Hi Stefan,
On Mon, Jan 25, 2016 at 07:04:37PM -0800, Stefan Agner wrote:
> 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@xxxxxxxx>
> ---
> .../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");
I'd prefer if we used device_property_* API instead of of_property_*, so
that properties would work not only on OF, but also on other platforms
and even legacy boards could potentially be converted to properties.
Thanks.
--
Dmitry
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