[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@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

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

[Shubhrajyoti Datta]

[-- Attachment #1: Type: text/plain, Size: 874 bytes --]

<snip>

> +       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);
>
We do a reinit every time is there a way to know if the context was lost?


> +       if (!err)
> +               chip->suspended = false;
> +
> +       mutex_unlock(&chip->lock);
> +       return err;
> +}
> +
>
> --
> 1.8.3.1
>
> --
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[-- Attachment #2: Type: text/html, Size: 1563 bytes --]

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

[Kevin Tsai]

[-- Attachment #1: Type: text/plain, Size: 1530 bytes --]

Hi sir,

This sensor doesn't have power on reset. It's necessary to re-initialize device after resume power.

Thanks.

Kevin Tsai
08/06/13
  ----- Original Message ----- 
  From: Shubhrajyoti Datta 
  To: Kevin Tsai 
  Cc: Jonathan Cameron ; Grant Likely ; Rob Herring ; Peter Meerwald ; Alexander Holler ; srinivas pandruvada ; Linux Kernel Mailing List ; linux-iio@vger.kernel.org ; devicetree@vger.kernel.org 
  Sent: Tuesday, August 06, 2013 23:31
  Subject: Re: [PATCH 1/1] Added Capella CM3218 Ambient Light Sensor IIO driver.




  <snip>

    +       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);

  We do a reinit every time is there a way to know if the context was lost?
   

    +       if (!err)
    +               chip->suspended = false;
    +
    +       mutex_unlock(&chip->lock);
    +       return err;
    +}
    +

    --
    1.8.3.1

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

[Peter Meerwald]

>  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

not much changed since last revision :(
some comments inline...

> 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.

will be called 'cm3218'.  It will provide access to ALS data via iio 
sysfs.

> +         This is recommended.

I think this should be dropped; or do you mean one should prefer the 
modules?

> +
>  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

old kernels are not supported; drop this and use the correct funtion 
directly

maybe you want to use devm_iio_device_alloc() introduced recently?

> +#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)

parenthesis not necessary here: (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
> + */

single line comment: /* Software Parameters */

> +#define	CM3218_MAX_CACHE_REGS		(0x03+1)	/* Reg.0x00 to 0x03 */
> +
> +/*
> + * Features
> + */

single line comment

> +#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);

dev_dbg()?

> +#endif	/* CM3218_DEBUG */
> +	ret = i2c_smbus_write_word_data(client, reg, value);
> +	if (ret) {

ret < 0?

> +		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;

return not needed here

> +		}
> +#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;
> +}

drop this function and inline into read_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 */

use multi-line comment

> +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);

struct cm3218_chip *chip = iio_priv(dev_get_drvdata(dev));

> +
> +	return sprintf(buf, "%d\n", chip->lensfactor);
> +}

you don't need this, handled by channel read/write below

> +
> +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;
> +}

you don't need this, handled by channel read/write below
no range checking??

> +
> +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 at beginning of line

> +
> +	if (status < 0) {
> +		dev_err(&client->dev, "Error in Reading data");

reading

> +		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);
> +}

drop this; use channels to present data

> +
> +#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);
> +}

I'd rather drop the debugging stuff; you could use 
probably use iio_info.debugfs_reg_access:

> +
> +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)

>= maybe?

> +		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, only assigned

> +
> +	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:

INFO_RAW? or INFO_PROCESSED?

> +		ret = cm3218_read_lux(client, val);
> +		if (!ret)
> +			ret = IIO_VAL_INT;

if (ret >= 0) ??

> +		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)

only needed for old kernels

> +
> +static const struct iio_chan_spec cm3218_channels[] = {
> +	{
> +		.type = IIO_LIGHT,
> +		.indexed = 1,

there is only one channel, no need to index

> +		.channel = 0,
> +		.info_mask = IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT,

INFO_RAW/PROCESSED?

> +	}
> +};
> +
> +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);

why 5 times? no sleep?

> +	}
> +
> +	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");

drop error msg

> +		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;
> +}

drop detect code

> +
> +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.

[Jonathan Cameron]

On 08/12/13 19:11, Peter Meerwald wrote:
> 
>>  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
> 
> not much changed since last revision :(
> some comments inline...
> 
>> 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.
> 
> will be called 'cm3218'.  It will provide access to ALS data via iio 
> sysfs.
> 
>> +         This is recommended.
> 
> I think this should be dropped; or do you mean one should prefer the 
> modules?
> 
>> +
>>  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
> 
> old kernels are not supported; drop this and use the correct funtion 
> directly
> 
> maybe you want to use devm_iio_device_alloc() introduced recently?
Definitely given you will be rerolling the driver anyway.

