>From 01b156ca1b27be83f4c74c288dbc0bcad178fe0b Mon Sep 17 00:00:00 2001 From: Andrea Collamati <andrea.collamati@xxxxxxxxx> Date: Mon, 10 Jul 2023 16:20:40 +0200 Subject: [PATCH] iio: add mcp4728 I2C DAC driver Microchip MCP4728 is a 12-bit quad channel digital-to-analog converter (DAC) with I2C interface. This patch adds support for per-channel gain, power state and power down mode control. Current state could be saved to on-chip EEPROM. Internal voltage reference and external vdd ref are supported. --- .../bindings/iio/dac/microchip,mcp4728.yaml | 42 ++ drivers/iio/dac/Kconfig | 12 + drivers/iio/dac/Makefile | 1 + drivers/iio/dac/mcp4728.c | 641 ++++++++++++++++++ 4 files changed, 696 insertions(+) create mode 100644 Documentation/devicetree/bindings/iio/dac/microchip,mcp4728.yaml create mode 100644 drivers/iio/dac/mcp4728.c diff --git a/Documentation/devicetree/bindings/iio/dac/microchip,mcp4728.yaml b/Documentation/devicetree/bindings/iio/dac/microchip,mcp4728.yaml new file mode 100644 index 000000000000..68f4e359a921 --- /dev/null +++ b/Documentation/devicetree/bindings/iio/dac/microchip,mcp4728.yaml @@ -0,0 +1,42 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/iio/dac/microchip,mcp4728.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Microchip mcp4728 + +maintainers: + - Andrea Collamati <andrea.collamati@xxxxxxxxx> + +properties: + compatible: + enum: + - microchip,mcp4728 + reg: + maxItems: 1 + + vdd-supply: + description: | + Provides both power and acts as the reference supply on the mcp4728 + when Internal Vref is not selected. + +required: + - compatible + - reg + - vdd-supply + +additionalProperties: false + +examples: + - | + i2c { + #address-cells = <1>; + #size-cells = <0>; + + mcp4728_dac@64 { + compatible = "microchip,mcp4728"; + reg = <0x60>; + vdd-supply = <&vdac_vdd>; + }; + }; diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig index c0bf0d84197f..6c96cd30994a 100644 --- a/drivers/iio/dac/Kconfig +++ b/drivers/iio/dac/Kconfig @@ -376,6 +376,18 @@ config MCP4725 To compile this driver as a module, choose M here: the module will be called mcp4725. +config MCP4728 + tristate "MCP4728 DAC driver" + depends on I2C + help + Say Y here if you want to build a driver for the Microchip + MCP4728 quad channel, 12-bit digital-to-analog converter (DAC) + with I2C interface. + + To compile this driver as a module, choose M here: the module + will be called mcp4728. + + config MCP4922 tristate "MCP4902, MCP4912, MCP4922 DAC driver" depends on SPI diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile index ec3e42713f00..35ac62a61b05 100644 --- a/drivers/iio/dac/Makefile +++ b/drivers/iio/dac/Makefile @@ -40,6 +40,7 @@ obj-$(CONFIG_M62332) += m62332.o obj-$(CONFIG_MAX517) += max517.o obj-$(CONFIG_MAX5821) += max5821.o obj-$(CONFIG_MCP4725) += mcp4725.o +obj-$(CONFIG_MCP4728) += mcp4728.o obj-$(CONFIG_MCP4922) += mcp4922.o obj-$(CONFIG_STM32_DAC_CORE) += stm32-dac-core.o obj-$(CONFIG_STM32_DAC) += stm32-dac.o diff --git a/drivers/iio/dac/mcp4728.c b/drivers/iio/dac/mcp4728.c new file mode 100644 index 000000000000..d304fa8ffa26 --- /dev/null +++ b/drivers/iio/dac/mcp4728.c @@ -0,0 +1,641 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Support for Microchip MCP4728 + * + * Copyright (C) 2023 Andrea Collamati <andrea.collamati@xxxxxxxxx> + * + * Based on mcp4725 by Peter Meerwald <pmeerw@xxxxxxxxxx> + * + * 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/module.h> +#include <linux/i2c.h> +#include <linux/err.h> +#include <linux/delay.h> +#include <linux/regulator/consumer.h> +#include <linux/mod_devicetable.h> +#include <linux/property.