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Subject[PATCHv2 1/2] leds: add driver for LM3530 ALS
Date
From: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>

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>
---
changes in v2:
modified according to comments from Richard Purdie
- i2c write in a loop in init function
- meaningful sysfs user input values

drivers/leds/Kconfig | 10 ++
drivers/leds/Makefile | 1 +
drivers/leds/leds-lm3530.c | 381 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/led-lm3530.h | 108 +++++++++++++
4 files changed, 500 insertions(+), 0 deletions(-)
create mode 100644 drivers/leds/leds-lm3530.c
create mode 100644 include/linux/led-lm3530.h

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 6f190f4..9bec869 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 aae6989..39c80fc 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 0000000..4d92754
--- /dev/null
+++ b/drivers/leds/leds-lm3530.c
@@ -0,0 +1,381 @@
+/*
+ * 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 count)
+{
+ int i;
+
+ if (str[0] == '\n')
+ return -1;
+
+ for (i = 0; i < LM3530_BL_MODE_MAX; i++)
+ if (!strncmp(mode_map[i].mode, str, count))
+ 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, size-1);
+ 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>");
diff --git a/include/linux/led-lm3530.h b/include/linux/led-lm3530.h
new file mode 100644
index 0000000..309bc91
--- /dev/null
+++ b/include/linux/led-lm3530.h
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2011 ST-Ericsson SA.
+ * Copyright (C) 2009 Motorola, Inc.
+ *
+ * License Terms: GNU General Public License v2
+ *
+ * Simple driver for National Semiconductor LM35330 Backlight driver chip
+ *
+ * Author: Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>
+ * based on leds-lm3530.c by Dan Murphy <D.Murphy@motorola.com>
+ */
+
+#ifndef _LINUX_LED_LM3530_H__
+#define _LINUX_LED_LM3530_H__
+
+#define LM3530_FS_CURR_5mA (0) /* Full Scale Current */
+#define LM3530_FS_CURR_8mA (1)
+#define LM3530_FS_CURR_12mA (2)
+#define LM3530_FS_CURR_15mA (3)
+#define LM3530_FS_CURR_19mA (4)
+#define LM3530_FS_CURR_22mA (5)
+#define LM3530_FS_CURR_26mA (6)
+#define LM3530_FS_CURR_29mA (7)
+
+#define LM3530_ALS_AVRG_TIME_32ms (0) /* ALS Averaging Time */
+#define LM3530_ALS_AVRG_TIME_64ms (1)
+#define LM3530_ALS_AVRG_TIME_128ms (2)
+#define LM3530_ALS_AVRG_TIME_256ms (3)
+#define LM3530_ALS_AVRG_TIME_512ms (4)
+#define LM3530_ALS_AVRG_TIME_1024ms (5)
+#define LM3530_ALS_AVRG_TIME_2048ms (6)
+#define LM3530_ALS_AVRG_TIME_4096ms (7)
+
+#define LM3530_RAMP_TIME_1ms (0) /* Brigtness Ramp Time */
+#define LM3530_RAMP_TIME_130ms (1) /* Max to 0 and vice versa */
+#define LM3530_RAMP_TIME_260ms (2)
+#define LM3530_RAMP_TIME_520ms (3)
+#define LM3530_RAMP_TIME_1s (4)
+#define LM3530_RAMP_TIME_2s (5)
+#define LM3530_RAMP_TIME_4s (6)
+#define LM3530_RAMP_TIME_8s (7)
+
+/* ALS Resistor Select */
+#define LM3530_ALS_IMPD_Z (0x00) /* ALS Impedence */
+#define LM3530_ALS_IMPD_13_53kOhm (0x01)
+#define LM3530_ALS_IMPD_9_01kOhm (0x02)
+#define LM3530_ALS_IMPD_5_41kOhm (0x03)
+#define LM3530_ALS_IMPD_2_27kOhm (0x04)
+#define LM3530_ALS_IMPD_1_94kOhm (0x05)
+#define LM3530_ALS_IMPD_1_81kOhm (0x06)
+#define LM3530_ALS_IMPD_1_6kOhm (0x07)
+#define LM3530_ALS_IMPD_1_138kOhm (0x08)
+#define LM3530_ALS_IMPD_1_05kOhm (0x09)
+#define LM3530_ALS_IMPD_1_011kOhm (0x0A)
+#define LM3530_ALS_IMPD_941Ohm (0x0B)
+#define LM3530_ALS_IMPD_759Ohm (0x0C)
+#define LM3530_ALS_IMPD_719Ohm (0x0D)
+#define LM3530_ALS_IMPD_700Ohm (0x0E)
+#define LM3530_ALS_IMPD_667Ohm (0x0F)
+
+enum lm3530_mode {
+ LM3530_BL_MODE_MANUAL = 0, /* "man" */
+ LM3530_BL_MODE_ALS, /* "als" */
+ LM3530_BL_MODE_PWM, /* "pwm" */
+ LM3530_BL_MODE_MAX,
+};
+
+/* ALS input select */
+enum lm3530_als_mode {
+ LM3530_INPUT_AVRG = 0, /* ALS1 and ALS2 input average */
+ LM3530_INPUT_ALS1, /* ALS1 Input */
+ LM3530_INPUT_ALS2, /* ALS2 Input */
+ LM3530_INPUT_CEIL, /* Max of ALS1 and ALS2 */
+};
+
+/**
+ * struct lm3530_platform_data
+ * @mode: mode of operation i.e. Manual, ALS or PWM
+ * @als_input_mode: select source of ALS input - ALS1/2 or average
+ * @max_current: full scale LED current
+ * @pwm_pol_hi: PWM input polarity - active high/active low
+ * @als_avrg_time: ALS input averaging time
+ * @brt_ramp_law: brightness mapping mode - exponential/linear
+ * @brt_ramp_fall: rate of fall of led current
+ * @brt_ramp_rise: rate of rise of led current
+ * @als1_resistor_sel: internal resistance from ALS1 input to ground
+ * @als2_resistor_sel: internal resistance from ALS2 input to ground
+ * @brt_val: brightness value (0-255)
+ */
+struct lm3530_platform_data {
+ enum lm3530_mode mode;
+ enum lm3530_als_mode als_input_mode;
+
+ u8 max_current;
+ bool pwm_pol_hi;
+ u8 als_avrg_time;
+
+ bool brt_ramp_law;
+ u8 brt_ramp_fall;
+ u8 brt_ramp_rise;
+
+ u8 als1_resistor_sel;
+ u8 als2_resistor_sel;
+
+ u8 brt_val;
+};
+
+#endif /* _LINUX_LED_LM3530_H__ */
--
1.7.2.dirty


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