On 14/04/15 10:32, Tiberiu Breana wrote:
> Minimal implementation of an IIO driver for the Sensortek
> STK3310 ambient light and proximity sensor. The STK3311
> model is also supported.
>
> Includes:
> - ACPI support;
> - read_raw and write_raw;
> - reading and setting configuration parameters for gain/scale
> and integration time for both ALS and PS.
>
> Signed-off-by: Tiberiu Breana <tiberiu.a.breana@xxxxxxxxx>
Looks good. One issue with the use of devm_iio_device_register and
a few comments inline.
You are very fond of the switch statement and general purpose
functions that perhaps get stretched too far! Sill nothing
really wrong with the approach, just a little different from
many.
Jonathan
> ---
> drivers/iio/light/Kconfig | 11 +
> drivers/iio/light/Makefile | 1 +
> drivers/iio/light/stk3310.c | 492 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 504 insertions(+)
> create mode 100644 drivers/iio/light/stk3310.c
>
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index 01a1a16..096129d 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -174,6 +174,17 @@ config LTR501
> This driver can also be built as a module. If so, the module
> will be called ltr501.
>
> +config STK3310
> + tristate "STK3310 ALS and proximity sensor"
> + depends on I2C
> + help
> + Say yes here to get support for the Sensortek STK3310 ambient light
> + and proximity sensor. The STK3311 model is also supported by this
> + driver.
> +
> + Choosing M will build the driver as a module. If so, the module
> + will be called stk3310.
> +
> config TCS3414
> tristate "TAOS TCS3414 digital color sensor"
> depends on I2C
> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> index ad7c30f..90e7fd2 100644
> --- a/drivers/iio/light/Makefile
> +++ b/drivers/iio/light/Makefile
> @@ -18,6 +18,7 @@ obj-$(CONFIG_JSA1212) += jsa1212.o
> obj-$(CONFIG_SENSORS_LM3533) += lm3533-als.o
> obj-$(CONFIG_LTR501) += ltr501.o
> obj-$(CONFIG_SENSORS_TSL2563) += tsl2563.o
> +obj-$(CONFIG_STK3310) += stk3310.o
> obj-$(CONFIG_TCS3414) += tcs3414.o
> obj-$(CONFIG_TCS3472) += tcs3472.o
> obj-$(CONFIG_TSL4531) += tsl4531.o
> diff --git a/drivers/iio/light/stk3310.c b/drivers/iio/light/stk3310.c
> new file mode 100644
> index 0000000..5bcf5a0
> --- /dev/null
> +++ b/drivers/iio/light/stk3310.c
> @@ -0,0 +1,492 @@
> +/**
> + * Sensortek STK3310/STK3311 Ambient Light and Proximity Sensor
> + *
> + * Copyright (c) 2015, Intel Corporation.
> + *
> + * This file is subject to the terms and conditions of version 2 of
> + * the GNU General Public License. See the file COPYING in the main
> + * directory of this archive for more details.
> + *
> + * IIO driver for STK3310/STK3311. 7-bit I2C address: 0x48.
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +#define STK3310_REG_STATE 0x00
> +#define STK3310_REG_PSCTRL 0x01
> +#define STK3310_REG_ALSCTRL 0x02
> +#define STK3310_REG_PS_DATA_MSB 0x11
> +#define STK3310_REG_ALS_DATA_MSB 0x13
> +#define STK3310_REG_PDT_ID 0x3E
> +
> +#define STK3310_STATE_EN_PS 0x01
> +#define STK3310_STATE_EN_ALS 0x02
> +#define STK3310_STATE_STANDBY 0x00
> +#define STK3310_STATE_MASK 0x07
> +
> +#define STK3310_GAIN_MASK 0x30
> +#define STK3310_IT_MASK 0x0F
> +#define STK3310_GAIN_SHIFT 4
> +#define STK3310_IT_SHIFT 0
> +
> +#define STK3310_CHIP_ID_VAL 0x13
> +#define STK3311_CHIP_ID_VAL 0x1D
> +
> +#define STK3310_GAIN_MAX 3
> +#define STK3310_IT_MAX 15
> +#define STK3310_PS_MAX_VAL 0xffff
> +
> +#define STK3310_SCALE_AVAILABLE "6.4 1.6 0.4 0.1"
> +
> +#define STK3310_DRIVER_NAME "stk3310"
> +
> +/*
> + * Maximum PS values with regard to scale. Used to export the 'inverse'
> + * PS value (high values for far objects, low values for near objects).
