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SubjectRe: [PATCH v3 07/11] iio: adc: at91-sama5d2_adc: add support for position and pressure channels
On Tue, 10 Apr 2018 11:57:53 +0300
Eugen Hristev <eugen.hristev@microchip.com> wrote:

> This implements the support for position and pressure for the included
> touchscreen support in the SAMA5D2 SOC ADC block.
> Two position channels are added and one for pressure.
> They can be read in raw format, or through a buffer.
> A normal use case is for a consumer driver to register a callback buffer
> for these channels.
> When the touchscreen channels are in the active scan mask,
> the driver will start the touchscreen sampling and push the data to the
> buffer.
>
> Some parts of this patch are based on initial original work by
> Mohamed Jamsheeth Hajanajubudeen and Bandaru Venkateswara Swamy
>
> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>

A few additional minor things I picked up on in this read.
Just trivial tidy ups or things I think could make the code
a little easier to read.

Looks good in general.

Jonathan

> ---
> Changes in v3:
> - prefix macros with AT91_SAMA5D2
> - reworked the x_pos and y_pos functions into a single one with two
> additional wrappers
> - reworked pressure report to have it grow naturally and not top down
> - fixed some checks regarding IIO_VOLTAGE as suggested
> - added a comment explaining some code in trigger handling
> - reworked the frequency get handler to use the saved value instead of
> reading it from the hardware.
> - added comment on deffered work queueing
> - pulled out INFO_RAW function into a separate utility function as suggested
> - added iio_dev ops structure at all times . The functions are needed in
> case we do not have a hardware trigger attached, but we want to use the
> consumer touchscreen driver, thus a callback buffer is attached. Then we still
> need to have buffer preenable and postdisable to configure the touch IRQs (etc.)
>
> Changes in v2:
> - the support is now based on callback buffer.
> drivers/iio/adc/at91-sama5d2_adc.c | 601 +++++++++++++++++++++++++++++++++----
> 1 file changed, 539 insertions(+), 62 deletions(-)
>
> diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
> index 8729d65..5368464 100644
> --- a/drivers/iio/adc/at91-sama5d2_adc.c
> +++ b/drivers/iio/adc/at91-sama5d2_adc.c
> @@ -102,14 +102,26 @@
> #define AT91_SAMA5D2_LCDR 0x20
> /* Interrupt Enable Register */
> #define AT91_SAMA5D2_IER 0x24
> +/* Interrupt Enable Register - TS X measurement ready */
> +#define AT91_SAMA5D2_IER_XRDY BIT(20)
> +/* Interrupt Enable Register - TS Y measurement ready */
> +#define AT91_SAMA5D2_IER_YRDY BIT(21)
> +/* Interrupt Enable Register - TS pressure measurement ready */
> +#define AT91_SAMA5D2_IER_PRDY BIT(22)
> /* Interrupt Enable Register - general overrun error */
> #define AT91_SAMA5D2_IER_GOVRE BIT(25)
> +/* Interrupt Enable Register - Pen detect */
> +#define AT91_SAMA5D2_IER_PEN BIT(29)
> +/* Interrupt Enable Register - No pen detect */
> +#define AT91_SAMA5D2_IER_NOPEN BIT(30)
> /* Interrupt Disable Register */
> #define AT91_SAMA5D2_IDR 0x28
> /* Interrupt Mask Register */
> #define AT91_SAMA5D2_IMR 0x2c
> /* Interrupt Status Register */
> #define AT91_SAMA5D2_ISR 0x30
> +/* Interrupt Status Register - Pen touching sense status */
> +#define AT91_SAMA5D2_ISR_PENS BIT(31)
> /* Last Channel Trigger Mode Register */
