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Subject[PATCH V2] misc : ROHM BH1780GLI Ambient light sensor Driver
From
From: Hemanth V <hemanthv@ti.com>
Date: Fri, 21 May 2010 15:52:03 +0530
Subject: [PATCH] misc: ROHM BH1780GLI Ambient light sensor Driver

This patch adds support for ROHM BH1780GLI Ambient light sensor.

BH1780 supports I2C interface. Driver supports read/update of power state and
read of lux value (through SYSFS). Writing value 3 to power_state enables the
sensor and current lux value could be read.

Signed-off-by: Hemanth V <hemanthv@ti.com>
Reviewed-by: Daniel Mack <daniel@caiaq.de>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
---
drivers/misc/Kconfig | 10 ++
drivers/misc/Makefile | 1 +
drivers/misc/bh1780gli.c | 273 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 284 insertions(+), 0 deletions(-)
create mode 100644 drivers/misc/bh1780gli.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 0d0d625..3f5bf0f 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -278,6 +278,16 @@ config SENSORS_TSL2550
This driver can also be built as a module. If so, the module
will be called tsl2550.

+config SENSORS_BH1780
+ tristate "ROHM BH1780GLI ambient light sensor"
+ depends on I2C && SYSFS
+ help
+ If you say yes here you get support for the ROHM BH1780GLI
+ ambient light sensor.
+
+ This driver can also be built as a module. If so, the module
+ will be called bh1780gli.
+
config EP93XX_PWM
tristate "EP93xx PWM support"
depends on ARCH_EP93XX
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 7b6f7ee..c479d91 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -30,3 +30,4 @@ obj-$(CONFIG_IWMC3200TOP) += iwmc3200top/
obj-y += eeprom/
obj-y += cb710/
obj-$(CONFIG_VMWARE_BALLOON) += vmware_balloon.o
+obj-$(CONFIG_SENSORS_BH1780) += bh1780gli.o
diff --git a/drivers/misc/bh1780gli.c b/drivers/misc/bh1780gli.c
new file mode 100644
index 0000000..774531d
--- /dev/null
+++ b/drivers/misc/bh1780gli.c
@@ -0,0 +1,273 @@
+/*
+ * bh1780gli.c
+ * ROHM Ambient Light Sensor Driver
+ *
+ * Copyright (C) 2010 Texas Instruments
+ * Author: Hemanth V <hemanthv@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+
+#define BH1780_REG_CONTROL 0x80
+#define BH1780_REG_PARTID 0x8A
+#define BH1780_REG_MANFID 0x8B
+#define BH1780_REG_DLOW 0x8C
+#define BH1780_REG_DHIGH 0x8D
+
+#define BH1780_REVMASK (0xf)
+#define BH1780_POWMASK (0x3)
+#define BH1780_POFF (0x0)
+#define BH1780_PON (0x3)
+
+/* power on settling time in ms */
+#define BH1780_PON_DELAY 2
+
+struct bh1780_data {
+ struct i2c_client *client;
+ int power_state;
+ /* lock for sysfs operations */
+ struct mutex lock;
+};
+
+static int bh1780_write(struct bh1780_data *ddata, u8 reg, u8 val, char *msg)
+{
+ int ret = i2c_smbus_write_byte_data(ddata->client, reg, val);
+ if (ret < 0)
+ dev_err(&ddata->client->dev,
+ "i2c_smbus_write_byte_data failed error %d\
+ Register (%s)\n", ret, msg);
+ return ret;
+}
+
+static int bh1780_read(struct bh1780_data *ddata, u8 reg, char *msg)
+{
+ int ret = i2c_smbus_read_byte_data(ddata->client, reg);
+ if (ret < 0)
+ dev_err(&ddata->client->dev,
+ "i2c_smbus_read_byte_data failed error %d\
+ Register (%s)\n", ret, msg);
+ return ret;
+}
+
+static ssize_t bh1780_show_lux(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct bh1780_data *ddata = platform_get_drvdata(pdev);
+ int lsb, msb;
+
+ lsb = bh1780_read(ddata, BH1780_REG_DLOW, "DLOW");
+ if (lsb < 0)
+ return lsb;
+
+ msb = bh1780_read(ddata, BH1780_REG_DHIGH, "DHIGH");
+ if (msb < 0)
+ return msb;
+
+ return sprintf(buf, "%d\n", (msb << 8) | lsb);
+}
+
+static ssize_t bh1780_show_power_state(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct bh1780_data *ddata = platform_get_drvdata(pdev);
+ int state;
+
+ state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