> 
>> +#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)
> 
> parenthesis not necessary here: (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
>> + */
> 
> single line comment: /* Software Parameters */
> 
>> +#define	CM3218_MAX_CACHE_REGS		(0x03+1)	/* Reg.0x00 to 0x03 */
>> +
>> +/*
>> + * Features
>> + */
> 
> single line comment
> 
>> +#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);
> 
> dev_dbg()?
> 
>> +#endif	/* CM3218_DEBUG */
>> +	ret = i2c_smbus_write_word_data(client, reg, value);
>> +	if (ret) {
> 
> ret < 0?
> 
>> +		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;
> 
> return not needed here
> 
>> +		}
>> +#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;
>> +}
> 
> drop this function and inline into read_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 */
> 
> use multi-line comment
> 
>> +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);
> 
> struct cm3218_chip *chip = iio_priv(dev_get_drvdata(dev));
> 
>> +
>> +	return sprintf(buf, "%d\n", chip->lensfactor);
>> +}
> 
> you don't need this, handled by channel read/write below
> 
>> +
>> +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;
>> +}
> 
> you don't need this, handled by channel read/write below
> no range checking??
> 
>> +
>> +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 at beginning of line
> 
>> +
>> +	if (status < 0) {
>> +		dev_err(&client->dev, "Error in Reading data");
> 
> reading
> 
>> +		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);
>> +}
> 
> drop this; use channels to present data
> 
>> +
>> +#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);
>> +}
> 
> I'd rather drop the debugging stuff; you could use 
> probably use iio_info.debugfs_reg_access:
> 
>> +
>> +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)
> 
>> = maybe?
> 
>> +		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, only assigned
> 
>> +
>> +	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:
> 
> INFO_RAW? or INFO_PROCESSED?
> 
>> +		ret = cm3218_read_lux(client, val);
>> +		if (!ret)
>> +			ret = IIO_VAL_INT;
> 
> if (ret >= 0) ??
> 
>> +		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)
> 
> only needed for old kernels
> 
>> +
>> +static const struct iio_chan_spec cm3218_channels[] = {
>> +	{
>> +		.type = IIO_LIGHT,
>> +		.indexed = 1,
> 
> there is only one channel, no need to index
> 
>> +		.channel = 0,
>> +		.info_mask = IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT,
> 
> INFO_RAW/PROCESSED?
> 
>> +	}
>> +};
>> +
>> +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);
> 
> why 5 times? no sleep?
> 
>> +	}
>> +
>> +	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");
> 
> drop error msg
> 
>> +		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;
>> +}
> 
> drop detect code
> 
>> +
>> +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");
>>
> 

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@capellamicro.com>
> ---
>  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);

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);

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

[Peter Meerwald]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 23304 bytes --]


> Thank you for your reply.  Can you advise me where is the best location?

just drivers/iio/light

regards, p.

> ________________________________
>  From: Peter Meerwald <pmeerw@pmeerw.net>
> To: Kevin Tsai <ktsai@capellamicro.com> 
> Cc: Jonathan Cameron <jic23@cam.ac.uk>; Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Grant Likely <grant.likely@linaro.org>; Rob Herring <rob.herring@calxeda.com>; linux-kernel@vger.kernel.org; linux-iio@vger.kernel.org; devel@driverdev.osuosl.org; devicetree-discuss@lists.ozlabs.org 
> Sent: Thursday, July 4, 2013 1:17 AM
> Subject: Re: [PATCH 1/1] Added Capella CM3218 Ambient Light Sensor IIO Driver.
>  
> 
> Hello,
> 
> some comments inline;
> new drivers should not go to staging but to mainline directly 
> 
> regards, p.
> 
> > Signed-off-by: Kevin Tsai <ktsai@capellamicro.com>
> > ---
> >  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)

-- 

Peter Meerwald
+43-664-2444418 (mobile)

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

[Kevin Tsai]

[-- Attachment #1: Type: text/plain, Size: 20939 bytes --]

Hi Peter,

Thank you for your reply.  Can you advise me where is the best location?

Thanks.

Kevin Tsai
07/04/13


________________________________
 From: Peter Meerwald <pmeerw@pmeerw.net>
To: Kevin Tsai <ktsai@capellamicro.com> 
Cc: Jonathan Cameron <jic23@cam.ac.uk>; Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Grant Likely <grant.likely@linaro.org>; Rob Herring <rob.herring@calxeda.com>; linux-kernel@vger.kernel.org; linux-iio@vger.kernel.org; devel@driverdev.osuosl.org; devicetree-discuss@lists.ozlabs.org 
Sent: Thursday, July 4, 2013 1:17 AM
Subject: Re: [PATCH 1/1] Added Capella CM3218 Ambient Light Sensor IIO Driver.
 

Hello,

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

regards, p.

> Signed-off-by: Kevin Tsai <ktsai@capellamicro.com>
> ---
>  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)

[-- Attachment #2: Type: text/html, Size: 35041 bytes --]

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@capellamicro.com>
> ---
>  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.

[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)

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

[Kevin Tsai]

Signed-off-by: Kevin Tsai <ktsai@capellamicro.com>
---
 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

[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