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

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 <[email protected]>

---
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

Documentation/devicetree/bindings/iio/potentiometer/mcp4131.txt new file +84 -0

new file mode 100644
index 0000000..3ccba16
@@ -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>;
+};

drivers/iio/potentiometer/Kconfig +18 -0

index fd75db7..5ef181a 100644
@@ -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

drivers/iio/potentiometer/Makefile +1 -0

index 8afe492..cd5c80b 100644
@@ -3,4 +3,5 @@
 #
 
 # When adding new entries keep the list in alphabetical order
+obj-$(CONFIG_MCP4131) += mcp4131.o
 obj-$(CONFIG_MCP4531) += mcp4531.o

drivers/iio/potentiometer/mcp4131.c new file +494 -0

new file mode 100644
index 0000000..4e7e2c6
@@ -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 <[email protected]>");
+MODULE_DESCRIPTION("MCP4131 digital potentiometer");
+MODULE_LICENSE("GPL v2");

Quoted 6 lines · Slawomir Stepien

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 <[email protected]>

One process comment below... And git actually copes fine with what you did (I wondered which way it would go until I tried it :)

Applied to the togreg branch of iio.git - initially pushed out as testing for the autobuilders to play pingpong with it.

A very nice, clean driver. Thanks for your hard work on this.

Note it is in a branch I happy to rebase for the next week, so if Joachim in particular would like to add a reviewed by tag, I'd be delighted to append it. Often reviewers don't get enough credit in my opinion!

Quoted 13 lines · Jonathan Cameron

Quoted 6 lines · Slawomir Stepien

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 <[email protected]>

One process comment below... And git actually copes fine with what you did (I wondered which way it would go until I tried it :)

Applied to the togreg branch of iio.git - initially pushed out as testing for the autobuilders to play pingpong with it.

Quoted 5 lines

A very nice, clean driver. Thanks for your hard work on this.

Note it is in a branch I happy to rebase for the next week, so if Joachim in particular would like to add a reviewed by tag, I'd be delighted to append it. Often reviewers don't get enough credit in my opinion!

Sure;

Reviewed-by Joachim Eastwood <[email protected]>

regards,
Joachim Eastwood
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html

Quoted 6 lines · Slawomir Stepien

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 <[email protected]>

One process comment below... And git actually copes fine with what you did (I wondered which way it would go until I tried it :)

Applied to the togreg branch of iio.git - initially pushed out as testing for the autobuilders to play pingpong with it.

A very nice, clean driver. Thanks for your hard work on this.

Note it is in a branch I happy to rebase for the next week, so if Joachim in particular would like to add a reviewed by tag, I'd be delighted to append it. Often reviewers don't get enough credit in my opinion!

Quoted 19 lines

---
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

Quoted 10 lines

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

Funnily enough, this is the only thing I can find wrong in this patch. Should not introduce an additional --- as you have done here.
The version stuff should simply have a blank line between it and the stats ;)

Quoted 9 lines · Jonathan Cameron

Quoted 6 lines · Slawomir Stepien

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 <[email protected]>

One process comment below... And git actually copes fine with what you did (I wondered which way it would go until I tried it :)

I did try it on my tree with git and it works so I decided to do it like that. I'll drop the additional --- next time.

Quoted 3 lines

Applied to the togreg branch of iio.git - initially pushed out as testing for the autobuilders to play pingpong with it.

Quoted 5 lines

A very nice, clean driver. Thanks for your hard work on this.

Note it is in a branch I happy to rebase for the next week, so if Joachim in particular would like to add a reviewed by tag, I'd be delighted to append it. Often reviewers don't get enough credit in my opinion!

Thank you all for the support and really good comments on this patch. I've learned a lot!

Quoted 29 lines

Quoted 29 lines

---
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

Quoted 3 lines

Funnily enough, this is the only thing I can find wrong in this patch. Should not introduce an additional --- as you have done here.
The version stuff should simply have a blank line between it and the stats ;)

How about the MAINTAINER file? I wasn't sure if I should add myself as the M of this driver...