[PATCH 1/1] Added Capella CM3218 Ambient Light Sensor IIO Driver.

[PATCH 1/1] Added Capella CM3218 Ambient Light Sensor IIO Driver.

[Kevin Tsai]

Signed-off-by: Kevin Tsai <ktsai-GubuWUlQtMwciDkP5Hr2oA@public.gmane.org>
---
 drivers/staging/iio/light/Kconfig  |   10 +
 drivers/staging/iio/light/Makefile |    1 +
 drivers/staging/iio/light/cm3218.c |  581 ++++++++++++++++++++++++++++++++++++
 3 files changed, 592 insertions(+)
 create mode 100644 drivers/staging/iio/light/cm3218.c

diff --git a/drivers/staging/iio/light/Kconfig b/drivers/staging/iio/light/Kconfig
index ca8d6e6..647af0c 100644
--- a/drivers/staging/iio/light/Kconfig
+++ b/drivers/staging/iio/light/Kconfig
@@ -40,4 +40,14 @@ config TSL2x7x
 	 tmd2672, tsl2772, tmd2772 devices.
 	 Provides iio_events and direct access via sysfs.
 
+config SENSORS_CM3218
+        tristate "CM3218 Ambient Light Sensor"
+        depends on I2C
+        help
+         Say Y here if you have a Capella Micro CM3218 Ambient Light Sensor.
+
+         To compile this driver as a module, choose M here.  This module
+         will be called to 'cm3218'.  It will access ALS data via iio sysfs.
+         This is recommended.
+
 endmenu
diff --git a/drivers/staging/iio/light/Makefile b/drivers/staging/iio/light/Makefile
index 9960fdf..63020ab 100644
--- a/drivers/staging/iio/light/Makefile
+++ b/drivers/staging/iio/light/Makefile
@@ -6,3 +6,4 @@ obj-$(CONFIG_SENSORS_ISL29018)	+= isl29018.o
 obj-$(CONFIG_SENSORS_ISL29028)	+= isl29028.o
 obj-$(CONFIG_TSL2583)	+= tsl2583.o
 obj-$(CONFIG_TSL2x7x)	+= tsl2x7x_core.o
+obj-$(CONFIG_SENSORS_CM3218)    += cm3218.o
diff --git a/drivers/staging/iio/light/cm3218.c b/drivers/staging/iio/light/cm3218.c
new file mode 100644
index 0000000..9c2584d
--- /dev/null
+++ b/drivers/staging/iio/light/cm3218.c
@@ -0,0 +1,581 @@
+/*
+ * A iio driver for CM3218 Ambient Light Sensor.
+ *
+ * IIO driver for monitoring ambient light intensity in lux.
+ *
+ * Copyright (c) 2013, Capella Microsystems Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA	02110-1301, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+/*
+ * SMBus ARA address
+ */
+#define	CM3218_ADDR_ARA			0x0C
+
+/*
+ * CM3218 CMD Registers
+ */
+#define	CM3218_REG_ADDR_CMD		0x00
+#define	CM3218_CMD_ALS_SD		0x0001
+#define	CM3218_CMD_ALS_INT_EN		0x0002
+#define	CM3218_CMD_ALS_IT_SHIFT		6
+#define	CM3218_CMD_ALS_IT_MASK		(3 << CM3218_CMD_ALS_IT_SHIFT)
+#define	CM3218_CMD_ALS_IT_05T		(0 << CM3218_CMD_ALS_IT_SHIFT)
+#define	CM3218_CMD_ALS_IT_1T		(1 << CM3218_CMD_ALS_IT_SHIFT)
+#define	CM3218_CMD_ALS_IT_2T		(2 << CM3218_CMD_ALS_IT_SHIFT)
+#define	CM3218_CMD_ALS_IT_4T		(3 << CM3218_CMD_ALS_IT_SHIFT)
+#define	CM3218_DEFAULT_CMD		(CM3218_CMD_ALS_IT_1T)
+
+#define	CM3218_REG_ADDR_ALS_WH		0x01
+#define	CM3218_DEFAULT_ALS_WH		0xFFFF
+
+#define	CM3218_REG_ADDR_ALS_WL		0x02
+#define	CM3218_DEFAULT_ALS_WL		0x0000
+
+#define	CM3218_REG_ADDR_ALS		0x04
+
+#define	CM3218_REG_ADDR_STATUS		0x06
+
+#define	CM3218_REG_ADDR_ID		0x07
+
+/*
+ * Software Parameters
+ */
+#define	CM3218_MAX_CACHE_REGS		(0x03+1)	/* Reg.0x00 to 0x03 */
+
+/*
+ * Features
+ */
+#define	CM3218_DEBUG
+
+static const unsigned short normal_i2c[] = {
+	0x10, 0x48, I2C_CLIENT_END };
+
+struct cm3218_chip {
+	struct i2c_client	*client;
+	struct mutex		lock;
+	unsigned int		lensfactor;
+	bool			suspended;
+	u16			reg_cache[CM3218_MAX_CACHE_REGS];
+};
+
+static int cm3218_read_ara(struct i2c_client *client)
+{
+	int status;
+	unsigned short addr;
+
+	addr = client->addr;
+	client->addr = CM3218_ADDR_ARA;
+	status = i2c_smbus_read_byte(client);
+	client->addr = addr;
+
+	if (status < 0)
+		return -ENODEV;
+
+	return 0;
+}
+
+static int cm3218_write(struct i2c_client *client, u8 reg, u16 value)
+{
+	u16 regval;
+	int ret;
+	struct cm3218_chip *chip = iio_priv(i2c_get_clientdata(client));
+
+#ifdef	CM3218_DEBUG
+	dev_err(&client->dev,
+		"Write to device register 0x%02X with 0x%04X\n", reg, value);
+#endif	/* CM3218_DEBUG */
+	regval = cpu_to_le16(value);
+	ret = i2c_smbus_write_word_data(client, reg, regval);
+	if (ret) {
+		dev_err(&client->dev, "Write to device fails: 0x%x\n", ret);
+	} else {
+		/* Update cache */
+		if (reg < CM3218_MAX_CACHE_REGS)
+			chip->reg_cache[reg] = value;
+	}
+
+	return ret;
+}
+
+static int cm3218_read(struct i2c_client *client, u8 reg)
+{
+	int regval;
+	int status;
+	struct cm3218_chip *chip = iio_priv(i2c_get_clientdata(client));
+
+	if (reg < CM3218_MAX_CACHE_REGS) {
+		regval = chip->reg_cache[reg];
+	} else {
+		status = i2c_smbus_read_word_data(client, reg);
+		if (status < 0) {
+			dev_err(&client->dev,
+				"Error in reading Reg.0x%02X\n", reg);
+			return status;
+		}
+		regval = le16_to_cpu(status);
+#ifdef	CM3218_DEBUG
+		dev_err(&client->dev,
+			"Read from device register 0x%02X = 0x%04X\n",
+			reg, regval);
+#endif	/* CM3218_DEBUG */
+	}
+
+	return regval;
+}
+
+static int cm3218_read_sensor_input(struct i2c_client *client)
+{
+	int status;
+	int lux;
+
+	status = cm3218_read(client, CM3218_REG_ADDR_ALS);
+	if (status < 0) {
+		dev_err(&client->dev, "Error in reading Lux DATA\n");
+		return status;
+	}
+	lux = status;
+
+	dev_vdbg(&client->dev, "lux = %u\n", lux);
+
+	return lux;
+}
+
+static int cm3218_read_lux(struct i2c_client *client, int *lux)
+{
+	struct cm3218_chip *chip = iio_priv(i2c_get_clientdata(client));
+	int lux_data;
+
+	lux_data = cm3218_read_sensor_input(client);
+
+	if (lux_data < 0)
+		return lux_data;
+
+	*lux  = lux_data * chip->lensfactor;
+	*lux /= 1000;
+	return 0;
+}
+
+/* Sysfs interface */
+/* lensfactor */
+static ssize_t show_lensfactor(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+
+	return sprintf(buf, "%d\n", chip->lensfactor);
+}
+
+static ssize_t store_lensfactor(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	unsigned long lval;
+
+/*
+	lval = kstrtoul(buf, NULL, 10);
+	if (lval == 0)
+		return -EINVAL;
+*/
+	if (kstrtoul(buf, 10, &lval))
+		return -EINVAL;
+
+	mutex_lock(&chip->lock);
+	chip->lensfactor = lval;
+	mutex_unlock(&chip->lock);
+
+	return count;
+}
+
+static ssize_t get_sensor_data(struct device *dev, char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	struct i2c_client *client = chip->client;
+	int value = 0;
+	int status;
+
+	mutex_lock(&chip->lock);
+	if (chip->suspended) {
+		mutex_unlock(&chip->lock);
+		return -EBUSY;
+	}
+
+	 status = cm3218_read_lux(client, &value);
+
+	if (status < 0) {
+		dev_err(&client->dev, "Error in Reading data");
+		mutex_unlock(&chip->lock);
+		return status;
+	}
+
+	mutex_unlock(&chip->lock);
+
+	return sprintf(buf, "%d\n", value);
+}
+
+
+/* Read lux */
+static ssize_t show_lux(struct device *dev,
+	struct device_attribute *devattr, char *buf)
+{
+	return get_sensor_data(dev, buf);
+}
+
+#ifdef	CM3218_DEBUG
+/* windows_high */
+static ssize_t show_cmd(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	struct i2c_client *client = chip->client;
+	int status;
+
+	status = cm3218_read(client, CM3218_REG_ADDR_CMD);
+	if (status < 0) {
+		dev_err(dev, "Error in getting CM3218_REG_ADDR_CMD\n");
+		return status;
+	}
+
+	return sprintf(buf, "%u\n", status);
+}
+