> #define AT91_SAMA5D2_LCTMR 0x34
> /* Last Channel Compare Window Register */
> @@ -131,8 +143,38 @@
> #define AT91_SAMA5D2_CDR0 0x50
> /* Analog Control Register */
> #define AT91_SAMA5D2_ACR 0x94
> +/* Analog Control Register - Pen detect sensitivity mask */
> +#define AT91_SAMA5D2_ACR_PENDETSENS_MASK GENMASK(1, 0)
> +
> /* Touchscreen Mode Register */
> #define AT91_SAMA5D2_TSMR 0xb0
> +/* Touchscreen Mode Register - No touch mode */
> +#define AT91_SAMA5D2_TSMR_TSMODE_NONE 0
> +/* Touchscreen Mode Register - 4 wire screen, no pressure measurement */
> +#define AT91_SAMA5D2_TSMR_TSMODE_4WIRE_NO_PRESS 1
> +/* Touchscreen Mode Register - 4 wire screen, pressure measurement */
> +#define AT91_SAMA5D2_TSMR_TSMODE_4WIRE_PRESS 2
> +/* Touchscreen Mode Register - 5 wire screen */
> +#define AT91_SAMA5D2_TSMR_TSMODE_5WIRE 3
> +/* Touchscreen Mode Register - Average samples mask */
> +#define AT91_SAMA5D2_TSMR_TSAV_MASK GENMASK(5, 4)
> +/* Touchscreen Mode Register - Average samples */
> +#define AT91_SAMA5D2_TSMR_TSAV(x) ((x) << 4)
> +/* Touchscreen Mode Register - Touch/trigger frequency ratio mask */
> +#define AT91_SAMA5D2_TSMR_TSFREQ_MASK GENMASK(11, 8)
> +/* Touchscreen Mode Register - Touch/trigger frequency ratio */
> +#define AT91_SAMA5D2_TSMR_TSFREQ(x) ((x) << 8)
> +/* Touchscreen Mode Register - Pen Debounce Time mask */
> +#define AT91_SAMA5D2_TSMR_PENDBC_MASK GENMASK(31, 28)
> +/* Touchscreen Mode Register - Pen Debounce Time */
> +#define AT91_SAMA5D2_TSMR_PENDBC(x) ((x) << 28)
> +/* Touchscreen Mode Register - No DMA for touch measurements */
> +#define AT91_SAMA5D2_TSMR_NOTSDMA BIT(22)
> +/* Touchscreen Mode Register - Disable pen detection */
> +#define AT91_SAMA5D2_TSMR_PENDET_DIS (0 << 24)
> +/* Touchscreen Mode Register - Enable pen detection */
> +#define AT91_SAMA5D2_TSMR_PENDET_ENA BIT(24)
> +
> /* Touchscreen X Position Register */
> #define AT91_SAMA5D2_XPOSR 0xb4
> /* Touchscreen Y Position Register */
> @@ -151,6 +193,12 @@
> #define AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_FALL 2
> /* Trigger Mode external trigger any edge */
> #define AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_ANY 3
> +/* Trigger Mode internal periodic */
> +#define AT91_SAMA5D2_TRGR_TRGMOD_PERIODIC 5
> +/* Trigger Mode - trigger period mask */
> +#define AT91_SAMA5D2_TRGR_TRGPER_MASK GENMASK(31, 16)
> +/* Trigger Mode - trigger period */
> +#define AT91_SAMA5D2_TRGR_TRGPER(x) ((x) << 16)
>
> /* Correction Select Register */
> #define AT91_SAMA5D2_COSR 0xd0
> @@ -169,6 +217,22 @@
> #define AT91_SAMA5D2_SINGLE_CHAN_CNT 12
> #define AT91_SAMA5D2_DIFF_CHAN_CNT 6
>
> +#define AT91_SAMA5D2_TIMESTAMP_CHAN_IDX (AT91_SAMA5D2_SINGLE_CHAN_CNT + \
> + AT91_SAMA5D2_DIFF_CHAN_CNT + 1)
> +
> +#define AT91_SAMA5D2_TOUCH_X_CHAN_IDX (AT91_SAMA5D2_SINGLE_CHAN_CNT + \
> + AT91_SAMA5D2_DIFF_CHAN_CNT * 2)
> +#define AT91_SAMA5D2_TOUCH_Y_CHAN_IDX (AT91_SAMA5D2_TOUCH_X_CHAN_IDX + 1)
> +#define AT91_SAMA5D2_TOUCH_P_CHAN_IDX (AT91_SAMA5D2_TOUCH_Y_CHAN_IDX + 1)
> +#define AT91_SAMA5D2_MAX_CHAN_IDX AT91_SAMA5D2_TOUCH_P_CHAN_IDX
> +
> +#define AT91_SAMA5D2_TOUCH_SAMPLE_PERIOD_US 2000 /* 2ms */
> +#define AT91_SAMA5D2_TOUCH_PEN_DETECT_DEBOUNCE_US 200
> +
> +#define AT91_SAMA5D2_XYZ_MASK GENMASK(11, 0)
> +
> +#define AT91_SAMA5D2_MAX_POS_BITS 12
> +
> /*
> * Maximum number of bytes to hold conversion from all channels
> * without the timestamp.
