| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * iio/dac/max5821.c |
| * Copyright (C) 2014 Philippe Reynes |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/i2c.h> |
| #include <linux/iio/iio.h> |
| #include <linux/regulator/consumer.h> |
| |
| #define MAX5821_MAX_DAC_CHANNELS 2 |
| |
| /* command bytes */ |
| #define MAX5821_LOAD_DAC_A_IN_REG_B 0x00 |
| #define MAX5821_LOAD_DAC_B_IN_REG_A 0x10 |
| #define MAX5821_EXTENDED_COMMAND_MODE 0xf0 |
| #define MAX5821_READ_DAC_A_COMMAND 0xf1 |
| #define MAX5821_READ_DAC_B_COMMAND 0xf2 |
| |
| #define MAX5821_EXTENDED_POWER_UP 0x00 |
| #define MAX5821_EXTENDED_POWER_DOWN_MODE0 0x01 |
| #define MAX5821_EXTENDED_POWER_DOWN_MODE1 0x02 |
| #define MAX5821_EXTENDED_POWER_DOWN_MODE2 0x03 |
| #define MAX5821_EXTENDED_DAC_A 0x04 |
| #define MAX5821_EXTENDED_DAC_B 0x08 |
| |
| enum max5821_device_ids { |
| ID_MAX5821, |
| }; |
| |
| struct max5821_data { |
| struct i2c_client *client; |
| struct regulator *vref_reg; |
| unsigned short vref_mv; |
| bool powerdown[MAX5821_MAX_DAC_CHANNELS]; |
| u8 powerdown_mode[MAX5821_MAX_DAC_CHANNELS]; |
| struct mutex lock; |
| }; |
| |
| static const char * const max5821_powerdown_modes[] = { |
| "three_state", |
| "1kohm_to_gnd", |
| "100kohm_to_gnd", |
| }; |
| |
| enum { |
| MAX5821_THREE_STATE, |
| MAX5821_1KOHM_TO_GND, |
| MAX5821_100KOHM_TO_GND |
| }; |
| |
| static int max5821_get_powerdown_mode(struct iio_dev *indio_dev, |
| const struct iio_chan_spec *chan) |
| { |
| struct max5821_data *st = iio_priv(indio_dev); |
| |
| return st->powerdown_mode[chan->channel]; |
| } |
| |
| static int max5821_set_powerdown_mode(struct iio_dev *indio_dev, |
| const struct iio_chan_spec *chan, |
| unsigned int mode) |
| { |
| struct max5821_data *st = iio_priv(indio_dev); |
| |
| st->powerdown_mode[chan->channel] = mode; |
| |
| return 0; |
| } |
| |
| static const struct iio_enum max5821_powerdown_mode_enum = { |
| .items = max5821_powerdown_modes, |
| .num_items = ARRAY_SIZE(max5821_powerdown_modes), |
| .get = max5821_get_powerdown_mode, |
| .set = max5821_set_powerdown_mode, |
| }; |
| |
| static ssize_t max5821_read_dac_powerdown(struct iio_dev *indio_dev, |
| uintptr_t private, |
| const struct iio_chan_spec *chan, |
| char *buf) |
| { |
| struct max5821_data *st = iio_priv(indio_dev); |
| |
| return sysfs_emit(buf, "%d\n", st->powerdown[chan->channel]); |
| } |
| |
| static int max5821_sync_powerdown_mode(struct max5821_data *data, |
| const struct iio_chan_spec *chan) |
| { |
| u8 outbuf[2]; |
| |
| outbuf[0] = MAX5821_EXTENDED_COMMAND_MODE; |
| |
| if (chan->channel == 0) |
| outbuf[1] = MAX5821_EXTENDED_DAC_A; |
| else |
| outbuf[1] = MAX5821_EXTENDED_DAC_B; |
| |
| if (data->powerdown[chan->channel]) |
| outbuf[1] |= data->powerdown_mode[chan->channel] + 1; |
| else |
| outbuf[1] |= MAX5821_EXTENDED_POWER_UP; |
| |
| return i2c_master_send(data->client, outbuf, 2); |
| } |
| |
| static ssize_t max5821_write_dac_powerdown(struct iio_dev *indio_dev, |
| uintptr_t private, |
| const struct iio_chan_spec *chan, |
| const char *buf, size_t len) |
| { |
| struct max5821_data *data = iio_priv(indio_dev); |
| bool powerdown; |
| int ret; |
| |
| ret = kstrtobool(buf, &powerdown); |
| if (ret) |
| return ret; |
| |
| data->powerdown[chan->channel] = powerdown; |
| |
| ret = max5821_sync_powerdown_mode(data, chan); |
| if (ret < 0) |
| return ret; |
