leds: add driver for LM3530 ALS

Simple backlight driver for National Semiconductor LM3530.  Presently only
manual mode is supported, PWM and ALS support to be added.

Signed-off-by: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Cc: Linus Walleij <linus.walleij@stericsson.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 389 insertions, 0 deletions

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 6f190f4cdbc0..9bec8699b8a3 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -34,6 +34,16 @@ config LEDS_ATMEL_PWM
           This option enables support for LEDs driven using outputs
           of the dedicated PWM controller found on newer Atmel SOCs.
 
+config LEDS_LM3530
+        tristate "LCD Backlight driver for LM3530"
+        depends on LEDS_CLASS
+        depends on I2C
+        help
+          This option enables support for the LCD backlight using
+          LM3530 ambient light sensor chip. This ALS chip can be
+          controlled manually or using PWM input or using ambient
+          light automatically.
+
 config LEDS_LOCOMO
         tristate "LED Support for Locomo device"
         depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index aae6989ff6b6..39c80fca84d2 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_LEDS_88PM860X)		+= leds-88pm860x.o
 obj-$(CONFIG_LEDS_ATMEL_PWM)            += leds-atmel-pwm.o
 obj-$(CONFIG_LEDS_BD2802)               += leds-bd2802.o
 obj-$(CONFIG_LEDS_LOCOMO)               += leds-locomo.o
+obj-$(CONFIG_LEDS_LM3530)               += leds-lm3530.o
 obj-$(CONFIG_LEDS_MIKROTIK_RB532)       += leds-rb532.o
 obj-$(CONFIG_LEDS_S3C24XX)              += leds-s3c24xx.o
 obj-$(CONFIG_LEDS_AMS_DELTA)            += leds-ams-delta.o
diff --git a/drivers/leds/leds-lm3530.c b/drivers/leds/leds-lm3530.c
new file mode 100644
index 000000000000..e7089a1f6cb6
--- /dev/null
+++ b/drivers/leds/leds-lm3530.c
@@ -0,0 +1,378 @@
+/*
+ * Copyright (C) 2011 ST-Ericsson SA.
+ * Copyright (C) 2009 Motorola, Inc.
+ *
+ * License Terms: GNU General Public License v2
+ *
+ * Simple driver for National Semiconductor LM3530 Backlight driver chip
+ *
+ * Author: Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>
+ * based on leds-lm3530.c by Dan Murphy <D.Murphy@motorola.com>
+ */
+
+#include <linux/i2c.h>
+#include <linux/leds.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/input.h>
+#include <linux/led-lm3530.h>
+#include <linux/types.h>
+
+#define LM3530_LED_DEV "lcd-backlight"
+#define LM3530_NAME "lm3530-led"
+
+#define LM3530_GEN_CONFIG               0x10
+#define LM3530_ALS_CONFIG               0x20
+#define LM3530_BRT_RAMP_RATE            0x30
+#define LM3530_ALS_ZONE_REG             0x40
+#define LM3530_ALS_IMP_SELECT           0x41
+#define LM3530_BRT_CTRL_REG             0xA0
+#define LM3530_ALS_ZB0_REG              0x60
+#define LM3530_ALS_ZB1_REG              0x61
+#define LM3530_ALS_ZB2_REG              0x62
+#define LM3530_ALS_ZB3_REG              0x63
+#define LM3530_ALS_Z0T_REG              0x70
+#define LM3530_ALS_Z1T_REG              0x71
+#define LM3530_ALS_Z2T_REG              0x72
+#define LM3530_ALS_Z3T_REG              0x73
+#define LM3530_ALS_Z4T_REG              0x74
+#define LM3530_REG_MAX                  15
+
+/* General Control Register */
+#define LM3530_EN_I2C_SHIFT             (0)
+#define LM3530_RAMP_LAW_SHIFT           (1)
+#define LM3530_MAX_CURR_SHIFT           (2)
+#define LM3530_EN_PWM_SHIFT             (5)
+#define LM3530_PWM_POL_SHIFT            (6)
+#define LM3530_EN_PWM_SIMPLE_SHIFT      (7)
+
+#define LM3530_ENABLE_I2C               (1 << LM3530_EN_I2C_SHIFT)
