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    Subject[PATCH 3/3] input: touchscreen: ad7879: add device tree support
    Date
    Add device tree support for the I2C variant of AD7879 (AD7879-1). This
    allows to specify the touchscreen controller as a I2C client node.
    Most of the options available as platform data are also available as
    device tree properties. Exporting the GPIO is currently not possible
    through device tree.

    Signed-off-by: Stefan Agner <stefan@agner.ch>
    ---
    .../bindings/input/touchscreen/ad7879-i2c.txt | 47 ++++++++++++++++
    drivers/input/touchscreen/ad7879-i2c.c | 63 +++++++++++++++++++++-
    drivers/input/touchscreen/ad7879-spi.c | 3 +-
    drivers/input/touchscreen/ad7879.c | 2 +-
    drivers/input/touchscreen/ad7879.h | 1 +
    5 files changed, 113 insertions(+), 3 deletions(-)
    create mode 100644 Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt

    diff --git a/Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt b/Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt
    new file mode 100644
    index 0000000..bf169a2
    --- /dev/null
    +++ b/Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt
    @@ -0,0 +1,47 @@
    +* Analog Devices AD7879-1/AD7889-1 touchscreen interface (I2C)
    +
    +Required properties:
    +- compatible: must be "adi,ad7879-1"
    +- reg: i2c slave address
    +- interrupt-parent: the phandle for the interrupt controller
    +- interrupts: touch controller interrupt
    +- resistance-plate-x : total resistance of X-plate (for pressure
    + calculation)
    +- touchscreen-max-pressure : maximum reported pressure
    +- touchscreen-swapped-x-y : X and Y axis are swapped (boolean)
    + Swapping is done after inverting the axis
    +Optional properties:
    +- first-conversion-delay : 0-12 in 128us steps (starting with 128us)
    + 13: 2.560ms
    + 14: 3.584ms
    + 15: 4.096ms
    +- acquisition-time : 0: 2us
    + 1: 4us
    + 2: 8us
    + 3: 16us
    +- median-filter-size : 0: disabled
    + 1: 4 measurements
    + 2: 8 measurements
    + 3: 16 measurements
    +- averaging : 0: 2 middle values (1 if median disabled)
    + 1: 4 middle values
    + 2: 8 middle values
    + 3: 16 values
    +- conversion-interval: : 0: convert one time only
    + 1-255: 515us + val * 35us (up to 9.440ms)
    +
    +Example:
    +
    + ad7879@2c {
    + compatible = "adi,ad7879-1";
    + reg = <0x2c>;
    + interrupt-parent = <&gpio1>;
    + interrupts = <13 IRQ_TYPE_EDGE_FALLING>;
    + resistance-plate-x = <120>;
    + touchscreen-max-pressure = <4096>;
    + first-conversion-delay = /bits/ 8 <3>;
    + acquisition-time = /bits/ 8 <1>;
    + median-filter-size = /bits/ 8 <2>;
    + averaging = /bits/ 8 <1>;
    + conversion-interval = /bits/ 8 <255>;
    + };
    diff --git a/drivers/input/touchscreen/ad7879-i2c.c b/drivers/input/touchscreen/ad7879-i2c.c
    index d66962c..08a2c9a 100644
    --- a/drivers/input/touchscreen/ad7879-i2c.c
    +++ b/drivers/input/touchscreen/ad7879-i2c.c
    @@ -11,6 +11,7 @@
    #include <linux/module.h>
    #include <linux/types.h>
    #include <linux/pm.h>
    +#include <linux/input/ad7879.h>

    #include "ad7879.h"

    @@ -54,9 +55,50 @@ static const struct ad7879_bus_ops ad7879_i2c_bus_ops = {
    .write = ad7879_i2c_write,
    };

