Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=a92c344d8c640a812c7a9f5a5202d862cd052a0f
Commit:     a92c344d8c640a812c7a9f5a5202d862cd052a0f
Parent:     066af983c74162fa98e7c5ffa8a5ead4a6979b1f
Author:     Rodolfo Giometti <[EMAIL PROTECTED]>
AuthorDate: Thu Jul 12 14:12:30 2007 +0200
Committer:  Jean Delvare <[EMAIL PROTECTED]>
CommitDate: Thu Jul 12 14:12:30 2007 +0200

    i2c: Add support for the TSL2550
    
    Add support for Taos TSL2550 ambient light sensors.
    (http://www.taosinc.com/product_detail.asp?cateid=4&proid=18).
    
    Signed-off-by: Rodolfo Giometti <[EMAIL PROTECTED]>
    Signed-off-by: Jean Delvare <[EMAIL PROTECTED]>
---
 drivers/i2c/chips/Kconfig   |   10 +
 drivers/i2c/chips/Makefile  |    1 +
 drivers/i2c/chips/tsl2550.c |  454 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 465 insertions(+), 0 deletions(-)

diff --git a/drivers/i2c/chips/Kconfig b/drivers/i2c/chips/Kconfig
index 09fbc59..3944e88 100644
--- a/drivers/i2c/chips/Kconfig
+++ b/drivers/i2c/chips/Kconfig
@@ -143,4 +143,14 @@ config SENSORS_MAX6875
          This driver can also be built as a module.  If so, the module
          will be called max6875.
 
+config SENSORS_TSL2550
+       tristate "Taos TSL2550 ambient light sensor"
+       depends on EXPERIMENTAL
+       help
+         If you say yes here you get support for the Taos TSL2550
+         ambient light sensor.
+
+         This driver can also be built as a module.  If so, the module
+         will be called tsl2550.
+
 endmenu
diff --git a/drivers/i2c/chips/Makefile b/drivers/i2c/chips/Makefile
index cc54a4d..d8cbeb3 100644
--- a/drivers/i2c/chips/Makefile
+++ b/drivers/i2c/chips/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_SENSORS_PCF8574) += pcf8574.o
 obj-$(CONFIG_SENSORS_PCF8591)  += pcf8591.o
 obj-$(CONFIG_ISP1301_OMAP)     += isp1301_omap.o
 obj-$(CONFIG_TPS65010)         += tps65010.o
+obj-$(CONFIG_SENSORS_TSL2550)  += tsl2550.o
 
 ifeq ($(CONFIG_I2C_DEBUG_CHIP),y)
 EXTRA_CFLAGS += -DDEBUG
diff --git a/drivers/i2c/chips/tsl2550.c b/drivers/i2c/chips/tsl2550.c
new file mode 100644
index 0000000..ef80330
--- /dev/null
+++ b/drivers/i2c/chips/tsl2550.c
@@ -0,0 +1,454 @@
+/*
+ *  tsl2550.c - Linux kernel modules for ambient light sensor
+ *
+ *  Copyright (C) 2007 Rodolfo Giometti <[EMAIL PROTECTED]>
+ *  Copyright (C) 2007 Eurotech S.p.A. <[EMAIL PROTECTED]>
+ *
+ *  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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+
+#define TSL2550_DRV_NAME       "tsl2550"
+#define DRIVER_VERSION         "1.1.0"
+
+/*
+ * Defines
+ */
+
+#define TSL2550_POWER_DOWN             0x00
+#define TSL2550_POWER_UP               0x03
+#define TSL2550_STANDARD_RANGE         0x18
+#define TSL2550_EXTENDED_RANGE         0x1d
+#define TSL2550_READ_ADC0              0x43
+#define TSL2550_READ_ADC1              0x83
+
+/*
+ * Structs
+ */
+
+struct tsl2550_data {
+       struct i2c_client *client;
+       struct mutex update_lock;
+
+       unsigned int power_state : 1;
+       unsigned int operating_mode : 1;
+};
+
+/*
+ * Global data
+ */
+
+static const u8 TSL2550_MODE_RANGE[2] = {
+       TSL2550_STANDARD_RANGE, TSL2550_EXTENDED_RANGE,
+};
+
+/*
+ * Management functions
+ */
+
+static int tsl2550_set_operating_mode(struct i2c_client *client, int mode)
+{
+       struct tsl2550_data *data = i2c_get_clientdata(client);
+
+       int ret = i2c_smbus_write_byte(client, TSL2550_MODE_RANGE[mode]);
+
+       data->operating_mode = mode;
+
+       return ret;
+}
+
+static int tsl2550_set_power_state(struct i2c_client *client, int state)
+{
+       struct tsl2550_data *data = i2c_get_clientdata(client);
+       int ret;
+
+       if (state == 0)
+               ret = i2c_smbus_write_byte(client, TSL2550_POWER_DOWN);
+       else {
+               ret = i2c_smbus_write_byte(client, TSL2550_POWER_UP);
+
+               /* On power up we should reset operating mode also... */
+               tsl2550_set_operating_mode(client, data->operating_mode);
+       }
+
+       data->power_state = state;
+
+       return ret;
+}
+
+static int tsl2550_get_adc_value(struct i2c_client *client, u8 cmd)
+{
+       unsigned long end;
+       int loop = 0, ret = 0;
+
+       /*
+        * Read ADC channel waiting at most 400ms (see data sheet for further
+        * info).
