Input: synaptics-rmi4 - add device tree support to the SPI transport driver

Synaptics RMI4 SPI Device Binding

The Synaptics RMI4 core is able to support RMI4 devices using different

transports and different functions. This file describes the device tree

bindings for devices using the SPI transport driver. Complete documentation

for other transports and functions can be found in

Documentation/devicetree/bindings/input/rmi4.

Required Properties:

- compatible: syna,rmi4-spi

- reg: Chip select address for the device

- #address-cells: Set to 1 to indicate that the function child nodes

		    consist of only on uint32 value.

- #size-cells: Set to 0 to indicate that the function child nodes do not

		have a size property.

Optional Properties:

- interrupts: interrupt which the rmi device is connected to.

- interrupt-parent: The interrupt controller.

See Documentation/devicetree/bindings/interrupt-controller/interrupts.txt

- spi-rx-delay-us: microsecond delay after a read transfer.

- spi-tx-delay-us: microsecond delay after a write transfer.

Function Parameters:

Parameters specific to RMI functions are contained in child nodes of the rmi device

 node. Documentation for the parameters of each function can be found in:

Documentation/devicetree/bindings/input/rmi4/rmi_f*.txt.

Example:

	spi@7000d800 {

		rmi4-spi-dev@0 {

			compatible = "syna,rmi4-spi";

			reg = <0x0>;

			#address-cells = <1>;

			#size-cells = <0>;

			spi-max-frequency = <4000000>;

			spi-cpha;

			spi-cpol;

			interrupt-parent = <&gpio>;

			interrupts = <TEGRA_GPIO(K, 2) 0x2>;

			spi-rx-delay-us = <30>;

			rmi4-f01@1 {

				reg = <0x1>;

				syna,nosleep-mode = <1>;

			};

			rmi4-f11@11 {

				reg = <0x11>;

				touchscreen-inverted-y;

				syna,sensor-type = <2>;

			};

		};

	};

                      used for MOSI. Defaults to 1 if not present.

- spi-rx-bus-width - (optional) The bus width(number of data wires) that

                      used for MISO. Defaults to 1 if not present.

- spi-rx-delay-us  - (optional) Microsecond delay after a read transfer.

- spi-tx-delay-us  - (optional) Microsecond delay after a write transfer.

Some SPI controllers and devices support Dual and Quad SPI transfer mode.

It allows data in the SPI system to be transferred in 2 wires(DUAL) or 4 wires(QUAD).

#include <linux/slab.h>

#include <linux/spi/spi.h>

#include <linux/irq.h>

#include <linux/of.h>

#include "rmi_driver.h"

#define RMI_SPI_DEFAULT_XFER_BUF_SIZE	64

	return 0;

}

#ifdef CONFIG_OF

static int rmi_spi_of_probe(struct spi_device *spi,

			struct rmi_device_platform_data *pdata)

{

	struct device *dev = &spi->dev;

	int retval;

	retval = rmi_of_property_read_u32(dev,

			&pdata->spi_data.read_delay_us,

			"spi-rx-delay-us", 1);

	if (retval)

		return retval;

	retval = rmi_of_property_read_u32(dev,

			&pdata->spi_data.write_delay_us,

			"spi-tx-delay-us", 1);

	if (retval)

		return retval;

	return 0;

}

static const struct of_device_id rmi_spi_of_match[] = {

	{ .compatible = "syna,rmi4-spi" },

	{},

};

MODULE_DEVICE_TABLE(of, rmi_spi_of_match);

#else

static inline int rmi_spi_of_probe(struct spi_device *spi,

				struct rmi_device_platform_data *pdata)

{

	return -ENODEV;

}

#endif

static int rmi_spi_probe(struct spi_device *spi)

{

	struct rmi_spi_xport *rmi_spi;

	pdata = &rmi_spi->xport.pdata;

	if (spi_pdata)

	if (spi->dev.of_node) {

		retval = rmi_spi_of_probe(spi, pdata);

		if (retval)

			return retval;

	} else if (spi_pdata) {

		*pdata = *spi_pdata;

	}

	if (pdata->spi_data.bits_per_word)

		spi->bits_per_word = pdata->spi_data.bits_per_word;

	.driver = {

		.name	= "rmi4_spi",

		.pm	= &rmi_spi_pm,

		.of_match_table = of_match_ptr(rmi_spi_of_match),

	},

	.id_table	= rmi_id,

	.probe		= rmi_spi_probe,