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Date: Wed, 16 Mar 2016 13:30:27 +0100 (CET)
From: Peter Meerwald-Stadler <pmeerw@...erw.net>
To: Slawomir Stepien <sst@...zta.fm>
cc: jic23@...nel.org, knaack.h@....de, lars@...afoo.de,
linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iio: add driver for Microchip MCP414X/416X/424X/426X
On Wed, 16 Mar 2016, Slawomir Stepien wrote:
> The following functionalities are supported:
> - write, read from volatile and non volatile memory
> - increase and decrease commands
> - read from status register
> - write and read to tcon register
>
> Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22059b.pdf
the driver naming is a mess: the subject says MCP414X, the file name is
mcp41xx, the DT compatible string says mcp4113x -- this does not match
plenty of the private API, some of which seems to be debug only?
what is really needed to interact with a poti?
comments below
> Signed-off-by: Slawomir Stepien <sst@...zta.fm>
> ---
> .../bindings/iio/potentiometer/mcp41xx.txt | 51 ++
> Documentation/iio/mcp41xx.txt | 86 +++
> drivers/iio/potentiometer/Kconfig | 18 +
> drivers/iio/potentiometer/Makefile | 1 +
> drivers/iio/potentiometer/mcp41xx.c | 709 +++++++++++++++++++++
> 5 files changed, 865 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/iio/potentiometer/mcp41xx.txt
> create mode 100644 Documentation/iio/mcp41xx.txt
> create mode 100644 drivers/iio/potentiometer/mcp41xx.c
>
> diff --git a/Documentation/devicetree/bindings/iio/potentiometer/mcp41xx.txt b/Documentation/devicetree/bindings/iio/potentiometer/mcp41xx.txt
> new file mode 100644
> index 0000000..6031142
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/potentiometer/mcp41xx.txt
> @@ -0,0 +1,51 @@
> +* Microchip MCP414X/416X/424X/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,mcp4113x-502"
> + "microchip,mcp4113x-103"
> + "microchip,mcp4113x-503"
> + "microchip,mcp4113x-104"
> + "microchip,mcp4114x-502"
> + "microchip,mcp4114x-103"
> + "microchip,mcp4114x-503"
> + "microchip,mcp4114x-104"
> + "microchip,mcp4115x-502"
> + "microchip,mcp4115x-103"
> + "microchip,mcp4115x-503"
> + "microchip,mcp4115x-104"
> + "microchip,mcp4116x-502"
> + "microchip,mcp4116x-103"
> + "microchip,mcp4116x-503"
> + "microchip,mcp4116x-104"
> + "microchip,mcp4123x-502"
> + "microchip,mcp4123x-103"
> + "microchip,mcp4123x-503"
> + "microchip,mcp4123x-104"
> + "microchip,mcp4124x-502"
> + "microchip,mcp4124x-103"
> + "microchip,mcp4124x-503"
> + "microchip,mcp4124x-104"
> + "microchip,mcp4125x-502"
> + "microchip,mcp4125x-103"
> + "microchip,mcp4125x-503"
> + "microchip,mcp4125x-104"
> + "microchip,mcp4126x-502"
> + "microchip,mcp4126x-103"
> + "microchip,mcp4126x-503"
> + "microchip,mcp4126x-104"
> +
> +Example:
> +mcp41xx: mcp41xx@0 {
> + compatible = "mcp416x-502";
> + reg = <0>;
> + spi-max-frequency = <500000>;
> +};
> diff --git a/Documentation/iio/mcp41xx.txt b/Documentation/iio/mcp41xx.txt
> new file mode 100644
> index 0000000..57dc889
> --- /dev/null
> +++ b/Documentation/iio/mcp41xx.txt
> @@ -0,0 +1,86 @@
> +Industrial I/O driver for MCP414X/416X/424X/426X Digital POTs
> +-------------------------------------------------------------
> +
> +Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22059a.pdf
> +
> +sysfs interface
> +---------------
> +N is the wiper number (0 = first wiper, 1 = second wiper)
> +
> +File: /sys/bus/iio/devices/../decr_wiperN
> +Mode: Write
> +Description:
> + Write anything to this file to decrease wiper N position by one step.
