[PATCH 1/2 V4] iio: mxs: Implement support for touchscreen
Dmitry Torokhov
dmitry.torokhov at gmail.com
Sat Jan 12 22:09:03 EST 2013
On Sat, Jan 12, 2013 at 12:35:07AM +0100, Marek Vasut wrote:
> This patch implements support for sampling of a touchscreen into
> the MXS LRADC driver. The LRADC block allows configuring some of
> it's channels into special mode where they either output the drive
> voltage or sample it, allowing it to operate a 4-wire or 5-wire
> resistive touchscreen.
>
> In case the touchscreen mode is enabled, the LRADC slot #7 is
> reserved for touchscreen only, therefore it is not possible to
> sample 8 LRADC channels at time, but only 7 channels.
>
> The touchscreen controller is configured such that the PENDOWN event
> disables touchscreen interrupts and triggers execution of worker
> thread, which then polls the touchscreen controller for X, Y and
> Pressure values. This reduces the overhead of interrupt-driven
> operation. Upon the PENUP event, the worker thread re-enables the
> PENDOWN detection interrupt and exits.
>
> Signed-off-by: Marek Vasut <marex at denx.de>
> Cc: Dmitry Torokhov <dmitry.torokhov at gmail.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov at gmail.com>
> Cc: Fabio Estevam <fabio.estevam at freescale.com>
> Cc: Jonathan Cameron <jic23 at kernel.org>
> Cc: Shawn Guo <shawn.guo at linaro.org>
> ---
> .../bindings/staging/iio/adc/mxs-lradc.txt | 6 +
> drivers/staging/iio/adc/mxs-lradc.c | 472 +++++++++++++++++++-
> 2 files changed, 454 insertions(+), 24 deletions(-)
>
> V2: - Replace the use_touchscreen* with enum mxs_lradc_ts, which now tracks
> touchscreen state (OFF, 4-wire, 5-wire)
> - Add "stop_touchscreen" bit, which indicates the touchscreen is going down
> and makes the driver not re-enable touchscreen interrupts and start any
> new touchscreen works.
> - Make all bitfields "unsigned int" instead of plain "int"
> - Use switch(plate) in mxs_lradc_ts_sample()
> - Cancel touchscreen thread in mxs_lradc_ts_close(), do this only after
> we are sure touchscreen interrupt is off and will never be re-enabled.
> This avoids serious race condition.
> - Call input_free_device() if input_register_device() fails to avoid memory
> leak.
> - Do not call input_free_device() after input_unregister_device() in
> mxs_lradc_ts_unregister() to avoid double-free
>
> V3: - Replace bitfields with bools
> - Make sure touchscreen workQ doesn't cause race condition upon closing
> the input device
> - Make touchscreen allocation failure fatal
> - Remove redundant check for lradc->ts_input in mxs_lradc_ts_unregister()
> - Drop __devinit and __devexit
>
> V4: - Do not unconfigure lradc->use_touchscreen in mxs_lradc_ts_register()
> when the probe fails
> - Return true/false from mxs_lradc_validate_scan_mask() instead of 1/0
>
> diff --git a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
> index 801d58c..4688205 100644
> --- a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
> +++ b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
> @@ -5,6 +5,12 @@ Required properties:
> - reg: Address and length of the register set for the device
> - interrupts: Should contain the LRADC interrupts
>
> +Optional properties:
> +- fsl,lradc-touchscreen-wires: Number of wires used to connect the touchscreen
> + to LRADC. Valid value is either 4 or 5. If this
> + property is not present, then the touchscreen is
> + disabled.
> +
> Examples:
>
> lradc at 80050000 {
> diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
> index 6249957..5a544d4 100644
> --- a/drivers/staging/iio/adc/mxs-lradc.c
> +++ b/drivers/staging/iio/adc/mxs-lradc.c
> @@ -32,6 +32,8 @@
> #include <linux/stmp_device.h>
> #include <linux/bitops.h>
> #include <linux/completion.h>
> +#include <linux/delay.h>
> +#include <linux/input.h>
>
> #include <mach/mxs.h>
> #include <mach/common.h>
> @@ -59,6 +61,21 @@
> #define LRADC_DELAY_TIMER_PER 200
> #define LRADC_DELAY_TIMER_LOOP 5
>
> +/*
> + * Once the pen touches the touchscreen, the touchscreen switches from
> + * IRQ-driven mode to polling mode to prevent interrupt storm. The polling
> + * is realized by worker thread, which is called every 20 or so milliseconds.
