On Tue, 21 Apr 2015, Tomasz Duszynski wrote: > Add support for ROHM BH1710/BH1715/BH1721/BH1750/BH1751 ambient light > sensors.
nice, some comments inline > Signed-off-by: Tomasz Duszynski <tdusz...@gmail.com> > --- > drivers/iio/light/Kconfig | 10 ++ > drivers/iio/light/Makefile | 1 + > drivers/iio/light/bh1750.c | 322 > +++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 333 insertions(+) > create mode 100644 drivers/iio/light/bh1750.c > > diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig > index 5a3237b..9fb79ca 100644 > --- a/drivers/iio/light/Kconfig > +++ b/drivers/iio/light/Kconfig > @@ -37,6 +37,16 @@ config APDS9300 > To compile this driver as a module, choose M here: the > module will be called apds9300. > > +config BH1750 > + tristate "BH1750 ambient light sensor" > + depends on I2C > + help > + Say Y here to build support for the BH1710, BH1715, BH1721, > + BH1750, BH1751 ambient light sensors. > + > + To compile this driver as a module, choose M here: the module will > + be called bh1750. > + > config CM32181 > depends on I2C > tristate "CM32181 driver" > diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile > index 74656c1..1a13184 100644 > --- a/drivers/iio/light/Makefile > +++ b/drivers/iio/light/Makefile > @@ -6,6 +6,7 @@ > obj-$(CONFIG_ADJD_S311) += adjd_s311.o > obj-$(CONFIG_AL3320A) += al3320a.o > obj-$(CONFIG_APDS9300) += apds9300.o > +obj-$(CONFIG_BH1750) += bh1750.o > obj-$(CONFIG_CM32181) += cm32181.o > obj-$(CONFIG_CM36651) += cm36651.o > obj-$(CONFIG_GP2AP020A00F) += gp2ap020a00f.o > diff --git a/drivers/iio/light/bh1750.c b/drivers/iio/light/bh1750.c > new file mode 100644 > index 0000000..83b5413 > --- /dev/null > +++ b/drivers/iio/light/bh1750.c > @@ -0,0 +1,322 @@ > +/* > + * ROHM BH1710/BH1715/BH1721/BH1750/BH1751 ambient light sensor driver > + * > + * Copyright (c) Tomasz Duszynski <tdusz...@gmail.com> > + * > + * 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. > + * > + * Data sheets: > + * > http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1710fvc-e.pdf > + * > http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1715fvc-e.pdf > + * > http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1721fvc-e.pdf > + * > http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1750fvi-e.pdf > + * > http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1751fvi-e.pdf > + * > + * 7-bit I2C slave addresses: > + * 0x23 (ADDR pin low) > + * 0x5C (ADDR pin high) > + * > + */ > + > +#include <linux/delay.h> > +#include <linux/i2c.h> > +#include <linux/iio/iio.h> > +#include <linux/iio/sysfs.h> > +#include <linux/module.h> > + > +#define BH1750_POWER_DOWN 0x00 > +#define BH1750_H_RES_MODE 0x10 /* auto-mode for BH1721 */ > +#define BH1750_CHANGE_INT_TIME_H_BIT 0x40 > +#define BH1750_CHANGE_INT_TIME_L_BIT 0x60 > + > +enum { > + BH1710, > + BH1715, > + BH1721, > + BH1750, > + BH1751 > +}; > + > +struct bh1750_chip_info { > + int id; why is the id stored in chip_info? the point of the chip_info table is to avoid switch blocks in the driver; I suggest to move remaining chip-dependent values to the table and drop the id > + int mtreg_min; > + int mtreg_max; > + int mtreg_default; u16, these are values stored in an u16 register > + int mtreg_to_usec; > + int mtreg_to_scale; > +}; > + > +struct bh1750_data { > + struct i2c_client *client; > + struct mutex lock; > + const struct bh1750_chip_info *chip_info; > + u16 mtreg; > +}; > + > +static const struct bh1750_chip_info chip_info_tbl[] = { > + [BH1710] = { BH1710, 140, 1022, 300, 400, 4000 }, > + [BH1715] = { BH1715, 31, 254, 69, 1740, 17391 }, > + [BH1721] = { BH1721, 