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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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