[PATCH v5] iio: potentiometer: add driver for Microchip MCP413X/414X/415X/416X/423X/424X/425X/426X

[Slawomir Stepien <sst@poczta.fm>]

The following functionalities are supported:
 - write, read from volatile memory

Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22060b.pdf

Signed-off-by: Slawomir Stepien <sst@poczta.fm>
---
Changes since v4:
- Added necessary include files and sorted all includes
- Added missing mutex unlock when there is CMDERR
- mcp4131_write_raw spi_write/mutex_unlock/return refactor

Changes since v3:
- Added 'potentiometer' to subject
- Replaced mcp4131_exec with spi_write and mcp4131_read
- Narrowed mutex locking and unlocking places

Changes since v2:
- Removed unnecessary parentheses in MCP4131_WIPER_SHIFT macro
- Replaced the rx and tx SPI buffers with one buf that is ____cacheline_aligned
- Changed mutex locking position
- Replaced the devid with pointer to model configuration
- Removed positive ("Registered" & "Unregistered") dev_info prints
- Removed the mcp4131_remove callback

Changes since v1:
- One line summary changed
- Fixed module name and OF compatible
- Based code on Peter Rosin's code from mcp4531.c
- No additional sysfs attributes
- Deleted not used devid struct memeber
- Changed mcp4131_exec function arguments:
 - write value is now u16
 - no need to pass return buffer array - rx array from mcp4131_data is used
- Added missing new line characters to dev_info
---
 .../bindings/iio/potentiometer/mcp4131.txt         |  84 ++++
 drivers/iio/potentiometer/Kconfig                  |  18 +
 drivers/iio/potentiometer/Makefile                 |   1 +
 drivers/iio/potentiometer/mcp4131.c                | 494 +++++++++++++++++++++
 4 files changed, 597 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/potentiometer/mcp4131.txt
 create mode 100644 drivers/iio/potentiometer/mcp4131.c

diff --git a/Documentation/devicetree/bindings/iio/potentiometer/mcp4131.txt b/Documentation/devicetree/bindings/iio/potentiometer/mcp4131.txt
new file mode 100644
index 0000000..3ccba16
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/potentiometer/mcp4131.txt
@@ -0,0 +1,84 @@
+* Microchip MCP413X/414X/415X/416X/423X/424X/425X/426X Digital Potentiometer
+  driver
+
+The node for this driver must be a child node of a SPI controller, hence
+all mandatory properties described in
+
+        Documentation/devicetree/bindings/spi/spi-bus.txt
+
+must be specified.
+
+Required properties:
+	- compatible:  	Must be one of the following, depending on the
+			model:
+			"microchip,mcp4131-502"
+			"microchip,mcp4131-103"
+			"microchip,mcp4131-503"
+			"microchip,mcp4131-104"
+			"microchip,mcp4132-502"
+			"microchip,mcp4132-103"
+			"microchip,mcp4132-503"
+			"microchip,mcp4132-104"
+			"microchip,mcp4141-502"
+			"microchip,mcp4141-103"
+			"microchip,mcp4141-503"
+			"microchip,mcp4141-104"
+			"microchip,mcp4142-502"
+			"microchip,mcp4142-103"
+			"microchip,mcp4142-503"
+			"microchip,mcp4142-104"
+			"microchip,mcp4151-502"
+			"microchip,mcp4151-103"
+			"microchip,mcp4151-503"
+			"microchip,mcp4151-104"
+			"microchip,mcp4152-502"
+			"microchip,mcp4152-103"
+			"microchip,mcp4152-503"
+			"microchip,mcp4152-104"
+			"microchip,mcp4161-502"
+			"microchip,mcp4161-103"
+			"microchip,mcp4161-503"
+			"microchip,mcp4161-104"
+			"microchip,mcp4162-502"
+			"microchip,mcp4162-103"