+#define LM3530_ENABLE_PWM               (1 << LM3530_EN_PWM_SHIFT)
+#define LM3530_POL_LOW                  (1 << LM3530_PWM_POL_SHIFT)
+#define LM3530_ENABLE_PWM_SIMPLE        (1 << LM3530_EN_PWM_SIMPLE_SHIFT)
+
+/* ALS Config Register Options */
+#define LM3530_ALS_AVG_TIME_SHIFT       (0)
+#define LM3530_EN_ALS_SHIFT             (3)
+#define LM3530_ALS_SEL_SHIFT            (5)
+
+#define LM3530_ENABLE_ALS               (3 << LM3530_EN_ALS_SHIFT)
+
+/* Brightness Ramp Rate Register */
+#define LM3530_BRT_RAMP_FALL_SHIFT      (0)
+#define LM3530_BRT_RAMP_RISE_SHIFT      (3)
+
+/* ALS Resistor Select */
+#define LM3530_ALS1_IMP_SHIFT           (0)
+#define LM3530_ALS2_IMP_SHIFT           (4)
+
+/* Zone Boundary Register defaults */
+#define LM3530_DEF_ZB_0                 (0x33)
+#define LM3530_DEF_ZB_1                 (0x66)
+#define LM3530_DEF_ZB_2                 (0x99)
+#define LM3530_DEF_ZB_3                 (0xCC)
+
+/* Zone Target Register defaults */
+#define LM3530_DEF_ZT_0                 (0x19)
+#define LM3530_DEF_ZT_1                 (0x33)
+#define LM3530_DEF_ZT_2                 (0x4C)
+#define LM3530_DEF_ZT_3                 (0x66)
+#define LM3530_DEF_ZT_4                 (0x7F)
+
+struct lm3530_mode_map {
+        const char *mode;
+        enum lm3530_mode mode_val;
+};
+
+static struct lm3530_mode_map mode_map[] = {
+        { "man", LM3530_BL_MODE_MANUAL },
+        { "als", LM3530_BL_MODE_ALS },
+        { "pwm", LM3530_BL_MODE_PWM },
+};
+
+/**
+ * struct lm3530_data
+ * @led_dev: led class device
+ * @client: i2c client
+ * @pdata: LM3530 platform data
+ * @mode: mode of operation - manual, ALS, PWM
+ */
+struct lm3530_data {
+        struct led_classdev led_dev;
+        struct i2c_client *client;
+        struct lm3530_platform_data *pdata;
+        enum lm3530_mode mode;
+};
+
+static const u8 lm3530_reg[LM3530_REG_MAX] = {
+        LM3530_GEN_CONFIG,
+        LM3530_ALS_CONFIG,
+        LM3530_BRT_RAMP_RATE,
+        LM3530_ALS_ZONE_REG,
+        LM3530_ALS_IMP_SELECT,
+        LM3530_BRT_CTRL_REG,
+        LM3530_ALS_ZB0_REG,
+        LM3530_ALS_ZB1_REG,
+        LM3530_ALS_ZB2_REG,
+        LM3530_ALS_ZB3_REG,
+        LM3530_ALS_Z0T_REG,
+        LM3530_ALS_Z1T_REG,
+        LM3530_ALS_Z2T_REG,
+        LM3530_ALS_Z3T_REG,
+        LM3530_ALS_Z4T_REG,
+};
+
+static int lm3530_get_mode_from_str(const char *str)
+{
+        int i;
+
+        for (i = 0; i < ARRAY_SIZE(mode_map); i++)
+                if (sysfs_streq(str, mode_map[i].mode))
+                        return mode_map[i].mode_val;
+
+        return -1;
+}
+
+static int lm3530_init_registers(struct lm3530_data *drvdata)
+{
+        int ret = 0;
+        int i;
+        u8 gen_config;
+        u8 als_config = 0;
+        u8 brt_ramp;
+        u8 als_imp_sel = 0;
+        u8 brightness;
+        u8 reg_val[LM3530_REG_MAX];
+        struct lm3530_platform_data *pltfm = drvdata->pdata;
+        struct i2c_client *client = drvdata->client;
+
+        gen_config = (pltfm->brt_ramp_law << LM3530_RAMP_LAW_SHIFT) |
+                        ((pltfm->max_current & 7) << LM3530_MAX_CURR_SHIFT);
+
+        if (drvdata->mode == LM3530_BL_MODE_MANUAL ||
+            drvdata->mode == LM3530_BL_MODE_ALS)
+                gen_config |= (LM3530_ENABLE_I2C);
+
+        if (drvdata->mode == LM3530_BL_MODE_ALS) {
+                als_config =
+                        (pltfm->als_avrg_time << LM3530_ALS_AVG_TIME_SHIFT) |
+                        (LM3530_ENABLE_ALS) |
+                        (pltfm->als_input_mode << LM3530_ALS_SEL_SHIFT);
+
+                als_imp_sel =
