[PATCH 04/15] iio: adc: at91_adc: Add support for touchscreens without TSMR
Jonathan Cameron
jic23 at kernel.org
Sun Mar 16 14:16:54 EDT 2014
On 05/03/14 17:35, Alexandre Belloni wrote:
> Old ADCs, as present on the sam9rl and the sam9g45 don't have a TSMR register
> and the touchscreen support should be handled differently.
>
> Signed-off-by: Alexandre Belloni <alexandre.belloni at free-electrons.com>
One comment inline about handling of devices where the platform data doesn't
include the touchscreen type. I'd expect zero to be the current default
rather than NONE...
> ---
> arch/arm/mach-at91/include/mach/at91_adc.h | 13 ++
> drivers/iio/adc/at91_adc.c | 199 ++++++++++++++++++++++-------
> include/linux/platform_data/at91_adc.h | 8 ++
> 3 files changed, 172 insertions(+), 48 deletions(-)
>
> diff --git a/arch/arm/mach-at91/include/mach/at91_adc.h b/arch/arm/mach-at91/include/mach/at91_adc.h
> index c287307b9a3b..7d80396346b2 100644
> --- a/arch/arm/mach-at91/include/mach/at91_adc.h
> +++ b/arch/arm/mach-at91/include/mach/at91_adc.h
> @@ -20,6 +20,9 @@
> #define AT91_ADC_START (1 << 1) /* Start Conversion */
>
> #define AT91_ADC_MR 0x04 /* Mode Register */
> +#define AT91_ADC_TSAMOD (3 << 0) /* ADC mode */
> +#define AT91_ADC_TSAMOD_ADC_ONLY_MODE (0 << 0) /* ADC Mode */
> +#define AT91_ADC_TSAMOD_TS_ONLY_MODE (1 << 0) /* Touch Screen Only Mode */
> #define AT91_ADC_TRGEN (1 << 0) /* Trigger Enable */
> #define AT91_ADC_TRGSEL (7 << 1) /* Trigger Selection */
> #define AT91_ADC_TRGSEL_TC0 (0 << 1)
> @@ -28,6 +31,7 @@
> #define AT91_ADC_TRGSEL_EXTERNAL (6 << 1)
> #define AT91_ADC_LOWRES (1 << 4) /* Low Resolution */
> #define AT91_ADC_SLEEP (1 << 5) /* Sleep Mode */
> +#define AT91_ADC_PENDET (1 << 6) /* Pen contact detection enable */
> #define AT91_ADC_PRESCAL_9260 (0x3f << 8) /* Prescalar Rate Selection */
> #define AT91_ADC_PRESCAL_9G45 (0xff << 8)
> #define AT91_ADC_PRESCAL_(x) ((x) << 8)
> @@ -37,6 +41,12 @@
> #define AT91_ADC_STARTUP_(x) ((x) << 16)
> #define AT91_ADC_SHTIM (0xf << 24) /* Sample & Hold Time */
> #define AT91_ADC_SHTIM_(x) ((x) << 24)
> +#define AT91_ADC_PENDBC (0x0f << 28) /* Pen Debounce time */
> +#define AT91_ADC_PENDBC_(x) ((x) << 28)
> +
> +#define AT91_ADC_TSR 0x0C
> +#define AT91_ADC_TSR_SHTIM (0xf << 24) /* Sample & Hold Time */
> +#define AT91_ADC_TSR_SHTIM_(x) ((x) << 24)
>
> #define AT91_ADC_CHER 0x10 /* Channel Enable Register */
> #define AT91_ADC_CHDR 0x14 /* Channel Disable Register */
> @@ -60,6 +70,8 @@
> #define AT91_ADC_IER 0x24 /* Interrupt Enable Register */
> #define AT91_ADC_IDR 0x28 /* Interrupt Disable Register */
> #define AT91_ADC_IMR 0x2C /* Interrupt Mask Register */
> +#define AT91RL_ADC_IER_PEN (1 << 20)
> +#define AT91RL_ADC_IER_NOPEN (1 << 21)
> #define AT91_ADC_IER_PEN (1 << 29)
> #define AT91_ADC_IER_NOPEN (1 << 30)
> #define AT91_ADC_IER_XRDY (1 << 20)
> @@ -102,6 +114,7 @@
