![Linus Torvalds](/assets/img/avatar_default.png)
A new driver has been added to support the PWM mode of the timer counter blocks found on Atmel AT91 SoCs. The VT8500 driver now supports changing the PWM signal polarity and the TI drivers (EHRPWM and ECAP) gained suspend and resume functionality. User drivers can now query the core for whether access to a PWM device will sleep (if the PWM chip is on a slow bus such as I2C or SPI). The pwm-backlight driver now handles the backlight BL_CORE_FBBLANK state in addition to the FB layer's blanking states. To round things off, a few fixes and cleanups are also included. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iQIcBAABAgAGBQJRKxfbAAoJEN0jrNd/PrOhcwEP/0plVf30QDMhcan1GR3l+jmK 3Q/cCNIWEZ75mRu+FtVYKUOduxkCOHR6LM4C2ScGnnpsS/X5oitc45FrblIwQaEI UeWVxDqI+pEp+rCdYVCND4lih60FJU0Cct0zZL2db4D4idF+8FRChhzwzSXhajnj ZZqz782Y2ig3YTLHtVGT1pp61DKxdu1Gz4U+fxo4G1/fnkquCYDzbCQovcmPSnnF gYB8hfxgT9JIt2cHrK6eKCHBF/4GToU+x5zDV2Ub15C2K/UQ+qgw82yl8MNd/ZS5 rFA06iW3icnJRRc8u6hu9WVjNVNTBrUqUlFhctNB01d5jF4R6uR6aEvovT9xe8NW Wa5v5WrjnL6SWpZVwb/3kwwJmkeU9zKESQt5KUw3VKnT8yr2BfxcH1gJIiuW6wK7 uYqknAvt2rwMEGzaKZJmQH682wNMxpJirs8hG9VjJc/v7AOnk6586HbRupAq8wWZ qK4n1Fto9RCg+b6e/hDId7+mN1GEcA5B8BOotPQ6ud+cinDZBKSbCSHhQG2LQ++F m81BbL82H2R2ICRoYNA74/bKq5OVOFFqHLHg5bUrG7ikdNbYOTK/4dF9qSS7DnT3 Bi6WnKpOtfpWbHBnDunP2vBFo3f+gXmbLJdgarxk7mneV8wp0GY6TYI1awWn0hI9 82JP3yiK5kW2JZv92o0H =Fcxi -----END PGP SIGNATURE----- Merge tag 'for-3.9-rc1' of git://gitorious.org/linux-pwm/linux-pwm Pull PWM changes from Thierry Reding: "A new driver has been added to support the PWM mode of the timer counter blocks found on Atmel AT91 SoCs. The VT8500 driver now supports changing the PWM signal polarity and the TI drivers (EHRPWM and ECAP) gained suspend and resume functionality. User drivers can now query the core for whether access to a PWM device will sleep (if the PWM chip is on a slow bus such as I2C or SPI). The pwm-backlight driver now handles the backlight BL_CORE_FBBLANK state in addition to the FB layer's blanking states. To round things off, a few fixes and cleanups are also included" * tag 'for-3.9-rc1' of git://gitorious.org/linux-pwm/linux-pwm: pwm: twl: Use to_twl() instead of container_of() pwm: tegra: assume CONFIG_OF pwm_backlight: Validate dft_brightness in main probe function pwm: Export pwm_{set,get}_chip_data() pwm: Make Kconfig entries more consistent pwm: Add can_sleep property to drivers pwm: Add pwm_can_sleep() as exported API to users pwm-backlight: handle BL_CORE_FBBLANK state pwm: pwm-tiecap: Low power sleep support pwm: pwm-tiehrpwm: Low power sleep support pwm: pwm-tiehrpwm: Update the clock handling of pwm-tiehrpwm driver pwm: vt8500: Add polarity support pwm: vt8500: Register write busy test performed incorrectly pwm: atmel: add Timer Counter Block PWM driver
324 lines
7.7 KiB
C
324 lines
7.7 KiB
C
/*
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* linux/drivers/video/backlight/pwm_bl.c
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*
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* simple PWM based backlight control, board code has to setup
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* 1) pin configuration so PWM waveforms can output
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* 2) platform_data being correctly configured
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/fb.h>
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#include <linux/backlight.h>
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#include <linux/err.h>
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#include <linux/pwm.h>
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#include <linux/pwm_backlight.h>
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#include <linux/slab.h>
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struct pwm_bl_data {
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struct pwm_device *pwm;
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struct device *dev;
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unsigned int period;
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unsigned int lth_brightness;
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unsigned int *levels;
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int (*notify)(struct device *,
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int brightness);
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void (*notify_after)(struct device *,
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int brightness);
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int (*check_fb)(struct device *, struct fb_info *);
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void (*exit)(struct device *);
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};
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static int pwm_backlight_update_status(struct backlight_device *bl)
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{
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struct pwm_bl_data *pb = bl_get_data(bl);
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int brightness = bl->props.brightness;
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int max = bl->props.max_brightness;
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if (bl->props.power != FB_BLANK_UNBLANK ||
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bl->props.fb_blank != FB_BLANK_UNBLANK ||
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bl->props.state & BL_CORE_FBBLANK)
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brightness = 0;
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if (pb->notify)
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brightness = pb->notify(pb->dev, brightness);
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if (brightness == 0) {