> + * This gives the touchscreen enough fluence and does not strain the system
> + * too much.
> + */
> +#define LRADC_TS_SAMPLE_DELAY_MS 5
> +
> +/*
> + * The LRADC reads the following amount of samples from each touchscreen
> + * channel and the driver then computes avarage of these.
> + */
> +#define LRADC_TS_SAMPLE_AMOUNT 4
> +
> static const char * const mxs_lradc_irq_name[] = {
> "mxs-lradc-touchscreen",
> "mxs-lradc-thresh0",
> @@ -75,6 +92,12 @@ static const char * const mxs_lradc_irq_name[] = {
> "mxs-lradc-button1",
> };
>
> +enum mxs_lradc_ts {
> + MXS_LRADC_TOUCHSCREEN_NONE = 0,
> + MXS_LRADC_TOUCHSCREEN_4WIRE,
> + MXS_LRADC_TOUCHSCREEN_5WIRE,
> +};
> +
> struct mxs_lradc {
> struct device *dev;
> void __iomem *base;
> @@ -86,21 +109,69 @@ struct mxs_lradc {
> struct mutex lock;
>
> struct completion completion;
> +
> + /*
> + * Touchscreen LRADC channels receives a private slot in the CTRL4
> + * register, the slot #7. Therefore only 7 slots instead of 8 in the
> + * CTRL4 register can be mapped to LRADC channels when using the
> + * touchscreen.
> + *
> + * Furthermore, certain LRADC channels are shared between touchscreen
> + * and/or touch-buttons and generic LRADC block. Therefore when using
> + * either of these, these channels are not available for the regular
> + * sampling. The shared channels are as follows:
> + *
> + * CH0 -- Touch button #0
> + * CH1 -- Touch button #1
> + * CH2 -- Touch screen XPUL
> + * CH3 -- Touch screen YPLL
> + * CH4 -- Touch screen XNUL
> + * CH5 -- Touch screen YNLR
> + * CH6 -- Touch screen WIPER (5-wire only)
> + *
> + * The bitfields below represents which parts of the LRADC block are
> + * switched into special mode of operation. These channels can not
> + * be sampled as regular LRADC channels. The driver will refuse any
> + * attempt to sample these channels.
> + */
> +#define CHAN_MASK_TOUCHBUTTON (0x3 << 0)
> +#define CHAN_MASK_TOUCHSCREEN_4WIRE (0xf << 2)
> +#define CHAN_MASK_TOUCHSCREEN_5WIRE (0x1f << 2)
> + enum mxs_lradc_ts use_touchscreen;
> + bool stop_touchscreen;
> + bool use_touchbutton;
> +
> + struct input_dev *ts_input;
> + struct work_struct ts_work;
> };
>
> #define LRADC_CTRL0 0x00
> -#define LRADC_CTRL0_TOUCH_DETECT_ENABLE (1 << 23)
> -#define LRADC_CTRL0_TOUCH_SCREEN_TYPE (1 << 22)
> +#define LRADC_CTRL0_TOUCH_DETECT_ENABLE (1 << 23)
> +#define LRADC_CTRL0_TOUCH_SCREEN_TYPE (1 << 22)
> +#define LRADC_CTRL0_YNNSW /* YM */ (1 << 21)
> +#define LRADC_CTRL0_YPNSW /* YP */ (1 << 20)
> +#define LRADC_CTRL0_YPPSW /* YP */ (1 << 19)
> +#define LRADC_CTRL0_XNNSW /* XM */ (1 << 18)
> +#define LRADC_CTRL0_XNPSW /* XM */ (1 << 17)
> +#define LRADC_CTRL0_XPPSW /* XP */ (1 << 16)
> +#define LRADC_CTRL0_PLATE_MASK (0x3f << 16)
>
> #define LRADC_CTRL1 0x10
> -#define LRADC_CTRL1_LRADC_IRQ(n) (1 << (n))
> -#define LRADC_CTRL1_LRADC_IRQ_MASK 0x1fff
> +#define LRADC_CTRL1_TOUCH_DETECT_IRQ_EN (1 << 24)
> #define LRADC_CTRL1_LRADC_IRQ_EN(n) (1 << ((n) + 16))
> #define LRADC_CTRL1_LRADC_IRQ_EN_MASK (0x1fff << 16)
> +#define LRADC_CTRL1_LRADC_IRQ_EN_OFFSET 16
> +#define LRADC_CTRL1_TOUCH_DETECT_IRQ (1 << 8)
> +#define LRADC_CTRL1_LRADC_IRQ(n) (1 << (n))
> +#define LRADC_CTRL1_LRADC_IRQ_MASK 0x1fff
> +#define LRADC_CTRL1_LRADC_IRQ_OFFSET 0
>
> #define LRADC_CTRL2 0x20
> #define LRADC_CTRL2_TEMPSENSE_PWD (1 << 15)
>
> +#define LRADC_STATUS 0x40
> +#define LRADC_STATUS_TOUCH_DETECT_RAW (1 << 0)
