1 files changed, 364 insertions, 24 deletions

diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
index 690a560e0dab..17df74908db1 100644
--- a/drivers/iio/adc/at91_adc.c
+++ b/drivers/iio/adc/at91_adc.c
@@ -11,6 +11,7 @@
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/io.h>
+#include <linux/input.h>
 #include <linux/interrupt.h>
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
@@ -39,7 +40,23 @@
 #define at91_adc_writel(st, reg, val) \
         (writel_relaxed(val, st->reg_base + reg))
 
+#define DRIVER_NAME             "at91_adc"
+#define MAX_POS_BITS            12
+
+#define TOUCH_SAMPLE_PERIOD_US          2000    /* 2ms */
+#define TOUCH_PEN_DETECT_DEBOUNCE_US    200
+
 struct at91_adc_caps {
+        bool    has_ts;         /* Support touch screen */
+        bool    has_tsmr;       /* only at91sam9x5, sama5d3 have TSMR reg */
+        /*
+         * Numbers of sampling data will be averaged. Can be 0~3.
+         * Hardware can average (2 ^ ts_filter_average) sample data.
+         */
+        u8      ts_filter_average;
+        /* Pen Detection input pull-up resistor, can be 0~3 */
+        u8      ts_pen_detect_sensitivity;
+
         /* startup time calculate function */
         u32 (*calc_startup_ticks)(u8 startup_time, u32 adc_clk_khz);
 
@@ -47,6 +64,12 @@ 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;
@@ -71,6 +94,26 @@ struct at91_adc_state {
         bool                    low_res;        /* the resolution corresponds to the lowest one */
         wait_queue_head_t       wq_data_avail;
         struct at91_adc_caps    *caps;
+
+        /*
+         * Following ADC channels are shared by touchscreen:
+         *
+         * CH0 -- Touch screen XP/UL
+         * CH1 -- Touch screen XM/UR
+         * CH2 -- Touch screen YP/LL
+         * CH3 -- Touch screen YM/Sense
+         * CH4 -- Touch screen LR(5-wire only)
+         *
+         * The bitfields below represents the reserved channel in the
+         * touchscreen mode.
+         */
+#define CHAN_MASK_TOUCHSCREEN_4WIRE     (0xf << 0)
+#define CHAN_MASK_TOUCHSCREEN_5WIRE     (0x1f << 0)
+        enum atmel_adc_ts_type  touchscreen_type;
+        struct input_dev        *ts_input;
+
+        u16                     ts_sample_period_val;
+        u32                     ts_pressure_threshold;
 };
 
 static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
@@ -99,14 +142,10 @@ static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
         return IRQ_HANDLED;
 }
 
-static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
+/* Handler for classic adc channel eoc trigger */
+void handle_adc_eoc_trigger(int irq, struct iio_dev *idev)
 {
-        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))
-                return IRQ_HANDLED;
 
