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Message-ID: <871v48vlgu.fsf@ti.com>
Date: Wed, 19 Jan 2011 09:42:41 -0800
From: Kevin Hilman <khilman@...com>
To: rpurdie@...ys.net, Andrew Morton <akpm@...ux-foundation.org>
Cc: davinci-linux-open-source@...ux.davincidsp.com,
spi-devel-general@...ts.sourceforge.net, sameo@...ux.intel.com,
dbrownell@...rs.sourceforge.net,
linux-arm-kernel@...ts.arm.linux.org.uk,
linux-kernel@...r.kernel.org, Cyril Chemparathy <cyril@...com>
Subject: Re: [PATCH v8 04/11] backlight: add support for tps6116x controller
Richard,
Cyril Chemparathy <cyril@...com> writes:
> TPS6116x is an EasyScale backlight controller device. This driver supports
> TPS6116x devices connected on a single GPIO.
>
> Signed-off-by: Cyril Chemparathy <cyril@...com>
Any comments on this driver?
With your Ack, I'll be happy to merge it via the davinci tree with the
rest of the series.
Thanks,
Kevin
> ---
> 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");
--
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