drivers/misc: ROHM BH1780GLI ambient light sensor driver

Add 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.

Currently this driver follows the same sysfs convention as supported by
drivers/misc/isl29003.c.

Signed-off-by: Hemanth V <hemanthv@ti.com>
Reviewed-by: Daniel Mack <daniel@caiaq.de>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 284 insertions, 0 deletions

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 488f25472291..2483183419b9 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -304,6 +304,16 @@ 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 67552d6e9327..21ae73c38005 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_LKDTM)		+= lkdtm.o
 obj-$(CONFIG_TIFM_CORE)         += tifm_core.o
 obj-$(CONFIG_TIFM_7XX1)         += tifm_7xx1.o
 obj-$(CONFIG_PHANTOM)           += phantom.o
+obj-$(CONFIG_SENSORS_BH1780)    += bh1780gli.o
 obj-$(CONFIG_SGI_IOC4)          += ioc4.o
 obj-$(CONFIG_ENCLOSURE_SERVICES) += enclosure.o
 obj-$(CONFIG_KGDB_TESTS)        += kgdbts.o
diff --git a/drivers/misc/bh1780gli.c b/drivers/misc/bh1780gli.c
new file mode 100644
index 000000000000..714c6b487313
--- /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>");