diff mbox

[3/3] input: touchscreen: ad7879: add device tree support

Message ID 1453777477-29706-3-git-send-email-stefan@agner.ch (mailing list archive)
State Changes Requested
Headers show

Commit Message

Stefan Agner Jan. 26, 2016, 3:04 a.m. UTC
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

Comments

kernel test robot Jan. 26, 2016, 3:28 a.m. UTC | #1
Hi Stefan,

[auto build test ERROR on input/next]
[also build test ERROR on v4.5-rc1 next-20160125]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]

url:    https://github.com/0day-ci/linux/commits/Stefan-Agner/input-touchscreen-ad7879-move-header-to-input-subdirectory/20160126-110813
base:   https://git.kernel.org/pub/scm/linux/kernel/git/dtor/input.git next
config: x86_64-randconfig-x012-01260845 (attached as .config)
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All error/warnings (new ones prefixed by >>):

   In file included from drivers/input/touchscreen/ad7879-spi.c:14:0:
>> drivers/input/touchscreen/ad7879.h:28:21: warning: 'struct ad7879_platform_data' declared inside parameter list
           const struct ad7879_bus_ops *bops);
                        ^
>> drivers/input/touchscreen/ad7879.h:28:21: warning: its scope is only this definition or declaration, which is probably not what you want
   drivers/input/touchscreen/ad7879-spi.c: In function 'ad7879_spi_probe':
>> drivers/input/touchscreen/ad7879-spi.c:131:55: error: 'pdata' undeclared (first use in this function)
     ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, pdata,
                                                          ^
   drivers/input/touchscreen/ad7879-spi.c:131:55: note: each undeclared identifier is reported only once for each function it appears in
>> drivers/input/touchscreen/ad7879-spi.c:131:7: error: too many arguments to function 'ad7879_probe'
     ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, pdata,
          ^
   In file included from drivers/input/touchscreen/ad7879-spi.c:14:0:
   drivers/input/touchscreen/ad7879.h:26:16: note: declared here
    struct ad7879 *ad7879_probe(struct device *dev, u8 devid, unsigned irq,
                   ^

