--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Support for Microchip MCP4728
+ *
+ * Copyright (C) 2023 Andrea Collamati <andrea.collamati@gmail.com>
+ *
+ * Based on mcp4725 by Peter Meerwald <pmeerw@pmeerw.net>
+ *
+ * Driver for the Microchip I2C 12-bit digital-to-analog quad channels
+ * converter (DAC).
+ *
+ * (7-bit I2C slave address 0x60, the three LSBs can be configured in
+ * hardware)
+ */
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
+
+#define MCP4728_RESOLUTION 12
+#define MCP4728_N_CHANNELS 4
+
+#define MCP4728_CMD_MASK GENMASK(7, 3)
+#define MCP4728_CHSEL_MASK GENMASK(2, 1)
+#define MCP4728_UDAC_MASK BIT(0)
+
+#define MCP4728_VREF_MASK BIT(7)
+#define MCP4728_PDMODE_MASK GENMASK(6, 5)
+#define MCP4728_GAIN_MASK BIT(4)
+
+#define MCP4728_DAC_H_MASK GENMASK(3, 0)
+#define MCP4728_DAC_L_MASK GENMASK(7, 0)
+
+#define MCP4728_RDY_MASK BIT(7)
+
+#define MCP4728_MW_CMD 0x08 /* Multiwrite Command */
+#define MCP4728_SW_CMD 0x0A /* Sequential Write Command with EEPROM */
+
+#define MCP4728_READ_RESPONSE_LEN (MCP4728_N_CHANNELS * 3 * 2)
+#define MCP4728_WRITE_EEPROM_LEN (1 + MCP4728_N_CHANNELS * 2)
+
+enum vref_mode {
+ MCP4728_VREF_EXTERNAL_VDD = 0,
+ MCP4728_VREF_INTERNAL_2048mV = 1,
+};
+
+enum gain_mode {
+ MCP4728_GAIN_X1 = 0,
+ MCP4728_GAIN_X2 = 1,
+};
+
+enum iio_powerdown_mode {
+ MCP4728_IIO_1K,
+ MCP4728_IIO_100K,
+ MCP4728_IIO_500K,
+};
+
+struct mcp4728_channel_data {
+ enum vref_mode ref_mode;
+ enum iio_powerdown_mode pd_mode;
+ enum gain_mode g_mode;
+ u16 dac_value;
+};
+
+/* MCP4728 Full Scale Ranges
+ * the device available ranges are
+ * - VREF = VDD FSR = from 0.0V to VDD
+ * - VREF = Internal Gain = 1 FSR = from 0.0V to VREF
+ * - VREF = Internal Gain = 2 FSR = from 0.0V to 2*VREF
+ */
+enum mcp4728_scale {
+ MCP4728_SCALE_VDD,
+ MCP4728_SCALE_VINT_NO_GAIN,
+ MCP4728_SCALE_VINT_GAIN_X2,
+ MCP4728_N_SCALES
+};
+
+struct mcp4728_data {
+ struct i2c_client *client;
+ struct regulator *vdd_reg;
+ bool powerdown;
+ int scales_avail[MCP4728_N_SCALES * 2];
+ struct mcp4728_channel_data chdata[MCP4728_N_CHANNELS];
+};
+
+#define MCP4728_CHAN(chan) { \
+ .type = IIO_VOLTAGE, \
+ .output = 1, \
+ .indexed = 1, \
+ .channel = chan, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_SCALE), \
+ .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SCALE), \
+ .ext_info = mcp4728_ext_info, \
+}
+
+static int mcp4728_suspend(struct device *dev);
+static int mcp4728_resume(struct device *dev);
+
+static ssize_t mcp4728_store_eeprom(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct mcp4728_data *data = iio_priv(indio_dev);
+ u8 outbuf[MCP4728_WRITE_EEPROM_LEN];
+ int tries = 20;
+ u8 inbuf[3];
+ bool state;
+ int ret;
+ unsigned int i;
+
+ ret = kstrtobool(buf, &state);
+ if (ret < 0)
+ return ret;
+
+ if (!state)
+ return 0;
+
+ outbuf[0] = FIELD_PREP(MCP4728_CMD_MASK, MCP4728_SW_CMD);
+
+ for (i = 0; i < MCP4728_N_CHANNELS; i++) {
+ struct mcp4728_channel_data *ch = &data->chdata[i];
+ int offset = 1 + i * 2;