+static ssize_t store_cmd(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	struct i2c_client *client = chip->client;
+	int status;
+	unsigned long lval;
+
+	if (kstrtoul(buf, 10, &lval))
+		return -EINVAL;
+
+	mutex_lock(&chip->lock);
+	if (lval > 0x10000)
+		lval = 0xFFFF;
+	status = cm3218_write(client, CM3218_REG_ADDR_CMD, (u16)lval);
+	if (status < 0) {
+		mutex_unlock(&chip->lock);
+		dev_err(dev, "Error in setting CM3218_REG_ADDR_CMD\n");
+		return status;
+	}
+	mutex_unlock(&chip->lock);
+
+	return count;
+}
+
+/* status */
+static ssize_t show_status(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	struct i2c_client *client = chip->client;
+	int status;
+
+	status = cm3218_read(client, CM3218_REG_ADDR_STATUS);
+	if (status < 0) {
+		dev_err(dev, "Error in getting CM3218_REG_ADDR_STATUS\n");
+		return status;
+	}
+
+	return sprintf(buf, "%u\n", status);
+}
+
+#endif	/* CM3218_DEBUG */
+
+/* Channel IO */
+static int cm3218_write_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      int val,
+			      int val2,
+			      long mask)
+{
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	int ret = -EINVAL;
+
+	mutex_lock(&chip->lock);
+	if (mask == IIO_CHAN_INFO_CALIBSCALE && chan->type == IIO_LIGHT) {
+		chip->lensfactor = val;
+		ret = 0;
+	}
+	mutex_unlock(&chip->lock);
+
+	return 0;
+}
+
+static int cm3218_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int *val,
+			     int *val2,
+			     long mask)
+{
+	int ret = -EINVAL;
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	struct i2c_client *client = chip->client;
+
+	mutex_lock(&chip->lock);
+	if (chip->suspended) {
+		mutex_unlock(&chip->lock);
+		return -EBUSY;
+	}
+	switch (mask) {
+	case 0:
+		ret = cm3218_read_lux(client, val);
+		if (!ret)
+			ret = IIO_VAL_INT;
+		break;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		*val = chip->lensfactor;
+		ret = IIO_VAL_INT_PLUS_MICRO;
+		break;
+	default:
+		break;
+	}
+	mutex_unlock(&chip->lock);
+	return ret;
+}
+
+#define IIO_CHAN_INFO_SEPARATE_BIT(type) BIT(type*2 + 1)
+#define IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT                   \
+	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_CALIBSCALE)
+
+static const struct iio_chan_spec cm3218_channels[] = {
+	{
+		.type = IIO_LIGHT,
+		.indexed = 1,
+		.channel = 0,
+		.info_mask = IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT,
+	}
+};
+
+static IIO_DEVICE_ATTR(illuminance0_input, S_IRUGO, show_lux, NULL, 0);
+static IIO_DEVICE_ATTR(illuminance0_calibscale, S_IRUGO | S_IWUSR,
+					show_lensfactor, store_lensfactor, 0);
+#ifdef	CM3218_DEBUG
+static IIO_DEVICE_ATTR(cmd, S_IRUGO | S_IWUSR, show_cmd, store_cmd, 0);
+static IIO_DEVICE_ATTR(status, S_IRUGO, show_status, NULL, 0);
+#endif	/* CM3218_DEBUG */
+
+#define CM3218_DEV_ATTR(name) (&iio_dev_attr_##name.dev_attr.attr)
+#define CM3218_CONST_ATTR(name) (&iio_const_attr_##name.dev_attr.attr)
+static struct attribute *cm3218_attributes[] = {
+	CM3218_DEV_ATTR(illuminance0_input),
+	CM3218_DEV_ATTR(illuminance0_calibscale),
+#ifdef	CM3218_DEBUG
+	CM3218_DEV_ATTR(cmd),
+	CM3218_DEV_ATTR(status),
+#endif	/* CM3218_DEBUG */
+	NULL
+};
+
+static const struct attribute_group cm3218_group = {
+	.attrs = cm3218_attributes,
+};
+
+static int cm3218_chip_init(struct i2c_client *client)
+{
+	struct cm3218_chip *chip = iio_priv(i2c_get_clientdata(client));
+	int status, i;
+
+	memset(chip->reg_cache, 0, sizeof(chip->reg_cache));
+
+	for (i = 0; i < 5; i++) {
+		status = cm3218_write(client, CM3218_REG_ADDR_CMD,
+				CM3218_CMD_ALS_SD);
+		if (status >= 0)
+			break;
+		cm3218_read_ara(client);
+	}
+
+	status = cm3218_write(client, CM3218_REG_ADDR_CMD, CM3218_DEFAULT_CMD);
+	if (status < 0) {
+		dev_err(&client->dev, "Init CM3218 CMD fails\n");
+		return status;
+	}
+
+
+	/* Clean interrupt status */
+	cm3218_read(client, CM3218_REG_ADDR_STATUS);
+
+	return 0;
+}
+
+static const struct iio_info cm3218_info = {
+	.attrs = &cm3218_group,
+	.driver_module = THIS_MODULE,
+	.read_raw = &cm3218_read_raw,
+	.write_raw = &cm3218_write_raw,
+};
+
+static int cm3218_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct cm3218_chip *chip;
+	struct iio_dev *indio_dev;
+	int err;
+
+	indio_dev = iio_device_alloc(sizeof(*chip));
+	if (indio_dev == NULL) {
+		dev_err(&client->dev, "iio allocation fails\n");
+		err = -ENOMEM;
+		goto exit;
+	}
+	chip = iio_priv(indio_dev);
+	chip->client = client;
+	i2c_set_clientdata(client, indio_dev);
+
+	mutex_init(&chip->lock);
+
+	chip->lensfactor = 1000;
+	chip->suspended = false;
+
+	err = cm3218_chip_init(client);
+	if (err)
+		goto exit_iio_free;
+
+	indio_dev->info = &cm3218_info;
+	indio_dev->channels = cm3218_channels;
+	indio_dev->num_channels = ARRAY_SIZE(cm3218_channels);
+	indio_dev->name = id->name;
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	err = iio_device_register(indio_dev);
+	if (err) {
+		dev_err(&client->dev, "iio registration fails\n");
+		goto exit_iio_free;
+	}
+
+	return 0;
+exit_iio_free:
+	iio_device_free(indio_dev);
+exit:
+	return err;
+}
+
+static int cm3218_detect(struct i2c_client *client,
+				   struct i2c_board_info *info)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	const char *name = NULL;
+
+	cm3218_read_ara(client);
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -ENODEV;
+
+	name = "cm3218";
+	strlcpy(info->type, name, I2C_NAME_SIZE);
+
+	return 0;
+}
+
+static int cm3218_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+	dev_dbg(&client->dev, "%s()\n", __func__);
+	iio_device_unregister(indio_dev);
+	iio_device_free(indio_dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int cm3218_suspend(struct device *dev)
+{
+	struct cm3218_chip *chip = iio_priv(dev_get_drvdata(dev));
+
+	mutex_lock(&chip->lock);
+
+	/* Since this driver uses only polling commands, we are by default in
+	 * auto shutdown (ie, power-down) mode.
+	 * So we do not have much to do here.
+	 */
+	chip->suspended = true;
+
+	mutex_unlock(&chip->lock);
+	return 0;
+}
+
+static int cm3218_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	struct i2c_client *client = chip->client;
+	int err;
+
+	mutex_lock(&chip->lock);
+
+	err = cm3218_chip_init(client);
+	if (!err)
+		chip->suspended = false;
+
+	mutex_unlock(&chip->lock);
+	return err;
+}
+
+static SIMPLE_DEV_PM_OPS(cm3218_pm_ops, cm3218_suspend, cm3218_resume);
+#define CM3218_PM_OPS (&cm3218_pm_ops)
+#else
+#define CM3218_PM_OPS NULL
+#endif
+
+static const struct i2c_device_id cm3218_id[] = {
+	{"cm3218", 0},
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, cm3218_id);
+
+static const struct of_device_id cm3218_of_match[] = {
+	{ .compatible = "invn,cm3218", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, cm3218_of_match);
+
+static struct i2c_driver cm3218_driver = {
+	.class	= I2C_CLASS_HWMON,
+	.driver	 = {
+			.name = "cm3218",
+			.pm = CM3218_PM_OPS,
+			.owner = THIS_MODULE,
+			.of_match_table = cm3218_of_match,
+		    },
+	.probe		= cm3218_probe,
+	.remove		= cm3218_remove,
+	.id_table       = cm3218_id,
+	.detect	 = cm3218_detect,
+	.address_list   = normal_i2c,
+};
+module_i2c_driver(cm3218_driver);
+
+MODULE_DESCRIPTION("CM3218 Ambient Light Sensor driver");
+MODULE_LICENSE("GPL");
-- 
1.7.9.5

