summaryrefslogtreecommitdiff
path: root/drivers/video
diff options
context:
space:
mode:
authorKim, Milo <Milo.Kim@ti.com>2012-03-24 02:02:01 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-24 03:58:33 +0400
commit7be865ab8634d4ec2a6bdb9459b268cd60e832af (patch)
treed7b73134707935d0bf6a912fa96e6dfcef47676a /drivers/video
parent050ea48bbfc80b6aa81f8df0d9f25e6e47d96e98 (diff)
downloadlinux-7be865ab8634d4ec2a6bdb9459b268cd60e832af.tar.xz
backlight: new backlight driver for LP855x devices
THis driver supports TI LP8550/LP8551/LP8552/LP8553/LP8556 backlight devices. The brightness can be controlled by the I2C or PWM input. The lp855x driver provides both modes. For the PWM control, pwm-specific functions can be defined in the platform data. And some information can be read via the sysfs(lp855x device attributes). For details, please refer to Documentation/backlight/lp855x-driver.txt. [axel.lin@gmail.com: add missing mutex_unlock in lp855x_read_byte() error path] [axel.lin@gmail.com: check platform data in lp855x_probe()] [axel.lin@gmail.com: small cleanups] [dan.carpenter@oracle.com: silence a compiler warning] [axel.lin@gmail.com: use id->driver_data to differentiate lp855x chips] [akpm@linux-foundation.org: simplify boolean return expression] Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com> Signed-off-by: Axel Lin <axel.lin@gmail.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.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>
Diffstat (limited to 'drivers/video')
-rw-r--r--drivers/video/backlight/Kconfig7
-rw-r--r--drivers/video/backlight/Makefile1
-rw-r--r--drivers/video/backlight/lp855x_bl.c331
3 files changed, 339 insertions, 0 deletions
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 681b36929fe4..49e7d83f869f 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -334,6 +334,13 @@ config BACKLIGHT_AAT2870
If you have a AnalogicTech AAT2870 say Y to enable the
backlight driver.
+config BACKLIGHT_LP855X
+ tristate "Backlight driver for TI LP855X"
+ depends on BACKLIGHT_CLASS_DEVICE && I2C
+ help
+ This supports TI LP8550, LP8551, LP8552, LP8553 and LP8556
+ backlight driver.
+
endif # BACKLIGHT_CLASS_DEVICE
endif # BACKLIGHT_LCD_SUPPORT
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index af5cf654ec7c..0ee06e0832bd 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_BACKLIGHT_GENERIC) += generic_bl.o
obj-$(CONFIG_BACKLIGHT_HP700) += jornada720_bl.o
obj-$(CONFIG_BACKLIGHT_HP680) += hp680_bl.o
obj-$(CONFIG_BACKLIGHT_LOCOMO) += locomolcd.o
+obj-$(CONFIG_BACKLIGHT_LP855X) += lp855x_bl.o
obj-$(CONFIG_BACKLIGHT_OMAP1) += omap1_bl.o
obj-$(CONFIG_BACKLIGHT_PROGEAR) += progear_bl.o
obj-$(CONFIG_BACKLIGHT_CARILLO_RANCH) += cr_bllcd.o
diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c
new file mode 100644
index 000000000000..72a0e0c917cf
--- /dev/null
+++ b/drivers/video/backlight/lp855x_bl.c
@@ -0,0 +1,331 @@
+/*
+ * TI LP855x Backlight Driver
+ *
+ * Copyright (C) 2011 Texas Instruments
+ *
+ * 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.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/backlight.h>
+#include <linux/err.h>
+#include <linux/lp855x.h>
+
+/* Registers */
+#define BRIGHTNESS_CTRL (0x00)
+#define DEVICE_CTRL (0x01)
+
+#define BUF_SIZE 20
+#define DEFAULT_BL_NAME "lcd-backlight"
+#define MAX_BRIGHTNESS 255
+
+struct lp855x {
+ const char *chipname;
+ enum lp855x_chip_id chip_id;
