Commit 1f0477f1 authored by Linus Walleij's avatar Linus Walleij Committed by Jonathan Cameron
Browse files

iio: light: new driver for the ROHM BH1780 



This is a reimplementation of the old misc device driver for the
ROHM BH1780 ambient light sensor (drivers/misc/bh1780gli.c).

Differences from the old driver:
- Uses the IIO framework
- Uses runtime PM to idle the hardware after 5 seconds
- No weird custom power management from userspace
- No homebrewn values in sysfs

This uses the same (undocumented) device tree compatible-string
as the old driver ("rohm,bh1780gli").

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Daniel Mack <daniel@caiaq.de>
Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent aa0eb886

drivers/iio/light/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -73,6 +73,17 @@ config BH1750 
	 To compile this driver as a module, choose M here: the module will

	 be called bh1750.



config BH1780

	tristate "ROHM BH1780 ambient light sensor"

	depends on I2C

	depends on !SENSORS_BH1780

	help

	 Say Y here to build support for the ROHM BH1780GLI ambient

	 light sensor.



	 To compile this driver as a module, choose M here: the module will

	 be called bh1780.



config CM32181

	depends on I2C

	tristate "CM32181 driver"

drivers/iio/light/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ obj-$(CONFIG_AL3320A) += al3320a.o 
obj-$(CONFIG_APDS9300)		+= apds9300.o

obj-$(CONFIG_APDS9960)		+= apds9960.o

obj-$(CONFIG_BH1750)		+= bh1750.o

obj-$(CONFIG_BH1780)		+= bh1780.o

obj-$(CONFIG_CM32181)		+= cm32181.o

obj-$(CONFIG_CM3232)		+= cm3232.o

obj-$(CONFIG_CM3323)		+= cm3323.o

drivers/iio/light/bh1780.c

0 → 100644
+297 −0
Original line number Diff line number Diff line 
/*

 * ROHM 1780GLI Ambient Light Sensor Driver

 *

 * Copyright (C) 2016 Linaro Ltd.

 * Author: Linus Walleij <linus.walleij@linaro.org>

 * Loosely based on the previous BH1780 ALS misc driver

 * Copyright (C) 2010 Texas Instruments

 * Author: Hemanth V <hemanthv@ti.com>

 */

#include <linux/i2c.h>

#include <linux/slab.h>

#include <linux/platform_device.h>

#include <linux/delay.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/pm_runtime.h>

#include <linux/iio/iio.h>

#include <linux/iio/sysfs.h>

#include <linux/bitops.h>



#define BH1780_CMD_BIT		BIT(7)

#define BH1780_REG_CONTROL	0x00

#define BH1780_REG_PARTID	0x0A

#define BH1780_REG_MANFID	0x0B

#define BH1780_REG_DLOW		0x0C

#define BH1780_REG_DHIGH	0x0D



#define BH1780_REVMASK		GENMASK(3,0)

#define BH1780_POWMASK		GENMASK(1,0)

#define BH1780_POFF		(0x0)

#define BH1780_PON		(0x3)



/* power on settling time in ms */

#define BH1780_PON_DELAY	2

/* max time before value available in ms */

#define BH1780_INTERVAL		250



struct bh1780_data {

	struct i2c_client *client;

};



static int bh1780_write(struct bh1780_data *bh1780, u8 reg, u8 val)

{

	int ret = i2c_smbus_write_byte_data(bh1780->client,

					    BH1780_CMD_BIT | reg,

					    val);

	if (ret < 0)

		dev_err(&bh1780->client->dev,

			"i2c_smbus_write_byte_data failed error "

			"%d, register %01x\n",

			ret, reg);

	return ret;

}



static int bh1780_read(struct bh1780_data *bh1780, u8 reg)

{

	int ret = i2c_smbus_read_byte_data(bh1780->client,

					   BH1780_CMD_BIT | reg);

	if (ret < 0)

		dev_err(&bh1780->client->dev,

			"i2c_smbus_read_byte_data failed error "

			"%d, register %01x\n",

			ret, reg);

	return ret;

}



static int bh1780_read_word(struct bh1780_data *bh1780, u8 reg)

{

	int ret = i2c_smbus_read_word_data(bh1780->client,

					   BH1780_CMD_BIT | reg);

	if (ret < 0)

		dev_err(&bh1780->client->dev,

			"i2c_smbus_read_word_data failed error "

			"%d, register %01x\n",

			ret, reg);

	return ret;

}



static int bh1780_debugfs_reg_access(struct iio_dev *indio_dev,

			      unsigned int reg, unsigned int writeval,

			      unsigned int *readval)

{

	struct bh1780_data *bh1780 = iio_priv(indio_dev);

	int ret;



	if (!readval)

		bh1780_write(bh1780, (u8)reg, (u8)writeval);



	ret = bh1780_read(bh1780, (u8)reg);

	if (ret < 0)

		return ret;



	*readval = ret;



	return 0;

}



static int bh1780_read_raw(struct iio_dev *indio_dev,

			   struct iio_chan_spec const *chan,

			   int *val, int *val2, long mask)

{

	struct bh1780_data *bh1780 = iio_priv(indio_dev);

	int value;



	switch (mask) {

	case IIO_CHAN_INFO_RAW:

		switch (chan->type) {

		case IIO_LIGHT:

			pm_runtime_get_sync(&bh1780->client->dev);

			value = bh1780_read_word(bh1780, BH1780_REG_DLOW);

			if (value < 0)

				return value;

			pm_runtime_mark_last_busy(&bh1780->client->dev);

			pm_runtime_put_autosuspend(&bh1780->client->dev);