> @@ -222,6 +286,37 @@
> .indexed = 1, \
> }
>
> +#define AT91_SAMA5D2_CHAN_TOUCH(num, name, mod) \
> + { \
> + .type = IIO_POSITIONRELATIVE, \
> + .modified = 1, \
> + .channel = num, \
> + .channel2 = mod, \
> + .scan_index = num, \
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = 12, \
> + .storagebits = 16, \
> + }, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
> + .datasheet_name = name, \
> + }
> +#define AT91_SAMA5D2_CHAN_PRESSURE(num, name) \
> + { \
> + .type = IIO_PRESSURE, \
> + .channel = num, \
> + .scan_index = num, \
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = 12, \
> + .storagebits = 16, \
> + }, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
> + .datasheet_name = name, \
> + }
> +
> #define at91_adc_readl(st, reg) readl_relaxed(st->base + reg)
> #define at91_adc_writel(st, reg, val) writel_relaxed(val, st->base + reg)
>
> @@ -260,6 +355,22 @@ struct at91_adc_dma {
> s64 dma_ts;
> };
>
> +/**
> + * at91_adc_touch - at91-sama5d2 touchscreen information struct
> + * @sample_period_val: the value for periodic trigger interval
> + * @touching: is the pen touching the screen or not
> + * @x_pos: temporary placeholder for pressure computation
> + * @channels_bitmask: bitmask with the touchscreen channels enabled
> + * @workq: workqueue for buffer data pushing
> + */
> +struct at91_adc_touch {
> + u16 sample_period_val;
> + bool touching;
> + u16 x_pos;
> + unsigned long channels_bitmask;
> + struct work_struct workq;
> +};
> +
> struct at91_adc_state {
> void __iomem *base;
> int irq;
> @@ -267,6 +378,7 @@ struct at91_adc_state {
> struct regulator *reg;
> struct regulator *vref;
> int vref_uv;
> + unsigned int current_sample_rate;
> struct iio_trigger *trig;
> const struct at91_adc_trigger *selected_trig;
> const struct iio_chan_spec *chan;
> @@ -275,6 +387,7 @@ struct at91_adc_state {
> struct at91_adc_soc_info soc_info;
> wait_queue_head_t wq_data_available;
> struct at91_adc_dma dma_st;
> + struct at91_adc_touch touch_st;
> u16 buffer[AT91_BUFFER_MAX_HWORDS];
> /*
> * lock to prevent concurrent 'single conversion' requests through
> @@ -329,8 +442,10 @@ static const struct iio_chan_spec at91_adc_channels[] = {
> AT91_SAMA5D2_CHAN_DIFF(6, 7, 0x68),
> AT91_SAMA5D2_CHAN_DIFF(8, 9, 0x70),
> AT91_SAMA5D2_CHAN_DIFF(10, 11, 0x78),
> - IIO_CHAN_SOFT_TIMESTAMP(AT91_SAMA5D2_SINGLE_CHAN_CNT
> - + AT91_SAMA5D2_DIFF_CHAN_CNT + 1),
> + IIO_CHAN_SOFT_TIMESTAMP(AT91_SAMA5D2_TIMESTAMP_CHAN_IDX),
> + AT91_SAMA5D2_CHAN_TOUCH(AT91_SAMA5D2_TOUCH_X_CHAN_IDX, "x", IIO_MOD_X),
> + AT91_SAMA5D2_CHAN_TOUCH(AT91_SAMA5D2_TOUCH_Y_CHAN_IDX, "y", IIO_MOD_Y),
> + AT91_SAMA5D2_CHAN_PRESSURE(AT91_SAMA5D2_TOUCH_P_CHAN_IDX, "pressure"),
> };
>
> static int at91_adc_chan_xlate(struct iio_dev *indio_dev, int chan)
> @@ -354,6 +469,160 @@ at91_adc_chan_get(struct iio_dev *indio_dev, int chan)
> return indio_dev->channels + index;
> }
>
> +static inline int at91_adc_of_xlate(struct iio_dev *indio_dev,
> + const struct of_phandle_args *iiospec)
> +{
> + return at91_adc_chan_xlate(indio_dev, iiospec->args[0]);
> +}
> +
> +static int at91_adc_configure_touch(struct at91_adc_state *st, bool state)
> +{
> + u32 clk_khz = st->current_sample_rate / 1000;
> + int i = 0;
> + u16 pendbc;
> + u32 tsmr, acr;
> +
> + if (!state) {
> + /* disabling touch IRQs and setting mode to no touch enabled */
> + at91_adc_writel(st, AT91_SAMA5D2_IDR,
> + AT91_SAMA5D2_IER_PEN | AT91_SAMA5D2_IER_NOPEN);
> + at91_adc_writel(st, AT91_SAMA5D2_TSMR, 0);
> + return 0;
> + }
> + /*
> + * debounce time is in microseconds, we need it in milliseconds to
> + * multiply with kilohertz, so, divide by 1000, but after the multiply.