vim +/pdata +131 drivers/input/touchscreen/ad7879-spi.c

     8	
     9	#include <linux/input.h>	/* BUS_SPI */
    10	#include <linux/pm.h>
    11	#include <linux/spi/spi.h>
    12	#include <linux/module.h>
    13	
  > 14	#include "ad7879.h"
    15	
    16	#define AD7879_DEVID		0x7A	/* AD7879/AD7889 */
    17	
    18	#define MAX_SPI_FREQ_HZ      5000000
    19	#define AD7879_CMD_MAGIC     0xE000
    20	#define AD7879_CMD_READ      (1 << 10)
    21	#define AD7879_CMD(reg)      (AD7879_CMD_MAGIC | ((reg) & 0xF))
    22	#define AD7879_WRITECMD(reg) (AD7879_CMD(reg))
    23	#define AD7879_READCMD(reg)  (AD7879_CMD(reg) | AD7879_CMD_READ)
    24	
    25	/*
    26	 * ad7879_read/write are only used for initial setup and for sysfs controls.
    27	 * The main traffic is done in ad7879_collect().
    28	 */
    29	
    30	static int ad7879_spi_xfer(struct spi_device *spi,
    31				   u16 cmd, u8 count, u16 *tx_buf, u16 *rx_buf)
    32	{
    33		struct spi_message msg;
    34		struct spi_transfer *xfers;
    35		void *spi_data;
    36		u16 *command;
    37		u16 *_rx_buf = _rx_buf; /* shut gcc up */
    38		u8 idx;
    39		int ret;
    40	
    41		xfers = spi_data = kzalloc(sizeof(*xfers) * (count + 2), GFP_KERNEL);
    42		if (!spi_data)
    43			return -ENOMEM;
    44	
    45		spi_message_init(&msg);
    46	
    47		command = spi_data;
    48		command[0] = cmd;
    49		if (count == 1) {
    50			/* ad7879_spi_{read,write} gave us buf on stack */
    51			command[1] = *tx_buf;
    52			tx_buf = &command[1];
    53			_rx_buf = rx_buf;
    54			rx_buf = &command[2];
    55		}
    56	
    57		++xfers;
    58		xfers[0].tx_buf = command;
    59		xfers[0].len = 2;
    60		spi_message_add_tail(&xfers[0], &msg);
    61		++xfers;
    62	
    63		for (idx = 0; idx < count; ++idx) {
    64			if (rx_buf)
    65				xfers[idx].rx_buf = &rx_buf[idx];
    66			if (tx_buf)
    67				xfers[idx].tx_buf = &tx_buf[idx];
    68			xfers[idx].len = 2;
    69			spi_message_add_tail(&xfers[idx], &msg);
    70		}
    71	
    72		ret = spi_sync(spi, &msg);
    73	
    74		if (count == 1)
    75			_rx_buf[0] = command[2];
    76	
    77		kfree(spi_data);
    78	
    79		return ret;
    80	}
    81	
    82	static int ad7879_spi_multi_read(struct device *dev,
    83					 u8 first_reg, u8 count, u16 *buf)
    84	{
    85		struct spi_device *spi = to_spi_device(dev);
    86	
    87		return ad7879_spi_xfer(spi, AD7879_READCMD(first_reg), count, NULL, buf);
    88	}
    89	
    90	static int ad7879_spi_read(struct device *dev, u8 reg)
    91	{
    92		struct spi_device *spi = to_spi_device(dev);
    93		u16 ret, dummy;
    94	
    95		return ad7879_spi_xfer(spi, AD7879_READCMD(reg), 1, &dummy, &ret) ? : ret;
    96	}
    97	
    98	static int ad7879_spi_write(struct device *dev, u8 reg, u16 val)
    99	{
   100		struct spi_device *spi = to_spi_device(dev);
   101		u16 dummy;
   102	
   103		return ad7879_spi_xfer(spi, AD7879_WRITECMD(reg), 1, &val, &dummy);
   104	}
   105	
   106	static const struct ad7879_bus_ops ad7879_spi_bus_ops = {
   107		.bustype	= BUS_SPI,
   108		.read		= ad7879_spi_read,
   109		.multi_read	= ad7879_spi_multi_read,
   110		.write		= ad7879_spi_write,
   111	};
   112	
   113	static int ad7879_spi_probe(struct spi_device *spi)
   114	{
   115		struct ad7879 *ts;
   116		int err;
   117	
   118		/* don't exceed max specified SPI CLK frequency */
   119		if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
   120			dev_err(&spi->dev, "SPI CLK %d Hz?\n", spi->max_speed_hz);
   121			return -EINVAL;
   122		}
   123	
   124		spi->bits_per_word = 16;
   125		err = spi_setup(spi);
   126		if (err) {
   127		        dev_dbg(&spi->dev, "spi master doesn't support 16 bits/word\n");
   128		        return err;
   129		}
   130	
 > 131		ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, pdata,
   132				  dev_get_platdata(&spi->dev), &ad7879_spi_bus_ops);
   133		if (IS_ERR(ts))
   134			return PTR_ERR(ts);

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
kernel test robot Jan. 26, 2016, 3:57 a.m. UTC | #2
Hi Stefan,

[auto build test ERROR on input/next]
[also build test ERROR on v4.5-rc1 next-20160125]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]

url:    https://github.com/0day-ci/linux/commits/Stefan-Agner/input-touchscreen-ad7879-move-header-to-input-subdirectory/20160126-110813
base:   https://git.kernel.org/pub/scm/linux/kernel/git/dtor/input.git next
config: x86_64-randconfig-s4-01261112 (attached as .config)
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All error/warnings (new ones prefixed by >>):

   In file included from drivers/input/touchscreen/ad7879-i2c.c:11:0:
>> drivers/input/touchscreen/ad7879-i2c.c:151:25: error: 'st1232_ts_dt_ids' undeclared here (not in a function)
    MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);
                            ^
   include/linux/module.h:223:21: note: in definition of macro 'MODULE_DEVICE_TABLE'
    extern const typeof(name) __mod_##type##__##name##_device_table  \
                        ^
>> include/linux/module.h:223:27: error: '__mod_of__st1232_ts_dt_ids_device_table' aliased to undefined symbol 'st1232_ts_dt_ids'
    extern const typeof(name) __mod_##type##__##name##_device_table  \
                              ^
>> drivers/input/touchscreen/ad7879-i2c.c:151:1: note: in expansion of macro 'MODULE_DEVICE_TABLE'
    MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);
    ^