> #define AT91_ADC_TRGR_TRGPER (0xffff << 16)
> #define AT91_ADC_TRGR_TRGPER_(x) ((x) << 16)
> #define AT91_ADC_TRGR_TRGMOD (0x7 << 0)
> +#define AT91_ADC_TRGR_NONE (0 << 0)
> #define AT91_ADC_TRGR_MOD_PERIOD_TRIG (5 << 0)
>
> #endif
> diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
> index 1beae65aef2c..3e92b16e9301 100644
> --- a/drivers/iio/adc/at91_adc.c
> +++ b/drivers/iio/adc/at91_adc.c
> @@ -46,6 +46,10 @@
> #define TOUCH_SAMPLE_PERIOD_US 2000 /* 2ms */
> #define TOUCH_PEN_DETECT_DEBOUNCE_US 200
>
> +#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
> +
> /**
> * struct at91_adc_reg_desc - Various informations relative to registers
> * @channel_base: Base offset for the channel data registers
> @@ -83,12 +87,6 @@ struct at91_adc_caps {
> struct at91_adc_reg_desc registers;
> };
>
> -enum atmel_adc_ts_type {
> - ATMEL_ADC_TOUCHSCREEN_NONE = 0,
> - ATMEL_ADC_TOUCHSCREEN_4WIRE = 4,
> - ATMEL_ADC_TOUCHSCREEN_5WIRE = 5,
> -};
> -
> struct at91_adc_state {
> struct clk *adc_clk;
> u16 *buffer;
> @@ -133,6 +131,11 @@ struct at91_adc_state {
>
> u16 ts_sample_period_val;
> u32 ts_pressure_threshold;
> + u16 ts_pendbc;
> +
> + u8 ts_bufferedmeasure;
> + u32 ts_prev_absx;
> + u32 ts_prev_absy;
> };
>
> static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
> @@ -239,19 +242,68 @@ static int at91_ts_sample(struct at91_adc_state *st)
> return 0;
> }
>
> -static irqreturn_t at91_adc_interrupt(int irq, void *private)
> +void handle_adc_rl_ts_irq(int irq, struct at91_adc_state *st, u32 status)
> +{
> + unsigned int reg;
> +
> + status &= at91_adc_readl(st, AT91_ADC_IMR);
> + if (status & AT91RL_ADC_IER_PEN) {
> + /* Disabling pen debounce is required to get a NOPEN irq */
> + reg = at91_adc_readl(st, AT91_ADC_MR);
> + reg &= ~AT91_ADC_PENDBC;
> + at91_adc_writel(st, AT91_ADC_MR, reg);
> +
> + at91_adc_writel(st, AT91_ADC_IDR, AT91RL_ADC_IER_PEN);
> + at91_adc_writel(st, AT91_ADC_IER, AT91RL_ADC_IER_NOPEN
> + | AT91_ADC_EOC(3));
> + /* Set up period trigger for sampling */
> + at91_adc_writel(st, st->registers->trigger_register,
> + AT91_ADC_TRGR_MOD_PERIOD_TRIG |
> + AT91_ADC_TRGR_TRGPER_(st->ts_sample_period_val));
> + } else if (status & AT91RL_ADC_IER_NOPEN) {
> + reg = at91_adc_readl(st, AT91_ADC_MR);
> + reg |= AT91_ADC_PENDBC_(st->ts_pendbc) & AT91_ADC_PENDBC;
> + at91_adc_writel(st, AT91_ADC_MR, reg);
> + at91_adc_writel(st, st->registers->trigger_register,
> + AT91_ADC_TRGR_NONE);
> +
> + at91_adc_writel(st, AT91_ADC_IDR, AT91RL_ADC_IER_NOPEN
> + | AT91_ADC_EOC(3));
> + at91_adc_writel(st, AT91_ADC_IER, AT91RL_ADC_IER_PEN);
> + st->ts_bufferedmeasure = 0;
> + input_report_key(st->ts_input, BTN_TOUCH, 0);
> + input_sync(st->ts_input);
> + } else if (status & AT91_ADC_EOC(3)) {
> + /* Conversion finished */
> + if (st->ts_bufferedmeasure) {
> + /* Last measurement is always discarded, since it can
> + * be erroneous.
