diff options
Diffstat (limited to 'drivers/iio/dac/max5821.c')
| -rw-r--r-- | drivers/iio/dac/max5821.c | 405 |
1 files changed, 405 insertions, 0 deletions
diff --git a/drivers/iio/dac/max5821.c b/drivers/iio/dac/max5821.c new file mode 100644 index 000000000..6e914495b --- /dev/null +++ b/drivers/iio/dac/max5821.c @@ -0,0 +1,405 @@ + /* + * iio/dac/max5821.c + * Copyright (C) 2014 Philippe Reynes + * + * 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/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 sprintf(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 = strtobool(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", &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; + } +} + +#ifdef CONFIG_PM_SLEEP +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 SIMPLE_DEV_PM_OPS(max5821_pm_ops, max5821_suspend, max5821_resume); +#define MAX5821_PM_OPS (&max5821_pm_ops) +#else +#define MAX5821_PM_OPS NULL +#endif /* CONFIG_PM_SLEEP */ + +static const struct iio_info max5821_info = { + .read_raw = max5821_read_raw, + .write_raw = max5821_write_raw, + .driver_module = THIS_MODULE, +}; + +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); + i2c_set_clientdata(client, 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)) { + ret = PTR_ERR(data->vref_reg); + dev_err(&client->dev, + "Failed to get vref regulator: %d\n", ret); + goto error_free_reg; + } + + ret = regulator_enable(data->vref_reg); + if (ret) { + dev_err(&client->dev, + "Failed to enable vref regulator: %d\n", ret); + goto error_free_reg; + } + + ret = regulator_get_voltage(data->vref_reg); + if (ret < 0) { + dev_err(&client->dev, + "Failed to get voltage on regulator: %d\n", ret); + goto error_disable_reg; + } + + data->vref_mv = ret / 1000; + + indio_dev->name = id->name; + indio_dev->dev.parent = &client->dev; + 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 iio_device_register(indio_dev); + +error_disable_reg: + regulator_disable(data->vref_reg); + +error_free_reg: + + return ret; +} + +static int max5821_remove(struct i2c_client *client) +{ + struct iio_dev *indio_dev = i2c_get_clientdata(client); + struct max5821_data *data = iio_priv(indio_dev); + + iio_device_unregister(indio_dev); + regulator_disable(data->vref_reg); + + return 0; +} + +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" }, + { } +}; + +static struct i2c_driver max5821_driver = { + .driver = { + .name = "max5821", + .pm = MAX5821_PM_OPS, + .owner = THIS_MODULE, + }, + .probe = max5821_probe, + .remove = max5821_remove, + .id_table = max5821_id, +}; +module_i2c_driver(max5821_driver); + +MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>"); +MODULE_DESCRIPTION("MAX5821 DAC"); +MODULE_LICENSE("GPL v2"); |