+
+ outbuf[offset] = FIELD_PREP(MCP4728_VREF_MASK, ch->ref_mode);
+
+ if (data->powerdown) {
+ u8 mcp4728_pd_mode = ch->pd_mode + 1;
+
+ outbuf[offset] |= FIELD_PREP(MCP4728_PDMODE_MASK,
+ mcp4728_pd_mode);
+ }
+
+ outbuf[offset] |= FIELD_PREP(MCP4728_GAIN_MASK, ch->g_mode);
+ outbuf[offset] |=
+ FIELD_PREP(MCP4728_DAC_H_MASK, ch->dac_value >> 8);
+ outbuf[offset + 1] =
+ FIELD_PREP(MCP4728_DAC_L_MASK, ch->dac_value);
+ }
+
+ ret = i2c_master_send(data->client, outbuf, MCP4728_WRITE_EEPROM_LEN);
+ if (ret < 0)
+ return ret;
+ else if (ret != MCP4728_WRITE_EEPROM_LEN)
+ return -EIO;
+
+ /* wait RDY signal for write complete, takes up to 50ms */
+ while (tries--) {
+ msleep(20);
+ ret = i2c_master_recv(data->client, inbuf, 3);
+ if (ret < 0)
+ return ret;
+ else if (ret != 3)
+ return -EIO;
+
+ if (FIELD_GET(MCP4728_RDY_MASK, inbuf[0]))
+ break;
+ }
+
+ if (tries < 0) {
+ dev_err(&data->client->dev, "%s failed, incomplete\n",
+ __func__);
+ return -EIO;
+ }
+ return len;
+}
+
+static IIO_DEVICE_ATTR(store_eeprom, 0200, NULL, mcp4728_store_eeprom, 0);
+
+static struct attribute *mcp4728_attributes[] = {
+ &iio_dev_attr_store_eeprom.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group mcp4728_attribute_group = {
+ .attrs = mcp4728_attributes,
+};
+
+static int mcp4728_program_channel_cfg(int channel, struct iio_dev *indio_dev)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+ struct mcp4728_channel_data *ch = &data->chdata[channel];
+ u8 outbuf[3];
+ int ret;
+
+ outbuf[0] = FIELD_PREP(MCP4728_CMD_MASK, MCP4728_MW_CMD);
+ outbuf[0] |= FIELD_PREP(MCP4728_CHSEL_MASK, channel);
+ outbuf[0] |= FIELD_PREP(MCP4728_UDAC_MASK, 0);
+
+ outbuf[1] = FIELD_PREP(MCP4728_VREF_MASK, ch->ref_mode);
+
+ if (data->powerdown)
+ outbuf[1] |= FIELD_PREP(MCP4728_PDMODE_MASK, ch->pd_mode + 1);
+
+ outbuf[1] |= FIELD_PREP(MCP4728_GAIN_MASK, ch->g_mode);
+ outbuf[1] |= FIELD_PREP(MCP4728_DAC_H_MASK, ch->dac_value >> 8);
+ outbuf[2] = FIELD_PREP(MCP4728_DAC_L_MASK, ch->dac_value);
+
+ ret = i2c_master_send(data->client, outbuf, 3);
+ if (ret < 0)
+ return ret;
+ else if (ret != 3)
+ return -EIO;
+
+ return 0;
+}
+
+static const char *const mcp4728_powerdown_modes[] = { "1kohm_to_gnd",
+ "100kohm_to_gnd",
+ "500kohm_to_gnd" };
+
+static int mcp4728_get_powerdown_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+
+ return data->chdata[chan->channel].pd_mode;
+}
+
+static int mcp4728_set_powerdown_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ unsigned int mode)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+
+ data->chdata[chan->channel].pd_mode = mode;
+
+ return 0;
+}
+
+static ssize_t mcp4728_read_powerdown(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ char *buf)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+
+ return sysfs_emit(buf, "%d\n", data->powerdown);
+}
+
+static ssize_t mcp4728_write_powerdown(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ const char *buf, size_t len)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+ bool state;