    +static struct ad7879_platform_data *ad7879_parse_dt(struct device *dev)
    +{
    + struct ad7879_platform_data *pdata;
    + struct device_node *np = dev->of_node;
    + int err;
    + u32 tmp;
    +
    + if (!np)
    + return NULL;
    +
    + pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
    +
    + if (!pdata)
    + return ERR_PTR(-ENOMEM);
    +
    + err = of_property_read_u32(np, "resistance-plate-x", &tmp);
    + if (err) {
    + dev_err(dev, "failed to get resistance-plate-x property\n");
    + return ERR_PTR(err);
    + }
    + pdata->x_plate_ohms = (u16)tmp;
    +
    + err = of_property_read_u32(np, "touchscreen-max-pressure", &tmp);
    + if (err) {
    + dev_err(dev, "failed to get touchscreen-max-pressure property\n");
    + return ERR_PTR(err);
    + }
    + pdata->pressure_min = (u16)tmp;
    +
    + of_property_read_u8(np, "first-conversion-delay", &pdata->first_conversion_delay);
    + of_property_read_u8(np, "acquisition-time", &pdata->acquisition_time);
    + of_property_read_u8(np, "median-filter-size", &pdata->median);
    + of_property_read_u8(np, "averaging", &pdata->averaging);
    + of_property_read_u8(np, "conversion-interval", &pdata->pen_down_acc_interval);
    +
    + pdata->swap_xy = of_property_read_bool(np, "touchscreen-swapped-x-y");
    +
    + return pdata;
    +}
    +
    static int ad7879_i2c_probe(struct i2c_client *client,
    const struct i2c_device_id *id)
    {
    + struct ad7879_platform_data *pdata;
    struct ad7879 *ts;

    if (!i2c_check_functionality(client->adapter,
    @@ -65,7 +107,17 @@ static int ad7879_i2c_probe(struct i2c_client *client,
    return -EIO;
    }

    - ts = ad7879_probe(&client->dev, AD7879_DEVID, client->irq,
    + pdata = dev_get_platdata(&client->dev);
    +
    + if (!pdata && IS_ENABLED(CONFIG_OF))
    + pdata = ad7879_parse_dt(&client->dev);
    +
    + if (IS_ERR_OR_NULL(pdata)) {
    + dev_err(&client->dev, "Need platform data\n");
    + return PTR_ERR(pdata);
    + }
    +
    + ts = ad7879_probe(&client->dev, AD7879_DEVID, client->irq, pdata,
    &ad7879_i2c_bus_ops);
    if (IS_ERR(ts))
    return PTR_ERR(ts);
    @@ -91,10 +143,19 @@ static const struct i2c_device_id ad7879_id[] = {
    };
    MODULE_DEVICE_TABLE(i2c, ad7879_id);

    +#ifdef CONFIG_OF
    +static const struct of_device_id ad7879_dt_ids[] = {
    + { .compatible = "adi,ad7879-1", },
    + { }
    +};
    +MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);
    +#endif
    +
    static struct i2c_driver ad7879_i2c_driver = {
    .driver = {
    .name = "ad7879",
    .pm = &ad7879_pm_ops,
    + .of_match_table = of_match_ptr(ad7879_dt_ids),
    },
    .probe = ad7879_i2c_probe,
    .remove = ad7879_i2c_remove,
    diff --git a/drivers/input/touchscreen/ad7879-spi.c b/drivers/input/touchscreen/ad7879-spi.c
    index 48033c2..8ebe604 100644
    --- a/drivers/input/touchscreen/ad7879-spi.c
    +++ b/drivers/input/touchscreen/ad7879-spi.c
    @@ -128,7 +128,8 @@ static int ad7879_spi_probe(struct spi_device *spi)
    return err;
    }

    - ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, &ad7879_spi_bus_ops);
    + ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, pdata,
    + dev_get_platdata(&spi->dev), &ad7879_spi_bus_ops);
    if (IS_ERR(ts))
    return PTR_ERR(ts);

    diff --git a/drivers/input/touchscreen/ad7879.c b/drivers/input/touchscreen/ad7879.c
    index e290e7b..e763c77 100644
    --- a/drivers/input/touchscreen/ad7879.c
    +++ b/drivers/input/touchscreen/ad7879.c
    @@ -486,9 +486,9 @@ static inline void ad7879_gpio_remove(struct ad7879 *ts)
    #endif

    struct ad7879 *ad7879_probe(struct device *dev, u8 devid, unsigned int irq,
    + struct ad7879_platform_data *pdata,
    const struct ad7879_bus_ops *bops)
    {
    - struct ad7879_platform_data *pdata = dev_get_platdata(dev);
    struct ad7879 *ts;
    struct input_dev *input_dev;
    int err;
    diff --git a/drivers/input/touchscreen/ad7879.h b/drivers/input/touchscreen/ad7879.h
    index 6fd13c4..fa363a0 100644
    --- a/drivers/input/touchscreen/ad7879.h
    +++ b/drivers/input/touchscreen/ad7879.h
    @@ -24,6 +24,7 @@ struct ad7879_bus_ops {
    extern const struct dev_pm_ops ad7879_pm_ops;

    struct ad7879 *ad7879_probe(struct device *dev, u8 devid, unsigned irq,
    + struct ad7879_platform_data *pdata,
    const struct ad7879_bus_ops *bops);
    void ad7879_remove(struct ad7879 *);

    --
    2.7.0
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