vim +/st1232_ts_dt_ids +151 drivers/input/touchscreen/ad7879-i2c.c

     5	 *
     6	 * Licensed under the GPL-2 or later.
     7	 */
     8	
     9	#include <linux/input.h>	/* BUS_I2C */
    10	#include <linux/i2c.h>
  > 11	#include <linux/module.h>
    12	#include <linux/types.h>
    13	#include <linux/pm.h>
    14	#include <linux/input/ad7879.h>
    15	
    16	#include "ad7879.h"
    17	
    18	#define AD7879_DEVID		0x79	/* AD7879-1/AD7889-1 */
    19	
    20	/* All registers are word-sized.
    21	 * AD7879 uses a high-byte first convention.
    22	 */
    23	static int ad7879_i2c_read(struct device *dev, u8 reg)
    24	{
    25		struct i2c_client *client = to_i2c_client(dev);
    26	
    27		return i2c_smbus_read_word_swapped(client, reg);
    28	}
    29	
    30	static int ad7879_i2c_multi_read(struct device *dev,
    31					 u8 first_reg, u8 count, u16 *buf)
    32	{
    33		struct i2c_client *client = to_i2c_client(dev);
    34		u8 idx;
    35	
    36		i2c_smbus_read_i2c_block_data(client, first_reg, count * 2, (u8 *)buf);
    37	
    38		for (idx = 0; idx < count; ++idx)
    39			buf[idx] = swab16(buf[idx]);
    40	
    41		return 0;
    42	}
    43	
    44	static int ad7879_i2c_write(struct device *dev, u8 reg, u16 val)
    45	{
    46		struct i2c_client *client = to_i2c_client(dev);
    47	
    48		return i2c_smbus_write_word_swapped(client, reg, val);
    49	}
    50	
    51	static const struct ad7879_bus_ops ad7879_i2c_bus_ops = {
    52		.bustype	= BUS_I2C,
    53		.read		= ad7879_i2c_read,
    54		.multi_read	= ad7879_i2c_multi_read,
    55		.write		= ad7879_i2c_write,
    56	};
    57	
    58	static struct ad7879_platform_data *ad7879_parse_dt(struct device *dev)
    59	{
    60		struct ad7879_platform_data *pdata;
    61		struct device_node *np = dev->of_node;
    62		int err;
    63		u32 tmp;
    64	
    65		if (!np)
    66			return NULL;
    67	
    68		pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
    69	
    70		if (!pdata)
    71			return ERR_PTR(-ENOMEM);
    72	
    73		err = of_property_read_u32(np, "resistance-plate-x", &tmp);
    74		if (err) {
    75			dev_err(dev, "failed to get resistance-plate-x property\n");
    76			return ERR_PTR(err);
    77		}
    78		pdata->x_plate_ohms = (u16)tmp;
    79	
    80		err = of_property_read_u32(np, "touchscreen-max-pressure", &tmp);
    81		if (err) {
    82			dev_err(dev, "failed to get touchscreen-max-pressure property\n");
    83			return ERR_PTR(err);
    84		}
    85		pdata->pressure_min = (u16)tmp;
    86	
    87		of_property_read_u8(np, "first-conversion-delay", &pdata->first_conversion_delay);
    88		of_property_read_u8(np, "acquisition-time", &pdata->acquisition_time);
    89		of_property_read_u8(np, "median-filter-size", &pdata->median);
    90		of_property_read_u8(np, "averaging", &pdata->averaging);
    91		of_property_read_u8(np, "conversion-interval", &pdata->pen_down_acc_interval);
    92	
    93		pdata->swap_xy = of_property_read_bool(np, "touchscreen-swapped-x-y");
    94	
    95		return pdata;
    96	}
    97	
    98	static int ad7879_i2c_probe(struct i2c_client *client,
    99					      const struct i2c_device_id *id)
   100	{
   101		struct ad7879_platform_data *pdata;
   102		struct ad7879 *ts;
   103	
   104		if (!i2c_check_functionality(client->adapter,
   105					     I2C_FUNC_SMBUS_WORD_DATA)) {
   106			dev_err(&client->dev, "SMBUS Word Data not Supported\n");
   107			return -EIO;
   108		}
   109	
   110		pdata = dev_get_platdata(&client->dev);
   111	
   112		if (!pdata && IS_ENABLED(CONFIG_OF))
   113			pdata = ad7879_parse_dt(&client->dev);
   114	
   115		if (IS_ERR_OR_NULL(pdata)) {
   116			dev_err(&client->dev, "Need platform data\n");
   117			return PTR_ERR(pdata);
   118		}
   119	
   120		ts = ad7879_probe(&client->dev, AD7879_DEVID, client->irq, pdata,
   121				  &ad7879_i2c_bus_ops);
   122		if (IS_ERR(ts))
   123			return PTR_ERR(ts);
   124	
   125		i2c_set_clientdata(client, ts);
   126	
   127		return 0;
   128	}
   129	
   130	static int ad7879_i2c_remove(struct i2c_client *client)
   131	{
   132		struct ad7879 *ts = i2c_get_clientdata(client);
   133	
   134		ad7879_remove(ts);
   135	
   136		return 0;
   137	}
   138	
   139	static const struct i2c_device_id ad7879_id[] = {
   140		{ "ad7879", 0 },
   141		{ "ad7889", 0 },
   142		{ }
   143	};
   144	MODULE_DEVICE_TABLE(i2c, ad7879_id);
   145	
   146	#ifdef CONFIG_OF
   147	static const struct of_device_id ad7879_dt_ids[] = {
   148		{ .compatible = "adi,ad7879-1", },
   149		{ }
   150	};
 > 151	MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);
   152	#endif
   153	
   154	static struct i2c_driver ad7879_i2c_driver = {

