| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * sky81452-backlight.c SKY81452 backlight driver |
| * |
| * Copyright 2014 Skyworks Solutions Inc. |
| * Author : Gyungoh Yoo <jack.yoo@skyworksinc.com> |
| */ |
| |
| #include <linux/backlight.h> |
| #include <linux/err.h> |
| #include <linux/gpio/consumer.h> |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/of.h> |
| #include <linux/platform_device.h> |
| #include <linux/regmap.h> |
| #include <linux/slab.h> |
| |
| /* registers */ |
| #define SKY81452_REG0 0x00 |
| #define SKY81452_REG1 0x01 |
| #define SKY81452_REG2 0x02 |
| #define SKY81452_REG4 0x04 |
| #define SKY81452_REG5 0x05 |
| |
| /* bit mask */ |
| #define SKY81452_CS 0xFF |
| #define SKY81452_EN 0x3F |
| #define SKY81452_IGPW 0x20 |
| #define SKY81452_PWMMD 0x10 |
| #define SKY81452_PHASE 0x08 |
| #define SKY81452_ILIM 0x04 |
| #define SKY81452_VSHRT 0x03 |
| #define SKY81452_OCP 0x80 |
| #define SKY81452_OTMP 0x40 |
| #define SKY81452_SHRT 0x3F |
| #define SKY81452_OPN 0x3F |
| |
| #define SKY81452_DEFAULT_NAME "lcd-backlight" |
| #define SKY81452_MAX_BRIGHTNESS (SKY81452_CS + 1) |
| |
| /** |
| * struct sky81452_bl_platform_data - backlight platform data |
| * @name: backlight driver name. |
| * If it is not defined, default name is lcd-backlight. |
| * @gpiod_enable:GPIO descriptor which control EN pin |
| * @enable: Enable mask for current sink channel 1, 2, 3, 4, 5 and 6. |
| * @ignore_pwm: true if DPWMI should be ignored. |
| * @dpwm_mode: true is DPWM dimming mode, otherwise Analog dimming mode. |
| * @phase_shift:true is phase shift mode. |
| * @short_detection_threshold: It should be one of 4, 5, 6 and 7V. |
| * @boost_current_limit: It should be one of 2300, 2750mA. |
| */ |
| struct sky81452_bl_platform_data { |
| const char *name; |
| struct gpio_desc *gpiod_enable; |
| unsigned int enable; |
| bool ignore_pwm; |
| bool dpwm_mode; |
| bool phase_shift; |
| unsigned int short_detection_threshold; |
| unsigned int boost_current_limit; |
| }; |
| |
| #define CTZ(b) __builtin_ctz(b) |
| |
| static int sky81452_bl_update_status(struct backlight_device *bd) |
| { |
| const struct sky81452_bl_platform_data *pdata = |
| dev_get_platdata(bd->dev.parent); |
| const unsigned int brightness = (unsigned int)bd->props.brightness; |
| struct regmap *regmap = bl_get_data(bd); |
| int ret; |
| |
| if (brightness > 0) { |
| ret = regmap_write(regmap, SKY81452_REG0, brightness - 1); |
| if (ret < 0) |
| return ret; |
| |
| return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN, |
| pdata->enable << CTZ(SKY81452_EN)); |
| } |
| |
| return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN, 0); |
| } |
| |
| static const struct backlight_ops sky81452_bl_ops = { |
| .update_status = sky81452_bl_update_status, |
| }; |
| |
| static ssize_t sky81452_bl_store_enable(struct device *dev, |
| struct device_attribute *attr, const char *buf, size_t count) |
| { |
| struct regmap *regmap = bl_get_data(to_backlight_device(dev)); |
| unsigned long value; |
| int ret; |
| |
| ret = kstrtoul(buf, 16, &value); |
| if (ret < 0) |
| return ret; |
| |
| ret = regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN, |
| value << CTZ(SKY81452_EN)); |
| if (ret < 0) |
| return ret; |
| |
| return count; |
| } |
| |