> + * round up to make sure pendbc is at least 1
> + */
> + pendbc = round_up(AT91_SAMA5D2_TOUCH_PEN_DETECT_DEBOUNCE_US *
> + clk_khz / 1000, 1);
> +
> + /* get the required exponent */
> + while (pendbc >> i++)
> + ;
> +
> + pendbc = i;
> +
> + tsmr = AT91_SAMA5D2_TSMR_TSMODE_4WIRE_PRESS;
> +
> + tsmr |= AT91_SAMA5D2_TSMR_TSAV(2) & AT91_SAMA5D2_TSMR_TSAV_MASK;
> + tsmr |= AT91_SAMA5D2_TSMR_PENDBC(pendbc) &
> + AT91_SAMA5D2_TSMR_PENDBC_MASK;
> + tsmr |= AT91_SAMA5D2_TSMR_NOTSDMA;
> + tsmr |= AT91_SAMA5D2_TSMR_PENDET_ENA;
> + tsmr |= AT91_SAMA5D2_TSMR_TSFREQ(2) & AT91_SAMA5D2_TSMR_TSFREQ_MASK;
> +
> + at91_adc_writel(st, AT91_SAMA5D2_TSMR, tsmr);
> +
> + acr = at91_adc_readl(st, AT91_SAMA5D2_ACR);
> + acr &= ~AT91_SAMA5D2_ACR_PENDETSENS_MASK;
> + acr |= 0x02 & AT91_SAMA5D2_ACR_PENDETSENS_MASK;
> + at91_adc_writel(st, AT91_SAMA5D2_ACR, acr);
> +
> + /* Sample Period Time = (TRGPER + 1) / ADCClock */
> + st->touch_st.sample_period_val =
> + round_up((AT91_SAMA5D2_TOUCH_SAMPLE_PERIOD_US *
> + clk_khz / 1000) - 1, 1);
> + /* enable pen detect IRQ */
> + at91_adc_writel(st, AT91_SAMA5D2_IER, AT91_SAMA5D2_IER_PEN);
> +
> + return 0;
> +}
> +
> +static u16 at91_adc_touch_pos(struct at91_adc_state *st, int reg)
> +{
> + u32 val;
> + u32 scale, result, pos;
> +
> + /*
> + * to obtain the actual position we must divide by scale
> + * and multiply with max, where
> + * max = 2^AT91_SAMA5D2_MAX_POS_BITS - 1
> + */
> + /* first half of register is the x or y, second half is the scale */
> + val = at91_adc_readl(st, reg);
> + if (!val)
> + dev_dbg(&iio_priv_to_dev(st)->dev, "pos is 0\n");
> +
> + pos = val & AT91_SAMA5D2_XYZ_MASK;
> + result = (pos << AT91_SAMA5D2_MAX_POS_BITS) - pos;
> + scale = (val >> 16) & AT91_SAMA5D2_XYZ_MASK;
> + if (scale == 0) {
> + dev_err(&iio_priv_to_dev(st)->dev, "scale is 0\n");
> + return 0;
> + }
> + result /= scale;
> +
> + return result;
> +}
> +
> +static u16 at91_adc_touch_x_pos(struct at91_adc_state *st)
> +{
> + st->touch_st.x_pos = at91_adc_touch_pos(st, AT91_SAMA5D2_XPOSR);
> + return st->touch_st.x_pos;
> +}
> +
> +static u16 at91_adc_touch_y_pos(struct at91_adc_state *st)
> +{
> + return at91_adc_touch_pos(st, AT91_SAMA5D2_YPOSR);
> +}
> +
> +static u16 at91_adc_touch_pressure(struct at91_adc_state *st)
> +{
> + u32 val;
> + u32 z1, z2;
> + u32 pres;
> + u32 rxp = 1;
> + u32 factor = 1000;
> +
> + /* calculate the pressure */
> + val = at91_adc_readl(st, AT91_SAMA5D2_PRESSR);
> + z1 = val & AT91_SAMA5D2_XYZ_MASK;
> + z2 = (val >> 16) & AT91_SAMA5D2_XYZ_MASK;
> +
> + if (z1 != 0)
> + pres = rxp * (st->touch_st.x_pos * factor / 1024) *
> + (z2 * factor / z1 - factor) /
> + factor;
> + else
> + pres = 0xFFFF; /* no pen contact */
> +
> + /*
> + * The pressure from device grows down, minimum is 0xFFFF, maximum 0x0.
> + * We compute it this way, but let's return it in the expected way,
> + * growing from 0 to 0xFFFF.
> + */
> + return 0xFFFF - pres;
> +}
> +
> +static int at91_adc_read_position(struct at91_adc_state *st, int chan, u16 *val)
> +{
> + *val = 0;
> + if (!st->touch_st.touching)
> + return -ENODATA;
> + if (chan == AT91_SAMA5D2_TOUCH_X_CHAN_IDX)
> + *val = at91_adc_touch_x_pos(st);
> + else if (chan == AT91_SAMA5D2_TOUCH_Y_CHAN_IDX)
> + *val = at91_adc_touch_y_pos(st);
> + else
> + return -ENODATA;
> +
> + return IIO_VAL_INT;
> +}
> +
> +static int at91_adc_read_pressure(struct at91_adc_state *st, int chan, u16 *val)
> +{
> + *val = 0;
> + if (!st->touch_st.touching)
> + return -ENODATA;
> + if (chan == AT91_SAMA5D2_TOUCH_P_CHAN_IDX)
> + *val = at91_adc_touch_pressure(st);
> + else
> + return -ENODATA;
> +
> + return IIO_VAL_INT;
> +}
> +
> static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
> {
> struct iio_dev *indio = iio_trigger_get_drvdata(trig);
> @@ -375,6 +644,10 @@ static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
>
> if (!chan)
> continue;
> + /* these channel types cannot be handled by this trigger */
> + if (chan->type == IIO_POSITIONRELATIVE ||
> + chan->type == IIO_PRESSURE)
> + continue;

A blank line here might help readability.