+			"microchip,mcp4162-503"
+			"microchip,mcp4162-104"
+			"microchip,mcp4231-502"
+			"microchip,mcp4231-103"
+			"microchip,mcp4231-503"
+			"microchip,mcp4231-104"
+			"microchip,mcp4232-502"
+			"microchip,mcp4232-103"
+			"microchip,mcp4232-503"
+			"microchip,mcp4232-104"
+			"microchip,mcp4241-502"
+			"microchip,mcp4241-103"
+			"microchip,mcp4241-503"
+			"microchip,mcp4241-104"
+			"microchip,mcp4242-502"
+			"microchip,mcp4242-103"
+			"microchip,mcp4242-503"
+			"microchip,mcp4242-104"
+			"microchip,mcp4251-502"
+			"microchip,mcp4251-103"
+			"microchip,mcp4251-503"
+			"microchip,mcp4251-104"
+			"microchip,mcp4252-502"
+			"microchip,mcp4252-103"
+			"microchip,mcp4252-503"
+			"microchip,mcp4252-104"
+			"microchip,mcp4261-502"
+			"microchip,mcp4261-103"
+			"microchip,mcp4261-503"
+			"microchip,mcp4261-104"
+			"microchip,mcp4262-502"
+			"microchip,mcp4262-103"
+			"microchip,mcp4262-503"
+			"microchip,mcp4262-104"
+
+Example:
+mcp4131: mcp4131@0 {
+	compatible = "mcp4131-502";
+	reg = <0>;
+	spi-max-frequency = <500000>;
+};
diff --git a/drivers/iio/potentiometer/Kconfig b/drivers/iio/potentiometer/Kconfig
index fd75db7..5ef181a 100644
--- a/drivers/iio/potentiometer/Kconfig
+++ b/drivers/iio/potentiometer/Kconfig
@@ -5,6 +5,24 @@
 
 menu "Digital potentiometers"
 
+config MCP4131
+	tristate "Microchip MCP413X/414X/415X/416X/423X/424X/425X/426X Digital Potentiometer driver"
+	depends on SPI
+	help
+	  Say yes here to build support for the Microchip
+	  MCP4131, MCP4132,
+	  MCP4141, MCP4142,
+	  MCP4151, MCP4152,
+	  MCP4161, MCP4162,
+	  MCP4231, MCP4232,
+	  MCP4241, MCP4242,
+	  MCP4251, MCP4252,
+	  MCP4261, MCP4262,
+	  digital potentiomenter chips.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called mcp4131.
+
 config MCP4531
 	tristate "Microchip MCP45xx/MCP46xx Digital Potentiometer driver"
 	depends on I2C
diff --git a/drivers/iio/potentiometer/Makefile b/drivers/iio/potentiometer/Makefile
index 8afe492..cd5c80b 100644
--- a/drivers/iio/potentiometer/Makefile
+++ b/drivers/iio/potentiometer/Makefile
@@ -3,4 +3,5 @@
 #
 
 # When adding new entries keep the list in alphabetical order
+obj-$(CONFIG_MCP4131) += mcp4131.o
 obj-$(CONFIG_MCP4531) += mcp4531.o
diff --git a/drivers/iio/potentiometer/mcp4131.c b/drivers/iio/potentiometer/mcp4131.c
new file mode 100644
index 0000000..4e7e2c6
--- /dev/null
+++ b/drivers/iio/potentiometer/mcp4131.c
@@ -0,0 +1,494 @@
+/*
+ * Industrial I/O driver for Microchip digital potentiometers
+ *
+ * Copyright (c) 2016 Slawomir Stepien
+ * Based on: Peter Rosin's code from mcp4531.c
+ *
+ * Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22060b.pdf
+ *
+ * DEVID	#Wipers	#Positions	Resistor Opts (kOhm)
+ * mcp4131	1	129		5, 10, 50, 100
+ * mcp4132	1	129		5, 10, 50, 100
+ * mcp4141	1	129		5, 10, 50, 100
+ * mcp4142	1	129		5, 10, 50, 100
+ * mcp4151	1	257		5, 10, 50, 100
+ * mcp4152	1	257		5, 10, 50, 100
+ * mcp4161	1	257		5, 10, 50, 100
+ * mcp4162	1	257		5, 10, 50, 100
+ * mcp4231	2	129		5, 10, 50, 100
+ * mcp4232	2	129		5, 10, 50, 100
+ * mcp4241	2	129		5, 10, 50, 100
+ * mcp4242	2	129		5, 10, 50, 100
+ * mcp4251	2	257		5, 10, 50, 100
+ * mcp4252	2	257		5, 10, 50, 100
+ * mcp4261	2	257		5, 10, 50, 100
+ * mcp4262	2	257		5, 10, 50, 100
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+/*
+ * TODO:
+ * 1. Write wiper setting to EEPROM for EEPROM capable models.