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pwm_config(pb->pwm, 0, pb->period);
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pwm_disable(pb->pwm);
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} else {
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int duty_cycle;
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if (pb->levels) {
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duty_cycle = pb->levels[brightness];
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max = pb->levels[max];
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} else {
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duty_cycle = brightness;
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}
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duty_cycle = pb->lth_brightness +
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(duty_cycle * (pb->period - pb->lth_brightness) / max);
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pwm_config(pb->pwm, duty_cycle, pb->period);
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pwm_enable(pb->pwm);
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}
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if (pb->notify_after)
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pb->notify_after(pb->dev, brightness);
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return 0;
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}
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static int pwm_backlight_get_brightness(struct backlight_device *bl)
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{
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return bl->props.brightness;
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}
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static int pwm_backlight_check_fb(struct backlight_device *bl,
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struct fb_info *info)
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{
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struct pwm_bl_data *pb = bl_get_data(bl);
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return !pb->check_fb || pb->check_fb(pb->dev, info);
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}
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static const struct backlight_ops pwm_backlight_ops = {
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.update_status = pwm_backlight_update_status,
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.get_brightness = pwm_backlight_get_brightness,
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.check_fb = pwm_backlight_check_fb,
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};
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#ifdef CONFIG_OF
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static int pwm_backlight_parse_dt(struct device *dev,
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struct platform_pwm_backlight_data *data)
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{
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struct device_node *node = dev->of_node;
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struct property *prop;
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int length;
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u32 value;
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int ret;
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if (!node)
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return -ENODEV;
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memset(data, 0, sizeof(*data));
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/* determine the number of brightness levels */
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prop = of_find_property(node, "brightness-levels", &length);
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if (!prop)
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return -EINVAL;
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data->max_brightness = length / sizeof(u32);
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/* read brightness levels from DT property */
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if (data->max_brightness > 0) {
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size_t size = sizeof(*data->levels) * data->max_brightness;
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data->levels = devm_kzalloc(dev, size, GFP_KERNEL);
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if (!data->levels)
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return -ENOMEM;
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ret = of_property_read_u32_array(node, "brightness-levels",
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data->levels,
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data->max_brightness);
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if (ret < 0)
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return ret;
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ret = of_property_read_u32(node, "default-brightness-level",
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&value);
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if (ret < 0)
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return ret;
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data->dft_brightness = value;
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data->max_brightness--;
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}
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/*
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* TODO: Most users of this driver use a number of GPIOs to control
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* backlight power. Support for specifying these needs to be
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* added.