+ int ret;
+
+ ret = kstrtobool(buf, &state);
+ if (ret)
+ return ret;
+
+ if (state)
+ ret = mcp4728_suspend(&data->client->dev);
+ else
+ ret = mcp4728_resume(&data->client->dev);
+
+ if (ret < 0)
+ return ret;
+
+ return len;
+}
+
+static const struct iio_enum mcp4728_powerdown_mode_enum = {
+ .items = mcp4728_powerdown_modes,
+ .num_items = ARRAY_SIZE(mcp4728_powerdown_modes),
+ .get = mcp4728_get_powerdown_mode,
+ .set = mcp4728_set_powerdown_mode,
+};
+
+static const struct iio_chan_spec_ext_info mcp4728_ext_info[] = {
+ {
+ .name = "powerdown",
+ .read = mcp4728_read_powerdown,
+ .write = mcp4728_write_powerdown,
+ .shared = IIO_SEPARATE,
+ },
+ IIO_ENUM("powerdown_mode", IIO_SEPARATE, &mcp4728_powerdown_mode_enum),
+ IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
+ &mcp4728_powerdown_mode_enum),
+ {},
+};
+
+static const struct iio_chan_spec mcp4728_channels[MCP4728_N_CHANNELS] = {
+ MCP4728_CHAN(0),
+ MCP4728_CHAN(1),
+ MCP4728_CHAN(2),
+ MCP4728_CHAN(3),
+};
+
+static void mcp4728_get_scale_avail(enum mcp4728_scale scale,
+ struct mcp4728_data *data, int *val,
+ int *val2)
+{
+ *val = data->scales_avail[scale * 2];
+ *val2 = data->scales_avail[scale * 2 + 1];
+}
+
+static void mcp4728_get_scale(int channel, struct mcp4728_data *data, int *val,
+ int *val2)
+{
+ int ref_mode = data->chdata[channel].ref_mode;
+ int g_mode = data->chdata[channel].g_mode;
+
+ if (ref_mode == MCP4728_VREF_EXTERNAL_VDD) {
+ mcp4728_get_scale_avail(MCP4728_SCALE_VDD, data, val, val2);
+ } else {
+ if (g_mode == MCP4728_GAIN_X1) {
+ mcp4728_get_scale_avail(MCP4728_SCALE_VINT_NO_GAIN,
+ data, val, val2);
+ } else {
+ mcp4728_get_scale_avail(MCP4728_SCALE_VINT_GAIN_X2,
+ data, val, val2);
+ }
+ }
+}
+
+static int mcp4728_find_matching_scale(struct mcp4728_data *data, int val,
+ int val2)
+{
+ for (int i = 0; i < MCP4728_N_SCALES; i++) {
+ if (data->scales_avail[i * 2] == val &&
+ data->scales_avail[i * 2 + 1] == val2)
+ return i;
+ }
+ return -EINVAL;
+}
+
+static int mcp4728_set_scale(int channel, struct mcp4728_data *data, int val,
+ int val2)
+{
+ int scale = mcp4728_find_matching_scale(data, val, val2);
+
+ if (scale < 0)
+ return scale;
+
+ switch (scale) {
+ case MCP4728_SCALE_VDD:
+ data->chdata[channel].ref_mode = MCP4728_VREF_EXTERNAL_VDD;
+ return 0;
+ case MCP4728_SCALE_VINT_NO_GAIN:
+ data->chdata[channel].ref_mode = MCP4728_VREF_INTERNAL_2048mV;
+ data->chdata[channel].g_mode = MCP4728_GAIN_X1;
+ return 0;
+ case MCP4728_SCALE_VINT_GAIN_X2:
+ data->chdata[channel].ref_mode = MCP4728_VREF_INTERNAL_2048mV;
+ data->chdata[channel].g_mode = MCP4728_GAIN_X2;
+ return 0;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int mcp4728_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val,
+ int *val2, long mask)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ *val = data->chdata[chan->channel].dac_value;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ mcp4728_get_scale(chan->channel, data, val, val2);
