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Subject[PATCH v8 04/11] backlight: add support for tps6116x controller
Date
TPS6116x is an EasyScale backlight controller device.  This driver supports
TPS6116x devices connected on a single GPIO.

Signed-off-by: Cyril Chemparathy <cyril@ti.com>
---
drivers/video/backlight/Kconfig | 7 +
drivers/video/backlight/Makefile | 2 +-
drivers/video/backlight/tps6116x.c | 299 ++++++++++++++++++++++++++++++++++++
3 files changed, 307 insertions(+), 1 deletions(-)
create mode 100644 drivers/video/backlight/tps6116x.c
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index e54a337..06e868e 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -307,6 +307,13 @@ config BACKLIGHT_PCF50633
If you have a backlight driven by a NXP PCF50633 MFD, say Y here to
enable its driver.

+config BACKLIGHT_TPS6116X
+ tristate "TPS6116X LCD Backlight"
+ depends on GENERIC_GPIO
+ help
+ This driver controls the LCD backlight level for EasyScale capable
+ SSP connected backlight controllers.
+
endif # BACKLIGHT_CLASS_DEVICE

endif # BACKLIGHT_LCD_SUPPORT
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 44c0f81..5d407c8 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -35,4 +35,4 @@ obj-$(CONFIG_BACKLIGHT_ADP5520) += adp5520_bl.o
obj-$(CONFIG_BACKLIGHT_ADP8860) += adp8860_bl.o
obj-$(CONFIG_BACKLIGHT_88PM860X) += 88pm860x_bl.o
obj-$(CONFIG_BACKLIGHT_PCF50633) += pcf50633-backlight.o
-
+obj-$(CONFIG_BACKLIGHT_TPS6116X)+= tps6116x.o
diff --git a/drivers/video/backlight/tps6116x.c b/drivers/video/backlight/tps6116x.c
new file mode 100644
index 0000000..7f846ab
--- /dev/null
+++ b/drivers/video/backlight/tps6116x.c
@@ -0,0 +1,299 @@
+/*
+ * TPS6116X LCD Backlight Controller Driver
+ *
+ * Copyright (C) 2010 Texas Instruments
+ *
+ * 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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
+ * whether express or implied; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/fb.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/backlight.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#define TPS6116X_MAX_INTENSITY 31
+#define TPS6116X_DEFAULT_INTENSITY 10
+
+/* Easyscale timing w/ margin (usecs) */
+#define T_POWER_SETTLE 2000
+#define T_ES_DELAY 120
+#define T_ES_DETECT 280
+#define T_ES_WINDOW (1000 - T_ES_DELAY - T_ES_DETECT)
+#define T_START 3
+#define T_EOS 3
+#define T_INACTIVE 3
+#define T_ACTIVE (3 * T_INACTIVE)
+
+#define CMD_SET 0x72
+
+struct tps6116x {
+ struct ti_ssp_device *handle;
+ struct device *dev;
+ int gpio;
+ struct mutex lock;
+ int intensity;
+ struct backlight_properties props;
+ struct backlight_device *bl;
+ struct regulator *regulator;
+ bool power;
+ bool suspended;
+};
+
+static int __set_power(struct tps6116x *hw, bool power)
+{
+ unsigned long flags;
+ int error;
+
+ if (power == hw->power)
+ return 0; /* nothing to do */
+
+ /* disabling is simple... choke power */
+ if (!power) {
+ error = regulator_disable(hw->regulator);
+ goto done;
+ }
+
+ /* set ctrl pin init state for easyscale detection */
+ gpio_set_value(hw->gpio, 0);
+
+ error = regulator_enable(hw->regulator);
+ if (error < 0)
+ goto done;
+
+ udelay(T_POWER_SETTLE);
+
+ /*
+ * Now that the controller is powered up, we need to put it into 1-wire
+ * mode. This is a timing sensitive operation, hence the irq disable.
+ * Ideally, this should happen rarely, and mostly at init, so disabling
+ * interrupts for the duration should not be a problem.
+ */
+ local_irq_save(flags);
+
+ gpio_set_value(hw->gpio, 1);
+ udelay(T_ES_DELAY);
+ gpio_set_value(hw->gpio, 0);
+ udelay(T_ES_DETECT);
+ gpio_set_value(hw->gpio, 1);
+
+ local_irq_restore(flags);
+
+done:
+ if (error >= 0)
+ hw->power = power;
+
+ return error;
+}
+
+static void __write_byte(struct tps6116x *hw, u8 data)
+{
+ int bit;
+
+ gpio_set_value(hw->gpio, 1);
+ udelay(T_START);
+
+ for (bit = 0; bit < 8; bit++, data <<= 1) {
+ int val = data & 0x80;
+ int t_lo = val ? T_INACTIVE : T_ACTIVE;
+ int t_hi = val ? T_ACTIVE : T_INACTIVE;
+
+ gpio_set_value(hw->gpio, 0);
+ udelay(t_lo);
+ gpio_set_value(hw->gpio, 1);
+ udelay(t_hi);
+ }
+
+ gpio_set_value(hw->gpio, 0);
+ udelay(T_EOS);
+ gpio_set_value(hw->gpio, 1);
+}