Re: [PATCH 1/1] Added Capella CM3218 Ambient Light Sensor IIO Driver.

[Peter Meerwald]

Hello,

some comments inline;
new drivers should not go to staging but to mainline directly 

regards, p.

> Signed-off-by: Kevin Tsai <ktsai-GubuWUlQtMwciDkP5Hr2oA@public.gmane.org>
> ---
>  drivers/staging/iio/light/Kconfig  |   10 +
>  drivers/staging/iio/light/Makefile |    1 +
>  drivers/staging/iio/light/cm3218.c |  581 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 592 insertions(+)
>  create mode 100644 drivers/staging/iio/light/cm3218.c
> 
> diff --git a/drivers/staging/iio/light/Kconfig b/drivers/staging/iio/light/Kconfig
> index ca8d6e6..647af0c 100644
> --- a/drivers/staging/iio/light/Kconfig
> +++ b/drivers/staging/iio/light/Kconfig
> @@ -40,4 +40,14 @@ config TSL2x7x
>  	 tmd2672, tsl2772, tmd2772 devices.
>  	 Provides iio_events and direct access via sysfs.
>  
> +config SENSORS_CM3218
> +        tristate "CM3218 Ambient Light Sensor"
> +        depends on I2C
> +        help
> +         Say Y here if you have a Capella Micro CM3218 Ambient Light Sensor.
> +
> +         To compile this driver as a module, choose M here.  This module
> +         will be called to 'cm3218'.  It will access ALS data via iio sysfs.
> +         This is recommended.
> +
>  endmenu
> diff --git a/drivers/staging/iio/light/Makefile b/drivers/staging/iio/light/Makefile
> index 9960fdf..63020ab 100644
> --- a/drivers/staging/iio/light/Makefile
> +++ b/drivers/staging/iio/light/Makefile
> @@ -6,3 +6,4 @@ obj-$(CONFIG_SENSORS_ISL29018)	+= isl29018.o
>  obj-$(CONFIG_SENSORS_ISL29028)	+= isl29028.o
>  obj-$(CONFIG_TSL2583)	+= tsl2583.o
>  obj-$(CONFIG_TSL2x7x)	+= tsl2x7x_core.o
> +obj-$(CONFIG_SENSORS_CM3218)    += cm3218.o
> diff --git a/drivers/staging/iio/light/cm3218.c b/drivers/staging/iio/light/cm3218.c
> new file mode 100644
> index 0000000..9c2584d
> --- /dev/null
> +++ b/drivers/staging/iio/light/cm3218.c
> @@ -0,0 +1,581 @@
> +/*
> + * A iio driver for CM3218 Ambient Light Sensor.
> + *
> + * IIO driver for monitoring ambient light intensity in lux.
> + *
> + * Copyright (c) 2013, Capella Microsystems Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, write to the Free Software Foundation, Inc.,
> + * 51 Franklin Street, Fifth Floor, Boston, MA	02110-1301, USA.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/i2c.h>
> +#include <linux/err.h>
> +#include <linux/mutex.h>
> +#include <linux/delay.h>
> +#include <linux/slab.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +/*
> + * SMBus ARA address
maybe Address for consistency? 

> + */
> +#define	CM3218_ADDR_ARA			0x0C
> +
> +/*
> + * CM3218 CMD Registers
> + */
> +#define	CM3218_REG_ADDR_CMD		0x00
> +#define	CM3218_CMD_ALS_SD		0x0001
> +#define	CM3218_CMD_ALS_INT_EN		0x0002
> +#define	CM3218_CMD_ALS_IT_SHIFT		6
> +#define	CM3218_CMD_ALS_IT_MASK		(3 << CM3218_CMD_ALS_IT_SHIFT)
> +#define	CM3218_CMD_ALS_IT_05T		(0 << CM3218_CMD_ALS_IT_SHIFT)
> +#define	CM3218_CMD_ALS_IT_1T		(1 << CM3218_CMD_ALS_IT_SHIFT)
> +#define	CM3218_CMD_ALS_IT_2T		(2 << CM3218_CMD_ALS_IT_SHIFT)
> +#define	CM3218_CMD_ALS_IT_4T		(3 << CM3218_CMD_ALS_IT_SHIFT)

> +#define	CM3218_DEFAULT_CMD		(CM3218_CMD_ALS_IT_1T)
no parenthesis needed 

> +
> +#define	CM3218_REG_ADDR_ALS_WH		0x01
> +#define	CM3218_DEFAULT_ALS_WH		0xFFFF
> +
> +#define	CM3218_REG_ADDR_ALS_WL		0x02
> +#define	CM3218_DEFAULT_ALS_WL		0x0000
> +
> +#define	CM3218_REG_ADDR_ALS		0x04
> +
> +#define	CM3218_REG_ADDR_STATUS		0x06
> +
> +#define	CM3218_REG_ADDR_ID		0x07
> +
> +/*
> + * Software Parameters
> + */
> +#define	CM3218_MAX_CACHE_REGS		(0x03+1)	/* Reg.0x00 to 0x03 */
> +
> +/*
> + * Features
> + */
> +#define	CM3218_DEBUG
> +
> +static const unsigned short normal_i2c[] = {
> +	0x10, 0x48, I2C_CLIENT_END };
> +
> +struct cm3218_chip {
> +	struct i2c_client	*client;
> +	struct mutex		lock;
> +	unsigned int		lensfactor;
> +	bool			suspended;
> +	u16			reg_cache[CM3218_MAX_CACHE_REGS];
> +};
> +
> +static int cm3218_read_ara(struct i2c_client *client)
> +{
> +	int status;
> +	unsigned short addr;
> +
> +	addr = client->addr;
> +	client->addr = CM3218_ADDR_ARA;
> +	status = i2c_smbus_read_byte(client);
> +	client->addr = addr;
> +
> +	if (status < 0)
> +		return -ENODEV;
> +
> +	return 0;
> +}
> +
> +static int cm3218_write(struct i2c_client *client, u8 reg, u16 value)
> +{
> +	u16 regval;
> +	int ret;
> +	struct cm3218_chip *chip = iio_priv(i2c_get_clientdata(client));
> +
> +#ifdef	CM3218_DEBUG
> +	dev_err(&client->dev,
> +		"Write to device register 0x%02X with 0x%04X\n", reg, value);
> +#endif	/* CM3218_DEBUG */

dev_dbg? and no _DEBUG

> +	regval = cpu_to_le16(value);
> +	ret = i2c_smbus_write_word_data(client, reg, regval);
> +	if (ret) {
> +		dev_err(&client->dev, "Write to device fails: 0x%x\n", ret);
> +	} else {
> +		/* Update cache */
> +		if (reg < CM3218_MAX_CACHE_REGS)
> +			chip->reg_cache[reg] = value;
> +	}
> +
> +	return ret;
> +}

there is regmap for caching register contents; maybe overkill..