> +Example:
> + echo > decr_wiper0
> +
> +
> +File: /sys/bus/iio/devices/../incr_wiperN
> +Mode: Write
> +Description:
> + Write anything to this file to increase wiper N position by one step.
> +Example:
> + echo > incr_wiper0
> +
> +
> +File: /sys/bus/iio/devices/../memory_map
> +Mode: Read/Write
> +Description:
> + Read the whole memory or write value to given memory address.
> + Read outputs two columns. First column is address and second column is
> + value at that address.
> + For write use hex values with leading 0x. First hex is address second
> + hex is the value.
> +Example:
> + cat memory_map
> + echo "0x00 0x80" > memory_map
> +
> +
> +File: /sys/bus/iio/devices/../nv_wiperN
> +Mode: Read/Write
> +Description:
> + Read or write to non volatile memory of wiper N.
> + Read outputs decimal value that corresponds to wiper position.
> + For write use decimal value that corresponds to wiper position.
> +Example:
> + cat nv_wiper0
> + echo "128" > nv_wiper0
> +
> +
> +File: /sys/bus/iio/devices/../out_resistance_scale
> +Mode: Read
> +Description:
> + Read the resistance scale of one step (in ohms).
> +Example:
> + cat out_resistance_scale
> +
> +
> +File: /sys/bus/iio/devices/../out_resistanceN_raw
this is already described in sysfs-bus-iio
> +Mode: Read/Write
> +Description:
> + Read or write to volatile memory of wiper N.
> + Read outputs decimal value that corresponds to wiper position.
> + For write use decimal value that corresponds to wiper position.
> +Example:
> + cat out_resistance0_raw
> + echo "128" > out_resistance0_raw
> +
> +
> +File: /sys/bus/iio/devices/../status_register
> +Mode: Read
> +Description:
> + Read status register.
> + Read outputs content in binary format.
> +Example:
> + cat status_register
> +
> +
> +File: /sys/bus/iio/devices/../tcon_register
> +Mode: ead/Write
> +Description:
> + Read or write to tcon register.
> + Read outputs content in binary format.
> + For write use binary format string.
> +Example:
> + cat tcon_register
> + echo "111111100" > tcon_register
> diff --git a/drivers/iio/potentiometer/Kconfig b/drivers/iio/potentiometer/Kconfig
> index fd75db7..4540367 100644
> --- a/drivers/iio/potentiometer/Kconfig
> +++ b/drivers/iio/potentiometer/Kconfig
> @@ -5,6 +5,24 @@
>
> menu "Digital potentiometers"
>
> +config MCP41XX
> + tristate "Microchip MCP414X/416X/424X/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 mcp41xx.
> +
> 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..1266ebf 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-$(CONFIG_MCP41XX) += mcp41xx.o
> obj-$(CONFIG_MCP4531) += mcp4531.o
> diff --git a/drivers/iio/potentiometer/mcp41xx.c b/drivers/iio/potentiometer/mcp41xx.c
> new file mode 100644
> index 0000000..654965b
> --- /dev/null
> +++ b/drivers/iio/potentiometer/mcp41xx.c
> @@ -0,0 +1,709 @@
> +/*
> + * Industrial I/O driver for MCP414X/416X/424X/426X Digital POTs
> + *
> + * Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22059a.pdf
> + *
> + * Copyright (c) 2016 Slawomir Stepien
> + *
> + * 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.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/spi/spi.h>
> +#include <linux/err.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +#define MCP41XX_WRITE (0x00 << 2)
> +#define MCP41XX_INCR (0x01 << 2)
> +#define MCP41XX_DECR (0x02 << 2)
> +#define MCP41XX_READ (0x03 << 2)
> +
> +#define MCP41XX_FULL_SCALE(t) (t[0] == 0xFF ? 256 : t[1])
> +#define MCP41XX_9BIT_VALUE(t) ((t[1] + (t[0] << 8)) & 0x1FF)