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*/
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return 0;
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}
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static struct of_device_id pwm_backlight_of_match[] = {
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{ .compatible = "pwm-backlight" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, pwm_backlight_of_match);
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#else
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static int pwm_backlight_parse_dt(struct device *dev,
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struct platform_pwm_backlight_data *data)
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{
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return -ENODEV;
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}
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#endif
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static int pwm_backlight_probe(struct platform_device *pdev)
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{
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struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
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struct platform_pwm_backlight_data defdata;
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struct backlight_properties props;
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struct backlight_device *bl;
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struct pwm_bl_data *pb;
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unsigned int max;
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int ret;
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if (!data) {
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ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
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if (ret < 0) {
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dev_err(&pdev->dev, "failed to find platform data\n");
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return ret;
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}
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data = &defdata;
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}
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if (data->init) {
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ret = data->init(&pdev->dev);
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if (ret < 0)
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return ret;
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}
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pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL);
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if (!pb) {
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dev_err(&pdev->dev, "no memory for state\n");
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ret = -ENOMEM;
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goto err_alloc;
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}
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if (data->levels) {
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max = data->levels[data->max_brightness];
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pb->levels = data->levels;
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} else
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max = data->max_brightness;
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pb->notify = data->notify;
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pb->notify_after = data->notify_after;
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pb->check_fb = data->check_fb;
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pb->exit = data->exit;
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pb->dev = &pdev->dev;
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pb->pwm = devm_pwm_get(&pdev->dev, NULL);
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if (IS_ERR(pb->pwm)) {
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dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
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pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
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if (IS_ERR(pb->pwm)) {
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dev_err(&pdev->dev, "unable to request legacy PWM\n");
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ret = PTR_ERR(pb->pwm);
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goto err_alloc;
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}
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}
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dev_dbg(&pdev->dev, "got pwm for backlight\n");
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/*
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* The DT case will set the pwm_period_ns field to 0 and store the
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* period, parsed from the DT, in the PWM device. For the non-DT case,
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* set the period from platform data.
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*/
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if (data->pwm_period_ns > 0)
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pwm_set_period(pb->pwm, data->pwm_period_ns);
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pb->period = pwm_get_period(pb->pwm);
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pb->lth_brightness = data->lth_brightness * (pb->period / max);
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memset(&props, 0, sizeof(struct backlight_properties));
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props.type = BACKLIGHT_RAW;
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props.max_brightness = data->max_brightness;
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bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb,
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&pwm_backlight_ops, &props);
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if (IS_ERR(bl)) {
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dev_err(&pdev->dev, "failed to register backlight\n");
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ret = PTR_ERR(bl);
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goto err_alloc;
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}
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if (data->dft_brightness > data->max_brightness) {
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dev_warn(&pdev->dev,
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"invalid default brightness level: %u, using %u\n",
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data->dft_brightness, data->max_brightness);
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data->dft_brightness = data->max_brightness;
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}
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bl->props.brightness = data->dft_brightness;
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backlight_update_status(bl);
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platform_set_drvdata(pdev, bl);
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return 0;
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err_alloc:
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if (data->exit)
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data->exit(&pdev->dev);
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return ret;
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}
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static int pwm_backlight_remove(struct platform_device *pdev)
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{
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struct backlight_device *bl = platform_get_drvdata(pdev);
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struct pwm_bl_data *pb = bl_get_data(bl);
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backlight_device_unregister(bl);
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pwm_config(pb->pwm, 0, pb->period);
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pwm_disable(pb->pwm);
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if (pb->exit)
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pb->exit(&pdev->dev);
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return 0;
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}
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#ifdef CONFIG_PM
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static int pwm_backlight_suspend(struct device *dev)
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{
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struct backlight_device *bl = dev_get_drvdata(dev);
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struct pwm_bl_data *pb = bl_get_data(bl);
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if (pb->notify)
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pb->notify(pb->dev, 0);
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pwm_config(pb->pwm, 0, pb->period);
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pwm_disable(pb->pwm);
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if (pb->notify_after)
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pb->notify_after(pb->dev, 0);
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return 0;
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}
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static int pwm_backlight_resume(struct device *dev)
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{
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struct backlight_device *bl = dev_get_drvdata(dev);
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backlight_update_status(bl);
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return 0;
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}
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static SIMPLE_DEV_PM_OPS(pwm_backlight_pm_ops, pwm_backlight_suspend,
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pwm_backlight_resume);
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#endif
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static struct platform_driver pwm_backlight_driver = {
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.driver = {
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.name = "pwm-backlight",
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.owner = THIS_MODULE,
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#ifdef CONFIG_PM
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.pm = &pwm_backlight_pm_ops,
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#endif
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.of_match_table = of_match_ptr(pwm_backlight_of_match),
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},
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.probe = pwm_backlight_probe,
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.remove = pwm_backlight_remove,
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};
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module_platform_driver(pwm_backlight_driver);
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MODULE_DESCRIPTION("PWM based Backlight Driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:pwm-backlight");
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