         if (iio_buffer_enabled(idev)) {
                 disable_irq_nosync(irq);
@@ -116,6 +155,115 @@ static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
                 st->done = true;
                 wake_up_interruptible(&st->wq_data_avail);
         }
+}
+
+static int at91_ts_sample(struct at91_adc_state *st)
+{
+        unsigned int xscale, yscale, reg, z1, z2;
+        unsigned int x, y, pres, xpos, ypos;
+        unsigned int rxp = 1;
+        unsigned int factor = 1000;
+        struct iio_dev *idev = iio_priv_to_dev(st);
+
+        unsigned int xyz_mask_bits = st->res;
+        unsigned int xyz_mask = (1 << xyz_mask_bits) - 1;
+
+        /* calculate position */
+        /* x position = (x / xscale) * max, max = 2^MAX_POS_BITS - 1 */
+        reg = at91_adc_readl(st, AT91_ADC_TSXPOSR);
+        xpos = reg & xyz_mask;
+        x = (xpos << MAX_POS_BITS) - xpos;
+        xscale = (reg >> 16) & xyz_mask;
+        if (xscale == 0) {
+                dev_err(&idev->dev, "Error: xscale == 0!\n");
+                return -1;
+        }
+        x /= xscale;
+
+        /* y position = (y / yscale) * max, max = 2^MAX_POS_BITS - 1 */
+        reg = at91_adc_readl(st, AT91_ADC_TSYPOSR);
+        ypos = reg & xyz_mask;
+        y = (ypos << MAX_POS_BITS) - ypos;
+        yscale = (reg >> 16) & xyz_mask;
+        if (yscale == 0) {
+                dev_err(&idev->dev, "Error: yscale == 0!\n");
+                return -1;
+        }
+        y /= yscale;
+
+        /* calculate the pressure */
+        reg = at91_adc_readl(st, AT91_ADC_TSPRESSR);
+        z1 = reg & xyz_mask;
+        z2 = (reg >> 16) & xyz_mask;
+
+        if (z1 != 0)
+                pres = rxp * (x * factor / 1024) * (z2 * factor / z1 - factor)
+                        / factor;
+        else
+                pres = st->ts_pressure_threshold;       /* no pen contacted */
+
+        dev_dbg(&idev->dev, "xpos = %d, xscale = %d, ypos = %d, yscale = %d, z1 = %d, z2 = %d, press = %d\n",
+                                xpos, xscale, ypos, yscale, z1, z2, pres);
+
+        if (pres < st->ts_pressure_threshold) {
+                dev_dbg(&idev->dev, "x = %d, y = %d, pressure = %d\n",
+                                        x, y, pres / factor);
+                input_report_abs(st->ts_input, ABS_X, x);
+                input_report_abs(st->ts_input, ABS_Y, y);
+                input_report_abs(st->ts_input, ABS_PRESSURE, pres);
+                input_report_key(st->ts_input, BTN_TOUCH, 1);
+                input_sync(st->ts_input);
+        } else {
+                dev_dbg(&idev->dev, "pressure too low: not reporting\n");
+        }
+
+        return 0;
+}
+
+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);
+        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 |
+                        ts_data_irq_mask);
+                /* 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 & AT91_ADC_IER_NOPEN) {
+                at91_adc_writel(st, st->registers->trigger_register, 0);
+                at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_NOPEN |
+                        ts_data_irq_mask);
+                at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
+
+                input_report_key(st->ts_input, BTN_TOUCH, 0);
+                input_sync(st->ts_input);
+        } else if ((status & ts_data_irq_mask) == ts_data_irq_mask) {
+                /* Now all touchscreen data is ready */
+
+                if (status & AT91_ADC_ISR_PENS) {
+                        /* validate data by pen contact */
+                        at91_ts_sample(st);
+                } else {
+                        /* triggered by event that is no pen contact, just read
+                         * them to clean the interrupt and discard all.
+                         */
+                        at91_adc_readl(st, AT91_ADC_TSXPOSR);
+                        at91_adc_readl(st, AT91_ADC_TSYPOSR);
+                        at91_adc_readl(st, AT91_ADC_TSPRESSR);
+                }
+        }
 
         return IRQ_HANDLED;
 }
@@ -125,6 +273,16 @@ static int at91_adc_channel_init(struct iio_dev *idev)
         struct at91_adc_state *st = iio_priv(idev);
         struct iio_chan_spec *chan_array, *timestamp;
         int bit, idx = 0;
+        unsigned long rsvd_mask = 0;
+
+        /* If touchscreen is enable, then reserve the adc channels */
+        if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
+                rsvd_mask = CHAN_MASK_TOUCHSCREEN_4WIRE;
+        else if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_5WIRE)
+                rsvd_mask = CHAN_MASK_TOUCHSCREEN_5WIRE;
+
+        /* set up the channel mask to reserve touchscreen channels */
+        st->channels_mask &= ~rsvd_mask;
 
         idev->num_channels = bitmap_weight(&st->channels_mask,
                                            st->num_channels) + 1;
@@ -473,6 +631,39 @@ static u32 calc_startup_ticks_9x5(u8 startup_time, u32 adc_clk_khz)
 
 static const struct of_device_id at91_adc_dt_ids[];
 
