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    Subject[PATCH 04/15] iio: adc: at91_adc: Add support for touchscreens without TSMR
    Date
    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@free-electrons.com>
    ---
    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 {
    + 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);
    --
    1.8.3.2


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