+        * To avoid long busy wait we spin for few milliseconds then
+        * start sleeping.
+        */
+       end = jiffies + msecs_to_jiffies(400);
+       while (time_before(jiffies, end)) {
+               i2c_smbus_write_byte(client, cmd);
+
+               if (loop++ < 5)
+                       mdelay(1);
+               else
+                       msleep(1);
+
+               ret = i2c_smbus_read_byte(client);
+               if (ret < 0)
+                       return ret;
+               else if (ret & 0x0080)
+                       break;
+       }
+       if (!(ret & 0x80))
+               return -EIO;
+       return ret & 0x7f;      /* remove the "valid" bit */
+}
+
+/*
+ * LUX calculation
+ */
+
+#define        TSL2550_MAX_LUX         1846
+
+static const u8 ratio_lut[] = {
+       100, 100, 100, 100, 100, 100, 100, 100,
+       100, 100, 100, 100, 100, 100, 99, 99,
+       99, 99, 99, 99, 99, 99, 99, 99,
+       99, 99, 99, 98, 98, 98, 98, 98,
+       98, 98, 97, 97, 97, 97, 97, 96,
+       96, 96, 96, 95, 95, 95, 94, 94,
+       93, 93, 93, 92, 92, 91, 91, 90,
+       89, 89, 88, 87, 87, 86, 85, 84,
+       83, 82, 81, 80, 79, 78, 77, 75,
+       74, 73, 71, 69, 68, 66, 64, 62,
+       60, 58, 56, 54, 52, 49, 47, 44,
+       42, 41, 40, 40, 39, 39, 38, 38,
+       37, 37, 37, 36, 36, 36, 35, 35,
+       35, 35, 34, 34, 34, 34, 33, 33,
+       33, 33, 32, 32, 32, 32, 32, 31,
+       31, 31, 31, 31, 30, 30, 30, 30,
+       30,
+};
+
+static const u16 count_lut[] = {
+       0, 1, 2, 3, 4, 5, 6, 7,
+       8, 9, 10, 11, 12, 13, 14, 15,
+       16, 18, 20, 22, 24, 26, 28, 30,
+       32, 34, 36, 38, 40, 42, 44, 46,
+       49, 53, 57, 61, 65, 69, 73, 77,
+       81, 85, 89, 93, 97, 101, 105, 109,
+       115, 123, 131, 139, 147, 155, 163, 171,
+       179, 187, 195, 203, 211, 219, 227, 235,
+       247, 263, 279, 295, 311, 327, 343, 359,
+       375, 391, 407, 423, 439, 455, 471, 487,
+       511, 543, 575, 607, 639, 671, 703, 735,
+       767, 799, 831, 863, 895, 927, 959, 991,
+       1039, 1103, 1167, 1231, 1295, 1359, 1423, 1487,
+       1551, 1615, 1679, 1743, 1807, 1871, 1935, 1999,
+       2095, 2223, 2351, 2479, 2607, 2735, 2863, 2991,
+       3119, 3247, 3375, 3503, 3631, 3759, 3887, 4015,
+};
+
+/*
+ * This function is described into Taos TSL2550 Designer's Notebook
+ * pages 2, 3.