> if (state) {
> at91_adc_writel(st, AT91_SAMA5D2_CHER,
> BIT(chan->channel));
> @@ -520,7 +793,21 @@ static int at91_adc_dma_start(struct iio_dev *indio_dev)
> static int at91_adc_buffer_postenable(struct iio_dev *indio_dev)
> {
> int ret;
> + struct at91_adc_state *st = iio_priv(indio_dev);
>
> + /* check if we are enabling triggered buffer or the touchscreen */
> + if (bitmap_subset(indio_dev->active_scan_mask,
> + &st->touch_st.channels_bitmask,
> + AT91_SAMA5D2_MAX_CHAN_IDX + 1)) {
> + /* touchscreen enabling */
> + at91_adc_configure_touch(st, true);
> + return 0;
> + }
> + /* if trigger is not hardware, nothing to do here */
> + if (!st->selected_trig->hw_trig)
> + return 0;
> +
> + /* we continue with the triggered buffer */
> ret = at91_adc_dma_start(indio_dev);
> if (ret) {
> dev_err(&indio_dev->dev, "buffer postenable failed\n");
> @@ -536,6 +823,19 @@ static int at91_adc_buffer_predisable(struct iio_dev *indio_dev)
> int ret;
> u8 bit;
>
> + /* check if we are disabling triggered buffer or the touchscreen */
> + if (bitmap_subset(indio_dev->active_scan_mask,
> + &st->touch_st.channels_bitmask,
> + AT91_SAMA5D2_MAX_CHAN_IDX + 1)) {
> + /* touchscreen disable */
> + at91_adc_configure_touch(st, false);
> + return 0;
> + }
> + /* if trigger is not hardware, nothing to do here */
> + if (!st->selected_trig->hw_trig)
> + return 0;
> +
> + /* continue with the triggered buffer */
> ret = iio_triggered_buffer_predisable(indio_dev);
> if (ret < 0)
> dev_err(&indio_dev->dev, "buffer predisable failed\n");
> @@ -558,6 +858,10 @@ static int at91_adc_buffer_predisable(struct iio_dev *indio_dev)
>
> if (!chan)
> continue;
> + /* these channel types are virtual, no need to do anything */
> + if (chan->type == IIO_POSITIONRELATIVE ||
> + chan->type == IIO_PRESSURE)
> + continue;
> if (st->dma_st.dma_chan)
> at91_adc_readl(st, chan->address);
> }
> @@ -622,7 +926,22 @@ static void at91_adc_trigger_handler_nodma(struct iio_dev *indio_dev,
>
> if (!chan)
> continue;
> - st->buffer[i] = at91_adc_readl(st, chan->address);
> + /*
> + * Our external trigger only supports the voltage channels.
> + * In case someone requested a different type of channel
> + * just put zeroes to buffer.
> + * This should not happen because we check the scan mode
> + * and scan mask when we enable the buffer, and we don't allow
> + * the buffer to start with a mixed mask (voltage and something
> + * else).
> + * Thus, emit a warning.
> + */
> + if (chan->type == IIO_VOLTAGE) {
> + st->buffer[i] = at91_adc_readl(st, chan->address);
> + } else {
> + st->buffer[i] = 0;
> + WARN(true, "This trigger cannot handle this type of channel");
> + }
> i++;
> }
> iio_push_to_buffers_with_timestamp(indio_dev, st->buffer,
> @@ -688,9 +1007,20 @@ static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
>
> static int at91_adc_buffer_init(struct iio_dev *indio)
> {
> - return devm_iio_triggered_buffer_setup(&indio->dev, indio,
> + struct at91_adc_state *st = iio_priv(indio);
> +
> + if (st->selected_trig->hw_trig) {
> + return devm_iio_triggered_buffer_setup(&indio->dev, indio,
> &iio_pollfunc_store_time,
> &at91_adc_trigger_handler, &at91_buffer_setup_ops);
> + }
> + /*
> + * we need to prepare the buffer ops in case we will get
> + * another buffer attached (like a callback buffer for the touchscreen)
> + */
> + indio->setup_ops = &at91_buffer_setup_ops;
> +
> + return 0;
> }
>
> static unsigned at91_adc_startup_time(unsigned startup_time_min,
> @@ -736,19 +1066,83 @@ static void at91_adc_setup_samp_freq(struct at91_adc_state *st, unsigned freq)
>
> dev_dbg(&indio_dev->dev, "freq: %u, startup: %u, prescal: %u\n",
> freq, startup, prescal);
> + st->current_sample_rate = freq;
> }
>
> -static unsigned at91_adc_get_sample_freq(struct at91_adc_state *st)
> +static inline unsigned at91_adc_get_sample_freq(struct at91_adc_state *st)
> {
> - unsigned f_adc, f_per = clk_get_rate(st->per_clk);
> - unsigned mr, prescal;
> + return st->current_sample_rate;
> +}
>
> - mr = at91_adc_readl(st, AT91_SAMA5D2_MR);
> - prescal = (mr >> AT91_SAMA5D2_MR_PRESCAL_OFFSET)
> - & AT91_SAMA5D2_MR_PRESCAL_MAX;
> - f_adc = f_per / (2 * (prescal + 1));
> +static void at91_adc_touch_data_handler(struct iio_dev *indio_dev)
> +{
> + struct at91_adc_state *st = iio_priv(indio_dev);
> + u8 bit;
> + u16 val;
> + int i = 0;
> +
> + for_each_set_bit(bit, indio_dev->active_scan_mask,
> + AT91_SAMA5D2_MAX_CHAN_IDX + 1) {
> + struct iio_chan_spec const *chan =
> + at91_adc_chan_get(indio_dev, bit);
>
> - return f_adc;
> + if (chan->type == IIO_POSITIONRELATIVE)
> + at91_adc_read_position(st, chan->channel, &val);
> + else if (chan->type == IIO_PRESSURE)
> + at91_adc_read_pressure(st, chan->channel, &val);
> + else
> + continue;
> + st->buffer[i] = val;
> + i++;
> + }
> + /*
> + * Schedule work to push to buffers.