+ return IIO_VAL_INT_PLUS_MICRO;
+ }
+ return -EINVAL;
+}
+
+static int mcp4728_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int val,
+ int val2, long mask)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ if (val < 0 || val > GENMASK(MCP4728_RESOLUTION - 1, 0))
+ return -EINVAL;
+ data->chdata[chan->channel].dac_value = val;
+ return mcp4728_program_channel_cfg(chan->channel, indio_dev);
+ case IIO_CHAN_INFO_SCALE:
+ ret = mcp4728_set_scale(chan->channel, data, val, val2);
+ if (ret)
+ return ret;
+
+ return mcp4728_program_channel_cfg(chan->channel, indio_dev);
+ default:
+ return -EINVAL;
+ }
+}
+
+static void mcp4728_init_scale_avail(enum mcp4728_scale scale, int vref_mv,
+ struct mcp4728_data *data)
+{
+ s64 tmp;
+ int value_micro;
+ int value_int;
+
+ tmp = (s64)vref_mv * 1000000LL >> MCP4728_RESOLUTION;
+ value_int = div_s64_rem(tmp, 1000000LL, &value_micro);
+
+ data->scales_avail[scale * 2] = value_int;
+ data->scales_avail[scale * 2 + 1] = value_micro;
+}
+
+static int mcp4728_init_scales_avail(struct mcp4728_data *data)
+{
+ int ret;
+
+ ret = regulator_get_voltage(data->vdd_reg);
+ if (ret < 0)
+ return ret;
+
+ mcp4728_init_scale_avail(MCP4728_SCALE_VDD, ret / 1000, data);
+ mcp4728_init_scale_avail(MCP4728_SCALE_VINT_NO_GAIN, 2048, data);
+ mcp4728_init_scale_avail(MCP4728_SCALE_VINT_GAIN_X2, 4096, data);
+
+ return 0;
+}
+
+static int mcp4728_read_avail(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ const int **vals, int *type, int *length,
+ long info)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+
+ switch (info) {
+ case IIO_CHAN_INFO_SCALE:
+ *type = IIO_VAL_INT_PLUS_MICRO;
+
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ *vals = data->scales_avail;
+ *length = MCP4728_N_SCALES * 2;
+ return IIO_AVAIL_LIST;
+ default:
+ return -EINVAL;
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info mcp4728_info = {
+ .read_raw = mcp4728_read_raw,
+ .write_raw = mcp4728_write_raw,
+ .read_avail = &mcp4728_read_avail,
+ .attrs = &mcp4728_attribute_group,
+};
+
+static int mcp4728_suspend(struct device *dev)
+{
+ struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct mcp4728_data *data = iio_priv(indio_dev);
+ unsigned int i;
+
+ data->powerdown = true;
+
+ for (i = 0; i < MCP4728_N_CHANNELS; i++) {
+ int err = mcp4728_program_channel_cfg(i, indio_dev);
+
+ if (err)
+ return err;
+ }
+ return 0;
+}
+
+static int mcp4728_resume(struct device *dev)
+{
+ struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct mcp4728_data *data = iio_priv(indio_dev);
+ int err = 0;
+ unsigned int i;
+
+ data->powerdown = false;
+
+ for (i = 0; i < MCP4728_N_CHANNELS; i++) {
+ int ret = mcp4728_program_channel_cfg(i, indio_dev);
+
+ if (ret)
+ err = ret;
+ }
+ return err;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(mcp4728_pm_ops, mcp4728_suspend,
+ mcp4728_resume);
+
+static int mcp4728_init_channels_data(struct mcp4728_data *data)
+{
+ u8 inbuf[MCP4728_READ_RESPONSE_LEN];
+ int ret;
