Re: [PATCH v2 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation

From: Rob Herring
Date: Sat Nov 14 2015 - 21:14:52 EST

On Fri, Nov 13, 2015 at 09:35:52PM +0100, H. Nikolaus Schaller wrote:
> commit b98abe52fa8e ("Input: add common DT binding for touchscreens")
> introduced common DT bindings for touchscreens [1] and a helper function to
> parse the DT.
>
> This has been integrated and interpretation of the inversion (flipping)
> properties for the x and y axis has been added to accommodate any
> orientation of the touch in relation to the LCD.
>
> By scaling the min/max ADC values to the screen size it is now possible to
> pre-calibrate the touch so that is (almost) exactly matches the LCD it is
> glued onto. This allows to well enough operate the touch before a user
> space calibration can improve the precision.
>
> calculate_pressure has been renamed to calculate_resistance because
> that is what it is doing.
>
> [1]: Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt

This still looks like it will break with old dtbs. It doesn't matter if
you update the in tree dts files, you should not force users to update
their dtb.

Rob

>
> Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
> ---
> .../bindings/input/touchscreen/tsc2007.txt | 20 +--
> drivers/input/touchscreen/tsc2007.c | 135 +++++++++++++++++----
> include/linux/i2c/tsc2007.h | 8 ++
> 3 files changed, 135 insertions(+), 28 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt b/Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt
> index ec365e1..6e9fd55 100644
> --- a/Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt
> +++ b/Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt
> @@ -6,6 +6,7 @@ Required properties:
> - ti,x-plate-ohms: X-plate resistance in ohms.
>
> Optional properties:
> +- generic touch screen properties: see touchscreen binding [2].
> - gpios: the interrupt gpio the chip is connected to (trough the penirq pin).
> The penirq pin goes to low when the panel is touched.
> (see GPIO binding[1] for more details).
> @@ -13,17 +14,20 @@ Optional properties:
> (see interrupt binding[0]).
> - interrupts: (gpio) interrupt to which the chip is connected
> (see interrupt binding[0]).
> -- ti,max-rt: maximum pressure.
> -- ti,fuzzx: specifies the absolute input fuzz x value.
> - If set, it will permit noise in the data up to +- the value given to the fuzz
> - parameter, that is used to filter noise from the event stream.
> -- ti,fuzzy: specifies the absolute input fuzz y value.
> -- ti,fuzzz: specifies the absolute input fuzz z value.
> +- ti,max-rt: maximum pressure resistance above which samples are ignored
> + (default: 4095).
> +- ti,report-resistance: report resistance (no pressure = max_rt) instead
> + of pressure (no pressure = 0).
> +- ti,min-x: minimum value reported by X axis ADC (default 0).
> +- ti,max-x: maximum value reported by X axis ADC (default 4095).
> +- ti,min-y: minimum value reported by Y axis ADC (default 0).
> +- ti,max-y: maximum value reported by Y axis ADC (default 4095).
> - ti,poll-period: how much time to wait (in milliseconds) before reading again the
> - values from the tsc2007.
> + values from the tsc2007 (default 1).
>
> [0]: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
> [1]: Documentation/devicetree/bindings/gpio/gpio.txt
> +[2]: Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt
>
> Example:
> &i2c1 {
> @@ -35,6 +39,8 @@ Example:
> interrupts = <0x0 0x8>;
> gpios = <&gpio4 0 0>;
> ti,x-plate-ohms = <180>;
> + touchscreen-size-x = <640>;
> + touchscreen-size-y = <480>;
> };
>
> /* ... */
> diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c
> index 5d0cd51..e0c7173 100644
> --- a/drivers/input/touchscreen/tsc2007.c
> +++ b/drivers/input/touchscreen/tsc2007.c
> @@ -29,6 +29,7 @@
> #include <linux/of_device.h>
> #include <linux/of.h>
> #include <linux/of_gpio.h>
> +#include <linux/input/touchscreen.h>
>
> #define TSC2007_MEASURE_TEMP0 (0x0 << 4)
> #define TSC2007_MEASURE_AUX (0x2 << 4)