+static int at91_adc_probe_dt_ts(struct device_node *node,
+        struct at91_adc_state *st, struct device *dev)
+{
+        int ret;
+        u32 prop;
+
+        ret = of_property_read_u32(node, "atmel,adc-ts-wires", &prop);
+        if (ret) {
+                dev_info(dev, "ADC Touch screen is disabled.\n");
+                return 0;
+        }
+
+        switch (prop) {
+        case 4:
+        case 5:
+                st->touchscreen_type = prop;
+                break;
+        default:
+                dev_err(dev, "Unsupported number of touchscreen wires (%d). Should be 4 or 5.\n", prop);
+                return -EINVAL;
+        }
+
+        prop = 0;
+        of_property_read_u32(node, "atmel,adc-ts-pressure-threshold", &prop);
+        st->ts_pressure_threshold = prop;
+        if (st->ts_pressure_threshold) {
+                return 0;
+        } else {
+                dev_err(dev, "Invalid pressure threshold for the touchscreen\n");
+                return -EINVAL;
+        }
+}
+
 static int at91_adc_probe_dt(struct at91_adc_state *st,
                              struct platform_device *pdev)
 {
@@ -554,6 +745,12 @@ static int at91_adc_probe_dt(struct at91_adc_state *st,
                 i++;
         }
 
+        /* Check if touchscreen is supported. */
+        if (st->caps->has_ts)
+                return at91_adc_probe_dt_ts(node, st, &idev->dev);
+        else
+                dev_info(&idev->dev, "not support touchscreen in the adc compatible string.\n");
+
         return 0;
 
 error_ret:
@@ -585,6 +782,114 @@ static const struct iio_info at91_adc_info = {
         .read_raw = &at91_adc_read_raw,
 };
 
+/* Touchscreen related functions */
+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);
+        return 0;
+}
+
+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);
+}
+
+static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz)
+{
+        u32 reg = 0, pendbc;
+        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);
+
+        while (pendbc >> ++i)
+                ;       /* Empty! Find the shift offset */
+        if (abs(pendbc - (1 << i)) < abs(pendbc - (1 << (i - 1))))
+                pendbc = i;
+        else
+                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 */
+        }
+
+        /* 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
+         * option only available on ES2 and higher
+         */
+        at91_adc_writel(st, AT91_ADC_ACR, st->caps->ts_pen_detect_sensitivity
+                        & AT91_ADC_ACR_PENDETSENS);
+
+        /* Sample Peroid Time = (TRGPER + 1) / ADCClock */
+        st->ts_sample_period_val = round_up((TOUCH_SAMPLE_PERIOD_US *
+                        adc_clk_khz / 1000) - 1, 1);
+
+        return 0;
+}
+
+static int at91_ts_register(struct at91_adc_state *st,
+                struct platform_device *pdev)
+{
+        struct input_dev *input;
+        struct iio_dev *idev = iio_priv_to_dev(st);
+        int ret;
+
+        input = input_allocate_device();
+        if (!input) {
+                dev_err(&idev->dev, "Failed to allocate TS device!\n");
+                return -ENOMEM;
+        }
+
+        input->name = DRIVER_NAME;
+        input->id.bustype = BUS_HOST;
+        input->dev.parent = &pdev->dev;
+        input->open = atmel_ts_open;
+        input->close = atmel_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, (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);
+
+        st->ts_input = input;
+        input_set_drvdata(input, st);
+
+        ret = input_register_device(input);
+        if (ret)
+                input_free_device(st->ts_input);
+
+        return ret;
+}
+
+static void at91_ts_unregister(struct at91_adc_state *st)
+{
+        input_unregister_device(st->ts_input);
+}
+
 static int at91_adc_probe(struct platform_device *pdev)
 {
         unsigned int prsc, mstrclk, ticks, adc_clk, adc_clk_khz, shtim;
@@ -636,7 +941,7 @@ static int at91_adc_probe(struct platform_device *pdev)
         at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_SWRST);
         at91_adc_writel(st, AT91_ADC_IDR, 0xFFFFFFFF);
         ret = request_irq(st->irq,
-                          at91_adc_eoc_trigger,
+                          at91_adc_interrupt,
                           0,
                           pdev->dev.driver->name,
                           idev);
@@ -681,6 +986,10 @@ static int at91_adc_probe(struct platform_device *pdev)
         mstrclk = clk_get_rate(st->clk);
         adc_clk = clk_get_rate(st->adc_clk);
         adc_clk_khz = adc_clk / 1000;
+
+        dev_dbg(&pdev->dev, "Master clock is set as: %d Hz, adc_clk should set as: %d Hz\n",
+                mstrclk, adc_clk);
+
         prsc = (mstrclk / (2 * adc_clk)) - 1;
 
         if (!st->startup_time) {
@@ -717,30 +1026,52 @@ static int at91_adc_probe(struct platform_device *pdev)
         init_waitqueue_head(&st->wq_data_avail);
         mutex_init(&st->lock);
 