> +
> +static int cm3218_read(struct i2c_client *client, u8 reg)
> +{
> +	int regval;
> +	int status;
> +	struct cm3218_chip *chip = iio_priv(i2c_get_clientdata(client));
> +
> +	if (reg < CM3218_MAX_CACHE_REGS) {
> +		regval = chip->reg_cache[reg];
> +	} else {
> +		status = i2c_smbus_read_word_data(client, reg);
> +		if (status < 0) {
> +			dev_err(&client->dev,
> +				"Error in reading Reg.0x%02X\n", reg);
> +			return status;
> +		}
> +		regval = le16_to_cpu(status);
> +#ifdef	CM3218_DEBUG
> +		dev_err(&client->dev,
> +			"Read from device register 0x%02X = 0x%04X\n",
> +			reg, regval);
> +#endif	/* CM3218_DEBUG */
> +	}
> +
> +	return regval;
> +}
> +
> +static int cm3218_read_sensor_input(struct i2c_client *client)
> +{
> +	int status;
> +	int lux;
> +
> +	status = cm3218_read(client, CM3218_REG_ADDR_ALS);
> +	if (status < 0) {
> +		dev_err(&client->dev, "Error in reading Lux DATA\n");
> +		return status;
> +	}
> +	lux = status;
> +
> +	dev_vdbg(&client->dev, "lux = %u\n", lux);
> +
> +	return lux;
> +}
> +
> +static int cm3218_read_lux(struct i2c_client *client, int *lux)
> +{
> +	struct cm3218_chip *chip = iio_priv(i2c_get_clientdata(client));
> +	int lux_data;
> +
> +	lux_data = cm3218_read_sensor_input(client);
> +
> +	if (lux_data < 0)
> +		return lux_data;
> +
> +	*lux  = lux_data * chip->lensfactor;
> +	*lux /= 1000;
> +	return 0;
> +}

these read wrappers could probably be avoided; most of the code is 
cascaded error handling

> +
> +/* Sysfs interface */
> +/* lensfactor */

comment style

> +static ssize_t show_lensfactor(struct device *dev,
> +			struct device_attribute *attr, char *buf)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct cm3218_chip *chip = iio_priv(indio_dev);
> +
> +	return sprintf(buf, "%d\n", chip->lensfactor);
> +}

the sysfs interface seems to be redundant; there is also CALIBSCALE

> +
> +static ssize_t store_lensfactor(struct device *dev,
> +		struct device_attribute *attr, const char *buf, size_t count)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct cm3218_chip *chip = iio_priv(indio_dev);
> +	unsigned long lval;
> +
> +/*
> +	lval = kstrtoul(buf, NULL, 10);
> +	if (lval == 0)
> +		return -EINVAL;
> +*/

remove comment before submission

> +	if (kstrtoul(buf, 10, &lval))
> +		return -EINVAL;
> +
> +	mutex_lock(&chip->lock);
> +	chip->lensfactor = lval;
> +	mutex_unlock(&chip->lock);
> +
> +	return count;
> +}
> +
> +static ssize_t get_sensor_data(struct device *dev, char *buf)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct cm3218_chip *chip = iio_priv(indio_dev);
> +	struct i2c_client *client = chip->client;
> +	int value = 0;
> +	int status;
> +
> +	mutex_lock(&chip->lock);
> +	if (chip->suspended) {
> +		mutex_unlock(&chip->lock);
> +		return -EBUSY;
> +	}
> +
> +	 status = cm3218_read_lux(client, &value);

extra space here

> +
> +	if (status < 0) {
> +		dev_err(&client->dev, "Error in Reading data");
> +		mutex_unlock(&chip->lock);
> +		return status;
> +	}
> +
> +	mutex_unlock(&chip->lock);
> +
> +	return sprintf(buf, "%d\n", value);
> +}
> +
> +
> +/* Read lux */
> +static ssize_t show_lux(struct device *dev,
> +	struct device_attribute *devattr, char *buf)
> +{
> +	return get_sensor_data(dev, buf);
> +}
> +
> +#ifdef	CM3218_DEBUG
> +/* windows_high */

there would be debugfs_reg_access in iio_info

> +static ssize_t show_cmd(struct device *dev,
> +	struct device_attribute *attr, char *buf)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct cm3218_chip *chip = iio_priv(indio_dev);
> +	struct i2c_client *client = chip->client;
> +	int status;
> +
> +	status = cm3218_read(client, CM3218_REG_ADDR_CMD);
> +	if (status < 0) {
> +		dev_err(dev, "Error in getting CM3218_REG_ADDR_CMD\n");
> +		return status;
> +	}
> +
> +	return sprintf(buf, "%u\n", status);
> +}
> +
> +static ssize_t store_cmd(struct device *dev,
> +		struct device_attribute *attr, const char *buf, size_t count)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct cm3218_chip *chip = iio_priv(indio_dev);
> +	struct i2c_client *client = chip->client;
> +	int status;
> +	unsigned long lval;
> +
> +	if (kstrtoul(buf, 10, &lval))
> +		return -EINVAL;
> +
> +	mutex_lock(&chip->lock);
> +	if (lval > 0x10000)
> +		lval = 0xFFFF;
> +	status = cm3218_write(client, CM3218_REG_ADDR_CMD, (u16)lval);
> +	if (status < 0) {
> +		mutex_unlock(&chip->lock);
> +		dev_err(dev, "Error in setting CM3218_REG_ADDR_CMD\n");
> +		return status;
> +	}
> +	mutex_unlock(&chip->lock);
> +
> +	return count;
> +}
> +
> +/* status */
> +static ssize_t show_status(struct device *dev,
> +			struct device_attribute *attr, char *buf)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct cm3218_chip *chip = iio_priv(indio_dev);
> +	struct i2c_client *client = chip->client;
> +	int status;
> +
> +	status = cm3218_read(client, CM3218_REG_ADDR_STATUS);
> +	if (status < 0) {
> +		dev_err(dev, "Error in getting CM3218_REG_ADDR_STATUS\n");
> +		return status;
> +	}
> +
> +	return sprintf(buf, "%u\n", status);
> +}
> +
> +#endif	/* CM3218_DEBUG */
> +
> +/* Channel IO */
> +static int cm3218_write_raw(struct iio_dev *indio_dev,
> +			      struct iio_chan_spec const *chan,
> +			      int val,
> +			      int val2,
> +			      long mask)
> +{
> +	struct cm3218_chip *chip = iio_priv(indio_dev);
> +	int ret = -EINVAL;

ret is not used?