> + */
> +static const int stk3310_ps_max[4] = {
> + STK3310_PS_MAX_VAL / 64,
> + STK3310_PS_MAX_VAL / 16,
> + STK3310_PS_MAX_VAL / 4,
> + STK3310_PS_MAX_VAL,
> +};
> +
> +static const int stk3310_scale_table[][2] = {
> + {6, 400000}, {1, 600000}, {0, 400000}, {0, 100000}
> +};
> +
> +/* Integration time in seconds, microseconds */
> +static const int stk3310_it_table[][2] = {
> + {0, 185000}, {0, 370000}, {0, 741000}, {0, 148000},
> + {0, 296000}, {0, 592000}, {0, 118400}, {0, 236800},
> + {0, 473600}, {0, 947200}, {0, 189440}, {0, 378880},
> + {0, 757760}, {1, 515520}, {3, 31040}, {6, 62080},
> +};
> +
> +enum stk3310_data_type {
> + STK3310_ALS,
> + STK3310_PS
> +};
> +
> +enum stk3310_config_type {
> + STK3310_GAIN,
> + STK3310_IT,
> + STK3310_TYPE_COUNT
> +};
> +
> +struct stk3310_data {
> + struct i2c_client *client;
> + struct mutex lock;
> + /* Cache table for storing config values */
> + int cache[2][STK3310_TYPE_COUNT];
> +};
> +
> +static const struct iio_chan_spec stk3310_channels[] = {
> + {
> + .channel = 0,
> + .type = IIO_LIGHT,
> + .info_mask_separate =
> + BIT(IIO_CHAN_INFO_RAW) |
> + BIT(IIO_CHAN_INFO_SCALE) |
> + BIT(IIO_CHAN_INFO_INT_TIME),
> + },
> + {
> + .channel = 1,
> + .type = IIO_PROXIMITY,
> + .info_mask_separate =
> + BIT(IIO_CHAN_INFO_RAW) |
> + BIT(IIO_CHAN_INFO_SCALE) |
> + BIT(IIO_CHAN_INFO_INT_TIME),
> + }
> +};
> +
> +static ssize_t stk3310_get_it_vals(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + int i;
> + int len;
> +
> + for (i = 0, len = 0; i < ARRAY_SIZE(stk3310_it_table); i++) {
> + len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06d ",
> + stk3310_it_table[i][0],
> + stk3310_it_table[i][1]);
> + }
> + buf[len - 1] = '\n';
> +
> + return len;
> +}
> +
> +static IIO_CONST_ATTR(in_illuminance_scale_available, STK3310_SCALE_AVAILABLE);
> +
> +static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,
> + S_IRUGO, stk3310_get_it_vals, NULL, 0);
> +
> +static IIO_DEVICE_ATTR(in_proximity_integration_time_available,
> + S_IRUGO, stk3310_get_it_vals, NULL, 0);
> +
> +static struct attribute *stk3310_attributes[] = {
> + &iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
> + &iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
> + &iio_dev_attr_in_proximity_integration_time_available.dev_attr.attr,
> + NULL,
> +};
> +
> +static const struct attribute_group stk3310_attribute_group = {
> + .attrs = stk3310_attributes
> +};
> +
> +static int stk3310_get_index(const int table[][2], int table_size,
> + int val, int val2)
> +{
> + int i;
> +
> + for (i = 0; i < table_size; i++) {
> + if (val == table[i][0] && val2 == table[i][1])
> + return i;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int stk3310_set_cfg(struct stk3310_data *data,
> + enum stk3310_data_type type,
> + enum stk3310_config_type cfg,
> + u8 val)
> +{
> + u8 reg;
> + u8 shift;
> + u8 masked_reg;
> + u8 mask;
> + int ret;
> +
> + if (val < 0)
> + return -EINVAL;
> + switch (type) {
> + case STK3310_ALS:
> + reg = STK3310_REG_ALSCTRL;
> + break;
> + case STK3310_PS:
> + reg = STK3310_REG_PSCTRL;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + switch (cfg) {
