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SubjectRe: [PATCH v7 5/9] iio: adc: at91-sama5d2_adc: add support for position and pressure channels
On Tue, 22 May 2018 14:22:44 +0200
Ludovic Desroches <ludovic.desroches@microchip.com> wrote:

> On Tue, May 22, 2018 at 10:52:35AM +0300, Eugen Hristev 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>
> Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>

Applied, thanks.

Jonathan
>
> > ---
> > Changes in v6:
> > - fixed a crash when issuing buffer enable from sysfs, if no trigger was
> > previously configured. This is because now the driver can work in software
> > buffer mode (to connect the callback buffer). So, when trying to enable the
> > buffer, check if we are going indeed to a triggered mode or not. If not, do
> > not allow buffer to be started (we do not have the right trigger).
> > It's in buffer_postenable and predisable.
> >
> > Changes in v4:
> > - use return value of at91_adc_configure_touch
> > - rewrote some part of the read_info_raw according to Jonathan's
> > suggestion
> >
> > 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 | 609 +++++++++++++++++++++++++++++++++----
> > 1 file changed, 551 insertions(+), 58 deletions(-)
> >
> > diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
> > index 8729d65..58c4c2b 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 +644,11 @@ 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;
> > +
> > if (state) {
> > at91_adc_writel(st, AT91_SAMA5D2_CHER,
> > BIT(chan->channel));
> > @@ -520,7 +794,20 @@ 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 */
> > + return at91_adc_configure_touch(st, true);
> > + }
> > + /* if we are not in triggered mode, we cannot enable the buffer. */
> > + if (!(indio_dev->currentmode & INDIO_ALL_TRIGGERED_MODES))
> > + return -EINVAL;
> > +
> > + /* 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 +823,18 @@ 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 */
> > + return at91_adc_configure_touch(st, false);
> > + }
> > + /* if we are not in triggered mode, nothing to do here */
> > + if (!(indio_dev->currentmode & INDIO_ALL_TRIGGERED_MODES))
> > + return -EINVAL;
> > +
> > + /* 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 +857,10 @@ 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 +925,22 @@ 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 +1006,20 @@ 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 +1065,83 @@ 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;
> >
> > - return f_adc;
> > + 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);
> > +
> > + 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 +1150,39 @@ 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 +1190,97 @@ 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 */
> > + /*
> > + * Keep in mind that we cannot use software trigger or touchscreen
> > + * if external trigger is enabled
> > + */
> > + if (chan->type == IIO_POSITIONRELATIVE) {
> > ret = iio_device_claim_direct_mode(indio_dev);
> > if (ret)
> > return ret;
> > mutex_lock(&st->lock);
> >
> > - st->chan = chan;
> > + ret = at91_adc_read_position(st, chan->channel,
> > + (u16 *)val);
> > + mutex_unlock(&st->lock);
> > + iio_device_release_direct_mode(indio_dev);
> >
> > - 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;
> > - }
> > + return ret;
> > + }
> > + if (chan->type == IIO_PRESSURE) {
> > + ret = iio_device_claim_direct_mode(indio_dev);
> > + if (ret)
> > + return ret;
> > + mutex_lock(&st->lock);
> >
> > - at91_adc_writel(st, AT91_SAMA5D2_IDR, BIT(chan->channel));
> > - at91_adc_writel(st, AT91_SAMA5D2_CHDR, BIT(chan->channel));
> > + ret = at91_adc_read_pressure(st, chan->channel,
> > + (u16 *)val);
> > + mutex_unlock(&st->lock);
> > + iio_device_release_direct_mode(indio_dev);
> >
> > - /* Needed to ACK the DRDY interruption */
> > - at91_adc_readl(st, AT91_SAMA5D2_LCDR);
> > + return ret;
> > + }
> >
> > - mutex_unlock(&st->lock);
> > + /* in this case we have a voltage channel */
> >
> > - iio_device_release_direct_mode(indio_dev);
> > + ret = iio_device_claim_direct_mode(indio_dev);
> > + if (ret)
> > return ret;
> > + mutex_lock(&st->lock);
> > +
> > + 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));
> > +
> > + /* Needed to ACK the DRDY interruption */
> > + at91_adc_readl(st, AT91_SAMA5D2_LCDR);
> > +
> > + mutex_unlock(&st->lock);
> > +
> > + 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 +1428,29 @@ 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 -EINVAL;
> > + 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 +1518,20 @@ 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 +1581,7 @@ 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 +1641,13 @@ 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");
> > @@ -1272,9 +1754,20 @@ 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))
> > - at91_adc_configure_trigger(st->trig, true);
> > + 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 */
> > + return at91_adc_configure_touch(st, true);
> > + } else {
> > + return at91_adc_configure_trigger(st->trig, true);
> > + }
> >
> > + /* not needed but more explicit */
> > return 0;
> >
> > vref_disable_resume:
> > --
> > 2.7.4
> >

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