> +
> +	mutex_lock(&chip->lock);
> +	if (mask == IIO_CHAN_INFO_CALIBSCALE && chan->type == IIO_LIGHT) {
> +		chip->lensfactor = val;
> +		ret = 0;
> +	}
> +	mutex_unlock(&chip->lock);
> +
> +	return 0;
> +}
> +
> +static int cm3218_read_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     int *val,
> +			     int *val2,
> +			     long mask)
> +{
> +	int ret = -EINVAL;
> +	struct cm3218_chip *chip = iio_priv(indio_dev);
> +	struct i2c_client *client = chip->client;
> +
> +	mutex_lock(&chip->lock);
> +	if (chip->suspended) {
> +		mutex_unlock(&chip->lock);
> +		return -EBUSY;
> +	}
> +	switch (mask) {
> +	case 0:

huh? this is not in the channels?

> +		ret = cm3218_read_lux(client, val);
> +		if (!ret)
> +			ret = IIO_VAL_INT;
> +		break;
> +	case IIO_CHAN_INFO_CALIBSCALE:
> +		*val = chip->lensfactor;
> +		ret = IIO_VAL_INT_PLUS_MICRO;
> +		break;
> +	default:
> +		break;
> +	}
> +	mutex_unlock(&chip->lock);
> +	return ret;
> +}
> +
> +#define IIO_CHAN_INFO_SEPARATE_BIT(type) BIT(type*2 + 1)
> +#define IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT                   \
> +	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_CALIBSCALE)
> +
> +static const struct iio_chan_spec cm3218_channels[] = {
> +	{
> +		.type = IIO_LIGHT,
> +		.indexed = 1,
> +		.channel = 0,
> +		.info_mask = IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT,

info_mask_separate was recently introduced

> +	}
> +};
> +
> +static IIO_DEVICE_ATTR(illuminance0_input, S_IRUGO, show_lux, NULL, 0);
> +static IIO_DEVICE_ATTR(illuminance0_calibscale, S_IRUGO | S_IWUSR,
> +					show_lensfactor, store_lensfactor, 0);

not needed; I think you just need the iio_chan_spec

> +#ifdef	CM3218_DEBUG
> +static IIO_DEVICE_ATTR(cmd, S_IRUGO | S_IWUSR, show_cmd, store_cmd, 0);
> +static IIO_DEVICE_ATTR(status, S_IRUGO, show_status, NULL, 0);
> +#endif	/* CM3218_DEBUG */
> +
> +#define CM3218_DEV_ATTR(name) (&iio_dev_attr_##name.dev_attr.attr)
> +#define CM3218_CONST_ATTR(name) (&iio_const_attr_##name.dev_attr.attr)
> +static struct attribute *cm3218_attributes[] = {
> +	CM3218_DEV_ATTR(illuminance0_input),
> +	CM3218_DEV_ATTR(illuminance0_calibscale),
> +#ifdef	CM3218_DEBUG
> +	CM3218_DEV_ATTR(cmd),
> +	CM3218_DEV_ATTR(status),
> +#endif	/* CM3218_DEBUG */
> +	NULL
> +};
> +
> +static const struct attribute_group cm3218_group = {
> +	.attrs = cm3218_attributes,
> +};
> +
> +static int cm3218_chip_init(struct i2c_client *client)
> +{
> +	struct cm3218_chip *chip = iio_priv(i2c_get_clientdata(client));
> +	int status, i;
> +
> +	memset(chip->reg_cache, 0, sizeof(chip->reg_cache));
> +
> +	for (i = 0; i < 5; i++) {
> +		status = cm3218_write(client, CM3218_REG_ADDR_CMD,
> +				CM3218_CMD_ALS_SD);
> +		if (status >= 0)
> +			break;
> +		cm3218_read_ara(client);
> +	}
> +
> +	status = cm3218_write(client, CM3218_REG_ADDR_CMD, CM3218_DEFAULT_CMD);
> +	if (status < 0) {
> +		dev_err(&client->dev, "Init CM3218 CMD fails\n");
> +		return status;
> +	}
> +
> +
> +	/* Clean interrupt status */
> +	cm3218_read(client, CM3218_REG_ADDR_STATUS);
> +
> +	return 0;
> +}
> +
> +static const struct iio_info cm3218_info = {
> +	.attrs = &cm3218_group,
> +	.driver_module = THIS_MODULE,
> +	.read_raw = &cm3218_read_raw,
> +	.write_raw = &cm3218_write_raw,
> +};
> +
> +static int cm3218_probe(struct i2c_client *client,
> +			 const struct i2c_device_id *id)
> +{
> +	struct cm3218_chip *chip;
> +	struct iio_dev *indio_dev;
> +	int err;
> +
> +	indio_dev = iio_device_alloc(sizeof(*chip));
> +	if (indio_dev == NULL) {
> +		dev_err(&client->dev, "iio allocation fails\n");
> +		err = -ENOMEM;
> +		goto exit;

maybe directly return -ENOMEM?

> +	}
> +	chip = iio_priv(indio_dev);
> +	chip->client = client;
> +	i2c_set_clientdata(client, indio_dev);
> +
> +	mutex_init(&chip->lock);
> +
> +	chip->lensfactor = 1000;

maybe some platform data, DT magic to allow passing the lens factor?

> +	chip->suspended = false;
> +
> +	err = cm3218_chip_init(client);
> +	if (err)
> +		goto exit_iio_free;
> +
> +	indio_dev->info = &cm3218_info;
> +	indio_dev->channels = cm3218_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(cm3218_channels);
> +	indio_dev->name = id->name;
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	err = iio_device_register(indio_dev);
> +	if (err) {
> +		dev_err(&client->dev, "iio registration fails\n");
> +		goto exit_iio_free;
> +	}
> +
> +	return 0;
> +exit_iio_free:
> +	iio_device_free(indio_dev);
> +exit:
> +	return err;
> +}
> +
> +static int cm3218_detect(struct i2c_client *client,
> +				   struct i2c_board_info *info)
> +{
> +	struct i2c_adapter *adapter = client->adapter;
> +	const char *name = NULL;
> +
> +	cm3218_read_ara(client);
> +
> +	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
> +		return -ENODEV;

the driver needs WORD_DATA
the check is after read_ara (which only needs BYTE_DATA)
what is read_ara() fails

> +
> +	name = "cm3218";
> +	strlcpy(info->type, name, I2C_NAME_SIZE);
> +
> +	return 0;
> +}
> +
> +static int cm3218_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +
> +	dev_dbg(&client->dev, "%s()\n", __func__);
> +	iio_device_unregister(indio_dev);
> +	iio_device_free(indio_dev);
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int cm3218_suspend(struct device *dev)
> +{
> +	struct cm3218_chip *chip = iio_priv(dev_get_drvdata(dev));
> +
> +	mutex_lock(&chip->lock);
> +
> +	/* Since this driver uses only polling commands, we are by default in
> +	 * auto shutdown (ie, power-down) mode.
> +	 * So we do not have much to do here.
> +	 */
> +	chip->suspended = true;
> +
> +	mutex_unlock(&chip->lock);
> +	return 0;
> +}
> +
> +static int cm3218_resume(struct device *dev)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct cm3218_chip *chip = iio_priv(indio_dev);
> +	struct i2c_client *client = chip->client;
> +	int err;
> +
> +	mutex_lock(&chip->lock);
> +
> +	err = cm3218_chip_init(client);
> +	if (!err)
> +		chip->suspended = false;
> +
> +	mutex_unlock(&chip->lock);
> +	return err;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(cm3218_pm_ops, cm3218_suspend, cm3218_resume);
> +#define CM3218_PM_OPS (&cm3218_pm_ops)
> +#else
> +#define CM3218_PM_OPS NULL
> +#endif
> +
> +static const struct i2c_device_id cm3218_id[] = {
> +	{"cm3218", 0},
> +	{}
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, cm3218_id);
> +
> +static const struct of_device_id cm3218_of_match[] = {
> +	{ .compatible = "invn,cm3218", },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, cm3218_of_match);
> +
> +static struct i2c_driver cm3218_driver = {
> +	.class	= I2C_CLASS_HWMON,
> +	.driver	 = {
> +			.name = "cm3218",
> +			.pm = CM3218_PM_OPS,
> +			.owner = THIS_MODULE,
> +			.of_match_table = cm3218_of_match,
> +		    },
> +	.probe		= cm3218_probe,
> +	.remove		= cm3218_remove,
> +	.id_table       = cm3218_id,
> +	.detect	 = cm3218_detect,
> +	.address_list   = normal_i2c,
> +};
> +module_i2c_driver(cm3218_driver);
> +
> +MODULE_DESCRIPTION("CM3218 Ambient Light Sensor driver");
> +MODULE_LICENSE("GPL");
> 

-- 

Peter Meerwald
+43-664-2444418 (mobile)

Re: [PATCH 1/1] Added Capella CM3218 Ambient Light Sensor IIO Driver.