> + * This is intended to push to the callback buffer that another driver
> + * registered. We are still in a handler from our IRQ. If we push
> + * directly, it means the other driver has it's callback called
> + * from our IRQ context. Which is something we better avoid.
> + * Let's schedule it after our IRQ is completed.
> + */
> + schedule_work(&st->touch_st.workq);
> +}
> +
> +static void at91_adc_pen_detect_interrupt(struct at91_adc_state *st)
> +{
> + at91_adc_writel(st, AT91_SAMA5D2_IDR, AT91_SAMA5D2_IER_PEN);
> + at91_adc_writel(st, AT91_SAMA5D2_IER, AT91_SAMA5D2_IER_NOPEN |
> + AT91_SAMA5D2_IER_XRDY | AT91_SAMA5D2_IER_YRDY |
> + AT91_SAMA5D2_IER_PRDY);
> + at91_adc_writel(st, AT91_SAMA5D2_TRGR,
> + AT91_SAMA5D2_TRGR_TRGMOD_PERIODIC |
> + AT91_SAMA5D2_TRGR_TRGPER(st->touch_st.sample_period_val));
> + st->touch_st.touching = true;
> +}
> +
> +static void at91_adc_no_pen_detect_interrupt(struct at91_adc_state *st)
> +{
> + struct iio_dev *indio_dev = iio_priv_to_dev(st);
> +
> + at91_adc_writel(st, AT91_SAMA5D2_TRGR,
> + AT91_SAMA5D2_TRGR_TRGMOD_NO_TRIGGER);
> + at91_adc_writel(st, AT91_SAMA5D2_IDR, AT91_SAMA5D2_IER_NOPEN |
> + AT91_SAMA5D2_IER_XRDY | AT91_SAMA5D2_IER_YRDY |
> + AT91_SAMA5D2_IER_PRDY);
> + st->touch_st.touching = false;
> +
> + at91_adc_touch_data_handler(indio_dev);
> +
> + at91_adc_writel(st, AT91_SAMA5D2_IER, AT91_SAMA5D2_IER_PEN);
> +}
> +
> +static void at91_adc_workq_handler(struct work_struct *workq)
> +{
> + struct at91_adc_touch *touch_st = container_of(workq,
> + struct at91_adc_touch, workq);
> + struct at91_adc_state *st = container_of(touch_st,
> + struct at91_adc_state, touch_st);
> + struct iio_dev *indio_dev = iio_priv_to_dev(st);
> +
> + iio_push_to_buffers(indio_dev, st->buffer);
> }
>
> static irqreturn_t at91_adc_interrupt(int irq, void *private)
> @@ -757,17 +1151,39 @@ static irqreturn_t at91_adc_interrupt(int irq, void *private)
> struct at91_adc_state *st = iio_priv(indio);
> u32 status = at91_adc_readl(st, AT91_SAMA5D2_ISR);
> u32 imr = at91_adc_readl(st, AT91_SAMA5D2_IMR);
> + u32 rdy_mask = AT91_SAMA5D2_IER_XRDY | AT91_SAMA5D2_IER_YRDY |
> + AT91_SAMA5D2_IER_PRDY;
>
> if (!(status & imr))
> return IRQ_NONE;
> -
> - if (iio_buffer_enabled(indio) && !st->dma_st.dma_chan) {
> + if (status & AT91_SAMA5D2_IER_PEN) {
> + /* pen detected IRQ */
> + at91_adc_pen_detect_interrupt(st);
> + } else if ((status & AT91_SAMA5D2_IER_NOPEN)) {
> + /* nopen detected IRQ */
> + at91_adc_no_pen_detect_interrupt(st);
> + } else if ((status & AT91_SAMA5D2_ISR_PENS) &&
> + ((status & rdy_mask) == rdy_mask)) {
> + /* periodic trigger IRQ - during pen sense */
> + at91_adc_touch_data_handler(indio);
> + } else if (status & AT91_SAMA5D2_ISR_PENS) {
> + /*
> + * touching, but the measurements are not ready yet.
> + * read and ignore.
