[PATCH] I2C: TSL2550 support.

Rodolfo Giometti
2007-06-19T14:46:40Z

Add support for Taos TSL2550 ambient light sensors.
(http://www.taosinc.com/product_detail.asp?cateid=4&proid=18).

Signed-off-by: Rodolfo Giometti <giometti@linux.it>
---
drivers/i2c/chips/Kconfig | 10 +
drivers/i2c/chips/Makefile | 1 +
drivers/i2c/chips/tsl2550.c | 453 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 464 insertions(+), 0 deletions(-)
create mode 100644 drivers/i2c/chips/tsl2550.c

diff --git a/drivers/i2c/chips/Kconfig b/drivers/i2c/chips/Kconfig
index ea085a0..1cfe50b 100644
--- a/drivers/i2c/chips/Kconfig
+++ b/drivers/i2c/chips/Kconfig
@@ -124,4 +124,14 @@ 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 779868e..1ef6a04 100644
--- a/drivers/i2c/chips/Makefile
+++ b/drivers/i2c/chips/Makefile
@@ -12,6 +12,7 @@ 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..ce43f64
--- /dev/null
+++ b/drivers/i2c/chips/tsl2550.c
@@ -0,0 +1,453 @@
+/*
+ * tsl2550.c - Linux kernel modules for ambient light sensor
+ *
+ * Copyright (C) 2007 Rodolfo Giometti <giometti@linux.it>
+ * Copyright (C) 2007 Eurotech S.p.A. <info@eurotech.it>
+ *
+ * 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, struct device_attribute *attr, 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, attr, 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
+ | I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
+ 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 <giometti@linux.it>");
+MODULE_DESCRIPTION("TSL2550 ambient light sensor driver");
+MODULE_LICENSE("GPL");
+
+module_init(tsl2550_init);
+module_exit(tsl2550_exit);
--
1.5.1.1

--

GNU/Linux Solutions e-mail: giometti@enneenne.com
Linux Device Driver giometti@gnudd.com
Embedded Systems giometti@linux.it
UNIX programming phone: +39 349 2432127