140, 1020, 300, 400, 4000 }, > + [BH1750] = { BH1750, 31, 254, 69, 1740, 17391 }, > + [BH1751] = { BH1751, 31, 254, 69, 1740, 17391 } > +}; > + > +static int bh1750_change_int_time(struct bh1750_data *data, int usec) > +{ > + int ret, val; > + u8 low = 0, high = 0; initialization not needed, low/high should always be set > + const struct bh1750_chip_info *chip_info = data->chip_info; > + > + if ((usec % chip_info->mtreg_to_usec) != 0) > + return -EINVAL; > + > + val = usec / chip_info->mtreg_to_usec; > + if (val < chip_info->mtreg_min || val > chip_info->mtreg_max) > + return -EINVAL; > + > + switch (chip_info->id) { > + case BH1710: > + low = val & 0x001F; > + high = (val & 0x03E0) >> 5; > + break; > + case BH1721: > + low = val & 0x0010; > + high = (val & 0x03E0) >> 5; break missing? > + case BH1715: > + case BH1750: > + case BH1751: > + low = val & 0x001F; > + high = (val & 0x00E0) >> 5; > + break; > + } > + > + ret = i2c_smbus_write_byte(data->client, BH1750_POWER_DOWN); > + if (ret < 0) > + return ret; > + > + ret = i2c_smbus_write_byte(data->client, > + BH1750_CHANGE_INT_TIME_H_BIT | high); > + if (ret < 0) > + return ret; > + > + ret = i2c_smbus_write_byte(data->client, > + BH1750_CHANGE_INT_TIME_L_BIT | low); > + if (ret < 0) > + return ret; > + > + data->mtreg = val; > + > + return i2c_smbus_write_byte(data->client, BH1750_H_RES_MODE); > +} > + > +static int bh1750_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long mask) > +{ > + u16 result; > + int ret, tmp; > + unsigned long delay; > + struct bh1750_data *data = iio_priv(indio_dev); > + const struct bh1750_chip_info *chip_info = data->chip_info; > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + switch (chan->type) { > + case IIO_INTENSITY: > + delay = chip_info->mtreg_to_usec * data->mtreg; > + mutex_lock(&data->lock); > + usleep_range(delay, delay + 20000); the driver uses continuous mode and there is no data-ready flag why not using one time mode?, I think this would better fit in what other drivers are doing > + ret = i2c_master_recv(data->client, > + (char *)&result, 2); almost all drivers use i2c_smbus_read_word_xxx() -- is there a reason not to? > + mutex_unlock(&data->lock); > + if (ret < 0) > + return ret; > + > + *val = swab16(result); > + return IIO_VAL_INT; > + default: > + return -EINVAL; > + } > + case IIO_CHAN_INFO_SCALE: > + tmp = chip_info->mtreg_to_scale * data->mtreg; use the variable delay as above; the same computation is done in every switch case > + *val = tmp / 1000000; > + *val2 = tmp % 1000000; > + return IIO_VAL_INT_PLUS_MICRO; > + case IIO_CHAN_INFO_INT_TIME: > + *val = 0; > + *val2 = chip_info->mtreg_to_usec * data->mtreg; > + return IIO_VAL_INT_PLUS_MICRO; > + default: > + return -EINVAL; > + } > +} > + > +static int bh1750_write_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int val, int val2, long mask) > +{ > + int ret; > + struct bh1750_data *data = iio_priv(indio_dev); > + > + switch (mask) { > + case IIO_CHAN_INFO_INT_TIME: > + if (val != 0) > + return -EINVAL; > + > + mutex_lock(&data->lock); > + ret = bh1750_change_int_time(data, val2); > + mutex_unlock(&data->lock); > + return ret; > + default: > + return -EINVAL; > + } > +} > + > +static ssize_t bh1750_show_int_time_available(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + int i, inc; > + size_t len = 0; > + struct bh1750_data *data = iio_priv(dev_to_iio_dev(dev)); > + const struct bh1750_chip_info *chip_info = data->chip_info; > + > + switch (chip_info->id) { > + case BH1710: > + case BH1721: > + /* All values won't fit into one page, so display every > + * second one. By doing so step size is increased > + * from 0.4ms to 0.8ms.