mirror of https://gitee.com/openkylin/linux.git
Fix LCD backlight issue for droid4
There was a bit of an integration glitch with the LED backlight series. The LED related parts got merged into v5.6-rc1, but the actual backlight driver got left out. This caused an issue on at least droid4 where the LCD backlight can not yet be enabled automatically. And the LCD backlight can no longer be enabled manually either via sysfs. The integration glitch happened because some pending comments from me. There was some confusion on which device tree property we should use for the default brightness property. After discussing how to fix this on the mailing lists, we came to the conclusion that it's best to fix this issue properly by adding the missing driver. The other solutions would mean backpedaling and try to come up with some temporary solution that really does not solve the issue for users. The patch for led_bl.c has been around for quite a while and tested by many users and was assumed to be merged as part of the LED backlight series. For the brightness property to use, we ended up using the more common "default-brightness-level" rather than "default-brightness" used by some backlight drivers. -----BEGIN PGP SIGNATURE----- iQJFBAABCAAvFiEEkgNvrZJU/QSQYIcQG9Q+yVyrpXMFAl5OppQRHHRvbnlAYXRv bWlkZS5jb20ACgkQG9Q+yVyrpXOB4g//b1K/jF80B8sKBhcR+XsSleo7q3wYdm7c dwlK6fAQVDFylk4/ZrLUgnuqPqIGGMeeSZsCE9upS/esQNJfiGid576hF/82huoL yqIxWQYxClfXmHX71s6BrI1rL/xXTjioSynBKeBb52+eUgnyRISGkOhm7xJE0ili Qv9SIGpPymZC+vPLS7hbt9E2vhpsMFEBOmQxXoIDL5PSaaTr5HalkNHgdxxPNne8 fftwD/z7exCj/8Gzsbq37aVNEwb+SQyu7jB38+mQLew1Tb3mpr1pdbWtJfIgrEqH XS7hMCd8kesPAXvY8fO4FukFatGbCsHrl/TXbe50utcVTVtRg8OasTTOf651vk94 Fzi/HxeTm0TT6BmJcivSbveab4XeYxoNrSn8XZKsErp5qNqQ5aHHLYM4oV8nUNjF 2f32ZinaLxKXu/TD0I2mQs/SOUVRm+1/f0rLuGcjshn0HsDF4Gjo9YkI2P3EDO/i V/kk+Y1vCGM5opgr6P7ndYe3xky/PK6XmDGXtgW+dZWMI4TPrDwfb1lp5FlMWTdH /wOVKxqjbbW0JsVidN8pJEMOzwH8/qKtrA1rt/szZhbwvBBdO4MdE0G7yxH2vMbE mZmSIUIvRTzaownEHhr315fga3OvPC/P/b1GLUSN4Jg95s9W539mX3hwKT7FA66m uLG/mAWEmv0= =Pox9 -----END PGP SIGNATURE----- Merge tag 'omap-for-v5.6/droid4-lcd-fix-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into arm/fixes Fix LCD backlight issue for droid4 There was a bit of an integration glitch with the LED backlight series. The LED related parts got merged into v5.6-rc1, but the actual backlight driver got left out. This caused an issue on at least droid4 where the LCD backlight can not yet be enabled automatically. And the LCD backlight can no longer be enabled manually either via sysfs. The integration glitch happened because some pending comments from me. There was some confusion on which device tree property we should use for the default brightness property. After discussing how to fix this on the mailing lists, we came to the conclusion that it's best to fix this issue properly by adding the missing driver. The other solutions would mean backpedaling and try to come up with some temporary solution that really does not solve the issue for users. The patch for led_bl.c has been around for quite a while and tested by many users and was assumed to be merged as part of the LED backlight series. For the brightness property to use, we ended up using the more common "default-brightness-level" rather than "default-brightness" used by some backlight drivers. * tag 'omap-for-v5.6/droid4-lcd-fix-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap: ARM: dts: droid4: Configure LED backlight for lm3532 backlight: add led-backlight driver Link: https://lore.kernel.org/r/pull-1582303901-96693@atomide.com Signed-off-by: Olof Johansson <olof@lixom.net>
This commit is contained in:
Olof Johansson
commit
515fa3ee9d
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@ -182,6 +182,14 @@ vibrator {
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pwm-names = "enable", "direction";
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direction-duty-cycle-ns = <10000000>;
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};
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backlight: backlight {
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compatible = "led-backlight";
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leds = <&backlight_led>;
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brightness-levels = <31 63 95 127 159 191 223 255>;
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default-brightness-level = <6>;
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};
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};
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&dss {
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@ -205,6 +213,8 @@ lcd0: display {
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vddi-supply = <&lcd_regulator>;
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reset-gpios = <&gpio4 5 GPIO_ACTIVE_HIGH>; /* gpio101 */
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backlight = <&backlight>;
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width-mm = <50>;
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height-mm = <89>;
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@ -393,12 +403,11 @@ led-controller@38 {
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ramp-up-us = <1024>;
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ramp-down-us = <8193>;
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led@0 {
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backlight_led: led@0 {
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reg = <0>;
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led-sources = <2>;
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ti,led-mode = <0>;
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label = ":backlight";
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linux,default-trigger = "backlight";
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};
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led@1 {
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@ -375,6 +375,7 @@ CONFIG_BACKLIGHT_GENERIC=m
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CONFIG_BACKLIGHT_PWM=m
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CONFIG_BACKLIGHT_PANDORA=m
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CONFIG_BACKLIGHT_GPIO=m
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CONFIG_BACKLIGHT_LED=m
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CONFIG_FRAMEBUFFER_CONSOLE=y
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CONFIG_FRAMEBUFFER_CONSOLE_ROTATION=y
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CONFIG_LOGO=y
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@ -456,6 +456,13 @@ config BACKLIGHT_RAVE_SP
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help
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Support for backlight control on RAVE SP device.
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config BACKLIGHT_LED
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tristate "Generic LED based Backlight Driver"
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depends on LEDS_CLASS && OF
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help
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If you have a LCD backlight adjustable by LED class driver, say Y
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to enable this driver.
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endif # BACKLIGHT_CLASS_DEVICE
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endmenu
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@ -57,3 +57,4 @@ obj-$(CONFIG_BACKLIGHT_TPS65217) += tps65217_bl.o
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obj-$(CONFIG_BACKLIGHT_WM831X) += wm831x_bl.o
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obj-$(CONFIG_BACKLIGHT_ARCXCNN) += arcxcnn_bl.o