> + */
> + status = at91_adc_readl(st, AT91_SAMA5D2_XPOSR);
> + status = at91_adc_readl(st, AT91_SAMA5D2_YPOSR);
> + status = at91_adc_readl(st, AT91_SAMA5D2_PRESSR);
> + } else if (iio_buffer_enabled(indio) && !st->dma_st.dma_chan) {
> + /* triggered buffer without DMA */
> disable_irq_nosync(irq);
> iio_trigger_poll(indio->trig);
> } else if (iio_buffer_enabled(indio) && st->dma_st.dma_chan) {
> + /* triggered buffer with DMA - should not happen */
> disable_irq_nosync(irq);
> WARN(true, "Unexpected irq occurred\n");
> } else if (!iio_buffer_enabled(indio)) {
> + /* software requested conversion */
> st->conversion_value = at91_adc_readl(st, st->chan->address);
> st->conversion_done = true;
> wake_up_interruptible(&st->wq_data_available);
> @@ -775,58 +1191,81 @@ static irqreturn_t at91_adc_interrupt(int irq, void *private)
> return IRQ_HANDLED;
> }
>
> -static int at91_adc_read_raw(struct iio_dev *indio_dev,
> - struct iio_chan_spec const *chan,
> - int *val, int *val2, long mask)
> +static int at91_adc_read_info_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan, int *val)
> {
> struct at91_adc_state *st = iio_priv(indio_dev);
> u32 cor = 0;
> int ret;
>
> - switch (mask) {
> - case IIO_CHAN_INFO_RAW:
> - /* we cannot use software trigger if hw trigger enabled */
> - ret = iio_device_claim_direct_mode(indio_dev);
> - if (ret)
> - return ret;
> - mutex_lock(&st->lock);
> + /*
> + * we cannot use software trigger or touchscreen
> + * if external trigger is enabled
> + */
> + ret = iio_device_claim_direct_mode(indio_dev);
> + if (ret)
> + return ret;
> + mutex_lock(&st->lock);
>
> - st->chan = chan;
> + if (chan->type == IIO_POSITIONRELATIVE) {
> + ret = at91_adc_read_position(st, chan->channel,
> + (u16 *)val);
> + goto at91_adc_read_info_raw_exit;
I know it is more lines of code, but I think I'd prefer to
get rid of this long goto as it's not an error case.

I would suggest moving the mutex inside this if statement
(and the next one) and do the lock / unlock / return all
within the if. For the other path, take the mutex after
these if statements.

> + }
> + if (chan->type == IIO_PRESSURE) {
> + ret = at91_adc_read_pressure(st, chan->channel,
> + (u16 *)val);
> + goto at91_adc_read_info_raw_exit;
> + }
>
> - if (chan->differential)
> - cor = (BIT(chan->channel) | BIT(chan->channel2)) <<
> - AT91_SAMA5D2_COR_DIFF_OFFSET;
> -
> - at91_adc_writel(st, AT91_SAMA5D2_COR, cor);
> - at91_adc_writel(st, AT91_SAMA5D2_CHER, BIT(chan->channel));
> - at91_adc_writel(st, AT91_SAMA5D2_IER, BIT(chan->channel));
> - at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_START);
> -
> - ret = wait_event_interruptible_timeout(st->wq_data_available,
> - st->conversion_done,
> - msecs_to_jiffies(1000));
> - if (ret == 0)
> - ret = -ETIMEDOUT;
> -
> - if (ret > 0) {
> - *val = st->conversion_value;
> - if (chan->scan_type.sign == 's')
> - *val = sign_extend32(*val, 11);
> - ret = IIO_VAL_INT;
> - st->conversion_done = false;
> - }
> + st->chan = chan;
> +
> + if (chan->differential)
> + cor = (BIT(chan->channel) | BIT(chan->channel2)) <<
> + AT91_SAMA5D2_COR_DIFF_OFFSET;
> +
> + at91_adc_writel(st, AT91_SAMA5D2_COR, cor);
> + at91_adc_writel(st, AT91_SAMA5D2_CHER, BIT(chan->channel));
> + at91_adc_writel(st, AT91_SAMA5D2_IER, BIT(chan->channel));
> + at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_START);
> +
> + ret = wait_event_interruptible_timeout(st->wq_data_available,
> + st->conversion_done,
> + msecs_to_jiffies(1000));
> + if (ret == 0)
> + ret = -ETIMEDOUT;
> +
> + if (ret > 0) {
> + *val = st->conversion_value;
> + if (chan->scan_type.sign == 's')
> + *val = sign_extend32(*val, 11);
> + ret = IIO_VAL_INT;
> + st->conversion_done = false;
> + }
> +
> + at91_adc_writel(st, AT91_SAMA5D2_IDR, BIT(chan->channel));
> + at91_adc_writel(st, AT91_SAMA5D2_CHDR, BIT(chan->channel));
>
> - at91_adc_writel(st, AT91_SAMA5D2_IDR, BIT(chan->channel));
> - at91_adc_writel(st, AT91_SAMA5D2_CHDR, BIT(chan->channel));
> + /* Needed to ACK the DRDY interruption */