[Lars-Peter Clausen]

On 07/04/2013 01:31 AM, Kevin Tsai wrote:

Maybe write at least a short commit message which states the features of the
chip.

> Signed-off-by: Kevin Tsai <ktsai-GubuWUlQtMwciDkP5Hr2oA@public.gmane.org>
> ---
>  drivers/staging/iio/light/Kconfig  |   10 +
>  drivers/staging/iio/light/Makefile |    1 +
>  drivers/staging/iio/light/cm3218.c |  581 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 592 insertions(+)
>  create mode 100644 drivers/staging/iio/light/cm3218.c
> 
> diff --git a/drivers/staging/iio/light/Kconfig b/drivers/staging/iio/light/Kconfig
> index ca8d6e6..647af0c 100644
> --- a/drivers/staging/iio/light/Kconfig
> +++ b/drivers/staging/iio/light/Kconfig
> @@ -40,4 +40,14 @@ config TSL2x7x
>  	 tmd2672, tsl2772, tmd2772 devices.
>  	 Provides iio_events and direct access via sysfs.
>  
> +config SENSORS_CM3218
> +        tristate "CM3218 Ambient Light Sensor"
> +        depends on I2C
> +        help
> +         Say Y here if you have a Capella Micro CM3218 Ambient Light Sensor.
> +
> +         To compile this driver as a module, choose M here.  This module
> +         will be called to 'cm3218'.  It will access ALS data via iio sysfs.
> +         This is recommended.
> +

Keep the entries in alphabetical order.

>  endmenu
> diff --git a/drivers/staging/iio/light/Makefile b/drivers/staging/iio/light/Makefile
> index 9960fdf..63020ab 100644
> --- a/drivers/staging/iio/light/Makefile
> +++ b/drivers/staging/iio/light/Makefile
> @@ -6,3 +6,4 @@ obj-$(CONFIG_SENSORS_ISL29018)	+= isl29018.o
>  obj-$(CONFIG_SENSORS_ISL29028)	+= isl29028.o
>  obj-$(CONFIG_TSL2583)	+= tsl2583.o
>  obj-$(CONFIG_TSL2x7x)	+= tsl2x7x_core.o
> +obj-$(CONFIG_SENSORS_CM3218)    += cm3218.o

Same here

> diff --git a/drivers/staging/iio/light/cm3218.c b/drivers/staging/iio/light/cm3218.c
> new file mode 100644
> index 0000000..9c2584d
> --- /dev/null
> +++ b/drivers/staging/iio/light/cm3218.c
> @@ -0,0 +1,581 @@
[...]
> +#include <linux/module.h>
> +#include <linux/i2c.h>
> +#include <linux/err.h>
> +#include <linux/mutex.h>
> +#include <linux/delay.h>

delay.h seems to be unused

> +#include <linux/slab.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
[...]
> +
> +static int cm3218_write(struct i2c_client *client, u8 reg, u16 value)
> +{
> +	u16 regval;
> +	int ret;
> +	struct cm3218_chip *chip = iio_priv(i2c_get_clientdata(client));
> +
> +#ifdef	CM3218_DEBUG
> +	dev_err(&client->dev,
> +		"Write to device register 0x%02X with 0x%04X\n", reg, value);
> +#endif	/* CM3218_DEBUG */
> +	regval = cpu_to_le16(value);
> +	ret = i2c_smbus_write_word_data(client, reg, regval);

This looks wrong, with this code the on-wire byteorder will differ between
big endian and little endian systems. Maybe you want
i2c_smbus_write_word_swapped?

But as Peter said, just use regmap for all IO.

> +	if (ret) {
> +		dev_err(&client->dev, "Write to device fails: 0x%x\n", ret);
> +	} else {
> +		/* Update cache */
> +		if (reg < CM3218_MAX_CACHE_REGS)
> +			chip->reg_cache[reg] = value;
> +	}
> +
> +	return ret;
[...]
> +
> +static int cm3218_detect(struct i2c_client *client,
> +				   struct i2c_board_info *info)
> +{
> +	struct i2c_adapter *adapter = client->adapter;
> +	const char *name = NULL;
> +
> +	cm3218_read_ara(client);
> +
> +	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
> +		return -ENODEV;
> +
> +	name = "cm3218";
> +	strlcpy(info->type, name, I2C_NAME_SIZE);
> +

Always returning zero means the chip will bind to any I2C devices which
happen to use the same address. I don't think you actually need detection,
so just remove it.

> +	return 0;
> +}
> +
> +static const struct i2c_device_id cm3218_id[] = {
> +	{"cm3218", 0},
> +	{}
> +};
> +

Nitpick: no need for the newline

> +MODULE_DEVICE_TABLE(i2c, cm3218_id);
> +
> +static const struct of_device_id cm3218_of_match[] = {
> +	{ .compatible = "invn,cm3218", },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, cm3218_of_match);
> +
> +static struct i2c_driver cm3218_driver = {
> +	.class	= I2C_CLASS_HWMON,
> +	.driver	 = {
> +			.name = "cm3218",
> +			.pm = CM3218_PM_OPS,
> +			.owner = THIS_MODULE,
> +			.of_match_table = cm3218_of_match,
> +		    },

Indention looks a bit strange here. Please use one tab per level.

> +	.probe		= cm3218_probe,
> +	.remove		= cm3218_remove,
> +	.id_table       = cm3218_id,
> +	.detect	 = cm3218_detect,
> +	.address_list   = normal_i2c,
> +};
> +module_i2c_driver(cm3218_driver);

[PATCH 1/1] Added Capella CM3218 Ambient Light Sensor IIO driver.

[Kevin Tsai]

Signed-off-by: Kevin Tsai <ktsai@capellamicro.com>
---
 drivers/iio/light/Kconfig  |  10 +
 drivers/iio/light/Makefile |   1 +
 drivers/iio/light/cm3218.c | 589 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 600 insertions(+)
 create mode 100644 drivers/iio/light/cm3218.c

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index 5ef1a39..dd1ea80 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -15,6 +15,16 @@ config ADJD_S311
 	 This driver can also be built as a module.  If so, the module
 	 will be called adjd_s311.
 
+config SENSORS_CM3218
+        tristate "CM3218 Ambient Light Sensor"
+        depends on I2C
+        help
+         Say Y here if you have a Capella Micro CM3218 Ambient Light Sensor.
+
+         To compile this driver as a module, choose M here.  This module
+         will be called to 'cm3218'.  It will access ALS data via iio sysfs.
+         This is recommended.
+
 config SENSORS_LM3533
 	tristate "LM3533 ambient light sensor"
 	depends on MFD_LM3533
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index 040d9c7..c4ebe37 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -3,6 +3,7 @@
 #
 
 obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
+obj-$(CONFIG_SENSORS_CM3218)    += cm3218.o
 obj-$(CONFIG_SENSORS_LM3533)	+= lm3533-als.o
 obj-$(CONFIG_SENSORS_TSL2563)	+= tsl2563.o
 obj-$(CONFIG_VCNL4000)		+= vcnl4000.o
diff --git a/drivers/iio/light/cm3218.c b/drivers/iio/light/cm3218.c
new file mode 100644
index 0000000..1989fbb
--- /dev/null
+++ b/drivers/iio/light/cm3218.c
@@ -0,0 +1,589 @@
+/*
+ * A iio driver for CM3218 Ambient Light Sensor.
+ *
+ * IIO driver for monitoring ambient light intensity in lux.
+ *
+ * Copyright (c) 2013, Capella Microsystems Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA	02110-1301, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+
+#if 0	/* ChromeOS still uses old API */
+#include "../iio.h"
+#include "../sysfs.h"
+#define	IIO_DEVICE_ALLOC	iio_allocate_device
+#define	IIO_DEVICE_FREE		iio_free_device
+#else
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#define	IIO_DEVICE_ALLOC	iio_device_alloc
+#define	IIO_DEVICE_FREE		iio_device_free
+#endif	/* 0 */
+
+/*
+ * SMBus ARA address
+ */
+#define	CM3218_ADDR_ARA			0x0C
+
+/*
+ * CM3218 CMD Registers
+ */
+#define	CM3218_REG_ADDR_CMD		0x00
+#define	CM3218_CMD_ALS_SD		0x0001
+#define	CM3218_CMD_ALS_INT_EN		0x0002
+#define	CM3218_CMD_ALS_IT_SHIFT		6
+#define	CM3218_CMD_ALS_IT_MASK		(3 << CM3218_CMD_ALS_IT_SHIFT)
+#define	CM3218_CMD_ALS_IT_05T		(0 << CM3218_CMD_ALS_IT_SHIFT)
+#define	CM3218_CMD_ALS_IT_1T		(1 << CM3218_CMD_ALS_IT_SHIFT)
+#define	CM3218_CMD_ALS_IT_2T		(2 << CM3218_CMD_ALS_IT_SHIFT)
+#define	CM3218_CMD_ALS_IT_4T		(3 << CM3218_CMD_ALS_IT_SHIFT)
+#define	CM3218_DEFAULT_CMD		(CM3218_CMD_ALS_IT_1T)
+
+#define	CM3218_REG_ADDR_ALS_WH		0x01
+#define	CM3218_DEFAULT_ALS_WH		0xFFFF
+
+#define	CM3218_REG_ADDR_ALS_WL		0x02
+#define	CM3218_DEFAULT_ALS_WL		0x0000
+
+#define	CM3218_REG_ADDR_ALS		0x04
+
+#define	CM3218_REG_ADDR_STATUS		0x06
+
+#define	CM3218_REG_ADDR_ID		0x07
+
+/*
+ * Software Parameters
+ */
+#define	CM3218_MAX_CACHE_REGS		(0x03+1)	/* Reg.0x00 to 0x03 */
+
+/*
+ * Features
+ */
+#define	CM3218_DEBUG
+
+static const unsigned short normal_i2c[] = {
+	0x10, 0x48, I2C_CLIENT_END };
+
+struct cm3218_chip {
+	struct i2c_client	*client;
+	struct mutex		lock;
+	unsigned int		lensfactor;
+	bool			suspended;
+	u16			reg_cache[CM3218_MAX_CACHE_REGS];
+};
+
+static int cm3218_read_ara(struct i2c_client *client)
+{
+	int status;
+	unsigned short addr;
+
+	addr = client->addr;
+	client->addr = CM3218_ADDR_ARA;
+	status = i2c_smbus_read_byte(client);
+	client->addr = addr;
+
+	if (status < 0)
+		return -ENODEV;
+
+	return 0;
+}
+
+static int cm3218_write(struct i2c_client *client, u8 reg, u16 value)
+{
+	int ret;
+	struct cm3218_chip *chip = iio_priv(i2c_get_clientdata(client));
+
+#ifdef	CM3218_DEBUG
+	dev_err(&client->dev,
+		"Write to device register 0x%02X with 0x%04X\n", reg, value);
+#endif	/* CM3218_DEBUG */
+	ret = i2c_smbus_write_word_data(client, reg, value);
+	if (ret) {
+		dev_err(&client->dev, "Write to device fails: 0x%x\n", ret);
+	} else {
+		/* Update cache */
+		if (reg < CM3218_MAX_CACHE_REGS)
+			chip->reg_cache[reg] = value;
+	}
+
+	return ret;
+}
+
+static int cm3218_read(struct i2c_client *client, u8 reg)
+{
+	int status;
+	struct cm3218_chip *chip = iio_priv(i2c_get_clientdata(client));
+
+	if (reg < CM3218_MAX_CACHE_REGS) {
+		status = chip->reg_cache[reg];
+	} else {
+		status = i2c_smbus_read_word_data(client, reg);
+		if (status < 0) {
+			dev_err(&client->dev,
+				"Error in reading Reg.0x%02X\n", reg);
+			return status;
+		}
+#ifdef	CM3218_DEBUG
+		dev_err(&client->dev,
+			"Read from device register 0x%02X = 0x%04X\n",
+			reg, status);
+#endif	/* CM3218_DEBUG */
+	}
+
+	return status;
+}
+
+static int cm3218_read_sensor_input(struct i2c_client *client)
+{
+	int status;
+
+	status = cm3218_read(client, CM3218_REG_ADDR_ALS);
+	if (status < 0)
+		return status;
+
+	dev_vdbg(&client->dev, "lux = %u\n", status);
+
+	return status;
+}
+
+static int cm3218_read_lux(struct i2c_client *client, int *lux)
+{
+	struct cm3218_chip *chip = iio_priv(i2c_get_clientdata(client));
+	int lux_data;
+
+	lux_data = cm3218_read_sensor_input(client);
+
+	if (lux_data < 0)
+		return lux_data;
+
+	*lux  = lux_data * chip->lensfactor;
+	*lux /= 1000;
+	return 0;
+}
+
+/* Sysfs interface */
+/* lensfactor */
+static ssize_t show_lensfactor(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+
+	return sprintf(buf, "%d\n", chip->lensfactor);
+}
+
+static ssize_t store_lensfactor(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	unsigned long lval;
+
+	if (kstrtoul(buf, 10, &lval))
+		return -EINVAL;
+
+	mutex_lock(&chip->lock);
+	chip->lensfactor = lval;
+	mutex_unlock(&chip->lock);
+
+	return count;
+}
+
+static ssize_t get_sensor_data(struct device *dev, char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	struct i2c_client *client = chip->client;
+	int value = 0;
+	int status;
+
+	mutex_lock(&chip->lock);
+	if (chip->suspended) {
+		mutex_unlock(&chip->lock);
+		return -EBUSY;
+	}
+
+	 status = cm3218_read_lux(client, &value);
+
+	if (status < 0) {
+		dev_err(&client->dev, "Error in Reading data");
+		mutex_unlock(&chip->lock);
+		return status;
+	}
+
+	mutex_unlock(&chip->lock);
+
+	return sprintf(buf, "%d\n", value);
+}
+
+
+/* Read lux */
+static ssize_t show_lux(struct device *dev,
+	struct device_attribute *devattr, char *buf)
+{
+	return get_sensor_data(dev, buf);
+}
+
+#ifdef	CM3218_DEBUG
+/* windows_high */
+static ssize_t show_cmd(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	struct i2c_client *client = chip->client;
+	int status;
+
+	status = cm3218_read(client, CM3218_REG_ADDR_CMD);
+	if (status < 0) {
+		dev_err(dev, "Error in getting CM3218_REG_ADDR_CMD\n");
+		return status;
+	}
+
+	return sprintf(buf, "%u\n", status);
+}
+
+static ssize_t store_cmd(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	struct i2c_client *client = chip->client;
+	int status;
+	unsigned long lval;
+
+	if (kstrtoul(buf, 10, &lval))
+		return -EINVAL;
+
+	mutex_lock(&chip->lock);
+	if (lval > 0x10000)
+		lval = 0xFFFF;
+	status = cm3218_write(client, CM3218_REG_ADDR_CMD, (u16)lval);
+	if (status < 0) {
+		mutex_unlock(&chip->lock);
+		dev_err(dev, "Error in setting CM3218_REG_ADDR_CMD\n");
+		return status;
+	}
+	mutex_unlock(&chip->lock);
+
+	return count;
+}
+
+/* status */
+static ssize_t show_status(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	struct i2c_client *client = chip->client;
+	int status;
+
+	status = cm3218_read(client, CM3218_REG_ADDR_STATUS);
+	if (status < 0) {
+		dev_err(dev, "Error in getting CM3218_REG_ADDR_STATUS\n");