> +
> #define LRADC_CH(n) (0x50 + (0x10 * (n)))
> #define LRADC_CH_ACCUMULATE (1 << 29)
> #define LRADC_CH_NUM_SAMPLES_MASK (0x1f << 24)
> @@ -132,6 +203,7 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
> {
> struct mxs_lradc *lradc = iio_priv(iio_dev);
> int ret;
> + unsigned long mask;
>
> if (m != IIO_CHAN_INFO_RAW)
> return -EINVAL;
> @@ -140,6 +212,12 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
> if (chan->channel > LRADC_MAX_TOTAL_CHANS)
> return -EINVAL;
>
> + /* Validate the channel if it doesn't intersect with reserved chans. */
> + bitmap_set(&mask, chan->channel, 1);
> + ret = iio_validate_scan_mask_onehot(iio_dev, &mask);
> + if (ret)
> + return -EINVAL;
> +
> /*
> * See if there is no buffered operation in progess. If there is, simply
> * bail out. This can be improved to support both buffered and raw IO at
> @@ -161,7 +239,11 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
> lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
> writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
>
> - writel(chan->channel, lradc->base + LRADC_CTRL4);
> + /* Clean the slot's previous content, then set new one. */
> + writel(LRADC_CTRL4_LRADCSELECT_MASK(0),
> + lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
> + writel(chan->channel, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
> +
> writel(0, lradc->base + LRADC_CH(0));
>
> /* Enable the IRQ and start sampling the channel. */
> @@ -195,6 +277,269 @@ static const struct iio_info mxs_lradc_iio_info = {
> };
>
> /*
> + * Touchscreen handling
> + */
> +enum lradc_ts_plate {
> + LRADC_SAMPLE_X,
> + LRADC_SAMPLE_Y,
> + LRADC_SAMPLE_PRESSURE,
> +};
> +
> +static int mxs_lradc_ts_touched(struct mxs_lradc *lradc)
> +{
> + uint32_t reg;
> +
> + /* Enable touch detection. */
> + writel(LRADC_CTRL0_PLATE_MASK,
> + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
> + writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
> + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
> +
> + msleep(LRADC_TS_SAMPLE_DELAY_MS);
> +
> + reg = readl(lradc->base + LRADC_STATUS);
> +
> + return reg & LRADC_STATUS_TOUCH_DETECT_RAW;
> +}
> +
> +static int32_t mxs_lradc_ts_sample(struct mxs_lradc *lradc,
> + enum lradc_ts_plate plate, int change)
> +{
> + unsigned long delay, jiff;
> + uint32_t reg, ctrl0 = 0, chan = 0;
> + /* The touchscreen always uses CTRL4 slot #7. */
> + const uint8_t slot = 7;
> + uint32_t val;
> +
> + /*
> + * There are three correct configurations of the controller sampling
> + * the touchscreen, each of these configuration provides different
> + * information from the touchscreen.
> + *
> + * The following table describes the sampling configurations:
> + * +-------------+-------+-------+-------+
> + * | Wire \ Axis | X | Y | Z |
> + * +---------------------+-------+-------+
> + * | X+ (CH2) | HI | TS | TS |
> + * +-------------+-------+-------+-------+
> + * | X- (CH4) | LO | SH | HI |
> + * +-------------+-------+-------+-------+
> + * | Y+ (CH3) | SH | HI | HI |
> + * +-------------+-------+-------+-------+
> + * | Y- (CH5) | TS | LO | SH |
> + * +-------------+-------+-------+-------+
> + *
> + * HI ... strong '1' ; LO ... strong '0'
> + * SH ... sample here ; TS ... tri-state
> + *
> + * There are a few other ways of obtaining the Z coordinate
> + * (aka. pressure), but the one in the table seems to be the
> + * most reliable one.