> +
> +#define MCP41XX_MIN_ADDR 0x00
> +#define MCP41XX_MAX_ADDR 0x0F
> +
> +#define MCP41XX_NV_OFFSET 0x02
> +
> +#define MCP41XX_TCON_ADDR 0x04
> +#define MCP41XX_STATUS_ADDR 0x05
> +
> +struct mcp41xx_cfg {
> + unsigned long int devid;
devid is not set/used
> + unsigned int wipers;
> + unsigned int num_pos;
> + unsigned int kohms;
> +};
> +
> +enum mcp41xx_type {
> + MCP413x_502,
> + 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 mcp41xx_cfg mcp41xx_cfg[] = {
> + [MCP413x_502] = { .wipers = 1, .num_pos = 129, .kohms = 5 },
> + [MCP413x_103] = { .wipers = 1, .num_pos = 129, .kohms = 10 },
> + [MCP413x_503] = { .wipers = 1, .num_pos = 129, .kohms = 50 },
> + [MCP413x_104] = { .wipers = 1, .num_pos = 129, .kohms = 100 },
> + [MCP414x_502] = { .wipers = 1, .num_pos = 129, .kohms = 5 },
> + [MCP414x_103] = { .wipers = 1, .num_pos = 129, .kohms = 10 },
> + [MCP414x_503] = { .wipers = 1, .num_pos = 129, .kohms = 50 },
> + [MCP414x_104] = { .wipers = 1, .num_pos = 129, .kohms = 100 },
> + [MCP415x_502] = { .wipers = 1, .num_pos = 257, .kohms = 5 },
> + [MCP415x_103] = { .wipers = 1, .num_pos = 257, .kohms = 10 },
> + [MCP415x_503] = { .wipers = 1, .num_pos = 257, .kohms = 50 },
> + [MCP415x_104] = { .wipers = 1, .num_pos = 257, .kohms = 100 },
> + [MCP416x_502] = { .wipers = 1, .num_pos = 257, .kohms = 5 },
> + [MCP416x_103] = { .wipers = 1, .num_pos = 257, .kohms = 10 },
> + [MCP416x_503] = { .wipers = 1, .num_pos = 257, .kohms = 50 },
> + [MCP416x_104] = { .wipers = 1, .num_pos = 257, .kohms = 100 },
> + [MCP423x_502] = { .wipers = 2, .num_pos = 129, .kohms = 5 },
> + [MCP423x_103] = { .wipers = 2, .num_pos = 129, .kohms = 10 },
> + [MCP423x_503] = { .wipers = 2, .num_pos = 129, .kohms = 50 },
> + [MCP423x_104] = { .wipers = 2, .num_pos = 129, .kohms = 100 },
> + [MCP424x_502] = { .wipers = 2, .num_pos = 129, .kohms = 5 },
> + [MCP424x_103] = { .wipers = 2, .num_pos = 129, .kohms = 10 },
> + [MCP424x_503] = { .wipers = 2, .num_pos = 129, .kohms = 50 },
> + [MCP424x_104] = { .wipers = 2, .num_pos = 129, .kohms = 100 },
> + [MCP425x_502] = { .wipers = 2, .num_pos = 257, .kohms = 5 },
> + [MCP425x_103] = { .wipers = 2, .num_pos = 257, .kohms = 10 },
> + [MCP425x_503] = { .wipers = 2, .num_pos = 257, .kohms = 50 },
> + [MCP425x_104] = { .wipers = 2, .num_pos = 257, .kohms = 100 },
> + [MCP426x_502] = { .wipers = 2, .num_pos = 257, .kohms = 5 },
> + [MCP426x_103] = { .wipers = 2, .num_pos = 257, .kohms = 10 },
> + [MCP426x_503] = { .wipers = 2, .num_pos = 257, .kohms = 50 },
> + [MCP426x_104] = { .wipers = 2, .num_pos = 257, .kohms = 100 },
> +};
> +
> +struct mcp41xx_data {
> + struct spi_device *spi;
> + struct mutex lock;
> + unsigned long devid;
> + u8 tx[2], rx[2];
> + struct spi_transfer xfer;
> + struct spi_message msg;
> +};
> +
> +#define MCP41XX_CHANNEL(ch) { \
> + .type = IIO_RESISTANCE, \
> + .output = 1, \
> + .indexed = 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 mcp41xx_channels[] = {
> + MCP41XX_CHANNEL(0),
> + MCP41XX_CHANNEL(1),
> +};
> +
> +/* Function based on: arch/parisc/kernel/traps.c */
> +static int printbinary(char *buf, unsigned long x, int nbits)
> +{
> + unsigned long mask = 1UL << (nbits - 2);
> +
> + while (mask != 0) {
> + *buf++ = (mask & x ? '1' : '0');
> + mask >>= 1;
> + }
> + *buf++ = '\n';
> + *buf = '\0';
> +
> + return nbits;
> +}
> +
> +static int mcp41xx_exec(struct mcp41xx_data *data,
> + u8 addr, u8 cmd,
> + int *trans, size_t n)
should trans really be int, not u8?