+                        (pltfm->als1_resistor_sel << LM3530_ALS1_IMP_SHIFT) |
+                        (pltfm->als2_resistor_sel << LM3530_ALS2_IMP_SHIFT);
+        }
+
+        if (drvdata->mode == LM3530_BL_MODE_PWM)
+                gen_config |= (LM3530_ENABLE_PWM) |
+                                (pltfm->pwm_pol_hi << LM3530_PWM_POL_SHIFT) |
+                                (LM3530_ENABLE_PWM_SIMPLE);
+
+        brt_ramp = (pltfm->brt_ramp_fall << LM3530_BRT_RAMP_FALL_SHIFT) |
+                        (pltfm->brt_ramp_rise << LM3530_BRT_RAMP_RISE_SHIFT);
+
+        brightness = pltfm->brt_val;
+
+        reg_val[0] = gen_config;        /* LM3530_GEN_CONFIG */
+        reg_val[1] = als_config;        /* LM3530_ALS_CONFIG */
+        reg_val[2] = brt_ramp;          /* LM3530_BRT_RAMP_RATE */
+        reg_val[3] = 0x00;              /* LM3530_ALS_ZONE_REG */
+        reg_val[4] = als_imp_sel;       /* LM3530_ALS_IMP_SELECT */
+        reg_val[5] = brightness;        /* LM3530_BRT_CTRL_REG */
+        reg_val[6] = LM3530_DEF_ZB_0;   /* LM3530_ALS_ZB0_REG */
+        reg_val[7] = LM3530_DEF_ZB_1;   /* LM3530_ALS_ZB1_REG */
+        reg_val[8] = LM3530_DEF_ZB_2;   /* LM3530_ALS_ZB2_REG */
+        reg_val[9] = LM3530_DEF_ZB_3;   /* LM3530_ALS_ZB3_REG */
+        reg_val[10] = LM3530_DEF_ZT_0;  /* LM3530_ALS_Z0T_REG */
+        reg_val[11] = LM3530_DEF_ZT_1;  /* LM3530_ALS_Z1T_REG */
+        reg_val[12] = LM3530_DEF_ZT_2;  /* LM3530_ALS_Z2T_REG */
+        reg_val[13] = LM3530_DEF_ZT_3;  /* LM3530_ALS_Z3T_REG */
+        reg_val[14] = LM3530_DEF_ZT_4;  /* LM3530_ALS_Z4T_REG */
+
+        for (i = 0; i < LM3530_REG_MAX; i++) {
+                ret = i2c_smbus_write_byte_data(client,
+                                lm3530_reg[i], reg_val[i]);
+                if (ret)
+                        break;
+        }
+
+        return ret;
+}
+
+static void lm3530_brightness_set(struct led_classdev *led_cdev,
+                                     enum led_brightness brt_val)
+{
+        int err;
+        struct lm3530_data *drvdata =
+            container_of(led_cdev, struct lm3530_data, led_dev);
+
+        switch (drvdata->mode) {
+        case LM3530_BL_MODE_MANUAL:
+
+                /* set the brightness in brightness control register*/
+                err = i2c_smbus_write_byte_data(drvdata->client,
+                                LM3530_BRT_CTRL_REG, brt_val / 2);
+                if (err)
+                        dev_err(&drvdata->client->dev,
+                                "Unable to set brightness: %d\n", err);
+                break;
+        case LM3530_BL_MODE_ALS:
+                break;
+        case LM3530_BL_MODE_PWM:
+                break;
+        default:
+                break;
+        }
+}
+
+
+static ssize_t lm3530_mode_set(struct device *dev, struct device_attribute
+                                   *attr, const char *buf, size_t size)
+{
+        int err;
+        struct i2c_client *client = container_of(
+                                        dev->parent, struct i2c_client, dev);
+        struct lm3530_data *drvdata = i2c_get_clientdata(client);
+        int mode;
+
+        mode = lm3530_get_mode_from_str(buf);
+        if (mode < 0) {
+                dev_err(dev, "Invalid mode\n");
+                return -EINVAL;
+        }
+
+        if (mode == LM3530_BL_MODE_MANUAL)
+                drvdata->mode = LM3530_BL_MODE_MANUAL;
+        else if (mode == LM3530_BL_MODE_ALS)
+                drvdata->mode = LM3530_BL_MODE_ALS;
+        else if (mode == LM3530_BL_MODE_PWM) {
+                dev_err(dev, "PWM mode not supported\n");
+                return -EINVAL;