> + */
> + switch (plate) {
> + case LRADC_SAMPLE_X:
> + ctrl0 = LRADC_CTRL0_XPPSW | LRADC_CTRL0_XNNSW;
> + chan = 3;
> + break;
> + case LRADC_SAMPLE_Y:
> + ctrl0 = LRADC_CTRL0_YPPSW | LRADC_CTRL0_YNNSW;
> + chan = 4;
> + break;
> + case LRADC_SAMPLE_PRESSURE:
> + ctrl0 = LRADC_CTRL0_YPPSW | LRADC_CTRL0_XNNSW;
> + chan = 5;
> + break;
> + }
> +
> + if (change) {
> + writel(LRADC_CTRL0_PLATE_MASK,
> + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
> + writel(ctrl0, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
> +
> + writel(LRADC_CTRL4_LRADCSELECT_MASK(slot),
> + lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
> + writel(chan << LRADC_CTRL4_LRADCSELECT_OFFSET(slot),
> + lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
> + }
> +
> + writel(0xffffffff, lradc->base + LRADC_CH(slot) + STMP_OFFSET_REG_CLR);
> + writel(1 << slot, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
> +
> + delay = jiffies + msecs_to_jiffies(LRADC_TS_SAMPLE_DELAY_MS);
> + do {
> + jiff = jiffies;
> + reg = readl_relaxed(lradc->base + LRADC_CTRL1);
> + if (reg & LRADC_CTRL1_LRADC_IRQ(slot))
> + break;
> + } while (time_before(jiff, delay));
> +
> + writel(LRADC_CTRL1_LRADC_IRQ(slot),
> + lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
> +
> + if (time_after_eq(jiff, delay))
> + return -ETIMEDOUT;
> +
> + val = readl(lradc->base + LRADC_CH(slot));
> + val &= LRADC_CH_VALUE_MASK;
> +
> + return val;
> +}
> +
> +static int32_t mxs_lradc_ts_sample_filter(struct mxs_lradc *lradc,
> + enum lradc_ts_plate plate)
> +{
> + int32_t val, tot = 0;
> + int i;
> +
> + val = mxs_lradc_ts_sample(lradc, plate, 1);
> +
> + /* Delay a bit so the touchscreen is stable. */
> + mdelay(2);
> +
> + for (i = 0; i < LRADC_TS_SAMPLE_AMOUNT; i++) {
> + val = mxs_lradc_ts_sample(lradc, plate, 0);
> + tot += val;
> + }
> +
> + return tot / LRADC_TS_SAMPLE_AMOUNT;
> +}
> +
> +static void mxs_lradc_ts_work(struct work_struct *ts_work)
> +{
> + struct mxs_lradc *lradc = container_of(ts_work,
> + struct mxs_lradc, ts_work);
> + int val_x, val_y, val_p;
> + bool valid = false;
> +
> + while (mxs_lradc_ts_touched(lradc)) {
> + /* Disable touch detector so we can sample the touchscreen. */
> + writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
> + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
> +
> + if (likely(valid)) {
> + input_report_abs(lradc->ts_input, ABS_X, val_x);
> + input_report_abs(lradc->ts_input, ABS_Y, val_y);
> + input_report_abs(lradc->ts_input, ABS_PRESSURE, val_p);
> + input_report_key(lradc->ts_input, BTN_TOUCH, 1);
> + input_sync(lradc->ts_input);
> + }
> +
> + valid = false;
> +
> + val_x = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_X);
> + if (val_x < 0)
> + continue;
> + val_y = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_Y);
> + if (val_y < 0)
> + continue;
> + val_p = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_PRESSURE);
> + if (val_p < 0)
> + continue;
> +
> + valid = true;
> + }
> +
> + input_report_abs(lradc->ts_input, ABS_PRESSURE, 0);
> + input_report_key(lradc->ts_input, BTN_TOUCH, 0);
> + input_sync(lradc->ts_input);
> +
> + /* Do not restart the TS IRQ if the driver is shutting down. */
> + if (lradc->stop_touchscreen)
> + return;
> +