| |
| return len; |
| } |
| |
| static const struct iio_chan_spec_ext_info max5821_ext_info[] = { |
| { |
| .name = "powerdown", |
| .read = max5821_read_dac_powerdown, |
| .write = max5821_write_dac_powerdown, |
| .shared = IIO_SEPARATE, |
| }, |
| IIO_ENUM("powerdown_mode", IIO_SEPARATE, &max5821_powerdown_mode_enum), |
| IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, &max5821_powerdown_mode_enum), |
| { }, |
| }; |
| |
| #define MAX5821_CHANNEL(chan) { \ |
| .type = IIO_VOLTAGE, \ |
| .indexed = 1, \ |
| .output = 1, \ |
| .channel = (chan), \ |
| .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ |
| .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE), \ |
| .ext_info = max5821_ext_info, \ |
| } |
| |
| static const struct iio_chan_spec max5821_channels[] = { |
| MAX5821_CHANNEL(0), |
| MAX5821_CHANNEL(1) |
| }; |
| |
| static const u8 max5821_read_dac_command[] = { |
| MAX5821_READ_DAC_A_COMMAND, |
| MAX5821_READ_DAC_B_COMMAND |
| }; |
| |
| static const u8 max5821_load_dac_command[] = { |
| MAX5821_LOAD_DAC_A_IN_REG_B, |
| MAX5821_LOAD_DAC_B_IN_REG_A |
| }; |
| |
| static int max5821_get_value(struct iio_dev *indio_dev, |
| int *val, int channel) |
| { |
| struct max5821_data *data = iio_priv(indio_dev); |
| struct i2c_client *client = data->client; |
| u8 outbuf[1]; |
| u8 inbuf[2]; |
| int ret; |
| |
| if ((channel != 0) && (channel != 1)) |
| return -EINVAL; |
| |
| outbuf[0] = max5821_read_dac_command[channel]; |
| |
| mutex_lock(&data->lock); |
| |
| ret = i2c_master_send(client, outbuf, 1); |
| if (ret < 0) { |
| mutex_unlock(&data->lock); |
| return ret; |
| } else if (ret != 1) { |
| mutex_unlock(&data->lock); |
| return -EIO; |
| } |
| |
| ret = i2c_master_recv(client, inbuf, 2); |
| if (ret < 0) { |
| mutex_unlock(&data->lock); |
| return ret; |
| } else if (ret != 2) { |
| mutex_unlock(&data->lock); |
| return -EIO; |
| } |
| |
| mutex_unlock(&data->lock); |
| |
| *val = ((inbuf[0] & 0x0f) << 6) | (inbuf[1] >> 2); |
| |
| return IIO_VAL_INT; |
| } |
| |
| static int max5821_set_value(struct iio_dev *indio_dev, |
| int val, int channel) |
| { |
| struct max5821_data *data = iio_priv(indio_dev); |
| struct i2c_client *client = data->client; |
| u8 outbuf[2]; |
| int ret; |
| |
| if ((val < 0) || (val > 1023)) |
| return -EINVAL; |
| |
| if ((channel != 0) && (channel != 1)) |
| return -EINVAL; |
| |
| outbuf[0] = max5821_load_dac_command[channel]; |
| outbuf[0] |= val >> 6; |
| outbuf[1] = (val & 0x3f) << 2; |
| |
| ret = i2c_master_send(client, outbuf, 2); |
| if (ret < 0) |
| return ret; |
| else if (ret != 2) |
| return -EIO; |
| else |
| return 0; |
| } |
| |
| static int max5821_read_raw(struct iio_dev *indio_dev, |
| struct iio_chan_spec const *chan, |
| int *val, int *val2, long mask) |
| { |
| struct max5821_data *data = iio_priv(indio_dev); |
| |
| switch (mask) { |
| case IIO_CHAN_INFO_RAW: |
| return max5821_get_value(indio_dev, val, chan->channel); |
| case IIO_CHAN_INFO_SCALE: |
| *val = data->vref_mv; |
| *val2 = 10; |
| return IIO_VAL_FRACTIONAL_LOG2; |
| default: |
| return -EINVAL; |
| } |
| } |
| |
| static int max5821_write_raw(struct iio_dev *indio_dev, |
| struct iio_chan_spec const *chan, |
| int val, int val2, long mask) |
| { |
| if (val2 != 0) |
| return -EINVAL; |
| |
| switch (mask) { |
| case IIO_CHAN_INFO_RAW: |
| return max5821_set_value(indio_dev, val, chan->channel); |