> +{
> + int err;
> + struct spi_device *spi = data->spi;
> +
> + /* Two bytes are needed for the response */
> + if (n != 2)
> + return -EINVAL;
why pass n if it is always 2?
> +
> + switch (cmd) {
> + case MCP41XX_READ:
> + data->xfer.len = 2; /* Two bytes transfer for this command */
> + data->tx[0] = (addr << 4) | MCP41XX_READ;
> + data->tx[1] = 0;
> + break;
> +
> + case MCP41XX_WRITE:
> + data->xfer.len = 2;
> + /* Shift trans[0] to see if this is full scale value write */
> + data->tx[0] = (addr << 4) | MCP41XX_WRITE | (trans[0] >> 8);
> + data->tx[1] = (trans[0]) & 0xFF; /* 8 bits here */
> + break;
> +
> + case MCP41XX_INCR:
> + data->xfer.len = 1; /* One byte transfer for this command */
> + data->tx[0] = (addr << 4) | MCP41XX_INCR;
> + break;
> +
> + case MCP41XX_DECR:
> + data->xfer.len = 1;
> + data->tx[0] = (addr << 4) | MCP41XX_DECR;
> + break;
> +
> + default:
> + return -EINVAL;
> + }
> +
> + dev_dbg(&spi->dev, "mcp41xx_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, "mcp41xx_exec: rx0: 0x%x rx1: 0x%x\n",
> + data->rx[0], data->rx[1]);
> +
> + /* Copy back the response */
> + trans[0] = data->rx[0];
> + trans[1] = data->rx[1];
> +
> + return 0;
> +}
> +
> +static ssize_t mcp41xx_show_memory_map(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + ssize_t i = 0;
> + int err;
> + int addr;
> + int trans[2];
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct mcp41xx_data *data = iio_priv(indio_dev);
> +
> + /* Read the whole memory */
> + for (addr = MCP41XX_MIN_ADDR; addr <= MCP41XX_MAX_ADDR; addr++) {
> + err = mcp41xx_exec(data,
> + addr, MCP41XX_READ,
> + trans, ARRAY_SIZE(trans));
> + if (err)
> + return i;
> +
> + /* First column is address, second is value */
> + i += scnprintf(&buf[i],
> + 12, "0x%02x 0x%03x\n",
> + addr, MCP41XX_9BIT_VALUE(trans));
> + }
> +
> + return i;
> +}
> +
> +static ssize_t mcp41xx_store_memory_map(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t len)
> +{
> + int err;
> + int addr;
> + int trans[2];
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct mcp41xx_data *data = iio_priv(indio_dev);
> +
> + err = sscanf(buf, "0x%x 0x%x\n", &addr, &trans[0]);
> + if (err != 2)
> + return err;
> +
> + err = mcp41xx_exec(data, addr, MCP41XX_WRITE, trans, ARRAY_SIZE(trans));
> + if (err)
> + return err;
> +
> + return len;
> +}
> +
> +static IIO_DEVICE_ATTR(memory_map, S_IRUGO | S_IWUSR,
> + mcp41xx_show_memory_map,
> + mcp41xx_store_memory_map,
> + 0);
> +
> +static ssize_t mcp41xx_show_nv_wiper(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + int err;
> + int trans[2];
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct mcp41xx_data *data = iio_priv(indio_dev);
> + struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +
> + err = mcp41xx_exec(data,
> + this_attr->address + MCP41XX_NV_OFFSET, MCP41XX_READ,
> + trans, ARRAY_SIZE(trans));
> + if (err)
> + return -EINVAL;
> +
> + return sprintf(buf, "%d\n", MCP41XX_FULL_SCALE(trans));
> +}
> +
> +static ssize_t mcp41xx_store_nv_wiper(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t len)