> + /* Restart the touchscreen interrupts. */
> + writel(LRADC_CTRL1_TOUCH_DETECT_IRQ,
> + lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
> + writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
> + lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
> +}
> +
> +static int mxs_lradc_ts_open(struct input_dev *dev)
> +{
> + struct mxs_lradc *lradc = input_get_drvdata(dev);
> +
> + /* The touchscreen is starting. */
> + lradc->stop_touchscreen = false;
> +
> + /* Enable the touch-detect circuitry. */
> + writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
> + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
> +
> + /* Enable the touch-detect IRQ. */
> + writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
> + lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
> +
> + return 0;
> +}
> +
> +static void mxs_lradc_ts_close(struct input_dev *dev)
> +{
> + struct mxs_lradc *lradc = input_get_drvdata(dev);
> +
> + /* Indicate the touchscreen is stopping. */
> + lradc->stop_touchscreen = true;
> + mb();
> +
> + /* Wait until touchscreen thread finishes any possible remnants. */
> + cancel_work_sync(&lradc->ts_work);
> +
> + /* Disable touchscreen touch-detect IRQ. */
> + writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
> + lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
> +
> + /* Power-down touchscreen touch-detect circuitry. */
> + writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
> + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
> +}
> +
> +static int mxs_lradc_ts_register(struct mxs_lradc *lradc)
> +{
> + struct input_dev *input;
> + struct device *dev = lradc->dev;
> + int ret;
> +
> + if (!lradc->use_touchscreen)
> + return 0;
> +
> + input = input_allocate_device();
> + if (!input) {
> + dev_err(dev, "Failed to allocate TS device!\n");
> + return -ENOMEM;
> + }
> +
> + input->name = DRIVER_NAME;
> + input->id.bustype = BUS_HOST;
> + input->dev.parent = dev;
> + input->open = mxs_lradc_ts_open;
> + input->close = mxs_lradc_ts_close;
> +
> + __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, LRADC_CH_VALUE_MASK, 0, 0);
> + input_set_abs_params(input, ABS_Y, 0, LRADC_CH_VALUE_MASK, 0, 0);
> + input_set_abs_params(input, ABS_PRESSURE, 0, LRADC_CH_VALUE_MASK, 0, 0);
> +
> + lradc->ts_input = input;
> + input_set_drvdata(input, lradc);
> + ret = input_register_device(input);
> + if (ret)
> + input_free_device(lradc->ts_input);
> +
> + return ret;
> +}
> +
> +static void mxs_lradc_ts_unregister(struct mxs_lradc *lradc)
> +{
> + if (!lradc->use_touchscreen)
> + return;
> +
> + cancel_work_sync(&lradc->ts_work);
> +
> + input_unregister_device(lradc->ts_input);
> +}
> +
> +/*
> * IRQ Handling
> */
> static irqreturn_t mxs_lradc_handle_irq(int irq, void *data)
> @@ -202,14 +547,24 @@ static irqreturn_t mxs_lradc_handle_irq(int irq, void *data)
> struct iio_dev *iio = data;
> struct mxs_lradc *lradc = iio_priv(iio);
> unsigned long reg = readl(lradc->base + LRADC_CTRL1);
> + const uint32_t ts_irq_mask =
> + LRADC_CTRL1_TOUCH_DETECT_IRQ_EN |
> + LRADC_CTRL1_TOUCH_DETECT_IRQ;
>
> if (!(reg & LRADC_CTRL1_LRADC_IRQ_MASK))
> return IRQ_NONE;
>
> /*
> - * Touchscreen IRQ handling code shall probably have priority
> - * and therefore shall be placed here.
