_UP(TOUCH_SCTIM_US * adc_clk_khz / 1000, 4); + dev_dbg(&idev->dev, "adc_clk at: %d KHz, tssctim at: %d\n", + adc_clk_khz, tssctim); + if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE) reg = AT91_ADC_TSMR_TSMODE_4WIRE_PRESS; else reg = AT91_ADC_TSMR_TSMODE_5WIRE; + reg |= AT91_ADC_TSMR_SCTIM_(tssctim) & AT91_ADC_TSMR_SCTIM; reg |= AT91_ADC_TSMR_TSAV_(st->caps->ts_filter_average) & AT91_ADC_TSMR_TSAV; reg |= AT91_ADC_TSMR_PENDBC_(st->ts_pendbc) & AT91_ADC_TSMR_PENDBC; |