> @@ -74,6 +75,14 @@ struct tsc2007 {
>
> u16 model;
> u16 x_plate_ohms;
> + bool swap_xy;
> + bool invert_x;
> + bool invert_y;
> + bool report_resistance;
> + u16 min_x;
> + u16 min_y;
> + u16 max_x;
> + u16 max_y;
> u16 max_rt;
> unsigned long poll_period; /* in jiffies */
> int fuzzx;
> @@ -128,7 +137,8 @@ static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
> tsc2007_xfer(tsc, PWRDOWN);
> }
>
> -static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc)
> +static u32 tsc2007_calculate_resistance(struct tsc2007 *tsc,
> + struct ts_event *tc)
> {
> u32 rt = 0;
>
> @@ -177,12 +187,13 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
> struct ts_event tc;
> u32 rt;
>
> + dev_dbg(&ts->client->dev, "soft irq %d\n", irq);
> while (!ts->stopped && tsc2007_is_pen_down(ts)) {
>
> /* pen is down, continue with the measurement */
> tsc2007_read_values(ts, &tc);
>
> - rt = tsc2007_calculate_pressure(ts, &tc);
> + rt = tsc2007_calculate_resistance(ts, &tc);
>
> if (!rt && !ts->get_pendown_state) {
> /*
> @@ -198,6 +209,48 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
> "DOWN point(%4d,%4d), pressure (%4u)\n",
> tc.x, tc.y, rt);
>
> + /* clamp to expected ADC range */
> + if (tc.x < ts->min_x)
> + tc.x = ts->min_x;
> + if (tc.x > ts->max_x)
> + tc.x = ts->max_x;
> + if (tc.y < ts->min_y)
> + tc.y = ts->min_y;
> + if (tc.y > ts->max_y)
> + tc.y = ts->max_y;
> +
> + dev_dbg(&ts->client->dev,
> + "Clamped point(%4d,%4d), pressure (%4u)\n",
> + tc.x, tc.y, rt);
> +
> + /* flip */
> + if (ts->invert_x)
> + tc.x = (ts->max_x - tc.x) + ts->min_x;
> + if (ts->invert_y)
> + tc.y = (ts->max_y - tc.y) + ts->min_y;
> + if (!ts->report_resistance)
> + rt = ts->max_rt - rt;
> +
> + dev_dbg(&ts->client->dev,
> + "Flipped point(%4d,%4d), pressure (%4u)\n",
> + tc.x, tc.y, rt);
> +
> + /* scale to desired output range */
> + tc.x = (input->absinfo[ABS_X].maximum *
> + (tc.x - ts->min_x)) / (ts->max_x - ts->min_x);
> + tc.y = (input->absinfo[ABS_Y].maximum *
> + (tc.y - ts->min_y)) / (ts->max_y - ts->min_y);
> + rt = (input->absinfo[ABS_PRESSURE].maximum * rt)
> + / ts->max_rt;
> +
> + /* swap x and y */
> + if (ts->swap_xy)
> + swap(tc.x, tc.y);
> +
> + /* report event */
> + dev_dbg(&ts->client->dev,
> + "shaped point(%4d,%4d), pressure (%4u)\n",
> + tc.x, tc.y, rt);
> input_report_key(input, BTN_TOUCH, 1);
> input_report_abs(input, ABS_X, tc.x);
> input_report_abs(input, ABS_Y, tc.y);
> @@ -207,8 +260,8 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
>
> } else {
> /*
> - * Sample found inconsistent by debouncing or pressure is
> - * beyond the maximum. Don't report it to user space,
> + * Sample found inconsistent by debouncing or resistance
> + * is beyond the maximum. Don't report it to user space,
> * repeat at least once more the measurement.
> */
> dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
> @@ -233,6 +286,7 @@ static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
> {
> struct tsc2007 *ts = handle;
>
> + dev_dbg(&ts->client->dev, "hard irq %d\n", irq);
> if (tsc2007_is_pen_down(ts))
> return IRQ_WAKE_THREAD;
>
> @@ -303,14 +357,25 @@ static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
> else
> ts->max_rt = MAX_12BIT;
>
> - if (!of_property_read_u32(np, "ti,fuzzx", &val32))
> - ts->fuzzx = val32;
> + ts->swap_xy = of_property_read_bool(np, "touchscreen-swapped-x-y");
> + ts->invert_x = of_property_read_bool(np, "touchscreen-inverted-x");
> + ts->invert_y = of_property_read_bool(np, "touchscreen-inverted-y");
> + ts->report_resistance =
> + of_property_read_bool(np, "ti,report-resistance");
>
> - if (!of_property_read_u32(np, "ti,fuzzy", &val32))
> - ts->fuzzy = val32;
> + if (!of_property_read_u32(np, "ti,min-x", &val32))
> + ts->min_x = val32;
> + if (!of_property_read_u32(np, "ti,max-x", &val32))
> + ts->max_x = val32;
> + else
> + ts->max_x = MAX_12BIT;
>
> - if (!of_property_read_u32(np, "ti,fuzzz", &val32))
> - ts->fuzzz = val32;
> + if (!of_property_read_u32(np, "ti,min-y", &val32))