| static ssize_t sky81452_bl_show_open_short(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct regmap *regmap = bl_get_data(to_backlight_device(dev)); |
| unsigned int reg, value = 0; |
| char tmp[3]; |
| int i, ret; |
| |
| reg = !strcmp(attr->attr.name, "open") ? SKY81452_REG5 : SKY81452_REG4; |
| ret = regmap_read(regmap, reg, &value); |
| if (ret < 0) |
| return ret; |
| |
| if (value & SKY81452_SHRT) { |
| *buf = 0; |
| for (i = 0; i < 6; i++) { |
| if (value & 0x01) { |
| sprintf(tmp, "%d ", i + 1); |
| strcat(buf, tmp); |
| } |
| value >>= 1; |
| } |
| strcat(buf, "\n"); |
| } else { |
| strcpy(buf, "none\n"); |
| } |
| |
| return strlen(buf); |
| } |
| |
| static ssize_t sky81452_bl_show_fault(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct regmap *regmap = bl_get_data(to_backlight_device(dev)); |
| unsigned int value = 0; |
| int ret; |
| |
| ret = regmap_read(regmap, SKY81452_REG4, &value); |
| if (ret < 0) |
| return ret; |
| |
| *buf = 0; |
| |
| if (value & SKY81452_OCP) |
| strcat(buf, "over-current "); |
| |
| if (value & SKY81452_OTMP) |
| strcat(buf, "over-temperature"); |
| |
| strcat(buf, "\n"); |
| return strlen(buf); |
| } |
| |
| static DEVICE_ATTR(enable, S_IWGRP | S_IWUSR, NULL, sky81452_bl_store_enable); |
| static DEVICE_ATTR(open, S_IRUGO, sky81452_bl_show_open_short, NULL); |
| static DEVICE_ATTR(short, S_IRUGO, sky81452_bl_show_open_short, NULL); |
| static DEVICE_ATTR(fault, S_IRUGO, sky81452_bl_show_fault, NULL); |
| |
| static struct attribute *sky81452_bl_attribute[] = { |
| &dev_attr_enable.attr, |
| &dev_attr_open.attr, |
| &dev_attr_short.attr, |
| &dev_attr_fault.attr, |
| NULL |
| }; |
| |
| static const struct attribute_group sky81452_bl_attr_group = { |
| .attrs = sky81452_bl_attribute, |
| }; |
| |
| #ifdef CONFIG_OF |
| static struct sky81452_bl_platform_data *sky81452_bl_parse_dt( |
| struct device *dev) |
| { |
| struct device_node *np = dev->of_node; |
| struct sky81452_bl_platform_data *pdata; |
| int num_entry; |
| unsigned int sources[6]; |
| int ret; |
| |
| if (!np) { |
| dev_err(dev, "backlight node not found.\n"); |
| return ERR_PTR(-ENODATA); |
| } |
| |
| pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); |
| if (!pdata) |
| return ERR_PTR(-ENOMEM); |
| |
| of_property_read_string(np, "name", &pdata->name); |
| pdata->ignore_pwm = of_property_read_bool(np, "skyworks,ignore-pwm"); |
| pdata->dpwm_mode = of_property_read_bool(np, "skyworks,dpwm-mode"); |
| pdata->phase_shift = of_property_read_bool(np, "skyworks,phase-shift"); |
| pdata->gpiod_enable = devm_gpiod_get_optional(dev, NULL, GPIOD_OUT_HIGH); |
| |
| ret = of_property_count_u32_elems(np, "led-sources"); |
| if (ret < 0) { |
| pdata->enable = SKY81452_EN >> CTZ(SKY81452_EN); |
| } else { |
| num_entry = ret; |
| if (num_entry > 6) |
| num_entry = 6; |
| |
| ret = of_property_read_u32_array(np, "led-sources", sources, |
| num_entry); |
| if (ret < 0) { |
| dev_err(dev, "led-sources node is invalid.\n"); |
| return ERR_PTR(-EINVAL); |
| } |
| |
| pdata->enable = 0; |
| while (--num_entry) |
| pdata->enable |= (1 << sources[num_entry]); |
| } |
| |
| ret = of_property_read_u32(np, |
| "skyworks,short-detection-threshold-volt", |
| &pdata->short_detection_threshold); |
| if (ret < 0) |
| pdata->short_detection_threshold = 7; |
| |
| ret = of_property_read_u32(np, "skyworks,current-limit-mA", |