+ */
+static int tsl2550_calculate_lux(u8 ch0, u8 ch1)
+{
+       unsigned int lux;
+
+       /* Look up count from channel values */
+       u16 c0 = count_lut[ch0];
+       u16 c1 = count_lut[ch1];
+
+       /*
+        * Calculate ratio.
+        * Note: the "128" is a scaling factor
+        */
+       u8 r = 128;
+
+       /* Avoid division by 0 and count 1 cannot be greater than count 0 */
+       if (c0 && (c1 <= c0))
+               r = c1 * 128 / c0;
+       else
+               return -1;
+
+       /* Calculate LUX */
+       lux = ((c0 - c1) * ratio_lut[r]) / 256;
+
+       /* LUX range check */
+       return lux > TSL2550_MAX_LUX ? TSL2550_MAX_LUX : lux;
+}
+
+/*
+ * SysFS support
+ */
+
+static ssize_t tsl2550_show_power_state(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       struct tsl2550_data *data = i2c_get_clientdata(to_i2c_client(dev));
+
+       return sprintf(buf, "%u\n", data->power_state);
+}
+
+static ssize_t tsl2550_store_power_state(struct device *dev,
+               struct device_attribute *attr, const char *buf, size_t count)
+{
+       struct i2c_client *client = to_i2c_client(dev);
+       struct tsl2550_data *data = i2c_get_clientdata(client);
+       unsigned long val = simple_strtoul(buf, NULL, 10);
+       int ret;
+
+       if (val < 0 || val > 1)
+               return -EINVAL;
+
+       mutex_lock(&data->update_lock);
+       ret = tsl2550_set_power_state(client, val);
+       mutex_unlock(&data->update_lock);
+
+       if (ret < 0)
+               return ret;
+
+       return count;
+}
+
+static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
+                  tsl2550_show_power_state, tsl2550_store_power_state);
+
+static ssize_t tsl2550_show_operating_mode(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       struct tsl2550_data *data = i2c_get_clientdata(to_i2c_client(dev));
+
+       return sprintf(buf, "%u\n", data->operating_mode);
+}
+
+static ssize_t tsl2550_store_operating_mode(struct device *dev,
+               struct device_attribute *attr, const char *buf, size_t count)
+{
+       struct i2c_client *client = to_i2c_client(dev);
+       struct tsl2550_data *data = i2c_get_clientdata(client);
+       unsigned long val = simple_strtoul(buf, NULL, 10);
+       int ret;
+
+       if (val < 0 || val > 1)
+               return -EINVAL;
+
+       if (data->power_state == 0)
+               return -EBUSY;
+
+       mutex_lock(&data->update_lock);
+       ret = tsl2550_set_operating_mode(client, val);
+       mutex_unlock(&data->update_lock);
+
+       if (ret < 0)
+               return ret;
+
+       return count;
+}
+
+static DEVICE_ATTR(operating_mode, S_IWUSR | S_IRUGO,
+                  tsl2550_show_operating_mode, tsl2550_store_operating_mode);
+
+static ssize_t __tsl2550_show_lux(struct i2c_client *client, char *buf)
+{
+       u8 ch0, ch1;
+       int ret;
+
+       ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC0);
+       if (ret < 0)
+               return ret;
+       ch0 = ret;
+
+       mdelay(1);
+
+       ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC1);
+       if (ret < 0)
+               return ret;
+       ch1 = ret;
+
+       /* Do the job */
+       ret = tsl2550_calculate_lux(ch0, ch1);
+       if (ret < 0)
+               return ret;
+
+       return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t tsl2550_show_lux1_input(struct device *dev,
+                       struct device_attribute *attr, char *buf)
+{
+       struct i2c_client *client = to_i2c_client(dev);
+       struct tsl2550_data *data = i2c_get_clientdata(client);
+       int ret;
+
+       /* No LUX data if not operational */
+       if (!data->power_state)
+               return -EBUSY;
+
+       mutex_lock(&data->update_lock);
+       ret = __tsl2550_show_lux(client, buf);
+       mutex_unlock(&data->update_lock);
+
+       return ret;