> + * Touchscreen IRQ handling code has priority and therefore
> + * is placed here. In case touchscreen IRQ arrives, disable
> + * it ASAP
> */
> + if (reg & LRADC_CTRL1_TOUCH_DETECT_IRQ) {
> + writel(ts_irq_mask,
> + lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
> + if (!lradc->stop_touchscreen)
> + schedule_work(&lradc->ts_work);
> + }
>
> if (iio_buffer_enabled(iio))
> iio_trigger_poll(iio->trig, iio_get_time_ns());
> @@ -306,8 +661,10 @@ static int mxs_lradc_buffer_preenable(struct iio_dev *iio)
> {
> struct mxs_lradc *lradc = iio_priv(iio);
> struct iio_buffer *buffer = iio->buffer;
> - int ret = 0, chan, ofs = 0, enable = 0;
> - uint32_t ctrl4 = 0;
> + int ret = 0, chan, ofs = 0;
> + unsigned long enable = 0;
> + uint32_t ctrl4_set = 0;
> + uint32_t ctrl4_clr = 0;
> uint32_t ctrl1_irq = 0;
> const uint32_t chan_value = LRADC_CH_ACCUMULATE |
> ((LRADC_DELAY_TIMER_LOOP - 1) << LRADC_CH_NUM_SAMPLES_OFFSET);
> @@ -339,17 +696,20 @@ static int mxs_lradc_buffer_preenable(struct iio_dev *iio)
> writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
>
> for_each_set_bit(chan, buffer->scan_mask, LRADC_MAX_TOTAL_CHANS) {
> - ctrl4 |= chan << LRADC_CTRL4_LRADCSELECT_OFFSET(ofs);
> + ctrl4_set |= chan << LRADC_CTRL4_LRADCSELECT_OFFSET(ofs);
> + ctrl4_clr |= LRADC_CTRL4_LRADCSELECT_MASK(ofs);
> ctrl1_irq |= LRADC_CTRL1_LRADC_IRQ_EN(ofs);
> writel(chan_value, lradc->base + LRADC_CH(ofs));
> - enable |= 1 << ofs;
> + bitmap_set(&enable, ofs, 1);
> ofs++;
> };
>
> writel(LRADC_DELAY_TRIGGER_LRADCS_MASK | LRADC_DELAY_KICK,
> lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_CLR);
>
> - writel(ctrl4, lradc->base + LRADC_CTRL4);
> + writel(ctrl4_clr, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
> + writel(ctrl4_set, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
> +
> writel(ctrl1_irq, lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
>
> writel(enable << LRADC_DELAY_TRIGGER_LRADCS_OFFSET,
> @@ -384,9 +744,33 @@ static int mxs_lradc_buffer_postdisable(struct iio_dev *iio)
> static bool mxs_lradc_validate_scan_mask(struct iio_dev *iio,
> const unsigned long *mask)
> {
> - const int mw = bitmap_weight(mask, iio->masklength);
> -
> - return mw <= LRADC_MAX_MAPPED_CHANS;
> + struct mxs_lradc *lradc = iio_priv(iio);
> + const int len = iio->masklength;
> + const int map_chans = bitmap_weight(mask, len);
> + int rsvd_chans = 0;
> + unsigned long rsvd_mask = 0;
> +
> + if (lradc->use_touchbutton)
> + rsvd_mask |= CHAN_MASK_TOUCHBUTTON;
> + if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_4WIRE)
> + rsvd_mask |= CHAN_MASK_TOUCHSCREEN_4WIRE;
> + if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE)
> + rsvd_mask |= CHAN_MASK_TOUCHSCREEN_5WIRE;
> +
> + if (lradc->use_touchbutton)
> + rsvd_chans++;
> + if (lradc->use_touchscreen)
> + rsvd_chans++;
> +
> + /* Test for attempts to map channels with special mode of operation. */
> + if (bitmap_intersects(mask, &rsvd_mask, len))
> + return false;
> +
> + /* Test for attempts to map more channels then available slots. */
> + if (map_chans + rsvd_chans > LRADC_MAX_MAPPED_CHANS)
> + return false;
> +
> + return true;
> }
>
> static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = {
> @@ -435,15 +819,29 @@ static const struct iio_chan_spec mxs_lradc_chan_spec[] = {
>
> static void mxs_lradc_hw_init(struct mxs_lradc *lradc)
> {
> - int i;
> - const uint32_t cfg =
> + /* The ADC always uses DELAY CHANNEL 0. */
> + const uint32_t adc_cfg =
> + (1 << (LRADC_DELAY_TRIGGER_DELAYS_OFFSET + 0)) |