+ */
+
+#include <linux/cache.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/types.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/spi/spi.h>
+
+#define MCP4131_WRITE		(0x00 << 2)
+#define MCP4131_READ		(0x03 << 2)
+
+#define MCP4131_WIPER_SHIFT	4
+#define MCP4131_CMDERR(r)	((r[0]) & 0x02)
+#define MCP4131_RAW(r)		((r[0]) == 0xff ? 0x100 : (r[1]))
+
+struct mcp4131_cfg {
+	int wipers;
+	int max_pos;
+	int kohms;
+};
+
+enum mcp4131_type {
+	MCP413x_502 = 0,
+	MCP413x_103,
+	MCP413x_503,
+	MCP413x_104,
+	MCP414x_502,
+	MCP414x_103,
+	MCP414x_503,
+	MCP414x_104,
+	MCP415x_502,
+	MCP415x_103,
+	MCP415x_503,
+	MCP415x_104,
+	MCP416x_502,
+	MCP416x_103,
+	MCP416x_503,
+	MCP416x_104,
+	MCP423x_502,
+	MCP423x_103,
+	MCP423x_503,
+	MCP423x_104,
+	MCP424x_502,
+	MCP424x_103,
+	MCP424x_503,
+	MCP424x_104,
+	MCP425x_502,
+	MCP425x_103,
+	MCP425x_503,
+	MCP425x_104,
+	MCP426x_502,
+	MCP426x_103,
+	MCP426x_503,
+	MCP426x_104,
+};
+
+static const struct mcp4131_cfg mcp4131_cfg[] = {
+	[MCP413x_502] = { .wipers = 1, .max_pos = 128, .kohms =   5, },
+	[MCP413x_103] = { .wipers = 1, .max_pos = 128, .kohms =  10, },
+	[MCP413x_503] = { .wipers = 1, .max_pos = 128, .kohms =  50, },
+	[MCP413x_104] = { .wipers = 1, .max_pos = 128, .kohms = 100, },
+	[MCP414x_502] = { .wipers = 1, .max_pos = 128, .kohms =   5, },
+	[MCP414x_103] = { .wipers = 1, .max_pos = 128, .kohms =  10, },
+	[MCP414x_503] = { .wipers = 1, .max_pos = 128, .kohms =  50, },
+	[MCP414x_104] = { .wipers = 1, .max_pos = 128, .kohms = 100, },
+	[MCP415x_502] = { .wipers = 1, .max_pos = 256, .kohms =   5, },
+	[MCP415x_103] = { .wipers = 1, .max_pos = 256, .kohms =  10, },
+	[MCP415x_503] = { .wipers = 1, .max_pos = 256, .kohms =  50, },
+	[MCP415x_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, },
+	[MCP416x_502] = { .wipers = 1, .max_pos = 256, .kohms =   5, },
+	[MCP416x_103] = { .wipers = 1, .max_pos = 256, .kohms =  10, },
+	[MCP416x_503] = { .wipers = 1, .max_pos = 256, .kohms =  50, },
+	[MCP416x_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, },
+	[MCP423x_502] = { .wipers = 2, .max_pos = 128, .kohms =   5, },
+	[MCP423x_103] = { .wipers = 2, .max_pos = 128, .kohms =  10, },
+	[MCP423x_503] = { .wipers = 2, .max_pos = 128, .kohms =  50, },
+	[MCP423x_104] = { .wipers = 2, .max_pos = 128, .kohms = 100, },
+	[MCP424x_502] = { .wipers = 2, .max_pos = 128, .kohms =   5, },
+	[MCP424x_103] = { .wipers = 2, .max_pos = 128, .kohms =  10, },
+	[MCP424x_503] = { .wipers = 2, .max_pos = 128, .kohms =  50, },
+	[MCP424x_104] = { .wipers = 2, .max_pos = 128, .kohms = 100, },
+	[MCP425x_502] = { .wipers = 2, .max_pos = 256, .kohms =   5, },
+	[MCP425x_103] = { .wipers = 2, .max_pos = 256, .kohms =  10, },
+	[MCP425x_503] = { .wipers = 2, .max_pos = 256, .kohms =  50, },
+	[MCP425x_104] = { .wipers = 2, .max_pos = 256, .kohms = 100, },
+	[MCP426x_502] = { .wipers = 2, .max_pos = 256, .kohms =   5, },