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +#define MCP4728_DRV_NAME "mcp4728" + +#define MCP4728_RESOLUTION 12 +#define MCP4728_N_CHANNELS 4 + +#define MCP4728_CMD_POS 3 +#define MCP4728_CMD_UDAC_POS 0 +#define MCP4728_CMD_CH_SEL_POS 1 + +#define MCP4728_CMD_VREF_MASK 0x80 +#define MCP4728_CMD_VREF_POS 7 + +#define MCP4728_CMD_PDMODE_MASK 0x60 +#define MCP4728_CMD_PDMODE_POS 5 + +#define MCP4728_CMD_GAIN_MASK 0x10 +#define MCP4728_CMD_GAIN_POS 4 + +#define MCP4728_MW_CMD 0x08 // Multiwrite Command +#define MCP4728_SW_CMD 0x0A // Sequential Write Command (include eeprom) + +#define MCP4728_READ_RESPONSE_LEN (MCP4728_N_CHANNELS * 3 * 2) // Read Message +#define MCP4728_WRITE_EEPROM_LEN \ + (1 + MCP4728_N_CHANNELS * 2) // Sequential Write + +enum vref_mode { + MCP4728_VREF_EXTERNAL_VDD = 0, + MCP4728_VRED_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; +}; + +struct mcp4728_data { + struct i2c_client *client; + int id; + struct regulator *vdd_reg; + bool powerdown; + struct mcp4728_channel_data channel_data[MCP4728_N_CHANNELS]; +}; + +#define MCP4728_CHAN(chan) \ + { \ + .type = IIO_VOLTAGE, .output = 1, .indexed = 1, \ + .channel = chan, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = 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] = MCP4728_SW_CMD << MCP4728_CMD_POS; // Command ID + + for (i = 0; i < MCP4728_N_CHANNELS; i++) { + struct mcp4728_channel_data *ch = &(data->channel_data[i]); + int offset = 1 + i * 2; + + outbuf[offset] = ch->ref_mode << MCP4728_CMD_VREF_POS; + if (data->powerdown) { + u8 mcp4728_pd_mode = ch->pd_mode + 1; + + outbuf[1] |= mcp4728_pd_mode << MCP4728_CMD_PDMODE_POS; + } + + outbuf[offset] |= ch->g_mode << MCP4728_CMD_GAIN_POS; + outbuf[offset] |= ch->dac_value >> 8; + outbuf[offset + 1] = ch->dac_value & 0xff; + } + + 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 (inbuf[0] & 0x80) // check RDY flag + 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, +}; + +enum chip_id { + MCP4728, +}; + +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->channel_data[channel]); + u8 outbuf[3]; + int ret; + + outbuf[0] = MCP4728_MW_CMD << MCP4728_CMD_POS; // Command ID + outbuf[0] |= channel << MCP4728_CMD_CH_SEL_POS; // Channel Selector + outbuf[0] |= 0; // UDAC = 0 + + outbuf[1] = ch->ref_mode << MCP4728_CMD_VREF_POS; + if (data->powerdown) { + u8 mcp4728_pd_mode = ch->pd_mode + 1; + + outbuf[1] |= mcp4728_pd_mode << MCP4728_CMD_PDMODE_POS; + } + + outbuf[1] |= ch->g_mode << MCP4728_CMD_GAIN_POS; + + outbuf[1] |= ch->dac_value >> 8; + outbuf[2] = ch->dac_value & 0xff; + + ret = i2c_master_send(data->client, outbuf, 3); + if (ret < 0) + return ret; + else if (ret != 3) + return -EIO; + else + return 0; +} + +// powerdown mode +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->channel_data[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->channel_data[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, +}; + +// vref mode +static const char *const mcp4728_vref_modes[] = { + "vdd_ext", + "internal", +}; + +static int mcp4728_get_vref_mode(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan) +{ + struct mcp4728_data *data = iio_priv(indio_dev); + + return data->channel_data[chan->channel].ref_mode; +} + +static int mcp4728_set_vref_mode(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + unsigned int mode) +{ + struct mcp4728_data *data = iio_priv(indio_dev); + int ret; + + data->channel_data[chan->channel].ref_mode = mode; + + if (mode == MCP4728_VREF_EXTERNAL_VDD && + data->channel_data[chan->channel].g_mode == MCP4728_GAIN_X2) { + dev_warn( + &data->client->dev, + "CH%d: Gain x2 not effective when vref is vdd, force to x1", + chan->channel); + data->channel_data[chan->channel].g_mode = MCP4728_GAIN_X1; + } + + ret = mcp4728_program_channel_cfg(chan->channel, indio_dev); + + return ret; +} +static const struct iio_enum mcp4728_vref_mode_enum = { + .items = mcp4728_vref_modes, + .num_items = ARRAY_SIZE(mcp4728_vref_modes), + .get = mcp4728_get_vref_mode, + .set = mcp4728_set_vref_mode, +}; + +// gain +static const char *const mcp4728_gain_modes[] = { + "x1", + "x2", +}; + +static int mcp4728_get_gain_mode(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan) +{ + struct mcp4728_data *data = iio_priv(indio_dev); + + return data->channel_data[chan->channel].g_mode; +} + +static int mcp4728_set_gain_mode(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + unsigned int mode) +{ + struct mcp4728_data *data = iio_priv(indio_dev); + int ret; + + if (mode == MCP4728_GAIN_X2 && + data->channel_data[chan->channel].ref_mode == + MCP4728_VREF_EXTERNAL_VDD) { + dev_err(&data->client->dev, + "CH%d: Gain x2 not effective when vref is vdd", + chan->channel); + return -EINVAL; + } + + data->channel_data[chan->channel].g_mode = mode; + + ret = mcp4728_program_channel_cfg(chan->channel, indio_dev); + + return ret; +} + +static const struct iio_enum mcp4728_gain_mode_enum = { + .items = mcp4728_gain_modes, + .num_items = ARRAY_SIZE(mcp4728_gain_modes), + .get = mcp4728_get_gain_mode, + .set = mcp4728_set_gain_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), + IIO_ENUM("vref_mode", IIO_SEPARATE, &mcp4728_vref_mode_enum), + IIO_ENUM_AVAILABLE("vref_mode", IIO_SHARED_BY_TYPE, + &mcp4728_vref_mode_enum), + IIO_ENUM("gain_mode", IIO_SEPARATE, &mcp4728_gain_mode_enum), + IIO_ENUM_AVAILABLE("gain_mode", IIO_SHARED_BY_TYPE, + &mcp4728_gain_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 int mcp4728_full_scale_mV(u32 *full_scale_mV, int channel, + struct mcp4728_data *data) +{ + int ret; + + if (data->channel_data[channel].ref_mode == MCP4728_VREF_EXTERNAL_VDD) + ret = regulator_get_voltage(data->vdd_reg); + else + ret = 2048000; + + if (ret < 0) + return ret; + + if (ret == 0) + return -EINVAL; + + *full_scale_mV = ret / 1000; + return 0; +} + +static u32 mcp4728_raw_to_mV(u32 raw, int channel, struct mcp4728_data *data) +{ + int ret; + u32 full_scale_mV; + + ret = mcp4728_full_scale_mV(&full_scale_mV, channel, data); + if (ret) + return ret; + + return (((raw + 1) * full_scale_mV) >> MCP4728_RESOLUTION); +} + +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); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + *val = data->channel_data[chan->channel].dac_value; + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + if (data->channel_data[chan->channel].ref_mode == + MCP4728_VREF_EXTERNAL_VDD) + ret = regulator_get_voltage(data->vdd_reg); + else + ret = 2048000; + + if (ret < 0) + return ret; + + *val = ret / 1000; + *val2 = MCP4728_RESOLUTION; + return IIO_VAL_FRACTIONAL_LOG2; + } + 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->channel_data[chan->channel].dac_value = val; + ret = mcp4728_program_channel_cfg(chan->channel, indio_dev); + break; + default: + ret = -EINVAL; + break; + } + + return ret; +} + +static const struct iio_info mcp4728_info = { + .read_raw = mcp4728_read_raw, + .write_raw = mcp4728_write_raw, + .attrs = &mcp4728_attribute_group, +}; + +static int mcp4728_suspend(struct device *dev) +{ + struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev)); + struct