-        ret = at91_adc_buffer_init(idev);
-        if (ret < 0) {
-                dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
-                goto error_disable_adc_clk;
-        }
+        /*
+         * Since touch screen will set trigger register as period trigger. So
+         * when touch screen is enabled, then we have to disable hardware
+         * trigger for classic adc.
+         */
+        if (!st->touchscreen_type) {
+                ret = at91_adc_buffer_init(idev);
+                if (ret < 0) {
+                        dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
+                        goto error_disable_adc_clk;
+                }
 
-        ret = at91_adc_trigger_init(idev);
-        if (ret < 0) {
-                dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
-                goto error_unregister_buffer;
+                ret = at91_adc_trigger_init(idev);
+                if (ret < 0) {
+                        dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
+                        at91_adc_buffer_remove(idev);
+                        goto error_disable_adc_clk;
+                }
+        } else {
+                if (!st->caps->has_tsmr) {
+                        dev_err(&pdev->dev, "We don't support non-TSMR adc\n");
+                        goto error_disable_adc_clk;
+                }
+
+                ret = at91_ts_register(st, pdev);
+                if (ret)
+                        goto error_disable_adc_clk;
+
+                at91_ts_hw_init(st, adc_clk_khz);
         }
 
         ret = iio_device_register(idev);
         if (ret < 0) {
                 dev_err(&pdev->dev, "Couldn't register the device.\n");
-                goto error_remove_triggers;
+                goto error_iio_device_register;
         }
 
         return 0;
 
-error_remove_triggers:
-        at91_adc_trigger_remove(idev);
-error_unregister_buffer:
-        at91_adc_buffer_remove(idev);
+error_iio_device_register:
+        if (!st->touchscreen_type) {
+                at91_adc_trigger_remove(idev);
+                at91_adc_buffer_remove(idev);
+        } else {
+                at91_ts_unregister(st);
+        }
 error_disable_adc_clk:
         clk_disable_unprepare(st->adc_clk);
 error_disable_clk:
@@ -756,8 +1087,12 @@ static int at91_adc_remove(struct platform_device *pdev)
         struct at91_adc_state *st = iio_priv(idev);
 
         iio_device_unregister(idev);
-        at91_adc_trigger_remove(idev);
-        at91_adc_buffer_remove(idev);
+        if (!st->touchscreen_type) {
+                at91_adc_trigger_remove(idev);
+                at91_adc_buffer_remove(idev);
+        } else {
+                at91_ts_unregister(st);
+        }
         clk_disable_unprepare(st->adc_clk);
         clk_disable_unprepare(st->clk);
         free_irq(st->irq, idev);
@@ -780,6 +1115,7 @@ static struct at91_adc_caps at91sam9260_caps = {
 };
 
 static struct at91_adc_caps at91sam9g45_caps = {
+        .has_ts = true,
         .calc_startup_ticks = calc_startup_ticks_9260,  /* same as 9260 */
         .num_channels = 8,
         .registers = {
@@ -793,6 +1129,10 @@ static struct at91_adc_caps at91sam9g45_caps = {
 };
 
 static struct at91_adc_caps at91sam9x5_caps = {
+        .has_ts = true,
+        .has_tsmr = true,
+        .ts_filter_average = 3,
+        .ts_pen_detect_sensitivity = 2,
         .calc_startup_ticks = calc_startup_ticks_9x5,
         .num_channels = 12,
         .registers = {
@@ -819,7 +1159,7 @@ static struct platform_driver at91_adc_driver = {
         .probe = at91_adc_probe,
         .remove = at91_adc_remove,
         .driver = {
-                   .name = "at91_adc",
+                   .name = DRIVER_NAME,
                    .of_match_table = of_match_ptr(at91_adc_dt_ids),
         },
 };