+ if (state < 0)
+ return state;
+
+ return sprintf(buf, "%d\n", state & BH1780_POWMASK);
+}
+
+static ssize_t bh1780_store_power_state(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct bh1780_data *ddata = platform_get_drvdata(pdev);
+ unsigned long val;
+ int error;
+
+ error = strict_strtoul(buf, 0, &val);
+ if (error)
+ return error;
+
+ if (val < BH1780_POFF || val > BH1780_PON)
+ return -EINVAL;
+
+ mutex_lock(&ddata->lock);
+
+ error = bh1780_write(ddata, BH1780_REG_CONTROL, val, "CONTROL");
+ if (error < 0) {
+ mutex_unlock(&ddata->lock);
+ return error;
+ }
+
+ msleep(BH1780_PON_DELAY);
+ ddata->power_state = val;
+ mutex_unlock(&ddata->lock);
+
+ return count;
+}
+
+static DEVICE_ATTR(lux, S_IRUGO, bh1780_show_lux, NULL);
+
+static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
+ bh1780_show_power_state, bh1780_store_power_state);
+
+static struct attribute *bh1780_attributes[] = {
+ &dev_attr_power_state.attr,
+ &dev_attr_lux.attr,
+ NULL
+};
+
+static const struct attribute_group bh1780_attr_group = {
+ .attrs = bh1780_attributes,
+};
+
+static int __devinit bh1780_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int ret;
+ struct bh1780_data *ddata = NULL;
+ struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
+
+ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) {
+ ret = -EIO;
+ goto err_op_failed;
+ }
+
+ ddata = kzalloc(sizeof(struct bh1780_data), GFP_KERNEL);
+ if (ddata == NULL) {
+ ret = -ENOMEM;
+ goto err_op_failed;
+ }
+
+ ddata->client = client;
+ i2c_set_clientdata(client, ddata);
+
+ ret = bh1780_read(ddata, BH1780_REG_PARTID, "PART ID");
+ if (ret < 0)
+ goto err_op_failed;
+
+ dev_info(&client->dev, "Ambient Light Sensor, Rev : %d\n",
+ (ret & BH1780_REVMASK));
+
+ mutex_init(&ddata->lock);
+
+ ret = sysfs_create_group(&client->dev.kobj, &bh1780_attr_group);
+ if (ret)
+ goto err_op_failed;
+
+ return 0;
+
+err_op_failed:
+ kfree(ddata);
+ return ret;
+}
+
+static int __devexit bh1780_remove(struct i2c_client *client)
+{
+ struct bh1780_data *ddata;
+
+ ddata = i2c_get_clientdata(client);
+ sysfs_remove_group(&client->dev.kobj, &bh1780_attr_group);
+ i2c_set_clientdata(client, NULL);
+ kfree(ddata);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int bh1780_suspend(struct i2c_client *client, pm_message_t mesg)
+{
+ struct bh1780_data *ddata;
+ int state, ret;
+
+ ddata = i2c_get_clientdata(client);
+ state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
+ if (state < 0)
+ return state;
+
+ ddata->power_state = state & BH1780_POWMASK;
+
+ ret = bh1780_write(ddata, BH1780_REG_CONTROL, BH1780_POFF,
+ "CONTROL");
+
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static int bh1780_resume(struct i2c_client *client)
+{
+ struct bh1780_data *ddata;
+ int state, ret;
+
+ ddata = i2c_get_clientdata(client);
+ state = ddata->power_state;
+
+ ret = bh1780_write(ddata, BH1780_REG_CONTROL, state,
+ "CONTROL");
+
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+#else
+#define bh1780_suspend NULL
+#define bh1780_resume NULL
+#endif /* CONFIG_PM */
+
+static const struct i2c_device_id bh1780_id[] = {
+ { "bh1780", 0 },
+ { },
+};
+
+static struct i2c_driver bh1780_driver = {
+ .probe = bh1780_probe,
+ .remove = bh1780_remove,
+ .id_table = bh1780_id,
+ .suspend = bh1780_suspend,
+ .resume = bh1780_resume,
+ .driver = {
+ .name = "bh1780"
+ },
+};
+
+static int __init bh1780_init(void)
+{
+ return i2c_add_driver(&bh1780_driver);
+}
+
+static void __exit bh1780_exit(void)
+{
+ i2c_del_driver(&bh1780_driver);
+}
+
+module_init(bh1780_init)
+module_exit(bh1780_exit)
+
+MODULE_DESCRIPTION("BH1780GLI Ambient Light Sensor Driver");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Hemanth V <hemanthv@ti.com>");
--
1.5.6.3


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