diff options
Diffstat (limited to 'drivers/iio/dac/mcp4725.c')
-rw-r--r-- | drivers/iio/dac/mcp4725.c | 177 |
1 files changed, 154 insertions, 23 deletions
diff --git a/drivers/iio/dac/mcp4725.c b/drivers/iio/dac/mcp4725.c index a612ec7..1f4a48e 100644 --- a/drivers/iio/dac/mcp4725.c +++ b/drivers/iio/dac/mcp4725.c @@ -12,14 +12,13 @@ * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC) * (7-bit I2C slave address 0x60, the three LSBs can be configured in * hardware) - * - * writing the DAC value to EEPROM is not supported */ #include <linux/module.h> #include <linux/init.h> #include <linux/i2c.h> #include <linux/err.h> +#include <linux/delay.h> #include <linux/iio/iio.h> #include <linux/iio/sysfs.h> @@ -32,15 +31,19 @@ struct mcp4725_data { struct i2c_client *client; u16 vref_mv; u16 dac_value; + bool powerdown; + unsigned powerdown_mode; }; -#ifdef CONFIG_PM_SLEEP static int mcp4725_suspend(struct device *dev) { + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct mcp4725_data *data = iio_priv(indio_dev); u8 outbuf[2]; - outbuf[0] = 0x3 << 4; /* power-down bits, 500 kOhm resistor */ + outbuf[0] = (data->powerdown_mode + 1) << 4; outbuf[1] = 0; + data->powerdown = true; return i2c_master_send(to_i2c_client(dev), outbuf, 2); } @@ -54,16 +57,150 @@ static int mcp4725_resume(struct device *dev) /* restore previous DAC value */ outbuf[0] = (data->dac_value >> 8) & 0xf; outbuf[1] = data->dac_value & 0xff; + data->powerdown = false; return i2c_master_send(to_i2c_client(dev), outbuf, 2); } +#ifdef CONFIG_PM_SLEEP static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume); #define MCP4725_PM_OPS (&mcp4725_pm_ops) #else #define MCP4725_PM_OPS NULL #endif +static ssize_t mcp4725_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 mcp4725_data *data = iio_priv(indio_dev); + int tries = 20; + u8 inoutbuf[3]; + bool state; + int ret; + + ret = strtobool(buf, &state); + if (ret < 0) + return ret; + + if (!state) + return 0; + + inoutbuf[0] = 0x60; /* write EEPROM */ + inoutbuf[1] = data->dac_value >> 4; + inoutbuf[2] = (data->dac_value & 0xf) << 4; + + ret = i2c_master_send(data->client, inoutbuf, 3); + if (ret < 0) + return ret; + else if (ret != 3) + return -EIO; + + /* wait for write complete, takes up to 50ms */ + while (tries--) { + msleep(20); + ret = i2c_master_recv(data->client, inoutbuf, 3); + if (ret < 0) + return ret; + else if (ret != 3) + return -EIO; + + if (inoutbuf[0] & 0x80) + break; + } + + if (tries < 0) { + dev_err(&data->client->dev, + "mcp4725_store_eeprom() failed, incomplete\n"); + return -EIO; + } + + return len; +} + +static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0); + +static struct attribute *mcp4725_attributes[] = { + &iio_dev_attr_store_eeprom.dev_attr.attr, + NULL, +}; + +static const struct attribute_group mcp4725_attribute_group = { + .attrs = mcp4725_attributes, +}; + +static const char * const mcp4725_powerdown_modes[] = { + "1kohm_to_gnd", + "100kohm_to_gnd", + "500kohm_to_gnd" +}; + +static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan) +{ + struct mcp4725_data *data = iio_priv(indio_dev); + + return data->powerdown_mode; +} + +static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, unsigned mode) +{ + struct mcp4725_data *data = iio_priv(indio_dev); + + data->powerdown_mode = mode; + + return 0; +} + +static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev, + uintptr_t private, const struct iio_chan_spec *chan, char *buf) +{ + struct mcp4725_data *data = iio_priv(indio_dev); + + return sprintf(buf, "%d\n", data->powerdown); +} + +static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev, + uintptr_t private, const struct iio_chan_spec *chan, + const char *buf, size_t len) +{ + struct mcp4725_data *data = iio_priv(indio_dev); + bool state; + int ret; + + ret = strtobool(buf, &state); + if (ret) + return ret; + + if (state) + ret = mcp4725_suspend(&data->client->dev); + else + ret = mcp4725_resume(&data->client->dev); + if (ret < 0) + return ret; + + return len; +} + +static const struct iio_enum mcp4725_powerdown_mode_enum = { + .items = mcp4725_powerdown_modes, + .num_items = ARRAY_SIZE(mcp4725_powerdown_modes), + .get = mcp4725_get_powerdown_mode, + .set = mcp4725_set_powerdown_mode, +}; + +static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = { + { + .name = "powerdown", + .read = mcp4725_read_powerdown, + .write = mcp4725_write_powerdown, + }, + IIO_ENUM("powerdown_mode", false, &mcp4725_powerdown_mode_enum), + IIO_ENUM_AVAILABLE("powerdown_mode", &mcp4725_powerdown_mode_enum), + { }, +}; + static const struct iio_chan_spec mcp4725_channel = { .type = IIO_VOLTAGE, .indexed = 1, @@ -72,6 +209,7 @@ static const struct iio_chan_spec mcp4725_channel = { .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), .scan_type = IIO_ST('u', 12, 16, 0), + .ext_info = mcp4725_ext_info, }; static int mcp4725_set_value(struct iio_dev *indio_dev, int val) @@ -138,6 +276,7 @@ static int mcp4725_write_raw(struct iio_dev *indio_dev, static const struct iio_info mcp4725_info = { .read_raw = mcp4725_read_raw, .write_raw = mcp4725_write_raw, + .attrs = &mcp4725_attribute_group, .driver_module = THIS_MODULE, }; @@ -148,19 +287,17 @@ static int mcp4725_probe(struct i2c_client *client, struct iio_dev *indio_dev; struct mcp4725_platform_data *platform_data = client->dev.platform_data; u8 inbuf[3]; + u8 pd; int err; if (!platform_data || !platform_data->vref_mv) { dev_err(&client->dev, "invalid platform data"); - err = -EINVAL; - goto exit; + return -EINVAL; } - indio_dev = iio_device_alloc(sizeof(*data)); - if (indio_dev == NULL) { - err = -ENOMEM; - goto exit; - } + 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; @@ -177,31 +314,25 @@ static int mcp4725_probe(struct i2c_client *client, err = i2c_master_recv(client, inbuf, 3); if (err < 0) { dev_err(&client->dev, "failed to read DAC value"); - goto exit_free_device; + return err; } + pd = (inbuf[0] >> 1) & 0x3; + data->powerdown = pd > 0 ? true : false; + data->powerdown_mode = pd ? pd-1 : 2; /* 500kohm_to_gnd */ data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4); err = iio_device_register(indio_dev); if (err) - goto exit_free_device; + return err; dev_info(&client->dev, "MCP4725 DAC registered\n"); return 0; - -exit_free_device: - iio_device_free(indio_dev); -exit: - return err; } static int mcp4725_remove(struct i2c_client *client) { - struct iio_dev *indio_dev = i2c_get_clientdata(client); - - iio_device_unregister(indio_dev); - iio_device_free(indio_dev); - + iio_device_unregister(i2c_get_clientdata(client)); return 0; } |