> + at91_adc_readl(st, AT91_SAMA5D2_LCDR);
>
> - /* Needed to ACK the DRDY interruption */
> - at91_adc_readl(st, AT91_SAMA5D2_LCDR);
> +at91_adc_read_info_raw_exit:
>
> - mutex_unlock(&st->lock);
> + mutex_unlock(&st->lock);
>
> - iio_device_release_direct_mode(indio_dev);
> - return ret;
> + iio_device_release_direct_mode(indio_dev);
> + return ret;
> +}
>
> +static int at91_adc_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long mask)
> +{
> + struct at91_adc_state *st = iio_priv(indio_dev);
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + return at91_adc_read_info_raw(indio_dev, chan, val);
> case IIO_CHAN_INFO_SCALE:
> *val = st->vref_uv / 1000;
> if (chan->differential)
> @@ -974,9 +1413,29 @@ static int at91_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val)
> return 0;
> }
>
> +static int at91_adc_update_scan_mode(struct iio_dev *indio_dev,
> + const unsigned long *scan_mask)
> +{
> + struct at91_adc_state *st = iio_priv(indio_dev);
> +
> + if (bitmap_subset(scan_mask, &st->touch_st.channels_bitmask,
> + AT91_SAMA5D2_MAX_CHAN_IDX + 1))
> + return 0;
> + /*
> + * if the new bitmap is a combination of touchscreen and regular
> + * channels, then we are not fine
> + */
> + if (bitmap_intersects(&st->touch_st.channels_bitmask, scan_mask,
> + AT91_SAMA5D2_MAX_CHAN_IDX + 1))
> + return -EBUSY;
> + return 0;
> +}
> +
> static const struct iio_info at91_adc_info = {
> .read_raw = &at91_adc_read_raw,
> .write_raw = &at91_adc_write_raw,
> + .update_scan_mode = &at91_adc_update_scan_mode,
> + .of_xlate = &at91_adc_of_xlate,
> .hwfifo_set_watermark = &at91_adc_set_watermark,
> };
>
> @@ -1044,13 +1503,20 @@ static int at91_adc_probe(struct platform_device *pdev)
>
> indio_dev->dev.parent = &pdev->dev;
> indio_dev->name = dev_name(&pdev->dev);
> - indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
> indio_dev->info = &at91_adc_info;
> indio_dev->channels = at91_adc_channels;
> indio_dev->num_channels = ARRAY_SIZE(at91_adc_channels);
>
> st = iio_priv(indio_dev);
>
> + bitmap_set(&st->touch_st.channels_bitmask,
> + AT91_SAMA5D2_TOUCH_X_CHAN_IDX, 1);
> + bitmap_set(&st->touch_st.channels_bitmask,
> + AT91_SAMA5D2_TOUCH_Y_CHAN_IDX, 1);
> + bitmap_set(&st->touch_st.channels_bitmask,
> + AT91_SAMA5D2_TOUCH_P_CHAN_IDX, 1);
> +
> ret = of_property_read_u32(pdev->dev.of_node,
> "atmel,min-sample-rate-hz",
> &st->soc_info.min_sample_rate);
> @@ -1100,6 +1566,7 @@ static int at91_adc_probe(struct platform_device *pdev)
>
> init_waitqueue_head(&st->wq_data_available);
> mutex_init(&st->lock);
> + INIT_WORK(&st->touch_st.workq, at91_adc_workq_handler);
>
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> if (!res)
> @@ -1159,13 +1626,13 @@ static int at91_adc_probe(struct platform_device *pdev)
>
> platform_set_drvdata(pdev, indio_dev);
>
> - if (st->selected_trig->hw_trig) {
> - ret = at91_adc_buffer_init(indio_dev);
> - if (ret < 0) {
> - dev_err(&pdev->dev, "couldn't initialize the buffer.\n");
> - goto per_clk_disable_unprepare;
> - }
> + ret = at91_adc_buffer_init(indio_dev);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "couldn't initialize the buffer.\n");
> + goto per_clk_disable_unprepare;
> + }
>
> + if (st->selected_trig->hw_trig) {
> ret = at91_adc_trigger_init(indio_dev);
> if (ret < 0) {
> dev_err(&pdev->dev, "couldn't setup the triggers.\n");
> @@ -1272,8 +1739,18 @@ static __maybe_unused int at91_adc_resume(struct device *dev)
> at91_adc_hw_init(st);
>
> /* reconfiguring trigger hardware state */
> - if (iio_buffer_enabled(indio_dev))
> + if (!iio_buffer_enabled(indio_dev))
> + return 0;
> +
> + /* check if we are enabling triggered buffer or the touchscreen */
> + if (bitmap_subset(indio_dev->active_scan_mask,
> + &st->touch_st.channels_bitmask,
> + AT91_SAMA5D2_MAX_CHAN_IDX + 1)) {
> + /* touchscreen enabling */
> + at91_adc_configure_touch(st, true);
> + } else {
> at91_adc_configure_trigger(st->trig, true);
> + }
>
> return 0;
>

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