> + * Always report previous measurement */
> + input_report_abs(st->ts_input, ABS_X, st->ts_prev_absx);
> + input_report_abs(st->ts_input, ABS_Y, st->ts_prev_absy);
> + input_report_key(st->ts_input, BTN_TOUCH, 1);
> + input_sync(st->ts_input);
> + } else
> + st->ts_bufferedmeasure = 1;
> +
> + /* Now make new measurement */
> + st->ts_prev_absx = at91_adc_readl(st, AT91_ADC_CHAN(st, 3))
> + << MAX_RLPOS_BITS;
> + st->ts_prev_absx /= at91_adc_readl(st, AT91_ADC_CHAN(st, 2));
> +
> + st->ts_prev_absy = at91_adc_readl(st, AT91_ADC_CHAN(st, 1))
> + << MAX_RLPOS_BITS;
> + st->ts_prev_absy /= at91_adc_readl(st, AT91_ADC_CHAN(st, 0));
> + }
> +}
> +
> +void handle_adc_9x5_ts_irq(int irq, struct at91_adc_state *st, u32 status)
> {
> - struct iio_dev *idev = private;
> - struct at91_adc_state *st = iio_priv(idev);
> - u32 status = at91_adc_readl(st, st->registers->status_register);
> const uint32_t ts_data_irq_mask =
> AT91_ADC_IER_XRDY |
> AT91_ADC_IER_YRDY |
> AT91_ADC_IER_PRDY;
>
> - if (status & st->registers->drdy_mask)
> - handle_adc_eoc_trigger(irq, idev);
> -
> if (status & AT91_ADC_IER_PEN) {
> at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
> at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_NOPEN |
> @@ -283,6 +335,21 @@ static irqreturn_t at91_adc_interrupt(int irq, void *private)
> at91_adc_readl(st, AT91_ADC_TSPRESSR);
> }
> }
> +}
> +
> +static irqreturn_t at91_adc_interrupt(int irq, void *private)
> +{
> + struct iio_dev *idev = private;
> + struct at91_adc_state *st = iio_priv(idev);
> + u32 status = at91_adc_readl(st, st->registers->status_register);
> +
> + if (status & st->registers->drdy_mask)
> + handle_adc_eoc_trigger(irq, idev);
> +
> + if (st->caps->has_tsmr)
> + handle_adc_9x5_ts_irq(irq, st, status);
> + else
> + handle_adc_rl_ts_irq(irq, st, status);
>
> return IRQ_HANDLED;
> }
> @@ -672,6 +739,8 @@ static int at91_adc_probe_dt_ts(struct device_node *node,
> return -EINVAL;
> }
>
> + if (!st->caps->has_tsmr)
> + return 0;
> prop = 0;
> of_property_read_u32(node, "atmel,adc-ts-pressure-threshold", &prop);
> st->ts_pressure_threshold = prop;
> @@ -795,6 +864,7 @@ static int at91_adc_probe_pdata(struct at91_adc_state *st,
> st->trigger_number = pdata->trigger_number;
> st->trigger_list = pdata->trigger_list;
> st->registers = &st->caps->registers;
> + st->touchscreen_type = pdata->touchscreen_type;
>
> return 0;
> }
> @@ -809,7 +879,10 @@ static int atmel_ts_open(struct input_dev *dev)
> {
> struct at91_adc_state *st = input_get_drvdata(dev);
>
> - at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
> + if (st->caps->has_tsmr)
> + at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
> + else
> + at91_adc_writel(st, AT91_ADC_IER, AT91RL_ADC_IER_PEN);
> return 0;
> }
>
> @@ -817,45 +890,61 @@ static void atmel_ts_close(struct input_dev *dev)
> {
> struct at91_adc_state *st = input_get_drvdata(dev);
>
> - at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
> + if (st->caps->has_tsmr)
> + at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
> + else
> + at91_adc_writel(st, AT91_ADC_IDR, AT91RL_ADC_IER_PEN);
> }
>
> static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz)
> {
> - u32 reg = 0, pendbc;
> + u32 reg = 0;
> int i = 0;
>
> - if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
> - reg = AT91_ADC_TSMR_TSMODE_4WIRE_PRESS;
> - else
> - reg = AT91_ADC_TSMR_TSMODE_5WIRE;
> -
> /* a Pen Detect Debounce Time is necessary for the ADC Touch to avoid
> * pen detect noise.