+		return status;
+	}
+
+	return sprintf(buf, "%u\n", status);
+}
+
+#endif	/* CM3218_DEBUG */
+
+/* Channel IO */
+static int cm3218_write_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      int val,
+			      int val2,
+			      long mask)
+{
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	int ret = -EINVAL;
+
+	mutex_lock(&chip->lock);
+	if (mask == IIO_CHAN_INFO_CALIBSCALE && chan->type == IIO_LIGHT) {
+		chip->lensfactor = val;
+		ret = 0;
+	}
+	mutex_unlock(&chip->lock);
+
+	return 0;
+}
+
+static int cm3218_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int *val,
+			     int *val2,
+			     long mask)
+{
+	int ret = -EINVAL;
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	struct i2c_client *client = chip->client;
+
+	mutex_lock(&chip->lock);
+	if (chip->suspended) {
+		mutex_unlock(&chip->lock);
+		return -EBUSY;
+	}
+	switch (mask) {
+	case 0:
+		ret = cm3218_read_lux(client, val);
+		if (!ret)
+			ret = IIO_VAL_INT;
+		break;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		*val = chip->lensfactor;
+		ret = IIO_VAL_INT_PLUS_MICRO;
+		break;
+	default:
+		break;
+	}
+	mutex_unlock(&chip->lock);
+	return ret;
+}
+
+#define IIO_CHAN_INFO_SEPARATE_BIT(type) BIT(type*2 + 1)
+#define IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT                   \
+	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_CALIBSCALE)
+
+static const struct iio_chan_spec cm3218_channels[] = {
+	{
+		.type = IIO_LIGHT,
+		.indexed = 1,
+		.channel = 0,
+		.info_mask = IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT,
+	}
+};
+
+static IIO_DEVICE_ATTR(illuminance0_input, S_IRUGO, show_lux, NULL, 0);
+static IIO_DEVICE_ATTR(illuminance0_calibscale, S_IRUGO | S_IWUSR,
+					show_lensfactor, store_lensfactor, 0);
+#ifdef	CM3218_DEBUG
+static IIO_DEVICE_ATTR(cmd, S_IRUGO | S_IWUSR, show_cmd, store_cmd, 0);
+static IIO_DEVICE_ATTR(status, S_IRUGO, show_status, NULL, 0);
+#endif	/* CM3218_DEBUG */
+
+#define CM3218_DEV_ATTR(name) (&iio_dev_attr_##name.dev_attr.attr)
+#define CM3218_CONST_ATTR(name) (&iio_const_attr_##name.dev_attr.attr)
+static struct attribute *cm3218_attributes[] = {
+	CM3218_DEV_ATTR(illuminance0_input),
+	CM3218_DEV_ATTR(illuminance0_calibscale),
+#ifdef	CM3218_DEBUG
+	CM3218_DEV_ATTR(cmd),
+	CM3218_DEV_ATTR(status),
+#endif	/* CM3218_DEBUG */
+	NULL
+};
+
+static const struct attribute_group cm3218_group = {
+	.attrs = cm3218_attributes,
+};
+
+static int cm3218_chip_init(struct i2c_client *client)
+{
+	struct cm3218_chip *chip = iio_priv(i2c_get_clientdata(client));
+	int status, i;
+
+	memset(chip->reg_cache, 0, sizeof(chip->reg_cache));
+
+	for (i = 0; i < 5; i++) {
+		status = cm3218_write(client, CM3218_REG_ADDR_CMD,
+				CM3218_CMD_ALS_SD);
+		if (status >= 0)
+			break;
+		cm3218_read_ara(client);
+	}
+
+	status = cm3218_write(client, CM3218_REG_ADDR_CMD, CM3218_DEFAULT_CMD);
+	if (status < 0) {
+		dev_err(&client->dev, "Init CM3218 CMD fails\n");
+		return status;
+	}
+
+
+	/* Clean interrupt status */
+	cm3218_read(client, CM3218_REG_ADDR_STATUS);
+
+	return 0;
+}
+
+static const struct iio_info cm3218_info = {
+	.attrs = &cm3218_group,
+	.driver_module = THIS_MODULE,
+	.read_raw = &cm3218_read_raw,
+	.write_raw = &cm3218_write_raw,
+};
+
+static int cm3218_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct cm3218_chip *chip;
+	struct iio_dev *indio_dev;
+	int err;
+
+	indio_dev = IIO_DEVICE_ALLOC(sizeof(*chip));
+	if (indio_dev == NULL) {
+		dev_err(&client->dev, "iio allocation fails\n");
+		err = -ENOMEM;
+		goto exit;
+	}
+	chip = iio_priv(indio_dev);
+	chip->client = client;
+	i2c_set_clientdata(client, indio_dev);
+
+	mutex_init(&chip->lock);
+
+	chip->lensfactor = 1000;
+	chip->suspended = false;
+
+	err = cm3218_chip_init(client);
+	if (err)
+		goto exit_iio_free;
+
+	indio_dev->info = &cm3218_info;
+	indio_dev->channels = cm3218_channels;
+	indio_dev->num_channels = ARRAY_SIZE(cm3218_channels);
+	indio_dev->name = id->name;
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	err = iio_device_register(indio_dev);
+	if (err) {
+		dev_err(&client->dev, "iio registration fails\n");
+		goto exit_iio_free;
+	}
+
+	return 0;
+exit_iio_free:
+	IIO_DEVICE_FREE(indio_dev);
+exit:
+	return err;
+}
+
+static int cm3218_detect(struct i2c_client *client,
+				   struct i2c_board_info *info)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	const char *name = NULL;
+	int id;
+
+	cm3218_read_ara(client);
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -ENODEV;
+
+	id = cm3218_read(client, CM3218_REG_ADDR_ID);
+	if (id < 0)
+		return -ENODEV;
+
+	switch (id&0xFF) {
+	case 0x18:
+		name = "cm3218";
+		break;
+	default:
+		return -ENODEV;
+	}
+
+	strlcpy(info->type, name, I2C_NAME_SIZE);
+
+	return 0;
+}
+
+static int cm3218_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+	dev_dbg(&client->dev, "%s()\n", __func__);
+	iio_device_unregister(indio_dev);
+	IIO_DEVICE_FREE(indio_dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int cm3218_suspend(struct device *dev)
+{
+	struct cm3218_chip *chip = iio_priv(dev_get_drvdata(dev));
+
+	mutex_lock(&chip->lock);
+
+	/* Since this driver uses only polling commands, we are by default in
+	 * auto shutdown (ie, power-down) mode.
+	 * So we do not have much to do here.
+	 */
+	chip->suspended = true;
+
+	mutex_unlock(&chip->lock);
+	return 0;
+}
+
+static int cm3218_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct cm3218_chip *chip = iio_priv(indio_dev);
+	struct i2c_client *client = chip->client;
+	int err;
+
+	mutex_lock(&chip->lock);
+
+	err = cm3218_chip_init(client);
+	if (!err)
+		chip->suspended = false;
+
+	mutex_unlock(&chip->lock);
+	return err;
+}
+
+static SIMPLE_DEV_PM_OPS(cm3218_pm_ops, cm3218_suspend, cm3218_resume);
+#define CM3218_PM_OPS (&cm3218_pm_ops)
+#else
+#define CM3218_PM_OPS NULL
+#endif
+
+static const struct i2c_device_id cm3218_id[] = {
+	{"cm3218", 0},
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, cm3218_id);
+
+static const struct of_device_id cm3218_of_match[] = {
+	{ .compatible = "invn,cm3218", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, cm3218_of_match);
+
+static struct i2c_driver cm3218_driver = {
+	.class = I2C_CLASS_HWMON,
+	.driver = {
+		.name = "cm3218",
+		.pm = CM3218_PM_OPS,
+		.owner = THIS_MODULE,
+		.of_match_table = cm3218_of_match,
+	},
+	.probe = cm3218_probe,
+	.remove = cm3218_remove,
+	.id_table = cm3218_id,
+	.detect = cm3218_detect,
+	.address_list = normal_i2c,
+};
+module_i2c_driver(cm3218_driver);
+
+MODULE_DESCRIPTION("CM3218 Ambient Light Sensor driver");
+MODULE_LICENSE("GPL");
-- 
1.8.3.1