--- /dev/null
+/*
+ * 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");
projects / platform / kernel / linux-exynos.git / commitdiff