> * The formula is : Pen Detect Debounce Time = (2 ^ pendbc) / ADCClock
> */
> - pendbc = round_up(TOUCH_PEN_DETECT_DEBOUNCE_US * adc_clk_khz / 1000, 1);
> + st->ts_pendbc = round_up(TOUCH_PEN_DETECT_DEBOUNCE_US * adc_clk_khz /
> + 1000, 1);
>
> - while (pendbc >> ++i)
> + while (st->ts_pendbc >> ++i)
> ; /* Empty! Find the shift offset */
> - if (abs(pendbc - (1 << i)) < abs(pendbc - (1 << (i - 1))))
> - pendbc = i;
> + if (abs(st->ts_pendbc - (1 << i)) < abs(st->ts_pendbc - (1 << (i - 1))))
> + st->ts_pendbc = i;
> else
> - pendbc = i - 1;
> + st->ts_pendbc = i - 1;
>
> - if (st->caps->has_tsmr) {
> - reg |= AT91_ADC_TSMR_TSAV_(st->caps->ts_filter_average)
> - & AT91_ADC_TSMR_TSAV;
> - reg |= AT91_ADC_TSMR_PENDBC_(pendbc) & AT91_ADC_TSMR_PENDBC;
> - reg |= AT91_ADC_TSMR_NOTSDMA;
> - reg |= AT91_ADC_TSMR_PENDET_ENA;
> - reg |= 0x03 << 8; /* TSFREQ, need bigger than TSAV */
> -
> - at91_adc_writel(st, AT91_ADC_TSMR, reg);
> - } else {
> - /* TODO: for 9g45 which has no TSMR */
> + if (!st->caps->has_tsmr) {
> + reg = at91_adc_readl(st, AT91_ADC_MR);
> + reg |= AT91_ADC_TSAMOD_TS_ONLY_MODE | AT91_ADC_PENDET;
> +
> + reg |= AT91_ADC_PENDBC_(st->ts_pendbc) & AT91_ADC_PENDBC;
> + at91_adc_writel(st, AT91_ADC_MR, reg);
> +
> + reg = AT91_ADC_TSR_SHTIM_(TOUCH_SHTIM) & AT91_ADC_TSR_SHTIM;
> + at91_adc_writel(st, AT91_ADC_TSR, reg);
> +
> + st->ts_sample_period_val = round_up((TOUCH_SAMPLE_PERIOD_US_RL *
> + adc_clk_khz / 1000) - 1, 1);
> +
> + return 0;
> }
>
> + 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_TSAV_(st->caps->ts_filter_average)
> + & AT91_ADC_TSMR_TSAV;
> + reg |= AT91_ADC_TSMR_PENDBC_(st->ts_pendbc) & AT91_ADC_TSMR_PENDBC;
> + reg |= AT91_ADC_TSMR_NOTSDMA;
> + reg |= AT91_ADC_TSMR_PENDET_ENA;
> + reg |= 0x03 << 8; /* TSFREQ, needs to be bigger than TSAV */
> +
> + at91_adc_writel(st, AT91_ADC_TSMR, reg);
> +
> /* Change adc internal resistor value for better pen detection,
> * default value is 100 kOhm.