+	[MCP426x_103] = { .wipers = 2, .max_pos = 256, .kohms =  10, },
+	[MCP426x_503] = { .wipers = 2, .max_pos = 256, .kohms =  50, },
+	[MCP426x_104] = { .wipers = 2, .max_pos = 256, .kohms = 100, },
+};
+
+struct mcp4131_data {
+	struct spi_device *spi;
+	const struct mcp4131_cfg *cfg;
+	struct mutex lock;
+	u8 buf[2] ____cacheline_aligned;
+};
+
+#define MCP4131_CHANNEL(ch) {					\
+	.type = IIO_RESISTANCE,					\
+	.indexed = 1,						\
+	.output = 1,						\
+	.channel = (ch),					\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+}
+
+static const struct iio_chan_spec mcp4131_channels[] = {
+	MCP4131_CHANNEL(0),
+	MCP4131_CHANNEL(1),
+};
+
+static int mcp4131_read(struct spi_device *spi, void *buf, size_t len)
+{
+	struct spi_transfer t = {
+		.tx_buf = buf, /* We need to send addr, cmd and 12 bits */
+		.rx_buf	= buf,
+		.len = len,
+	};
+	struct spi_message m;
+
+	spi_message_init(&m);
+	spi_message_add_tail(&t, &m);
+
+	return spi_sync(spi, &m);
+}
+
+static int mcp4131_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	int err;
+	struct mcp4131_data *data = iio_priv(indio_dev);
+	int address = chan->channel;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&data->lock);
+
+		data->buf[0] = (address << MCP4131_WIPER_SHIFT) | MCP4131_READ;
+		data->buf[1] = 0;
+
+		err = mcp4131_read(data->spi, data->buf, 2);
+		if (err) {
+			mutex_unlock(&data->lock);
+			return err;
+		}
+
+		/* Error, bad address/command combination */
+		if (!MCP4131_CMDERR(data->buf)) {
+			mutex_unlock(&data->lock);
+			return -EIO;
+		}
+
+		*val = MCP4131_RAW(data->buf);
+		mutex_unlock(&data->lock);
+
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		*val = 1000 * data->cfg->kohms;
+		*val2 = data->cfg->max_pos;
+		return IIO_VAL_FRACTIONAL;
+	}
+
+	return -EINVAL;
+}
+
+static int mcp4131_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int val, int val2, long mask)
+{
+	int err;
+	struct mcp4131_data *data = iio_priv(indio_dev);
+	int address = chan->channel << MCP4131_WIPER_SHIFT;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (val > data->cfg->max_pos || val < 0)
+			return -EINVAL;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	mutex_lock(&data->lock);
+
+	data->buf[0] = address << MCP4131_WIPER_SHIFT;
+	data->buf[0] |= MCP4131_WRITE | (val >> 8);
+	data->buf[1] = val & 0xFF; /* 8 bits here */
+
+	err = spi_write(data->spi, data->buf, 2);
+	mutex_unlock(&data->lock);
+
+	return err;
+}
+
+static const struct iio_info mcp4131_info = {
+	.read_raw = mcp4131_read_raw,
+	.write_raw = mcp4131_write_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static int mcp4131_probe(struct spi_device *spi)
+{
+	int err;
+	struct device *dev = &spi->dev;
+	unsigned long devid = spi_get_device_id(spi)->driver_data;
+	struct mcp4131_data *data;
+	struct iio_dev *indio_dev;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	spi_set_drvdata(spi, indio_dev);