mcp4728_data *data = iio_priv(indio_dev); + int err = 0; + unsigned int i; + + data->powerdown = true; + + for (i = 0; i < MCP4728_N_CHANNELS; i++) { + int ret = mcp4728_program_channel_cfg(i, indio_dev); + + if (ret) + err = ret; //save last error + } + return err; +} + +static int mcp4728_resume(struct device *dev) +{ + struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(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; //save last error + } + 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) { + dev_err(&data->client->dev, + "failed to read mcp4728 conf. Err=%d\n", ret); + return ret; + } else if (ret != MCP4728_READ_RESPONSE_LEN) { + dev_err(&data->client->dev, + "failed to read mcp4728 conf. Wrong Response Len ret=%d\n", + ret); + return -EIO; + } + + for (i = 0; i < MCP4728_N_CHANNELS; i++) { + struct mcp4728_channel_data *ch = &(data->channel_data[i]); + u8 r2 = inbuf[i * 6 + 1]; + u8 r3 = inbuf[i * 6 + 2]; + u32 dac_mv; + + ch->dac_value = (r2 & 0x0F) << 8 | r3; + ch->ref_mode = (r2 & MCP4728_CMD_VREF_MASK) >> + MCP4728_CMD_VREF_POS; + ch->pd_mode = (r2 & MCP4728_CMD_PDMODE_MASK) >> + MCP4728_CMD_PDMODE_POS; + ch->g_mode = (r2 & MCP4728_CMD_GAIN_MASK) >> + MCP4728_CMD_GAIN_POS; + if (ch->g_mode == MCP4728_GAIN_X2 && + ch->ref_mode == MCP4728_VREF_EXTERNAL_VDD) + dev_warn(&data->client->dev, + "CH%d: Gain x2 not effective when vref is vdd", + i); + + dac_mv = mcp4728_raw_to_mV(ch->dac_value, i, data); + dev_info(&data->client->dev, + "CH%d: Voltage=%dmV VRef=%d PowerDown=%d Gain=%d\n", i, + dac_mv, ch->ref_mode, ch->pd_mode, ch->g_mode); + } + + return 0; +} + +static int mcp4728_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct mcp4728_data *data; + struct iio_dev *indio_dev; + int err; + + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); + if (indio_dev == NULL) + return -ENOMEM; + data = iio_priv(indio_dev); + i2c_set_clientdata(client, indio_dev); + data->client = client; + if (dev_fwnode(&client->dev)) + data->id = (uintptr_t)device_get_match_data(&client->dev); + else + data->id = id->driver_data; + + 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) + goto err_disable_vdd_reg; + + err = mcp4728_init_channels_data(data); + if (err) { + dev_err(&client->dev, + "failed to read mcp4728 current configuration\n"); + goto err_disable_vdd_reg; + } + + 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; + + err = iio_device_register(indio_dev); + if (err) + goto err_disable_vdd_reg; + + return 0; + +err_disable_vdd_reg: + regulator_disable(data->vdd_reg); + + return err; +} + +static int mcp4728_remove(struct i2c_client *client) +{ + struct iio_dev *indio_dev = i2c_get_clientdata(client); + struct mcp4728_data *data = iio_priv(indio_dev); + + iio_device_unregister(indio_dev); + regulator_disable(data->vdd_reg); + return 0; +} + +static const struct i2c_device_id mcp4728_id[] = { { "mcp4728", MCP4728 }, {} }; +MODULE_DEVICE_TABLE(i2c, mcp4728_id); + +static const struct of_device_id mcp4728_of_match[] = { + { .compatible = "microchip,mcp4728", .data = (void *)MCP4728 }, + {} +}; +MODULE_DEVICE_TABLE(of, mcp4728_of_match); + +static struct i2c_driver mcp4728_driver = { + .driver = { + .name = MCP4728_DRV_NAME, + .of_match_table = mcp4728_of_match, + .pm = pm_sleep_ptr(&mcp4728_pm_ops), + }, + .probe = mcp4728_probe, + .remove = mcp4728_remove, + .id_table = mcp4728_id, +}; +module_i2c_driver(mcp4728_driver); + +MODULE_AUTHOR("Andrea Collamati <andrea.collamati@xxxxxxxxx>"); +MODULE_DESCRIPTION("MCP4728 12-bit DAC"); +MODULE_LICENSE("GPL"); -- 2.17.1
