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 <[email protected]> > --- > .../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