+
+static void __set_intensity(struct tps6116x *hw, int intensity)
+{
+ unsigned long flags;
+
+ intensity = clamp(intensity, 0, TPS6116X_MAX_INTENSITY);
+
+ local_irq_save(flags);
+ __write_byte(hw, CMD_SET);
+ __write_byte(hw, intensity);
+ local_irq_restore(flags);
+}
+
+static int set_intensity(struct tps6116x *hw, int intensity)
+{
+ int error = 0;
+
+ if (intensity == hw->intensity)
+ return 0;
+
+ mutex_lock(&hw->lock);
+
+ error = __set_power(hw, intensity ? true : false);
+ if (error < 0)
+ goto error;
+
+ if (intensity > 0)
+ __set_intensity(hw, intensity);
+
+ hw->intensity = intensity;
+error:
+ mutex_unlock(&hw->lock);
+
+ return error;
+}
+
+static int get_brightness(struct backlight_device *bl)
+{
+ struct tps6116x *hw = bl_get_data(bl);
+
+ return hw->intensity;
+}
+
+static int update_status(struct backlight_device *bl)
+{
+ struct tps6116x *hw = bl_get_data(bl);
+ int intensity = bl->props.brightness;
+
+ if (hw->suspended || hw->props.state & BL_CORE_SUSPENDED)
+ intensity = 0;
+ if (bl->props.power != FB_BLANK_UNBLANK)
+ intensity = 0;
+ if (bl->props.fb_blank != FB_BLANK_UNBLANK)
+ intensity = 0;
+
+ return set_intensity(hw, intensity);
+}
+
+static const struct backlight_ops tps6116x_backlight_ops = {
+ .options = BL_CORE_SUSPENDRESUME,
+ .get_brightness = get_brightness,
+ .update_status = update_status,
+};
+
+static int __devinit tps6116x_probe(struct platform_device *pdev)
+{
+ struct tps6116x *hw;
+ struct device *dev = &pdev->dev;
+ struct backlight_properties props;
+ int error;
+
+ hw = kzalloc(sizeof(struct tps6116x), GFP_KERNEL);
+ if (!hw) {
+ dev_err(dev, "cannot allocate driver data\n");
+ return -ENOMEM;
+ }
+ platform_set_drvdata(pdev, hw);
+
+ hw->gpio = (int)dev->platform_data;
+ hw->dev = dev;
+
+ mutex_init(&hw->lock);
+
+ hw->regulator = regulator_get(dev, "vlcd");
+ if (IS_ERR(hw->regulator)) {
+ error = PTR_ERR(hw->regulator);
+ dev_err(dev, "cannot claim regulator\n");
+ goto error_regulator;
+ }
+
+ error = gpio_request_one(hw->gpio, GPIOF_DIR_OUT, dev_name(dev));
+ if (error < 0) {
+ dev_err(dev, "cannot claim gpio\n");
+ goto error_gpio;
+ }
+
+ memset(&props, 0, sizeof(props));
+ props.max_brightness = TPS6116X_MAX_INTENSITY;
+ props.brightness = TPS6116X_DEFAULT_INTENSITY;
+ props.power = FB_BLANK_UNBLANK;
+
+ hw->bl = backlight_device_register("tps6116x", hw->dev, hw,
+ &tps6116x_backlight_ops, &props);
+ if (IS_ERR(hw->bl)) {
+ error = PTR_ERR(hw->bl);
+ dev_err(dev, "backlight registration failed\n");
+ goto error_register;
+ }
+
+ update_status(hw->bl);
+ dev_info(dev, "registered backlight controller\n");
+ return 0;
+
+error_register:
+ gpio_free(hw->gpio);
+error_gpio:
+ regulator_put(hw->regulator);
+error_regulator:
+ kfree(hw);
+ platform_set_drvdata(pdev, NULL);
+ return error;
+}
+
+static int __devexit tps6116x_remove(struct platform_device *pdev)
+{
+ struct tps6116x *hw = platform_get_drvdata(pdev);
+
+ backlight_device_unregister(hw->bl);
+ regulator_disable(hw->regulator);
+ regulator_put(hw->regulator);
+ gpio_free(hw->gpio);
+ kfree(hw);
+ platform_set_drvdata(pdev, NULL);
+ return 0;
+}
+
+static int tps6116x_suspend(struct platform_device *pdev, pm_message_t state)
+{
+ struct tps6116x *hw = platform_get_drvdata(pdev);
+ hw->suspended = true;
+ update_status(hw->bl);
+ return 0;
+}
+
+static int tps6116x_resume(struct platform_device *pdev)
+{
+ struct tps6116x *hw = platform_get_drvdata(pdev);
+ hw->suspended = false;
+ update_status(hw->bl);
+ return 0;
+}
+
+static struct platform_driver tps6116x_driver = {
+ .probe = tps6116x_probe,
+ .remove = __devexit_p(tps6116x_remove),
+ .suspend = tps6116x_suspend,
+ .resume = tps6116x_resume,
+ .driver = {
+ .name = "tps6116x",
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init tps6116x_init(void)
+{
+ return platform_driver_register(&tps6116x_driver);
+}
+module_init(tps6116x_init);
+
+static void __exit tps6116x_exit(void)
+{
+ platform_driver_unregister(&tps6116x_driver);
+}
+module_exit(tps6116x_exit);
+
+MODULE_DESCRIPTION("SSP TPS6116X Driver");
+MODULE_AUTHOR("Cyril Chemparathy");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:tps6116x");
--
1.7.1


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