> + case STK3310_GAIN:
> + if (val > STK3310_GAIN_MAX)
> + return -EINVAL;
> + shift = STK3310_GAIN_SHIFT;
> + mask = STK3310_GAIN_MASK;
> + break;
> + case STK3310_IT:
> + if (val > STK3310_IT_MAX)
> + return -EINVAL;
> + shift = STK3310_IT_SHIFT;
> + mask = STK3310_IT_MASK;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + ret = i2c_smbus_read_byte_data(data->client, reg);
Isn't this already in the cache?
> + if (ret < 0) {
> + dev_err(&data->client->dev, "register read failed\n");
> + return ret;
> + }
> + masked_reg = ret & (~mask);
> + masked_reg |= (val << shift);
> +
> + ret = i2c_smbus_write_byte_data(data->client, reg, masked_reg);
> + if (ret < 0)
> + dev_err(&data->client->dev, "sensor configuration failed\n");
> + else
> + data->cache[type][cfg] = val;
This isn't actually the value written. Would caching masked_reg make more sense?
Also, why cache at all? You often seem to reread it anyway as in this function.
> +
> + return ret;
> +}
> +
> +static int stk3310_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long mask)
> +{
> + int ret;
> + int index;
> + u8 reg;
> + enum stk3310_data_type type;
> + struct stk3310_data *data = iio_priv(indio_dev);
> + struct i2c_client *client = data->client;
> +
> + switch (chan->type) {
> + case IIO_LIGHT:
> + type = STK3310_ALS;
> + reg = STK3310_REG_ALS_DATA_MSB;
> + break;
> + case IIO_PROXIMITY:
> + type = STK3310_PS;
> + reg = STK3310_REG_PS_DATA_MSB;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + mutex_lock(&data->lock);
> + ret = i2c_smbus_read_word_swapped(client, reg);
> + if (ret < 0) {
> + dev_err(&client->dev, "register read failed\n");
> + mutex_unlock(&data->lock);
> + return ret;
> + }
> + *val = ret;
> + index = data->cache[STK3310_ALS][STK3310_GAIN];
> + if (type == STK3310_PS) {
> + /*
> + * Invert the proximity data so we return low values
> + * for close objects and high values for far ones.
> + */
> + index = data->cache[STK3310_PS][STK3310_GAIN];
> + *val = stk3310_ps_max[index] - *val;
> + }
> + mutex_unlock(&data->lock);
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_INT_TIME:
> + index = data->cache[type][STK3310_IT];
> + *val = stk3310_it_table[index][0];
> + *val2 = stk3310_it_table[index][1];
> + return IIO_VAL_INT_PLUS_MICRO;
> + case IIO_CHAN_INFO_SCALE:
> + index = data->cache[type][STK3310_GAIN];
> + *val = stk3310_scale_table[index][0];
> + *val2 = stk3310_scale_table[index][1];
> + return IIO_VAL_INT_PLUS_MICRO;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int stk3310_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int val, int val2, long mask)
> +{
> + int ret;
> + int index;
> + enum stk3310_data_type type;
> + struct stk3310_data *data = iio_priv(indio_dev);
> +
> + switch (chan->type) {
> + case IIO_LIGHT:
> + type = STK3310_ALS;
> + break;
> + case IIO_PROXIMITY:
> + type = STK3310_PS;
> + break;
> + default:
> + return -EINVAL;
> + }
Hmm. You could pass the iio type directly into set_cfg and have only
one switch statement rather than the two current ones... I guess the
reason you do it like this is for consistency with the rest of the driver.