> +{
> + int err;
> + int trans[2];
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct mcp41xx_data *data = iio_priv(indio_dev);
> + struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +
> + err = kstrtoint(buf, 10, &trans[0]);
> + if (err)
> + return -EINVAL;
> +
> + err = mcp41xx_exec(data,
> + this_attr->address + MCP41XX_NV_OFFSET, MCP41XX_WRITE,
> + trans, ARRAY_SIZE(trans));
> + if (err)
> + return -EINVAL;
> +
> + return len;
> +}
> +
> +#define MCP41XX_NV_WIPER(n) IIO_DEVICE_ATTR(nv_wiper##n, S_IRUGO | S_IWUSR, \
> + mcp41xx_show_nv_wiper, mcp41xx_store_nv_wiper, n)
> +
> +MCP41XX_NV_WIPER(0);
> +MCP41XX_NV_WIPER(1);
> +
> +static ssize_t mcp41xx_store_incr_wiper(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t len)
> +{
> + int err;
> + int trans[2];
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct mcp41xx_data *data = iio_priv(indio_dev);
> + struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +
> + err = mcp41xx_exec(data,
> + this_attr->address, MCP41XX_INCR,
> + trans, ARRAY_SIZE(trans));
> + if (err)
> + return -EINVAL;
> +
> + return len;
> +}
> +
> +static ssize_t mcp41xx_store_decr_wiper(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t len)
> +{
> + int err;
> + int trans[2];
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct mcp41xx_data *data = iio_priv(indio_dev);
> + struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +
> + err = mcp41xx_exec(data,
> + this_attr->address, MCP41XX_DECR,
> + trans, ARRAY_SIZE(trans));
> + if (err)
> + return -EINVAL;
> +
> + return len;
> +}
> +
> +#define MCP41XX_INCR_ATTR(n) IIO_DEVICE_ATTR(incr_wiper##n, S_IWUSR, \
> + NULL, mcp41xx_store_incr_wiper, n)
> +
> +MCP41XX_INCR_ATTR(0);
> +MCP41XX_INCR_ATTR(1);
> +
> +#define MCP41XX_DECR_ATTR(n) IIO_DEVICE_ATTR(decr_wiper##n, S_IWUSR, \
> + NULL, mcp41xx_store_decr_wiper, n)
> +
> +MCP41XX_DECR_ATTR(0);
> +MCP41XX_DECR_ATTR(1);
> +
> +static ssize_t mcp41xx_show_status_register(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + int err;
> + int trans[2];
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct mcp41xx_data *data = iio_priv(indio_dev);
> + unsigned long val;
> +
> + err = mcp41xx_exec(data,
> + MCP41XX_STATUS_ADDR, MCP41XX_READ,
> + trans, ARRAY_SIZE(trans));
> + if (err)
> + return -EINVAL;
> +
> + val = MCP41XX_9BIT_VALUE(trans);
> + return printbinary(buf, val, 10); /* One extra for new line */
> +}
> +
> +static IIO_DEVICE_ATTR(status_register, S_IRUGO,
> + mcp41xx_show_status_register,
> + NULL,
> + 0);
> +
> +static ssize_t mcp41xx_show_tcon_register(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + int err;
> + int trans[2];
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct mcp41xx_data *data = iio_priv(indio_dev);
> + unsigned long val;
> +
> + err = mcp41xx_exec(data,
> + MCP41XX_TCON_ADDR, MCP41XX_READ,
> + trans, ARRAY_SIZE(trans));
> + if (err)
> + return -EINVAL;
> +
> + val = MCP41XX_9BIT_VALUE(trans);
> + return printbinary(buf, val, 10); /* One extra for new line */
> +}
> +