+	data->spi = spi;
+	data->cfg = &mcp4131_cfg[devid];
+
+	mutex_init(&data->lock);
+
+	indio_dev->dev.parent = dev;
+	indio_dev->info = &mcp4131_info;
+	indio_dev->channels = mcp4131_channels;
+	indio_dev->num_channels = data->cfg->wipers;
+	indio_dev->name = spi_get_device_id(spi)->name;
+
+	err = devm_iio_device_register(dev, indio_dev);
+	if (err) {
+		dev_info(&spi->dev, "Unable to register %s\n", indio_dev->name);
+		return err;
+	}
+
+	return 0;
+}
+
+#if defined(CONFIG_OF)
+static const struct of_device_id mcp4131_dt_ids[] = {
+	{ .compatible = "microchip,mcp4131-502",
+		.data = &mcp4131_cfg[MCP413x_502] },
+	{ .compatible = "microchip,mcp4131-103",
+		.data = &mcp4131_cfg[MCP413x_103] },
+	{ .compatible = "microchip,mcp4131-503",
+		.data = &mcp4131_cfg[MCP413x_503] },
+	{ .compatible = "microchip,mcp4131-104",
+		.data = &mcp4131_cfg[MCP413x_104] },
+	{ .compatible = "microchip,mcp4132-502",
+		.data = &mcp4131_cfg[MCP413x_502] },
+	{ .compatible = "microchip,mcp4132-103",
+		.data = &mcp4131_cfg[MCP413x_103] },
+	{ .compatible = "microchip,mcp4132-503",
+		.data = &mcp4131_cfg[MCP413x_503] },
+	{ .compatible = "microchip,mcp4132-104",
+		.data = &mcp4131_cfg[MCP413x_104] },
+	{ .compatible = "microchip,mcp4141-502",
+		.data = &mcp4131_cfg[MCP414x_502] },
+	{ .compatible = "microchip,mcp4141-103",
+		.data = &mcp4131_cfg[MCP414x_103] },
+	{ .compatible = "microchip,mcp4141-503",
+		.data = &mcp4131_cfg[MCP414x_503] },
+	{ .compatible = "microchip,mcp4141-104",
+		.data = &mcp4131_cfg[MCP414x_104] },
+	{ .compatible = "microchip,mcp4142-502",
+		.data = &mcp4131_cfg[MCP414x_502] },
+	{ .compatible = "microchip,mcp4142-103",
+		.data = &mcp4131_cfg[MCP414x_103] },
+	{ .compatible = "microchip,mcp4142-503",
+		.data = &mcp4131_cfg[MCP414x_503] },
+	{ .compatible = "microchip,mcp4142-104",
+		.data = &mcp4131_cfg[MCP414x_104] },
+	{ .compatible = "microchip,mcp4151-502",
+		.data = &mcp4131_cfg[MCP415x_502] },
+	{ .compatible = "microchip,mcp4151-103",
+		.data = &mcp4131_cfg[MCP415x_103] },
+	{ .compatible = "microchip,mcp4151-503",
+		.data = &mcp4131_cfg[MCP415x_503] },
+	{ .compatible = "microchip,mcp4151-104",
+		.data = &mcp4131_cfg[MCP415x_104] },
+	{ .compatible = "microchip,mcp4152-502",
+		.data = &mcp4131_cfg[MCP415x_502] },
+	{ .compatible = "microchip,mcp4152-103",
+		.data = &mcp4131_cfg[MCP415x_103] },
+	{ .compatible = "microchip,mcp4152-503",
+		.data = &mcp4131_cfg[MCP415x_503] },
+	{ .compatible = "microchip,mcp4152-104",
+		.data = &mcp4131_cfg[MCP415x_104] },
+	{ .compatible = "microchip,mcp4161-502",
+		.data = &mcp4131_cfg[MCP416x_502] },
+	{ .compatible = "microchip,mcp4161-103",
+		.data = &mcp4131_cfg[MCP416x_103] },
+	{ .compatible = "microchip,mcp4161-503",
+		.data = &mcp4131_cfg[MCP416x_503] },
+	{ .compatible = "microchip,mcp4161-104",