+}
+
+static DEVICE_ATTR(lux1_input, S_IRUGO,
+                  tsl2550_show_lux1_input, NULL);
+
+static struct attribute *tsl2550_attributes[] = {
+       &dev_attr_power_state.attr,
+       &dev_attr_operating_mode.attr,
+       &dev_attr_lux1_input.attr,
+       NULL
+};
+
+static const struct attribute_group tsl2550_attr_group = {
+       .attrs = tsl2550_attributes,
+};
+
+/*
+ * Initialization function
+ */
+
+static void tsl2550_init_client(struct i2c_client *client)
+{
+       struct tsl2550_data *data = i2c_get_clientdata(client);
+
+       /* Power up the device and set the default operating mode */
+       tsl2550_set_power_state(client, 1);
+       tsl2550_set_operating_mode(client, data->operating_mode);
+}
+
+/*
+ * I2C init/probing/exit functions
+ */
+
+static struct i2c_driver tsl2550_driver;
+static int __devinit tsl2550_probe(struct i2c_client *client)
+{
+       struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
+       struct tsl2550_data *data;
+       int *opmode, err = 0;
+
+       if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) {
+               err = -EIO;
+               goto exit;
+       }
+
+       data = kzalloc(sizeof(struct tsl2550_data), GFP_KERNEL);
+       if (!data) {
+               err = -ENOMEM;
+               goto exit;
+       }
+       data->client = client;
+       i2c_set_clientdata(client, data);
+
+       /* Check platform data */
+       opmode = client->dev.platform_data;
+       if (opmode) {
+               if (*opmode < 0 || *opmode > 1) {
+                       dev_err(&client->dev, "invalid operating_mode (%d)\n",
+                                       *opmode);
+                       err = -EINVAL;
+                       goto exit_kfree;
+               }
+               data->operating_mode = *opmode;
+       } else
+               data->operating_mode = 0;       /* default mode is standard */
+       dev_info(&client->dev, "%s operating mode\n",
+                       data->operating_mode ? "extended" : "standard");
+
+       /*
+        * Probe the chip. To do so we try to power up the device and then to
+        * read back the 0x03 code
+        */
+       err = i2c_smbus_write_byte(client, TSL2550_POWER_UP);
+       if (err < 0)
+               goto exit_kfree;
+       mdelay(1);
+       err = i2c_smbus_read_byte(client);
+       if (err != TSL2550_POWER_UP) {
+               err = -ENODEV;
+               goto exit_kfree;
+       }
+
+       mutex_init(&data->update_lock);
+
+       /* Initialize the TSL2550 chip */
+       tsl2550_init_client(client);
+
+       /* Register sysfs hooks */
+       err = sysfs_create_group(&client->dev.kobj, &tsl2550_attr_group);
+       if (err)
+               goto exit_kfree;
+
+       dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION);
+
+       return 0;
+
+exit_kfree:
+       kfree(data);
+exit:
+       return err;
+}
+
+static int __devexit tsl2550_remove(struct i2c_client *client)
+{
+       sysfs_remove_group(&client->dev.kobj, &tsl2550_attr_group);
+
+       /* Power down the device */
+       tsl2550_set_power_state(client, 0);
+
+       kfree(i2c_get_clientdata(client));
+
+       return 0;
+}
+
+static struct i2c_driver tsl2550_driver = {
+       .driver = {
+               .name   = TSL2550_DRV_NAME,
+               .owner  = THIS_MODULE,
+       },
+       .probe  = tsl2550_probe,
+       .remove = __devexit_p(tsl2550_remove),
+};
+
+static int __init tsl2550_init(void)
+{
+       return i2c_add_driver(&tsl2550_driver);
+}
+
+static void __exit tsl2550_exit(void)
+{
+       i2c_del_driver(&tsl2550_driver);
+}
+
+MODULE_AUTHOR("Rodolfo Giometti <[EMAIL PROTECTED]>");
+MODULE_DESCRIPTION("TSL2550 ambient light sensor driver");
+MODULE_LICENSE("GPL");
+
+module_init(tsl2550_init);
+module_exit(tsl2550_exit);
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