+ struct i2c_client *client;
+ struct backlight_device *bl;
+ struct device *dev;
+ struct mutex xfer_lock;
+ struct lp855x_platform_data *pdata;
+};
+
+static int lp855x_read_byte(struct lp855x *lp, u8 reg, u8 *data)
+{
+ int ret;
+
+ mutex_lock(&lp->xfer_lock);
+ ret = i2c_smbus_read_byte_data(lp->client, reg);
+ if (ret < 0) {
+ mutex_unlock(&lp->xfer_lock);
+ dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
+ return ret;
+ }
+ mutex_unlock(&lp->xfer_lock);
+
+ *data = (u8)ret;
+ return 0;
+}
+
+static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
+{
+ int ret;
+
+ mutex_lock(&lp->xfer_lock);
+ ret = i2c_smbus_write_byte_data(lp->client, reg, data);
+ mutex_unlock(&lp->xfer_lock);
+
+ return ret;
+}
+
+static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
+{
+ u8 start, end;
+
+ switch (lp->chip_id) {
+ case LP8550:
+ case LP8551:
+ case LP8552:
+ case LP8553:
+ start = EEPROM_START;
+ end = EEPROM_END;
+ break;
+ case LP8556:
+ start = EPROM_START;
+ end = EPROM_END;
+ break;
+ default:
+ return false;
+ }
+
+ return (addr >= start && addr <= end);
+}
+
+static int lp855x_init_registers(struct lp855x *lp)
+{
+ u8 val, addr;
+ int i, ret;
+ struct lp855x_platform_data *pd = lp->pdata;
+
+ val = pd->initial_brightness;
+ ret = lp855x_write_byte(lp, BRIGHTNESS_CTRL, val);
+ if (ret)
+ return ret;
+
+ val = pd->device_control;
+ ret = lp855x_write_byte(lp, DEVICE_CTRL, val);
+ if (ret)
+ return ret;
+
+ if (pd->load_new_rom_data && pd->size_program) {
+ for (i = 0; i < pd->size_program; i++) {
+ addr = pd->rom_data[i].addr;
+ val = pd->rom_data[i].val;
+ if (!lp855x_is_valid_rom_area(lp, addr))
+ continue;
+
+ ret = lp855x_write_byte(lp, addr, val);
+ if (ret)
+ return ret;
+ }
+ }
+
+ return ret;
+}
+
+static int lp855x_bl_update_status(struct backlight_device *bl)
+{
+ struct lp855x *lp = bl_get_data(bl);
+ enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
+
+ if (bl->props.state & BL_CORE_SUSPENDED)
+ bl->props.brightness = 0;
+
+ if (mode == PWM_BASED) {
+ struct lp855x_pwm_data *pd = &lp->pdata->pwm_data;
+ int br = bl->props.brightness;
+ int max_br = bl->props.max_brightness;
+
+ if (pd->pwm_set_intensity)
+ pd->pwm_set_intensity(br, max_br);
+
+ } else if (mode == REGISTER_BASED) {
+ u8 val = bl->props.brightness;
+ lp855x_write_byte(lp, BRIGHTNESS_CTRL, val);
+ }
+
+ return 0;
+}
+
+static int lp855x_bl_get_brightness(struct backlight_device *bl)
+{
+ struct lp855x *lp = bl_get_data(bl);
+ enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
+
+ if (mode == PWM_BASED) {
+ struct lp855x_pwm_data *pd = &lp->pdata->pwm_data;
+ int max_br = bl->props.max_brightness;
+
+ if (pd->pwm_get_intensity)
+ bl->props.brightness = pd->pwm_get_intensity(max_br);
+
+ } else if (mode == REGISTER_BASED) {
+ u8 val = 0;
+
+ lp855x_read_byte(lp, BRIGHTNESS_CTRL, &val);
+ bl->props.brightness = val;
+ }
+
+ return bl->props.brightness;
+}
+
+static const struct backlight_ops lp855x_bl_ops = {
+ .options = BL_CORE_SUSPENDRESUME,
+ .update_status = lp855x_bl_update_status,
+ .get_brightness = lp855x_bl_get_brightness,
+};
+
+static int lp855x_backlight_register(struct lp855x *lp)
+{
+ struct backlight_device *bl;
+ struct backlight_properties props;
+ struct lp855x_platform_data *pdata = lp->pdata;
+ char *name = pdata->name ? : DEFAULT_BL_NAME;
+
+ props.type = BACKLIGHT_PLATFORM;
+ props.max_brightness = MAX_BRIGHTNESS;
+