> +static ssize_t mcp41xx_store_tcon_register(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t len)
> +{
> + int err;
> + int trans[2];
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct mcp41xx_data *data = iio_priv(indio_dev);
> +
> + err = kstrtoint(buf, 2, &trans[0]);
> + if (err)
> + return -EINVAL;
> +
> + err = mcp41xx_exec(data,
> + MCP41XX_TCON_ADDR, MCP41XX_WRITE,
> + trans, ARRAY_SIZE(trans));
> + if (err)
> + return -EINVAL;
> +
> + return len;
> +}
> +
> +static IIO_DEVICE_ATTR(tcon_register, S_IRUGO | S_IWUSR,
> + mcp41xx_show_tcon_register,
> + mcp41xx_store_tcon_register,
> + 0);
> +
> +/* All available attributes that can be created */
> +static struct iio_dev_attr *mcp41xx_all_attrs[] = {
> + &iio_dev_attr_memory_map,
> + &iio_dev_attr_nv_wiper0,
> + &iio_dev_attr_nv_wiper1,
> + &iio_dev_attr_incr_wiper0,
> + &iio_dev_attr_incr_wiper1,
> + &iio_dev_attr_decr_wiper0,
> + &iio_dev_attr_decr_wiper1,
> + &iio_dev_attr_status_register,
> + &iio_dev_attr_tcon_register,
> +};
> +
> +/* This will be filled dynamically in probe() */
> +static struct attribute **mcp41xx_attributes;
> +static struct attribute_group mcp41xx_attribute_group;
> +
> +static int mcp41xx_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long mask)
> +{
> + int err;
> + int trans[2];
> + struct mcp41xx_data *data = iio_priv(indio_dev);
> + int address = chan->channel;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + err = mcp41xx_exec(data,
> + address, MCP41XX_READ,
> + trans, ARRAY_SIZE(trans));
> + if (err)
> + return err;
> +
> + *val = MCP41XX_FULL_SCALE(trans);
> +
> + return IIO_VAL_INT;
> +
> + case IIO_CHAN_INFO_SCALE:
> + *val = 1000 * mcp41xx_cfg[data->devid].kohms;
> + *val2 = mcp41xx_cfg[data->devid].num_pos;
> +
> + return IIO_VAL_FRACTIONAL;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int mcp41xx_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int val, int val2, long mask)
> +{
> + int trans[2];
> + struct mcp41xx_data *data = iio_priv(indio_dev);
> + int address = chan->channel;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + trans[0] = val;
> +
> + return mcp41xx_exec(data,
> + address, MCP41XX_WRITE,
> + trans, ARRAY_SIZE(trans));
> + }
> +
> + return -EINVAL;
> +}
> +
> +static const struct iio_info mcp41xx_info = {
> + .attrs = &mcp41xx_attribute_group,
> + .read_raw = mcp41xx_read_raw,
> + .write_raw = mcp41xx_write_raw,
> + .driver_module = THIS_MODULE,
> +};
> +
> +static int mcp41xx_probe(struct spi_device *spi)
> +{
> + int l, i, addr;
> + int err;
> + size_t attrs_count;
> + struct iio_dev *indio_dev;
> + struct mcp41xx_data *data;
> +
> + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + data = iio_priv(indio_dev);
> + data->spi = spi;
> + data->devid = spi_get_device_id(spi)->driver_data;
> + spi_set_drvdata(spi, indio_dev);
> +
> + data->xfer.tx_buf = data->tx;
> + data->xfer.rx_buf = data->rx;
> +
> + mutex_init(&data->lock);
> +
> + indio_dev->dev.parent = &spi->dev;
> + indio_dev->info = &mcp41xx_info;
> + indio_dev->channels = mcp41xx_channels;
