Re: [PATCH v2] iio: add driver for Microchip MCP413X/414X/415X/416X/423X/424X/425X/426X

[Jonathan Cameron <jic23@kernel.org>]

On 19/03/16 13:48, Peter Meerwald-Stadler wrote:
> 
>> The following functionalities are supported:
>>  - write, read from volatile memory
>>
>> Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22060b.pdf
> 
> comments below
A few more little bits from me.  Mostly looking good though.

Jonathan
>  
>> Signed-off-by: Slawomir Stepien <sst@poczta.fm>
>> ---
>> This is v2 of patch: "iio: add driver for Microchip MCP414X/416X/424X/426X"
>>
>> 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                | 523 +++++++++++++++++++++
>>  4 files changed, 626 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..3553c9e
>> --- /dev/null
>> +++ b/drivers/iio/potentiometer/mcp4131.c
>> @@ -0,0 +1,523 @@
>> +/*
>> + * 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/module.h>
>> +#include <linux/spi/spi.h>
>> +#include <linux/err.h>
>> +
>> +#include <linux/iio/iio.h>
>> +
>> +#define MCP4131_WRITE		(0x00 << 2)
>> +#define MCP4131_READ		(0x03 << 2)
>> +
>> +#define MCP4131_WIPER_SHIFT	(4)
> 
> () not needed
> 
>> +#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;

This is only used to lookup elements of your cfg array, I'd just have
a pointer to the relevant element of that array in here instead.

struct mcp4131_cfg *cfg;

and in probe do
data->cfg = &mcp4131_cfg[id];
>> +	unsigned long devid;
>> +	struct mutex lock;
>> +	u8 tx[2], rx[2];
> 
> alignment requirements for SPI transfer?
By which he means put them at the end of this structure and
mark the with __cacheline_aligned.  It's not technically about alignment
but rather about ensuring nothing else is in the cacheline which will on some
spi devices be scrubbed when a transaction occurs.
> 
>> +	struct spi_transfer xfer;
>> +	struct spi_message msg;
>> +};
>> +
>> +#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_exec(struct mcp4131_data *data,
>> +		u8 addr, u8 cmd,
>> +		u16 val)
>> +{
>> +	int err;
>> +	struct spi_device *spi = data->spi;
>> +
>> +	data->rx[0] = 0;
>> +	data->rx[1] = 0;
> 
> initialization needed?
> 
> setup of data->xfer + data->tx is done outside the lock, this seems wrong
agreed.
> 
>> +
>> +	switch (cmd) {
>> +	case MCP4131_READ:
>> +		data->xfer.len = 2; /* Two bytes transfer for this command */
>> +		data->tx[0] = (addr << MCP4131_WIPER_SHIFT) | MCP4131_READ;
>> +		data->tx[1] = 0;
>> +		break;
>> +
>> +	case MCP4131_WRITE:
>> +		data->xfer.len = 2;
>> +		data->tx[0] = (addr << MCP4131_WIPER_SHIFT) |
>> +			MCP4131_WRITE | (val >> 8);
>> +		data->tx[1] = val & 0xFF; /* 8 bits here */
>> +		break;
>> +
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	dev_dbg(&spi->dev, "mcp4131_exec: tx0: 0x%x tx1: 0x%x\n",
>> +			data->tx[0], data->tx[1]);
>> +
>> +	mutex_lock(&data->lock);
>> +	spi_message_init(&data->msg);
>> +	spi_message_add_tail(&data->xfer, &data->msg);
>> +
>> +	err = spi_sync(spi, &data->msg);
>> +	if (err) {
>> +		dev_err(&spi->dev, "spi_sync(): %d\n", err);
>> +		mutex_unlock(&data->lock);
>> +		return err;
>> +	}
>> +	mutex_unlock(&data->lock);
>> +
>> +	dev_dbg(&spi->dev, "mcp4131_exec: rx0: 0x%x rx1: 0x%x\n",
>> +			data->rx[0], data->rx[1]);
>> +
>> +	return 0;
>> +}
>> +
>> +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:
>> +		err = mcp4131_exec(data, address, MCP4131_READ, 0);
>> +		if (err)
>> +			return err;
>> +
>> +		/* Error, bad address/command combination */
>> +		if (!MCP4131_CMDERR(data->rx))
>> +			return -EIO;
>> +
>> +		*val = MCP4131_RAW(data->rx);
>> +		return IIO_VAL_INT;
>> +
>> +	case IIO_CHAN_INFO_SCALE:

Now I'd change the way you are doing this slightly so that you have
data->cfg pointing to mcp4131[data->devid].  Moves the 'what part am I?'
question to a single place in the probe function giving slightly cleaner code.
>> +		*val = 1000 * mcp4131_cfg[data->devid].kohms;
>> +		*val2 = mcp4131_cfg[data->devid].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)
>> +{
>> +	struct mcp4131_data *data = iio_priv(indio_dev);
>> +	int address = chan->channel << MCP4131_WIPER_SHIFT;
>> +
>> +	switch (mask) {
>> +	case IIO_CHAN_INFO_RAW:
>> +		if (val > mcp4131_cfg[data->devid].max_pos || val < 0)
>> +			return -EINVAL;
>> +		break;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	return mcp4131_exec(data, address, MCP4131_WRITE, val);
>> +}
>> +
>> +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->devid = devid;
>> +
>> +	data->xfer.tx_buf = data->tx;
>> +	data->xfer.rx_buf = data->rx;
>> +
>> +	mutex_init(&data->lock);
>> +
>> +	indio_dev->dev.parent = dev;
>> +	indio_dev->info = &mcp4131_info;
>> +	indio_dev->channels = mcp4131_channels;
>> +	indio_dev->num_channels = mcp4131_cfg[devid].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;
>> +	}
>> +
>> +	dev_info(&spi->dev, "Registered %s\n", indio_dev->name);
> 
> I'd rather drop this message
Agreed, adds noise and it's easy to check if the register succeeded anyway
by just looking to see if the device is there in sysfs.
> 
>> +
>> +	return 0;
>> +}
>> +
>> +static int mcp4131_remove(struct spi_device *spi)
>> +{
>> +	struct iio_dev *indio_dev = spi_get_drvdata(spi);
>> +	struct mcp4131_data *data = iio_priv(indio_dev);
>> +
>> +	mutex_destroy(&data->lock);
> 
> no need to call
Hmm. This is an oddity, the mutex_destroy exists to aid in debugging locking
issues by explicity marking the mutex as do not use - iff the mutex
debugging is enabled.  In this case the storage is promptly deleted anyway
so any attempt to use the mutex would result in a null pointer dereference
anyway.  Hence probably not worth having it here.
> 
>> +	devm_iio_device_unregister(&spi->dev, indio_dev);
> 
> don't call this explicitly, it is done automatically after _remove
> 
>> +
>> +	dev_info(&spi->dev, "Unregistered %s\n", indio_dev->name);
> 
> don't
> 
> I think the entire _remove can be removed
> 
>> +
>> +	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,
>> +	.remove		= mcp4131_remove,
>> +	.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");
>>
>