| &pdata->boost_current_limit); |
| if (ret < 0) |
| pdata->boost_current_limit = 2750; |
| |
| return pdata; |
| } |
| #else |
| static struct sky81452_bl_platform_data *sky81452_bl_parse_dt( |
| struct device *dev) |
| { |
| return ERR_PTR(-EINVAL); |
| } |
| #endif |
| |
| static int sky81452_bl_init_device(struct regmap *regmap, |
| struct sky81452_bl_platform_data *pdata) |
| { |
| unsigned int value; |
| |
| value = pdata->ignore_pwm ? SKY81452_IGPW : 0; |
| value |= pdata->dpwm_mode ? SKY81452_PWMMD : 0; |
| value |= pdata->phase_shift ? 0 : SKY81452_PHASE; |
| |
| if (pdata->boost_current_limit == 2300) |
| value |= SKY81452_ILIM; |
| else if (pdata->boost_current_limit != 2750) |
| return -EINVAL; |
| |
| if (pdata->short_detection_threshold < 4 || |
| pdata->short_detection_threshold > 7) |
| return -EINVAL; |
| value |= (7 - pdata->short_detection_threshold) << CTZ(SKY81452_VSHRT); |
| |
| return regmap_write(regmap, SKY81452_REG2, value); |
| } |
| |
| static int sky81452_bl_probe(struct platform_device *pdev) |
| { |
| struct device *dev = &pdev->dev; |
| struct regmap *regmap = dev_get_drvdata(dev->parent); |
| struct sky81452_bl_platform_data *pdata; |
| struct backlight_device *bd; |
| struct backlight_properties props; |
| const char *name; |
| int ret; |
| |
| pdata = sky81452_bl_parse_dt(dev); |
| if (IS_ERR(pdata)) |
| return PTR_ERR(pdata); |
| |
| ret = sky81452_bl_init_device(regmap, pdata); |
| if (ret < 0) { |
| dev_err(dev, "failed to initialize. err=%d\n", ret); |
| return ret; |
| } |
| |
| memset(&props, 0, sizeof(props)); |
| props.max_brightness = SKY81452_MAX_BRIGHTNESS; |
| name = pdata->name ? pdata->name : SKY81452_DEFAULT_NAME; |
| bd = devm_backlight_device_register(dev, name, dev, regmap, |
| &sky81452_bl_ops, &props); |
| if (IS_ERR(bd)) { |
| dev_err(dev, "failed to register. err=%ld\n", PTR_ERR(bd)); |
| return PTR_ERR(bd); |
| } |
| |
| platform_set_drvdata(pdev, bd); |
| |
| ret = sysfs_create_group(&bd->dev.kobj, &sky81452_bl_attr_group); |
| if (ret < 0) { |
| dev_err(dev, "failed to create attribute. err=%d\n", ret); |
| return ret; |
| } |
| |
| return ret; |
| } |
| |
| static void sky81452_bl_remove(struct platform_device *pdev) |
| { |
| const struct sky81452_bl_platform_data *pdata = |
| dev_get_platdata(&pdev->dev); |
| struct backlight_device *bd = platform_get_drvdata(pdev); |
| |
| sysfs_remove_group(&bd->dev.kobj, &sky81452_bl_attr_group); |
| |
| bd->props.power = FB_BLANK_UNBLANK; |
| bd->props.brightness = 0; |
| backlight_update_status(bd); |
| |
| if (pdata->gpiod_enable) |
| gpiod_set_value_cansleep(pdata->gpiod_enable, 0); |
| } |
| |
| #ifdef CONFIG_OF |
| static const struct of_device_id sky81452_bl_of_match[] = { |
| { .compatible = "skyworks,sky81452-backlight", }, |
| { } |
| }; |
| MODULE_DEVICE_TABLE(of, sky81452_bl_of_match); |
| #endif |
| |
| static struct platform_driver sky81452_bl_driver = { |
| .driver = { |
| .name = "sky81452-backlight", |
| .of_match_table = of_match_ptr(sky81452_bl_of_match), |
| }, |
| .probe = sky81452_bl_probe, |
| .remove_new = sky81452_bl_remove, |
| }; |
| |
| module_platform_driver(sky81452_bl_driver); |
| |
| MODULE_DESCRIPTION("Skyworks SKY81452 backlight driver"); |
| MODULE_AUTHOR("Gyungoh Yoo <jack.yoo@skyworksinc.com>"); |
| MODULE_LICENSE("GPL v2"); |