> + indio_dev->num_channels = mcp41xx_cfg[data->devid].wipers;
> + indio_dev->name = spi_get_device_id(spi)->name;
> +
> + /* Dynamic attributes */
> + attrs_count = ARRAY_SIZE(mcp41xx_all_attrs);
> + mcp41xx_attributes = kzalloc(
> + sizeof(struct attribute *) * (attrs_count + 1),
> + GFP_KERNEL);
> + if (mcp41xx_attributes == NULL)
> + return -ENOMEM;
> +
> + i = 0;
> + for (l = 0; l < attrs_count; l++) {
> + /* Attrs with address == 0 or address == wipers are added */
> + addr = mcp41xx_all_attrs[l]->address;
> + if (addr == 0 || addr == indio_dev->num_channels - 1) {
> + mcp41xx_attributes[i] =
> + &mcp41xx_all_attrs[l]->dev_attr.attr;
> + i++;
> + }
> + }
> + mcp41xx_attribute_group.attrs = mcp41xx_attributes;
> +
> + err = devm_iio_device_register(&spi->dev, indio_dev);
> + if (err) {
> + dev_info(&spi->dev, "Unable to register %s", indio_dev->name);
\n missing
> + return err;
> + }
> +
> + dev_info(&spi->dev, "Registered %s", indio_dev->name);
\n
> +
> + return 0;
> +}
> +
> +static int mcp41xx_remove(struct spi_device *spi)
> +{
> + struct iio_dev *indio_dev = spi_get_drvdata(spi);
> + struct mcp41xx_data *data = iio_priv(indio_dev);
> +
> + mutex_destroy(&data->lock);
> + devm_iio_device_unregister(&spi->dev, indio_dev);
> + kfree(mcp41xx_attributes);
> +
> + dev_info(&spi->dev, "Unregistered %s", indio_dev->name);
> +
> + return 0;
> +}
> +
> +#if defined CONFIG_OF
> +static const struct of_device_id mcp41xx_dt_ids[] = {
> + { .compatible = "microchip,mcp4113x-502",
> + .data = &mcp41xx_cfg[MCP413x_502] },
> + { .compatible = "microchip,mcp4113x-103",
> + .data = &mcp41xx_cfg[MCP413x_103] },
> + { .compatible = "microchip,mcp4113x-503",
> + .data = &mcp41xx_cfg[MCP413x_503] },
> + { .compatible = "microchip,mcp4113x-104",
> + .data = &mcp41xx_cfg[MCP413x_104] },
> + { .compatible = "microchip,mcp4114x-502",
> + .data = &mcp41xx_cfg[MCP414x_502] },
> + { .compatible = "microchip,mcp4114x-103",
> + .data = &mcp41xx_cfg[MCP414x_103] },
> + { .compatible = "microchip,mcp4114x-503",
> + .data = &mcp41xx_cfg[MCP414x_503] },
> + { .compatible = "microchip,mcp4114x-104",
> + .data = &mcp41xx_cfg[MCP414x_104] },
> + { .compatible = "microchip,mcp4115x-502",
> + .data = &mcp41xx_cfg[MCP415x_502] },
> + { .compatible = "microchip,mcp4115x-103",
> + .data = &mcp41xx_cfg[MCP415x_103] },
> + { .compatible = "microchip,mcp4115x-503",
> + .data = &mcp41xx_cfg[MCP415x_503] },
> + { .compatible = "microchip,mcp4115x-104",
> + .data = &mcp41xx_cfg[MCP415x_104] },
> + { .compatible = "microchip,mcp4116x-502",
> + .data = &mcp41xx_cfg[MCP416x_502] },
> + { .compatible = "microchip,mcp4116x-103",
> + .data = &mcp41xx_cfg[MCP416x_103] },
> + { .compatible = "microchip,mcp4116x-503",
> + .data = &mcp41xx_cfg[MCP416x_503] },
> + { .compatible = "microchip,mcp4116x-104",
> + .data = &mcp41xx_cfg[MCP416x_104] },
> + { .compatible = "microchip,mcp4123x-502",
> + .data = &mcp41xx_cfg[MCP423x_502] },
> + { .compatible = "microchip,mcp4123x-103",
> + .data = &mcp41xx_cfg[MCP423x_103] },
> + { .compatible = "microchip,mcp4123x-503",