+ if (pdata->initial_brightness > props.max_brightness)
+ pdata->initial_brightness = props.max_brightness;
+
+ props.brightness = pdata->initial_brightness;
+
+ bl = backlight_device_register(name, lp->dev, lp,
+ &lp855x_bl_ops, &props);
+ if (IS_ERR(bl))
+ return PTR_ERR(bl);
+
+ lp->bl = bl;
+
+ return 0;
+}
+
+static void lp855x_backlight_unregister(struct lp855x *lp)
+{
+ if (lp->bl)
+ backlight_device_unregister(lp->bl);
+}
+
+static ssize_t lp855x_get_chip_id(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct lp855x *lp = dev_get_drvdata(dev);
+ return scnprintf(buf, BUF_SIZE, "%s\n", lp->chipname);
+}
+
+static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct lp855x *lp = dev_get_drvdata(dev);
+ enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
+ char *strmode = NULL;
+
+ if (mode == PWM_BASED)
+ strmode = "pwm based";
+ else if (mode == REGISTER_BASED)
+ strmode = "register based";
+
+ return scnprintf(buf, BUF_SIZE, "%s\n", strmode);
+}
+
+static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
+static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
+
+static struct attribute *lp855x_attributes[] = {
+ &dev_attr_chip_id.attr,
+ &dev_attr_bl_ctl_mode.attr,
+ NULL,
+};
+
+static const struct attribute_group lp855x_attr_group = {
+ .attrs = lp855x_attributes,
+};
+
+static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
+{
+ struct lp855x *lp;
+ struct lp855x_platform_data *pdata = cl->dev.platform_data;
+ enum lp855x_brightness_ctrl_mode mode;
+ int ret;
+
+ if (!pdata) {
+ dev_err(&cl->dev, "no platform data supplied\n");
+ return -EINVAL;
+ }
+
+ if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
+ return -EIO;
+
+ lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
+ if (!lp)
+ return -ENOMEM;
+
+ mode = pdata->mode;
+ lp->client = cl;
+ lp->dev = &cl->dev;
+ lp->pdata = pdata;
+ lp->chipname = id->name;
+ lp->chip_id = id->driver_data;
+ i2c_set_clientdata(cl, lp);
+
+ mutex_init(&lp->xfer_lock);
+
+ ret = lp855x_init_registers(lp);
+ if (ret) {
+ dev_err(lp->dev, "i2c communication err: %d", ret);
+ if (mode == REGISTER_BASED)
+ goto err_dev;
+ }
+
+ ret = lp855x_backlight_register(lp);
+ if (ret) {
+ dev_err(lp->dev,
+ "failed to register backlight. err: %d\n", ret);
+ goto err_dev;
+ }
+
+ ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
+ if (ret) {
+ dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
+ goto err_sysfs;
+ }
+
+ backlight_update_status(lp->bl);
+ return 0;
+
+err_sysfs:
+ lp855x_backlight_unregister(lp);
+err_dev:
+ return ret;
+}
+
+static int __devexit lp855x_remove(struct i2c_client *cl)
+{
+ struct lp855x *lp = i2c_get_clientdata(cl);
+
+ lp->bl->props.brightness = 0;
+ backlight_update_status(lp->bl);
+ sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
+ lp855x_backlight_unregister(lp);
+
+ return 0;
+}
+
+static const struct i2c_device_id lp855x_ids[] = {
+ {"lp8550", LP8550},
+ {"lp8551", LP8551},
+ {"lp8552", LP8552},
+ {"lp8553", LP8553},
+ {"lp8556", LP8556},
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, lp855x_ids);
+
+static struct i2c_driver lp855x_driver = {
+ .driver = {
+ .name = "lp855x",
+ },
+ .probe = lp855x_probe,
+ .remove = __devexit_p(lp855x_remove),
+ .id_table = lp855x_ids,
+};
+
+module_i2c_driver(lp855x_driver);
+
+MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
+MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
+MODULE_LICENSE("GPL");