> * 0 = 200 kOhm, 1 = 150 kOhm, 2 = 100 kOhm, 3 = 50 kOhm
> @@ -864,7 +953,7 @@ static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz)
> at91_adc_writel(st, AT91_ADC_ACR, st->caps->ts_pen_detect_sensitivity
> & AT91_ADC_ACR_PENDETSENS);
>
> - /* Sample Peroid Time = (TRGPER + 1) / ADCClock */
> + /* Sample Period Time = (TRGPER + 1) / ADCClock */
> st->ts_sample_period_val = round_up((TOUCH_SAMPLE_PERIOD_US *
> adc_clk_khz / 1000) - 1, 1);
>
> @@ -893,17 +982,37 @@ static int at91_ts_register(struct at91_adc_state *st,
> __set_bit(EV_ABS, input->evbit);
> __set_bit(EV_KEY, input->evbit);
> __set_bit(BTN_TOUCH, input->keybit);
> - input_set_abs_params(input, ABS_X, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
> - input_set_abs_params(input, ABS_Y, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
> - input_set_abs_params(input, ABS_PRESSURE, 0, 0xffffff, 0, 0);
> + if (st->caps->has_tsmr) {
> + input_set_abs_params(input, ABS_X, 0, (1 << MAX_POS_BITS) - 1,
> + 0, 0);
> + input_set_abs_params(input, ABS_Y, 0, (1 << MAX_POS_BITS) - 1,
> + 0, 0);
> + input_set_abs_params(input, ABS_PRESSURE, 0, 0xffffff, 0, 0);
> + } else {
> + if (st->touchscreen_type != ATMEL_ADC_TOUCHSCREEN_4WIRE) {
> + dev_err(&pdev->dev,
> + "This touchscreen controller only support 4 wires\n");
> + ret = -EINVAL;
> + goto err;
> + }
> +
> + input_set_abs_params(input, ABS_X, 0, (1 << MAX_RLPOS_BITS) - 1,
> + 0, 0);
> + input_set_abs_params(input, ABS_Y, 0, (1 << MAX_RLPOS_BITS) - 1,
> + 0, 0);
> + }
>
> st->ts_input = input;
> input_set_drvdata(input, st);
>
> ret = input_register_device(input);
> if (ret)
> - input_free_device(st->ts_input);
> + goto err;
> +
> + return ret;
>
> +err:
> + input_free_device(st->ts_input);
> return ret;
> }
>
> @@ -1070,12 +1179,6 @@ static int at91_adc_probe(struct platform_device *pdev)
> goto error_disable_adc_clk;
> }
> } else {
> - if (!st->caps->has_tsmr) {
> - dev_err(&pdev->dev, "We don't support non-TSMR adc\n");
> - ret = -ENODEV;
> - goto error_disable_adc_clk;
> - }
> -
> ret = at91_ts_register(st, pdev);
> if (ret)
> goto error_disable_adc_clk;
> diff --git a/include/linux/platform_data/at91_adc.h b/include/linux/platform_data/at91_adc.h
> index fcf73879dbfe..7819fc787731 100644
> --- a/include/linux/platform_data/at91_adc.h
> +++ b/include/linux/platform_data/at91_adc.h
> @@ -7,6 +7,12 @@
> #ifndef _AT91_ADC_H_
> #define _AT91_ADC_H_
>
> +enum atmel_adc_ts_type {
This means that the default for existing touch screens (where the platform
data won't include setting this value) will be none. Is that correct?
> + ATMEL_ADC_TOUCHSCREEN_NONE = 0,
> + ATMEL_ADC_TOUCHSCREEN_4WIRE = 4,
> + ATMEL_ADC_TOUCHSCREEN_5WIRE = 5,
> +};
> +
> /**
> * struct at91_adc_trigger - description of triggers
> * @name: name of the trigger advertised to the user
> @@ -28,6 +34,7 @@ struct at91_adc_trigger {
> * @trigger_number: Number of triggers available in the ADC
> * @use_external_triggers: does the board has external triggers availables
> * @vref: Reference voltage for the ADC in millivolts
> + * @touchscreen_type: If a touchscreen is connected, its type (4 or 5 wires)
> */
> struct at91_adc_data {
> unsigned long channels_used;
> @@ -36,6 +43,7 @@ struct at91_adc_data {
> u8 trigger_number;
> bool use_external_triggers;
> u16 vref;
> + enum atmel_adc_ts_type touchscreen_type;
> };
>
> extern void __init at91_add_device_adc(struct at91_adc_data *data);
>
More information about the linux-arm-kernel
mailing list