+        }
+
+        err = lm3530_init_registers(drvdata);
+        if (err) {
+                dev_err(dev, "Setting %s Mode failed :%d\n", buf, err);
+                return err;
+        }
+
+        return sizeof(drvdata->mode);
+}
+
+static DEVICE_ATTR(mode, 0644, NULL, lm3530_mode_set);
+
+static int __devinit lm3530_probe(struct i2c_client *client,
+                           const struct i2c_device_id *id)
+{
+        struct lm3530_platform_data *pdata = client->dev.platform_data;
+        struct lm3530_data *drvdata;
+        int err = 0;
+
+        if (pdata == NULL) {
+                dev_err(&client->dev, "platform data required\n");
+                err = -ENODEV;
+                goto err_out;
+        }
+
+        /* BL mode */
+        if (pdata->mode > LM3530_BL_MODE_PWM) {
+                dev_err(&client->dev, "Illegal Mode request\n");
+                err = -EINVAL;
+                goto err_out;
+        }
+
+        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+                dev_err(&client->dev, "I2C_FUNC_I2C not supported\n");
+                err = -EIO;
+                goto err_out;
+        }
+
+        drvdata = kzalloc(sizeof(struct lm3530_data), GFP_KERNEL);
+        if (drvdata == NULL) {
+                err = -ENOMEM;
+                goto err_out;
+        }
+
+        drvdata->mode = pdata->mode;
+        drvdata->client = client;
+        drvdata->pdata = pdata;
+        drvdata->led_dev.name = LM3530_LED_DEV;
+        drvdata->led_dev.brightness_set = lm3530_brightness_set;
+
+        i2c_set_clientdata(client, drvdata);
+
+        err = lm3530_init_registers(drvdata);
+        if (err < 0) {
+                dev_err(&client->dev, "Register Init failed: %d\n", err);
+                err = -ENODEV;
+                goto err_reg_init;
+        }
+
+        err = led_classdev_register((struct device *)
+                                      &client->dev, &drvdata->led_dev);
+        if (err < 0) {
+                dev_err(&client->dev, "Register led class failed: %d\n", err);
+                err = -ENODEV;
+                goto err_class_register;
+        }
+
+        err = device_create_file(drvdata->led_dev.dev, &dev_attr_mode);
+        if (err < 0) {
+                dev_err(&client->dev, "File device creation failed: %d\n", err);
+                err = -ENODEV;
+                goto err_create_file;
+        }
+
+        return 0;
+
+err_create_file:
+        led_classdev_unregister(&drvdata->led_dev);
+err_class_register:
+err_reg_init:
+        kfree(drvdata);
+err_out:
+        return err;
+}
+
+static int __devexit lm3530_remove(struct i2c_client *client)
+{
+        struct lm3530_data *drvdata = i2c_get_clientdata(client);
+
+        device_remove_file(drvdata->led_dev.dev, &dev_attr_mode);
+        led_classdev_unregister(&drvdata->led_dev);
+        kfree(drvdata);
+        return 0;
+}
+
+static const struct i2c_device_id lm3530_id[] = {
+        {LM3530_NAME, 0},
+        {}
+};
+
+static struct i2c_driver lm3530_i2c_driver = {
+        .probe = lm3530_probe,
+        .remove = lm3530_remove,
+        .id_table = lm3530_id,
+        .driver = {
+                .name = LM3530_NAME,
+                .owner = THIS_MODULE,
+        },
+};
+
+static int __init lm3530_init(void)
+{
+        return i2c_add_driver(&lm3530_i2c_driver);
+}
+
+static void __exit lm3530_exit(void)
+{
+        i2c_del_driver(&lm3530_i2c_driver);
+}
+
+module_init(lm3530_init);
+module_exit(lm3530_exit);
+
+MODULE_DESCRIPTION("Back Light driver for LM3530");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>");