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obj-$(CONFIG_BACKLIGHT_RAVE_SP) += rave-sp-backlight.o
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obj-$(CONFIG_BACKLIGHT_LED) += led_bl.o
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@ -0,0 +1,260 @@
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2015-2019 Texas Instruments Incorporated - http://www.ti.com/
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* Author: Tomi Valkeinen <tomi.valkeinen@ti.com>
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*
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* Based on pwm_bl.c
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*/
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#include <linux/backlight.h>
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#include <linux/leds.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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struct led_bl_data {
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struct device *dev;
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struct backlight_device *bl_dev;
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struct led_classdev **leds;
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bool enabled;
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int nb_leds;
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unsigned int *levels;
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unsigned int default_brightness;
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unsigned int max_brightness;
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};
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static void led_bl_set_brightness(struct led_bl_data *priv, int level)
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{
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int i;
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int bkl_brightness;
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if (priv->levels)
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bkl_brightness = priv->levels[level];
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else
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bkl_brightness = level;
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for (i = 0; i < priv->nb_leds; i++)
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led_set_brightness(priv->leds[i], bkl_brightness);
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priv->enabled = true;
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}
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static void led_bl_power_off(struct led_bl_data *priv)
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{
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int i;
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if (!priv->enabled)
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return;
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for (i = 0; i < priv->nb_leds; i++)
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led_set_brightness(priv->leds[i], LED_OFF);
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priv->enabled = false;
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}
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static int led_bl_update_status(struct backlight_device *bl)
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{
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struct led_bl_data *priv = bl_get_data(bl);
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int brightness = bl->props.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 (brightness > 0)
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led_bl_set_brightness(priv, brightness);
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else
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led_bl_power_off(priv);
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return 0;
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}
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static const struct backlight_ops led_bl_ops = {
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.update_status = led_bl_update_status,
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};
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static int led_bl_get_leds(struct device *dev,
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struct led_bl_data *priv)
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{
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int i, nb_leds, ret;
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struct device_node *node = dev->of_node;
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struct led_classdev **leds;
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unsigned int max_brightness;
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unsigned int default_brightness;
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ret = of_count_phandle_with_args(node, "leds", NULL);
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if (ret < 0) {
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dev_err(dev, "Unable to get led count\n");
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return -EINVAL;
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}
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nb_leds = ret;
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if (nb_leds < 1) {
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dev_err(dev, "At least one LED must be specified!\n");
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return -EINVAL;
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}
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leds = devm_kzalloc(dev, sizeof(struct led_classdev *) * nb_leds,
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GFP_KERNEL);
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if (!leds)
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return -ENOMEM;
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for (i = 0; i < nb_leds; i++) {
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leds[i] = devm_of_led_get(dev, i);
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if (IS_ERR(leds[i]))
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return PTR_ERR(leds[i]);
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}
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/* check that the LEDs all have the same brightness range */
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max_brightness = leds[0]->max_brightness;
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for (i = 1; i < nb_leds; i++) {
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if (max_brightness != leds[i]->max_brightness) {
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dev_err(dev, "LEDs must have identical ranges\n");
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return -EINVAL;
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}
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}
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/* get the default brightness from the first LED from the list */
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default_brightness = leds[0]->brightness;
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priv->nb_leds = nb_leds;
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priv->leds = leds;
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priv->max_brightness = max_brightness;
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priv->default_brightness = default_brightness;
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return 0;
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}
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static int led_bl_parse_levels(struct device *dev,
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struct led_bl_data *priv)
