diff options
Diffstat (limited to 'drivers/video/backlight/sky81452-backlight.c')
| -rw-r--r-- | drivers/video/backlight/sky81452-backlight.c | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/drivers/video/backlight/sky81452-backlight.c b/drivers/video/backlight/sky81452-backlight.c new file mode 100644 index 000000000..a2f77625b --- /dev/null +++ b/drivers/video/backlight/sky81452-backlight.c @@ -0,0 +1,354 @@ +/* + * sky81452-backlight.c SKY81452 backlight driver + * + * Copyright 2014 Skyworks Solutions Inc. + * Author : Gyungoh Yoo <jack.yoo@skyworksinc.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/backlight.h> +#include <linux/err.h> +#include <linux/gpio.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_gpio.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> +#include <linux/platform_data/sky81452-backlight.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) + +#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 = of_node_get(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) { + of_node_put(np); + 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->gpio_enable = of_get_gpio(np, 0); + + 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"); + of_node_put(np); + 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; + + of_node_put(np); + 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 = dev_get_platdata(dev); + struct backlight_device *bd; + struct backlight_properties props; + const char *name; + int ret; + + if (!pdata) { + pdata = sky81452_bl_parse_dt(dev); + if (IS_ERR(pdata)) + return PTR_ERR(pdata); + } + + if (gpio_is_valid(pdata->gpio_enable)) { + ret = devm_gpio_request_one(dev, pdata->gpio_enable, + GPIOF_OUT_INIT_HIGH, "sky81452-en"); + if (ret < 0) { + dev_err(dev, "failed to request GPIO. err=%d\n", ret); + return ret; + } + } + + 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 int 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 (gpio_is_valid(pdata->gpio_enable)) + gpio_set_value_cansleep(pdata->gpio_enable, 0); + + return 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 = 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"); |