			*val = value;



			return IIO_VAL_INT;

		default:

			return -EINVAL;

		}

	case IIO_CHAN_INFO_INT_TIME:

		*val = 0;

		*val2 = BH1780_INTERVAL * 1000;

		return IIO_VAL_INT_PLUS_MICRO;

	default:

		return -EINVAL;

	}

}



static const struct iio_info bh1780_info = {

	.driver_module = THIS_MODULE,

	.read_raw = bh1780_read_raw,

	.debugfs_reg_access = bh1780_debugfs_reg_access,

};



static const struct iio_chan_spec bh1780_channels[] = {

	{

		.type = IIO_LIGHT,

		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |

				      BIT(IIO_CHAN_INFO_INT_TIME)

	}

};



static int bh1780_probe(struct i2c_client *client,

			const struct i2c_device_id *id)

{

	int ret;

	struct bh1780_data *bh1780;

	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);

	struct iio_dev *indio_dev;



	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))

		return -EIO;



	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*bh1780));

	if (!indio_dev)

		return -ENOMEM;



	bh1780 = iio_priv(indio_dev);

	bh1780->client = client;

	i2c_set_clientdata(client, indio_dev);



	/* Power up the device */

	ret = bh1780_write(bh1780, BH1780_REG_CONTROL, BH1780_PON);

	if (ret < 0)

		return ret;

	msleep(BH1780_PON_DELAY);

	pm_runtime_get_noresume(&client->dev);

	pm_runtime_set_active(&client->dev);

	pm_runtime_enable(&client->dev);



	ret = bh1780_read(bh1780, BH1780_REG_PARTID);

	if (ret < 0)

		goto out_disable_pm;

	dev_info(&client->dev,

		 "Ambient Light Sensor, Rev : %lu\n",

		 (ret & BH1780_REVMASK));



	/*

	 * As the device takes 250 ms to even come up with a fresh

	 * measurement after power-on, do not shut it down unnecessarily.

	 * Set autosuspend to a five seconds.

	 */

	pm_runtime_set_autosuspend_delay(&client->dev, 5000);

	pm_runtime_use_autosuspend(&client->dev);

	pm_runtime_put(&client->dev);



	indio_dev->dev.parent = &client->dev;

	indio_dev->info = &bh1780_info;

	indio_dev->name = id->name;

	indio_dev->channels = bh1780_channels;

	indio_dev->num_channels = ARRAY_SIZE(bh1780_channels);

	indio_dev->modes = INDIO_DIRECT_MODE;



	ret = iio_device_register(indio_dev);

	if (ret)

		goto out_disable_pm;

	return 0;



out_disable_pm:

	pm_runtime_put_noidle(&client->dev);

	pm_runtime_disable(&client->dev);

	return ret;

}



static int bh1780_remove(struct i2c_client *client)

{

	struct iio_dev *indio_dev = i2c_get_clientdata(client);

	struct bh1780_data *bh1780 = iio_priv(indio_dev);

	int ret;



	iio_device_unregister(indio_dev);

	pm_runtime_get_sync(&client->dev);

	pm_runtime_put_noidle(&client->dev);

	pm_runtime_disable(&client->dev);

	ret = bh1780_write(bh1780, BH1780_REG_CONTROL, BH1780_POFF);

	if (ret < 0) {

		dev_err(&client->dev, "failed to power off\n");

		return ret;

	}



	return 0;

}



#ifdef CONFIG_PM

static int bh1780_runtime_suspend(struct device *dev)

{

	struct i2c_client *client = to_i2c_client(dev);

	struct bh1780_data *bh1780 = i2c_get_clientdata(client);

	int ret;



	ret = bh1780_write(bh1780, BH1780_REG_CONTROL, BH1780_POFF);

	if (ret < 0) {

		dev_err(dev, "failed to runtime suspend\n");

		return ret;

	}



	return 0;

}



static int bh1780_runtime_resume(struct device *dev)

{

	struct i2c_client *client = to_i2c_client(dev);

	struct bh1780_data *bh1780 = i2c_get_clientdata(client);

	int ret;



	ret = bh1780_write(bh1780, BH1780_REG_CONTROL, BH1780_PON);

	if (ret < 0) {

		dev_err(dev, "failed to runtime resume\n");

		return ret;

	}



	/* Wait for power on, then for a value to be available */

	msleep(BH1780_PON_DELAY + BH1780_INTERVAL);



	return 0;

}

#endif /* CONFIG_PM */



static const struct dev_pm_ops bh1780_dev_pm_ops = {

	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,

				pm_runtime_force_resume)

	SET_RUNTIME_PM_OPS(bh1780_runtime_suspend,

			   bh1780_runtime_resume, NULL)

};



static const struct i2c_device_id bh1780_id[] = {

	{ "bh1780", 0 },

	{ },

};



MODULE_DEVICE_TABLE(i2c, bh1780_id);



#ifdef CONFIG_OF

static const struct of_device_id of_bh1780_match[] = {

	{ .compatible = "rohm,bh1780gli", },

	{},

};

MODULE_DEVICE_TABLE(of, of_bh1780_match);

#endif



static struct i2c_driver bh1780_driver = {

	.probe		= bh1780_probe,

	.remove		= bh1780_remove,

	.id_table	= bh1780_id,

	.driver = {

		.name = "bh1780",

		.pm = &bh1780_dev_pm_ops,

		.of_match_table = of_match_ptr(of_bh1780_match),

	},

};



module_i2c_driver(bh1780_driver);



MODULE_DESCRIPTION("ROHM BH1780GLI Ambient Light Sensor Driver");

MODULE_LICENSE("GPL");

MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");

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