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{
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struct device_node *node = dev->of_node;
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int num_levels;
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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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num_levels = of_property_count_u32_elems(node, "brightness-levels");
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if (num_levels > 1) {
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int i;
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unsigned int db;
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u32 *levels = NULL;
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levels = devm_kzalloc(dev, sizeof(u32) * num_levels,
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GFP_KERNEL);
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if (!levels)
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return -ENOMEM;
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ret = of_property_read_u32_array(node, "brightness-levels",
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levels,
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num_levels);
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if (ret < 0)
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return ret;
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/*
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* Try to map actual LED brightness to backlight brightness
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* level
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*/
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db = priv->default_brightness;
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for (i = 0 ; i < num_levels; i++) {
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if ((i && db > levels[i-1]) && db <= levels[i])
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break;
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}
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priv->default_brightness = i;
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priv->max_brightness = num_levels - 1;
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priv->levels = levels;
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} else if (num_levels >= 0)
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dev_warn(dev, "Not enough levels defined\n");
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ret = of_property_read_u32(node, "default-brightness-level", &value);
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if (!ret && value <= priv->max_brightness)
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priv->default_brightness = value;
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else if (!ret && value > priv->max_brightness)
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dev_warn(dev, "Invalid default brightness. Ignoring it\n");
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return 0;
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}
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static int led_bl_probe(struct platform_device *pdev)
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{
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struct backlight_properties props;
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struct led_bl_data *priv;
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int ret, i;
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priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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platform_set_drvdata(pdev, priv);
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priv->dev = &pdev->dev;
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ret = led_bl_get_leds(&pdev->dev, priv);
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if (ret)
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return ret;
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ret = led_bl_parse_levels(&pdev->dev, priv);
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if (ret < 0) {
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dev_err(&pdev->dev, "Failed to parse DT data\n");
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return ret;
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}
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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 = priv->max_brightness;
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props.brightness = priv->default_brightness;
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props.power = (priv->default_brightness > 0) ? FB_BLANK_POWERDOWN :
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FB_BLANK_UNBLANK;
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priv->bl_dev = backlight_device_register(dev_name(&pdev->dev),
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&pdev->dev, priv, &led_bl_ops, &props);
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if (IS_ERR(priv->bl_dev)) {
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dev_err(&pdev->dev, "Failed to register backlight\n");
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return PTR_ERR(priv->bl_dev);
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}
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for (i = 0; i < priv->nb_leds; i++)
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led_sysfs_disable(priv->leds[i]);
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backlight_update_status(priv->bl_dev);
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return 0;
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}
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static int led_bl_remove(struct platform_device *pdev)
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{
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struct led_bl_data *priv = platform_get_drvdata(pdev);
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struct backlight_device *bl = priv->bl_dev;
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int i;
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backlight_device_unregister(bl);
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led_bl_power_off(priv);
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for (i = 0; i < priv->nb_leds; i++)
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led_sysfs_enable(priv->leds[i]);
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return 0;
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}
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static const struct of_device_id led_bl_of_match[] = {
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{ .compatible = "led-backlight" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, led_bl_of_match);
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static struct platform_driver led_bl_driver = {
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.driver = {
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.name = "led-backlight",
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.of_match_table = of_match_ptr(led_bl_of_match),
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},
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.probe = led_bl_probe,
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.remove = led_bl_remove,
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};
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module_platform_driver(led_bl_driver);
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MODULE_DESCRIPTION("LED based Backlight Driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:led-backlight");
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