*/ multi-line comment style?; missing space before */ > + inc = 2; > + break; > + default: > + inc = 1; > + break; > + } > + > + for (i = chip_info->mtreg_min; i <= chip_info->mtreg_max; i += inc) > + len += scnprintf(buf + len, PAGE_SIZE - len, "0.%06d ", > + i * chip_info->mtreg_to_usec); > + > + buf[len - 1] = '\n'; > + > + return len; > +} > + > +static IIO_DEV_ATTR_INT_TIME_AVAIL(bh1750_show_int_time_available); > + > +static struct attribute *bh1750_attributes[] = { > + &iio_dev_attr_integration_time_available.dev_attr.attr, > + NULL, > +}; > + > +static struct attribute_group bh1750_attribute_group = { > + .attrs = bh1750_attributes, > +}; > + > +static const struct iio_info bh1750_info = { > + .driver_module = THIS_MODULE, > + .attrs = &bh1750_attribute_group, > + .read_raw = bh1750_read_raw, > + .write_raw = bh1750_write_raw, > +}; > + > +static const struct iio_chan_spec bh1750_channels[] = { > + { > + .type = IIO_INTENSITY, > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | > + BIT(IIO_CHAN_INFO_SCALE) | > + BIT(IIO_CHAN_INFO_INT_TIME) > + } > +}; > + > +static int bh1750_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + int ret, usec; > + struct bh1750_data *data; > + struct iio_dev *indio_dev; > + > + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C | > + I2C_FUNC_SMBUS_WRITE_BYTE)) > + return -ENODEV; > + > + 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; > + data->chip_info = &chip_info_tbl[id->driver_data]; > + > + usec = data->chip_info->mtreg_to_usec * data->chip_info->mtreg_default; > + ret = bh1750_change_int_time(data, usec); > + if (ret < 0) > + return ret; > + > + mutex_init(&data->lock); > + indio_dev->dev.parent = &client->dev; > + indio_dev->info = &bh1750_info; > + indio_dev->name = id->name; > + indio_dev->channels = bh1750_channels; > + indio_dev->num_channels = ARRAY_SIZE(bh1750_channels); > + indio_dev->modes = INDIO_DIRECT_MODE; > + > + return devm_iio_device_register(&client->dev, indio_dev); chip should probably be powered down if this fails; or use one-time mode > +} > + > +#ifdef CONFIG_PM_SLEEP > +static int bh1750_suspend(struct device *dev) > +{ > + int ret; > + struct bh1750_data *data = > + iio_priv(i2c_get_clientdata(to_i2c_client(dev))); > + > + mutex_lock(&data->lock); > + ret = i2c_smbus_write_byte(data->client, BH1750_POWER_DOWN); > + mutex_unlock(&data->lock); > + > + return ret; > +} > + > +static int bh1750_resume(struct device *dev) > +{ > + struct bh1750_data *data = > + iio_priv(i2c_get_clientdata(to_i2c_client(dev))); > + > + return i2c_smbus_write_byte(data->client, BH1750_H_RES_MODE); > +} > + > +static SIMPLE_DEV_PM_OPS(bh1750_pm_ops, bh1750_suspend, bh1750_resume); > +#define BH1750_PM_OPS (&bh1750_pm_ops) > +#else > +#define BH1750_PM_OPS NULL > +#endif > + > +static const struct i2c_device_id bh1750_id[] = { > + { "bh1710", BH1710 }, > + { "bh1715", BH1715 }, > + { "bh1721", BH1721 }, > + { "bh1750", BH1750 }, > + { "bh1751", BH1751 }, > + { } > +}; > +MODULE_DEVICE_TABLE(i2c, bh1750_id); > + > +static struct i2c_driver bh1750_driver = { > + .driver = { > + .name = "bh1750", > + .owner = THIS_MODULE, > + .pm = BH1750_PM_OPS, > + }, .remove to power down > + .probe = bh1750_probe, > + .id_table = bh1750_id, > + > +}; > +module_i2c_driver(bh1750_driver); > + > +MODULE_AUTHOR("Tomasz Duszynski <tdusz...@gmail.com>"); > +MODULE_DESCRIPTION("ROHM BH1710/BH1715/BH1721/BH1750/BH1751 als driver"); > +MODULE_LICENSE("GPL v2"); > -- Peter Meerwald +43-664-2444418 (mobile) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