+		.data = &mcp4131_cfg[MCP416x_104] },
+	{ .compatible = "microchip,mcp4162-502",
+		.data = &mcp4131_cfg[MCP416x_502] },
+	{ .compatible = "microchip,mcp4162-103",
+		.data = &mcp4131_cfg[MCP416x_103] },
+	{ .compatible = "microchip,mcp4162-503",
+		.data = &mcp4131_cfg[MCP416x_503] },
+	{ .compatible = "microchip,mcp4162-104",
+		.data = &mcp4131_cfg[MCP416x_104] },
+	{ .compatible = "microchip,mcp4231-502",
+		.data = &mcp4131_cfg[MCP423x_502] },
+	{ .compatible = "microchip,mcp4231-103",
+		.data = &mcp4131_cfg[MCP423x_103] },
+	{ .compatible = "microchip,mcp4231-503",
+		.data = &mcp4131_cfg[MCP423x_503] },
+	{ .compatible = "microchip,mcp4231-104",
+		.data = &mcp4131_cfg[MCP423x_104] },
+	{ .compatible = "microchip,mcp4232-502",
+		.data = &mcp4131_cfg[MCP423x_502] },
+	{ .compatible = "microchip,mcp4232-103",
+		.data = &mcp4131_cfg[MCP423x_103] },
+	{ .compatible = "microchip,mcp4232-503",
+		.data = &mcp4131_cfg[MCP423x_503] },
+	{ .compatible = "microchip,mcp4232-104",
+		.data = &mcp4131_cfg[MCP423x_104] },
+	{ .compatible = "microchip,mcp4241-502",
+		.data = &mcp4131_cfg[MCP424x_502] },
+	{ .compatible = "microchip,mcp4241-103",
+		.data = &mcp4131_cfg[MCP424x_103] },
+	{ .compatible = "microchip,mcp4241-503",
+		.data = &mcp4131_cfg[MCP424x_503] },
+	{ .compatible = "microchip,mcp4241-104",
+		.data = &mcp4131_cfg[MCP424x_104] },
+	{ .compatible = "microchip,mcp4242-502",
+		.data = &mcp4131_cfg[MCP424x_502] },
+	{ .compatible = "microchip,mcp4242-103",
+		.data = &mcp4131_cfg[MCP424x_103] },
+	{ .compatible = "microchip,mcp4242-503",
+		.data = &mcp4131_cfg[MCP424x_503] },
+	{ .compatible = "microchip,mcp4242-104",
+		.data = &mcp4131_cfg[MCP424x_104] },
+	{ .compatible = "microchip,mcp4251-502",
+		.data = &mcp4131_cfg[MCP425x_502] },
+	{ .compatible = "microchip,mcp4251-103",
+		.data = &mcp4131_cfg[MCP425x_103] },
+	{ .compatible = "microchip,mcp4251-503",
+		.data = &mcp4131_cfg[MCP425x_503] },
+	{ .compatible = "microchip,mcp4251-104",
+		.data = &mcp4131_cfg[MCP425x_104] },
+	{ .compatible = "microchip,mcp4252-502",
+		.data = &mcp4131_cfg[MCP425x_502] },
+	{ .compatible = "microchip,mcp4252-103",
+		.data = &mcp4131_cfg[MCP425x_103] },
+	{ .compatible = "microchip,mcp4252-503",
+		.data = &mcp4131_cfg[MCP425x_503] },
+	{ .compatible = "microchip,mcp4252-104",
+		.data = &mcp4131_cfg[MCP425x_104] },
+	{ .compatible = "microchip,mcp4261-502",
+		.data = &mcp4131_cfg[MCP426x_502] },
+	{ .compatible = "microchip,mcp4261-103",
+		.data = &mcp4131_cfg[MCP426x_103] },
+	{ .compatible = "microchip,mcp4261-503",
+		.data = &mcp4131_cfg[MCP426x_503] },
+	{ .compatible = "microchip,mcp4261-104",
+		.data = &mcp4131_cfg[MCP426x_104] },
+	{ .compatible = "microchip,mcp4262-502",
+		.data = &mcp4131_cfg[MCP426x_502] },
+	{ .compatible = "microchip,mcp4262-103",
+		.data = &mcp4131_cfg[MCP426x_103] },
+	{ .compatible = "microchip,mcp4262-503",