> (LRADC_DELAY_TIMER_PER << LRADC_DELAY_DELAY_OFFSET);
>
> stmp_reset_block(lradc->base);
>
> - for (i = 0; i < LRADC_MAX_DELAY_CHANS; i++)
> - writel(cfg | (1 << (LRADC_DELAY_TRIGGER_DELAYS_OFFSET + i)),
> - lradc->base + LRADC_DELAY(i));
> + /* Configure DELAY CHANNEL 0 for generic ADC sampling. */
> + writel(adc_cfg, lradc->base + LRADC_DELAY(0));
> +
> + /* Disable remaining DELAY CHANNELs */
> + writel(0, lradc->base + LRADC_DELAY(1));
> + writel(0, lradc->base + LRADC_DELAY(2));
> + writel(0, lradc->base + LRADC_DELAY(3));
> +
> + /* Configure the touchscreen type */
> + writel(LRADC_CTRL0_TOUCH_SCREEN_TYPE,
> + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
> +
> + if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE) {
> + writel(LRADC_CTRL0_TOUCH_SCREEN_TYPE,
> + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
> + }
>
> /* Start internal temperature sensing. */
> writel(0, lradc->base + LRADC_CTRL2);
> @@ -460,12 +858,14 @@ static void mxs_lradc_hw_stop(struct mxs_lradc *lradc)
> writel(0, lradc->base + LRADC_DELAY(i));
> }
>
> -static int __devinit mxs_lradc_probe(struct platform_device *pdev)
> +static int mxs_lradc_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> + struct device_node *node = dev->of_node;
> struct mxs_lradc *lradc;
> struct iio_dev *iio;
> struct resource *iores;
> + uint32_t ts_wires = 0;
> int ret = 0;
> int i;
>
> @@ -487,6 +887,21 @@ static int __devinit mxs_lradc_probe(struct platform_device *pdev)
> goto err_addr;
> }
>
> + INIT_WORK(&lradc->ts_work, mxs_lradc_ts_work);
> +
> + /* Check if touchscreen is enabled in DT. */
> + ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",
> + &ts_wires);
> + if (ret)
> + dev_info(dev, "Touchscreen not enabled.\n");
> + else if (ts_wires == 4)
> + lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_4WIRE;
> + else if (ts_wires == 5)
> + lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_5WIRE;
> + else
> + dev_warn(dev, "Unsupported number of touchscreen wires (%d)\n",
> + ts_wires);
> +
> /* Grab all IRQ sources */
> for (i = 0; i < 13; i++) {
> lradc->irq[i] = platform_get_irq(pdev, i);
> @@ -524,11 +939,16 @@ static int __devinit mxs_lradc_probe(struct platform_device *pdev)
> if (ret)
> goto err_trig;
>
> + /* Register the touchscreen input device. */
> + ret = mxs_lradc_ts_register(lradc);
> + if (ret)
> + goto err_dev;
> +
> /* Register IIO device. */
> ret = iio_device_register(iio);
> if (ret) {
> dev_err(dev, "Failed to register IIO device\n");
> - goto err_dev;
> + goto err_ts;
> }
>
> /* Configure the hardware. */
> @@ -536,6 +956,8 @@ static int __devinit mxs_lradc_probe(struct platform_device *pdev)
>
> return 0;
>
> +err_ts:
> + mxs_lradc_ts_unregister(lradc);
> err_dev:
> mxs_lradc_trigger_remove(iio);
> err_trig:
> @@ -545,11 +967,13 @@ err_addr:
> return ret;
> }
>
> -static int __devexit mxs_lradc_remove(struct platform_device *pdev)
> +static int mxs_lradc_remove(struct platform_device *pdev)
> {
> struct iio_dev *iio = platform_get_drvdata(pdev);
> struct mxs_lradc *lradc = iio_priv(iio);
>
> + mxs_lradc_ts_unregister(lradc);
> +
> mxs_lradc_hw_stop(lradc);
>
> iio_device_unregister(iio);
> @@ -573,7 +997,7 @@ static struct platform_driver mxs_lradc_driver = {
> .of_match_table = mxs_lradc_dt_ids,
> },
> .probe = mxs_lradc_probe,
> - .remove = __devexit_p(mxs_lradc_remove),
> + .remove = mxs_lradc_remove,
> };
>
> module_platform_driver(mxs_lradc_driver);
> --
> 1.7.10.4
>
--
Dmitry
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