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_INT_TIME:
> + index = stk3310_get_index(stk3310_it_table,
> + ARRAY_SIZE(stk3310_it_table),
> + val, val2);
> + if (index < 0)
> + return -EINVAL;
> + mutex_lock(&data->lock);
> + ret = stk3310_set_cfg(data, type, STK3310_IT, index);
> + mutex_unlock(&data->lock);
> + return ret;
> +
> + case IIO_CHAN_INFO_SCALE:
> + index = stk3310_get_index(stk3310_scale_table,
> + ARRAY_SIZE(stk3310_scale_table),
> + val, val2);
> + if (index < 0)
> + return -EINVAL;
> + mutex_lock(&data->lock);
> + ret = stk3310_set_cfg(data, type, STK3310_GAIN, index);
> + mutex_unlock(&data->lock);
> + return ret;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static const struct iio_info stk3310_info = {
> + .driver_module = THIS_MODULE,
> + .read_raw = stk3310_read_raw,
> + .write_raw = stk3310_write_raw,
> + .attrs = &stk3310_attribute_group,
> +};
> +
> +static int stk3310_cache_store(struct stk3310_data *data)
> +{
> + int ret;
> +
> + mutex_lock(&data->lock);
> + ret = i2c_smbus_read_byte_data(data->client, STK3310_REG_ALSCTRL);
> + if (ret < 0) {
> + dev_err(&data->client->dev, "register read failed\n");
> + mutex_unlock(&data->lock);
> + return ret;
> + }
> +
> + data->cache[STK3310_ALS][STK3310_GAIN] =
> + (ret & STK3310_GAIN_MASK) >> STK3310_GAIN_SHIFT;
> + data->cache[STK3310_ALS][STK3310_IT] =
> + (ret & STK3310_IT_MASK) >> STK3310_IT_SHIFT;
> +
> + ret = i2c_smbus_read_byte_data(data->client, STK3310_REG_PSCTRL);
> + if (ret < 0) {
> + dev_err(&data->client->dev, "register read failed\n");
> + mutex_unlock(&data->lock);
> + return ret;
> + }
> +
> + data->cache[STK3310_PS][STK3310_GAIN] =
> + (ret & STK3310_GAIN_MASK) >> STK3310_GAIN_SHIFT;
> + data->cache[STK3310_PS][STK3310_IT] =
> + (ret & STK3310_IT_MASK) >> STK3310_IT_SHIFT;
> + mutex_unlock(&data->lock);
> +
Hmm. The moment I see caching in a driver I think maybe this would
be cleaner with regmap... Here there isn't much being cached though
so I don't really mind either way.