+		.data = &mcp4131_cfg[MCP426x_503] },
+	{ .compatible = "microchip,mcp4262-104",
+		.data = &mcp4131_cfg[MCP426x_104] },
+	{}
+};
+MODULE_DEVICE_TABLE(of, mcp4131_dt_ids);
+#endif /* CONFIG_OF */
+
+static const struct spi_device_id mcp4131_id[] = {
+	{ "mcp4131-502", MCP413x_502 },
+	{ "mcp4131-103", MCP413x_103 },
+	{ "mcp4131-503", MCP413x_503 },
+	{ "mcp4131-104", MCP413x_104 },
+	{ "mcp4132-502", MCP413x_502 },
+	{ "mcp4132-103", MCP413x_103 },
+	{ "mcp4132-503", MCP413x_503 },
+	{ "mcp4132-104", MCP413x_104 },
+	{ "mcp4141-502", MCP414x_502 },
+	{ "mcp4141-103", MCP414x_103 },
+	{ "mcp4141-503", MCP414x_503 },
+	{ "mcp4141-104", MCP414x_104 },
+	{ "mcp4142-502", MCP414x_502 },
+	{ "mcp4142-103", MCP414x_103 },
+	{ "mcp4142-503", MCP414x_503 },
+	{ "mcp4142-104", MCP414x_104 },
+	{ "mcp4151-502", MCP415x_502 },
+	{ "mcp4151-103", MCP415x_103 },
+	{ "mcp4151-503", MCP415x_503 },
+	{ "mcp4151-104", MCP415x_104 },
+	{ "mcp4152-502", MCP415x_502 },
+	{ "mcp4152-103", MCP415x_103 },
+	{ "mcp4152-503", MCP415x_503 },
+	{ "mcp4152-104", MCP415x_104 },
+	{ "mcp4161-502", MCP416x_502 },
+	{ "mcp4161-103", MCP416x_103 },
+	{ "mcp4161-503", MCP416x_503 },
+	{ "mcp4161-104", MCP416x_104 },
+	{ "mcp4162-502", MCP416x_502 },
+	{ "mcp4162-103", MCP416x_103 },
+	{ "mcp4162-503", MCP416x_503 },
+	{ "mcp4162-104", MCP416x_104 },
+	{ "mcp4231-502", MCP423x_502 },
+	{ "mcp4231-103", MCP423x_103 },
+	{ "mcp4231-503", MCP423x_503 },
+	{ "mcp4231-104", MCP423x_104 },
+	{ "mcp4232-502", MCP423x_502 },
+	{ "mcp4232-103", MCP423x_103 },
+	{ "mcp4232-503", MCP423x_503 },
+	{ "mcp4232-104", MCP423x_104 },
+	{ "mcp4241-502", MCP424x_502 },
+	{ "mcp4241-103", MCP424x_103 },
+	{ "mcp4241-503", MCP424x_503 },
+	{ "mcp4241-104", MCP424x_104 },
+	{ "mcp4242-502", MCP424x_502 },
+	{ "mcp4242-103", MCP424x_103 },
+	{ "mcp4242-503", MCP424x_503 },
+	{ "mcp4242-104", MCP424x_104 },
+	{ "mcp4251-502", MCP425x_502 },
+	{ "mcp4251-103", MCP425x_103 },
+	{ "mcp4251-503", MCP425x_503 },
+	{ "mcp4251-104", MCP425x_104 },
+	{ "mcp4252-502", MCP425x_502 },
+	{ "mcp4252-103", MCP425x_103 },
+	{ "mcp4252-503", MCP425x_503 },
+	{ "mcp4252-104", MCP425x_104 },
+	{ "mcp4261-502", MCP426x_502 },
+	{ "mcp4261-103", MCP426x_103 },
+	{ "mcp4261-503", MCP426x_503 },
+	{ "mcp4261-104", MCP426x_104 },
+	{ "mcp4262-502", MCP426x_502 },
+	{ "mcp4262-103", MCP426x_103 },
+	{ "mcp4262-503", MCP426x_503 },
+	{ "mcp4262-104", MCP426x_104 },
+	{}
+};
+MODULE_DEVICE_TABLE(spi, mcp4131_id);
+
+static struct spi_driver mcp4131_driver = {
+	.driver = {
+		.name	= "mcp4131",
+		.of_match_table = of_match_ptr(mcp4131_dt_ids),
+	},
+	.probe		= mcp4131_probe,
+	.id_table	= mcp4131_id,
+};
+
+module_spi_driver(mcp4131_driver);
+
+MODULE_AUTHOR("Slawomir Stepien <sst@poczta.fm>");
+MODULE_DESCRIPTION("MCP4131 digital potentiometer");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4