> + ts->min_y = val32;
> + if (!of_property_read_u32(np, "ti,max-y", &val32))
> + ts->max_y = val32;
> + else
> + ts->max_y = MAX_12BIT;
>
> if (!of_property_read_u64(np, "ti,poll-period", &val64))
> ts->poll_period = msecs_to_jiffies(val64);
> @@ -324,6 +389,16 @@ static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
> return -EINVAL;
> }
>
> + dev_dbg(&client->dev,
> + "min/max_x (%4d,%4d)\n",
> + ts->min_x, ts->max_x);
> + dev_dbg(&client->dev,
> + "min/max_y (%4d,%4d)\n",
> + ts->min_y, ts->max_y);
> + dev_dbg(&client->dev,
> + "max_rt (%4d)\n",
> + ts->max_rt);
> +
> ts->gpio = of_get_gpio(np, 0);
> if (gpio_is_valid(ts->gpio))
> ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
> @@ -332,6 +407,10 @@ static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
> "GPIO not specified in DT (of_get_gpio returned %d)\n",
> ts->gpio);
>
> + dev_dbg(&client->dev,
> + "ts-gpio: %d\n",
> + ts->gpio);
> +
> return 0;
> }
> #else
> @@ -349,6 +428,14 @@ static int tsc2007_probe_pdev(struct i2c_client *client, struct tsc2007 *ts,
> ts->model = pdata->model;
> ts->x_plate_ohms = pdata->x_plate_ohms;
> ts->max_rt = pdata->max_rt ? : MAX_12BIT;
> + ts->swap_xy = pdata->swap_xy;
> + ts->invert_x = pdata->invert_x;
> + ts->invert_y = pdata->invert_y;
> + ts->report_resistance = pdata->report_resistance;
> + ts->min_x = pdata->min_x ? : 0;
> + ts->min_y = pdata->min_y ? : 0;
> + ts->max_x = pdata->max_x ? : MAX_12BIT;
> + ts->max_y = pdata->max_y ? : MAX_12BIT;
> ts->poll_period = msecs_to_jiffies(pdata->poll_period ? : 1);
> ts->get_pendown_state = pdata->get_pendown_state;
> ts->clear_penirq = pdata->clear_penirq;
> @@ -388,13 +475,6 @@ static int tsc2007_probe(struct i2c_client *client,
> if (!ts)
> return -ENOMEM;
>
> - if (pdata)
> - err = tsc2007_probe_pdev(client, ts, pdata, id);
> - else
> - err = tsc2007_probe_dt(client, ts);
> - if (err)
> - return err;
> -
> input_dev = devm_input_allocate_device(&client->dev);
> if (!input_dev)
> return -ENOMEM;
> @@ -421,10 +501,21 @@ static int tsc2007_probe(struct i2c_client *client,
> input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
> input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
>
> - input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
> - input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
> - input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
> - ts->fuzzz, 0);
> + if (pdata)
> + err = tsc2007_probe_pdev(client, ts, pdata, id);
> + else
> + err = tsc2007_probe_dt(client, ts);
> + if (err)
> + return err;
> +
> + input_set_abs_params(input_dev, ABS_X, 0, ts->max_x-ts->min_x,
> + ts->fuzzx, 0);
> + input_set_abs_params(input_dev, ABS_Y, 0, ts->max_y-ts->min_y,
> + ts->fuzzy, 0);
> + input_set_abs_params(input_dev, ABS_PRESSURE, 0, ts->max_rt,
> + ts->fuzzz, 0);
> +
> + touchscreen_parse_properties(input_dev, false);
>
> if (pdata) {
> if (pdata->exit_platform_hw) {
> @@ -443,6 +534,8 @@ static int tsc2007_probe(struct i2c_client *client,
> pdata->init_platform_hw();
> }
>
> + dev_dbg(&client->dev, "request irq %d\n",
> + ts->irq);
> err = devm_request_threaded_irq(&client->dev, ts->irq,
> tsc2007_hard_irq, tsc2007_soft_irq,
> IRQF_ONESHOT,
> diff --git a/include/linux/i2c/tsc2007.h b/include/linux/i2c/tsc2007.h
> index 4f35b6a..632db20 100644
> --- a/include/linux/i2c/tsc2007.h
> +++ b/include/linux/i2c/tsc2007.h
> @@ -6,6 +6,14 @@
> struct tsc2007_platform_data {
> u16 model; /* 2007. */
> u16 x_plate_ohms; /* must be non-zero value */
> + bool swap_xy; /* swap x and y axis */
> + bool invert_x;
> + bool invert_y;
> + bool report_resistance;
> + u16 min_x; /* min and max values reported by ADC */
> + u16 min_y;
> + u16 max_x;
> + u16 max_y;
> u16 max_rt; /* max. resistance above which samples are ignored */
> unsigned long poll_period; /* time (in ms) between samples */
> int fuzzx; /* fuzz factor for X, Y and pressure axes */
> --
> 2.5.1
>
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