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
kernel test robot Jan. 26, 2016, 4:50 a.m. UTC | #3
Hi Stefan,

[auto build test ERROR on input/next]
[also build test ERROR on v4.5-rc1 next-20160125]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]

url:    https://github.com/0day-ci/linux/commits/Stefan-Agner/input-touchscreen-ad7879-move-header-to-input-subdirectory/20160126-110813
base:   https://git.kernel.org/pub/scm/linux/kernel/git/dtor/input.git next
config: sh-allmodconfig (attached as .config)
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=sh 

All errors (new ones prefixed by >>):

   drivers/input/touchscreen/ad7879-i2c.c:151:1: error: 'st1232_ts_dt_ids' undeclared here (not in a function)
>> drivers/input/touchscreen/ad7879-i2c.c:151:1: error: '__mod_of__st1232_ts_dt_ids_device_table' aliased to undefined symbol 'st1232_ts_dt_ids'

vim +151 drivers/input/touchscreen/ad7879-i2c.c

   145	
   146	#ifdef CONFIG_OF
   147	static const struct of_device_id ad7879_dt_ids[] = {
   148		{ .compatible = "adi,ad7879-1", },
   149		{ }
   150	};
 > 151	MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);
   152	#endif
   153	
   154	static struct i2c_driver ad7879_i2c_driver = {

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
Hennerich, Michael Jan. 26, 2016, 8:14 a.m. UTC | #4
On 01/26/2016 04:04 AM, 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@agner.ch>


Hi Stefan,

Thanks for the patch -
There is something similar in our tree but I forgot to send it mainline 
a long time ago.

https://github.com/analogdevicesinc/linux/commit/69b16d4b616a4bbe9001d3f67d3ff54f3deb85ce

There are some build issues can you have a look?

I also don't understand why "exporting the GPIO is not possible through 
device tree"?

Can you explain?

Regards,
Michael


> ---
>   .../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 *);
>
>
Stefan Agner Jan. 26, 2016, 5:10 p.m. UTC | #5
On 2016-01-26 00:14, Michael Hennerich wrote:
> On 01/26/2016 04:04 AM, 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@agner.ch>
> 
> 
> Hi Stefan,
> 
> Thanks for the patch -
> There is something similar in our tree but I forgot to send it
> mainline a long time ago.
> 
> https://github.com/analogdevicesinc/linux/commit/69b16d4b616a4bbe9001d3f67d3ff54f3deb85ce

Yeah I saw that patch. I tried to use the standard touchscreen
properties where applicable.

Also, my implementation is currently only for I2C. However, when I now
think about it, I might as well move my code into ad7879.c which would
enable to use the same bindings for SPI devices too.

> 
> There are some build issues can you have a look?

Yeah I saw, shame on me. Will fix them.

> 
> I also don't understand why "exporting the GPIO is not possible
> through device tree"?
> 
> Can you explain?

I should have written "not implemented" instead of "not possible".

To implement proper device tree GPIO bindings it would need some more
changes. I did not look into that, hence the current device tree
bindings do not allow to enable the GPIO functionality.

--
Stefan

> 
> Regards,
> Michael
> 
> 
>> ---
>>   .../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 *);
>>
>>
--
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Dmitry Torokhov Jan. 27, 2016, 11:38 p.m. UTC | #6
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@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");

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.
Rob Herring (Arm) Jan. 29, 2016, 3 a.m. UTC | #7
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@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)

These all should be prefixed with "adi,". Also, please state the sizes 
are 8-bit.

> +
> +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>;
> +	};
--
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diff mbox

Patch

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 *);