+ unsigned int i;
+
+ ret = i2c_master_recv(data->client, inbuf, MCP4728_READ_RESPONSE_LEN);
+ if (ret < 0) {
+ return dev_err_probe(&data->client->dev, ret,
+ "failed to read mcp4728 conf.\n");
+ } else if (ret != MCP4728_READ_RESPONSE_LEN) {
+ return dev_err_probe(&data->client->dev, -EIO,
+ "failed to read mcp4728 conf. Wrong Response Len ret=%d\n",
+ ret);
+ }
+
+ for (i = 0; i < MCP4728_N_CHANNELS; i++) {
+ struct mcp4728_channel_data *ch = &data->chdata[i];
+ u8 r2 = inbuf[i * 6 + 1];
+ u8 r3 = inbuf[i * 6 + 2];
+
+ ch->dac_value = FIELD_GET(MCP4728_DAC_H_MASK, r2) << 8 |
+ FIELD_GET(MCP4728_DAC_L_MASK, r3);
+ ch->ref_mode = FIELD_GET(MCP4728_VREF_MASK, r2);
+ ch->pd_mode = FIELD_GET(MCP4728_PDMODE_MASK, r2);
+ ch->g_mode = FIELD_GET(MCP4728_GAIN_MASK, r2);
+ }
+
+ return 0;
+}
+
+static void mcp4728_reg_disable(void *reg)
+{
+ regulator_disable(reg);
+}
+
+static int mcp4728_probe(struct i2c_client *client)
+{
+ const struct i2c_device_id *id = i2c_client_get_device_id(client);
+ struct mcp4728_data *data;
+ struct iio_dev *indio_dev;
+ int err;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ data = iio_priv(indio_dev);
+ i2c_set_clientdata(client, indio_dev);
+ data->client = client;
+
+ data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
+ if (IS_ERR(data->vdd_reg))
+ return PTR_ERR(data->vdd_reg);
+
+ err = regulator_enable(data->vdd_reg);
+ if (err)
+ return err;
+
+ err = devm_add_action_or_reset(&client->dev, mcp4728_reg_disable,
+ data->vdd_reg);
+ if (err)
+ return err;
+
+ /*
+ * MCP4728 has internal EEPROM that save each channel boot
+ * configuration. It means that device configuration is unknown to the
+ * driver at kernel boot. mcp4728_init_channels_data() reads back DAC
+ * settings and stores them in data structure.
+ */
+ err = mcp4728_init_channels_data(data);
+ if (err) {
+ return dev_err_probe(&client->dev, err,
+ "failed to read mcp4728 current configuration\n");
+ }
+
+ err = mcp4728_init_scales_avail(data);
+ if (err) {
+ return dev_err_probe(&client->dev, err,
+ "failed to init scales\n");
+ }
+
+ indio_dev->name = id->name;
+ indio_dev->info = &mcp4728_info;
+ indio_dev->channels = mcp4728_channels;
+ indio_dev->num_channels = MCP4728_N_CHANNELS;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id mcp4728_id[] = {
+ { "mcp4728", 0 },
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, mcp4728_id);
+
+static const struct of_device_id mcp4728_of_match[] = {
+ { .compatible = "microchip,mcp4728" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, mcp4728_of_match);
+
+static struct i2c_driver mcp4728_driver = {
+ .driver = {
+ .name = "mcp4728",
+ .of_match_table = mcp4728_of_match,
+ .pm = pm_sleep_ptr(&mcp4728_pm_ops),
+ },
+ .probe = mcp4728_probe,
+ .id_table = mcp4728_id,
+};
+module_i2c_driver(mcp4728_driver);
+
+MODULE_AUTHOR("Andrea Collamati <andrea.collamati@gmail.com>");
+MODULE_DESCRIPTION("MCP4728 12-bit DAC");
+MODULE_LICENSE("GPL");
projects / linux-2.6-microblaze.git / commitdiff