> + return ret;
> +}
> +
> +static int stk3310_set_state(struct stk3310_data *data, u8 state)
> +{
> + int ret;
> + int masked_reg;
> + struct i2c_client *client = data->client;
> +
> + /* 3-bit state; 0b100 is not supported. */
> + if (state < 0 || state > 7 || state == 4)
> + return -EINVAL;
> +
> + mutex_lock(&data->lock);
> + ret = i2c_smbus_read_byte_data(data->client, STK3310_REG_STATE);
> + if (ret < 0) {
> + mutex_unlock(&data->lock);
> + dev_err(&client->dev, "register read failed\n");
> + return ret;
> + }
> + masked_reg = ret & (~STK3310_STATE_MASK);
> + masked_reg |= state;
> +
> + ret = i2c_smbus_write_byte_data(data->client, STK3310_REG_STATE,
> + masked_reg);
> + if (ret < 0)
> + dev_err(&client->dev, "failed to change sensor state\n");
> +
> + mutex_unlock(&data->lock);
> +
> + return ret;
> +}
> +
> +static int stk3310_init(struct iio_dev *indio_dev)
> +{
> + int ret;
> + u8 state;
> + struct stk3310_data *data = iio_priv(indio_dev);
> + struct i2c_client *client = data->client;
> +
> + ret = i2c_smbus_read_byte_data(client, STK3310_REG_PDT_ID);
> + if (ret != STK3310_CHIP_ID_VAL &&
> + ret != STK3311_CHIP_ID_VAL) {
> + dev_err(&client->dev, "invalid chip id: 0x%x\n", ret);
> + return -ENODEV;
> + }
> +
> + state = STK3310_STATE_EN_ALS | STK3310_STATE_EN_PS;
> + ret = stk3310_set_state(data, state);
> + if (ret < 0) {
> + dev_err(&client->dev, "failed to enable sensor");
> + return ret;
> + }
> +
> + /* Cache the initial configuration values */
> + return stk3310_cache_store(data);
> +}
> +
> +static int stk3310_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + int ret;
> + struct iio_dev *indio_dev;
> + struct stk3310_data *data;
> +
> + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> + if (!indio_dev) {
> + dev_err(&client->dev, "iio allocation failed!\n");
> + return -ENOMEM;
> + }
> +
> + data = iio_priv(indio_dev);
> + data->client = client;
> + i2c_set_clientdata(client, indio_dev);
> + mutex_init(&data->lock);
> +
> + indio_dev->dev.parent = &client->dev;
> + indio_dev->info = &stk3310_info;
> + indio_dev->name = STK3310_DRIVER_NAME;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->channels = stk3310_channels;
> + indio_dev->num_channels = ARRAY_SIZE(stk3310_channels);
> +
> + ret = stk3310_init(indio_dev);
> + if (ret < 0) {
> + dev_err(&client->dev, "sensor initialization failed\n");
> + return ret;
> + }
> +
> + ret = devm_iio_device_register(&client->dev, indio_dev);
> + if (ret < 0) {
> + dev_err(&client->dev, "device_register failed\n");
> + stk3310_set_state(data, STK3310_STATE_STANDBY);
> + }
> +
> + return ret;
> +}
> +
> +static int stk3310_remove(struct i2c_client *client)
> +{
> + struct iio_dev *indio_dev = i2c_get_clientdata(client);
> + struct stk3310_data *data = iio_priv(indio_dev);
> +
> + return stk3310_set_state(data, STK3310_STATE_STANDBY);
Could roll all of this into one line.
return stk3310_set_state(iio_priv(i2c_get_clientdata(client)));
without loosing significant readabliity.
Howwever you are not quite unrolling your probe in the oposite
order in the remove. There will be a window in which the userspace
interfaces are present and you have put the device into standby.
Basic rule of thumb: Don't use devm_ version of iio_device_register
if you have anything at all in your remove function.
Use the non devm version and ensure it is unregistered before putting
the device into standby.
> +}
> +
> +static const struct i2c_device_id stk3310_i2c_id[] = {
> + {"STK3310", 0},
> + {"STK3311", 0},
> + {}
> +};
> +
> +static const struct acpi_device_id stk3310_acpi_id[] = {
> + {"STK3310", 0},
> + {"STK3311", 0},
> + {}
> +};
> +
> +MODULE_DEVICE_TABLE(acpi, stk3310_acpi_id);
> +
> +static struct i2c_driver stk3310_driver = {
> + .driver = {
> + .name = "stk3310",
> + .acpi_match_table = ACPI_PTR(stk3310_acpi_id),
> + },
> + .probe = stk3310_probe,
> + .remove = stk3310_remove,
> + .id_table = stk3310_i2c_id,
> +};
> +
> +module_i2c_driver(stk3310_driver);
> +
> +MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@xxxxxxxxx>");
> +MODULE_DESCRIPTION("STK3310 Ambient Light and Proximity Sensor driver");
> +MODULE_LICENSE("GPL v2");
>
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