> + .data = &mcp41xx_cfg[MCP423x_503] },
> + { .compatible = "microchip,mcp4123x-104",
> + .data = &mcp41xx_cfg[MCP423x_104] },
> + { .compatible = "microchip,mcp4124x-502",
> + .data = &mcp41xx_cfg[MCP424x_502] },
> + { .compatible = "microchip,mcp4124x-103",
> + .data = &mcp41xx_cfg[MCP424x_103] },
> + { .compatible = "microchip,mcp4124x-503",
> + .data = &mcp41xx_cfg[MCP424x_503] },
> + { .compatible = "microchip,mcp4124x-104",
> + .data = &mcp41xx_cfg[MCP424x_104] },
> + { .compatible = "microchip,mcp4125x-502",
> + .data = &mcp41xx_cfg[MCP425x_502] },
> + { .compatible = "microchip,mcp4125x-103",
> + .data = &mcp41xx_cfg[MCP425x_103] },
> + { .compatible = "microchip,mcp4125x-503",
> + .data = &mcp41xx_cfg[MCP425x_503] },
> + { .compatible = "microchip,mcp4125x-104",
> + .data = &mcp41xx_cfg[MCP425x_104] },
> + { .compatible = "microchip,mcp4126x-502",
> + .data = &mcp41xx_cfg[MCP426x_502] },
> + { .compatible = "microchip,mcp4126x-103",
> + .data = &mcp41xx_cfg[MCP426x_103] },
> + { .compatible = "microchip,mcp4126x-503",
> + .data = &mcp41xx_cfg[MCP426x_503] },
> + { .compatible = "microchip,mcp4126x-104",
> + .data = &mcp41xx_cfg[MCP426x_104] },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, mcp41xx_dt_ids);
> +#endif
> +
> +static const struct spi_device_id mcp41xx_id[] = {
> + { "mcp413x-502", MCP413x_502 },
> + { "mcp413x-103", MCP413x_103 },
> + { "mcp413x-503", MCP413x_503 },
> + { "mcp413x-104", MCP413x_104 },
> + { "mcp414x-502", MCP414x_502 },
> + { "mcp414x-103", MCP414x_103 },
> + { "mcp414x-503", MCP414x_503 },
> + { "mcp414x-104", MCP414x_104 },
> + { "mcp415x-502", MCP415x_502 },
> + { "mcp415x-103", MCP415x_103 },
> + { "mcp415x-503", MCP415x_503 },
> + { "mcp415x-104", MCP415x_104 },
> + { "mcp416x-502", MCP416x_502 },
> + { "mcp416x-103", MCP416x_103 },
> + { "mcp416x-503", MCP416x_503 },
> + { "mcp416x-104", MCP416x_104 },
> + { "mcp423x-502", MCP423x_502 },
> + { "mcp423x-103", MCP423x_103 },
> + { "mcp423x-503", MCP423x_503 },
> + { "mcp423x-104", MCP423x_104 },
> + { "mcp424x-502", MCP424x_502 },
> + { "mcp424x-103", MCP424x_103 },
> + { "mcp424x-503", MCP424x_503 },
> + { "mcp424x-104", MCP424x_104 },
> + { "mcp425x-502", MCP425x_502 },
> + { "mcp425x-103", MCP425x_103 },
> + { "mcp425x-503", MCP425x_503 },
> + { "mcp425x-104", MCP425x_104 },
> + { "mcp426x-502", MCP426x_502 },
> + { "mcp426x-103", MCP426x_103 },
> + { "mcp426x-503", MCP426x_503 },
> + { "mcp426x-104", MCP426x_104 },
> + {}
> +};
> +MODULE_DEVICE_TABLE(spi, mcp41xx_id);
> +
> +static struct spi_driver mcp41xx_driver = {
> + .driver = {
> + .name = "mcp41xx",
> + .of_match_table = of_match_ptr(mcp41xx_dt_ids),
> + },
> + .probe = mcp41xx_probe,
> + .remove = mcp41xx_remove,
> + .id_table = mcp41xx_id,
> +};
> +
> +module_spi_driver(mcp41xx_driver);
> +
> +MODULE_AUTHOR("Slawomir Stepien <sst@...zta.fm>");
> +MODULE_DESCRIPTION("MCP41XX digital potentiometer");
> +MODULE_LICENSE("GPL v2");
>
--
Peter Meerwald-Stadler
+43-664-2444418 (mobile)
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