| default: |
| return -EINVAL; |
| } |
| } |
| |
| static int max5821_suspend(struct device *dev) |
| { |
| u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE, |
| MAX5821_EXTENDED_DAC_A | |
| MAX5821_EXTENDED_DAC_B | |
| MAX5821_EXTENDED_POWER_DOWN_MODE2 }; |
| |
| return i2c_master_send(to_i2c_client(dev), outbuf, 2); |
| } |
| |
| static int max5821_resume(struct device *dev) |
| { |
| u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE, |
| MAX5821_EXTENDED_DAC_A | |
| MAX5821_EXTENDED_DAC_B | |
| MAX5821_EXTENDED_POWER_UP }; |
| |
| return i2c_master_send(to_i2c_client(dev), outbuf, 2); |
| } |
| |
| static DEFINE_SIMPLE_DEV_PM_OPS(max5821_pm_ops, max5821_suspend, |
| max5821_resume); |
| |
| static const struct iio_info max5821_info = { |
| .read_raw = max5821_read_raw, |
| .write_raw = max5821_write_raw, |
| }; |
| |
| static void max5821_regulator_disable(void *reg) |
| { |
| regulator_disable(reg); |
| } |
| |
| static int max5821_probe(struct i2c_client *client, |
| const struct i2c_device_id *id) |
| { |
| struct max5821_data *data; |
| struct iio_dev *indio_dev; |
| u32 tmp; |
| int ret; |
| |
| indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); |
| if (!indio_dev) |
| return -ENOMEM; |
| data = iio_priv(indio_dev); |
| data->client = client; |
| mutex_init(&data->lock); |
| |
| /* max5821 start in powerdown mode 100Kohm to ground */ |
| for (tmp = 0; tmp < MAX5821_MAX_DAC_CHANNELS; tmp++) { |
| data->powerdown[tmp] = true; |
| data->powerdown_mode[tmp] = MAX5821_100KOHM_TO_GND; |
| } |
| |
| data->vref_reg = devm_regulator_get(&client->dev, "vref"); |
| if (IS_ERR(data->vref_reg)) |
| return dev_err_probe(&client->dev, PTR_ERR(data->vref_reg), |
| "Failed to get vref regulator\n"); |
| |
| ret = regulator_enable(data->vref_reg); |
| if (ret) { |
| dev_err(&client->dev, |
| "Failed to enable vref regulator: %d\n", ret); |
| return ret; |
| } |
| |
| ret = devm_add_action_or_reset(&client->dev, max5821_regulator_disable, |
| data->vref_reg); |
| if (ret) { |
| dev_err(&client->dev, |
| "Failed to add action to managed regulator: %d\n", ret); |
| return ret; |
| } |
| |
| ret = regulator_get_voltage(data->vref_reg); |
| if (ret < 0) { |
| dev_err(&client->dev, |
| "Failed to get voltage on regulator: %d\n", ret); |
| return ret; |
| } |
| |
| data->vref_mv = ret / 1000; |
| |
| indio_dev->name = id->name; |
| indio_dev->num_channels = ARRAY_SIZE(max5821_channels); |
| indio_dev->channels = max5821_channels; |
| indio_dev->modes = INDIO_DIRECT_MODE; |
| indio_dev->info = &max5821_info; |
| |
| return devm_iio_device_register(&client->dev, indio_dev); |
| } |
| |
| static const struct i2c_device_id max5821_id[] = { |
| { "max5821", ID_MAX5821 }, |
| { } |
| }; |
| MODULE_DEVICE_TABLE(i2c, max5821_id); |
| |
| static const struct of_device_id max5821_of_match[] = { |
| { .compatible = "maxim,max5821" }, |
| { } |
| }; |
| MODULE_DEVICE_TABLE(of, max5821_of_match); |
| |
| static struct i2c_driver max5821_driver = { |
| .driver = { |
| .name = "max5821", |
| .of_match_table = max5821_of_match, |
| .pm = pm_sleep_ptr(&max5821_pm_ops), |
| }, |
| .probe = max5821_probe, |
| .id_table = max5821_id, |
| }; |
| module_i2c_driver(max5821_driver); |
| |
| MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>"); |
| MODULE_DESCRIPTION("MAX5821 DAC"); |
| MODULE_LICENSE("GPL v2"); |