1/* 2 * Backlight driver for Marvell Semiconductor 88PM8606 3 * 4 * Copyright (C) 2009 Marvell International Ltd. 5 * Haojian Zhuang <haojian.zhuang@marvell.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11 12#include <linux/init.h> 13#include <linux/kernel.h> 14#include <linux/of.h> 15#include <linux/platform_device.h> 16#include <linux/slab.h> 17#include <linux/fb.h> 18#include <linux/i2c.h> 19#include <linux/backlight.h> 20#include <linux/mfd/88pm860x.h> 21#include <linux/module.h> 22 23#define MAX_BRIGHTNESS (0xFF) 24#define MIN_BRIGHTNESS (0) 25 26#define CURRENT_BITMASK (0x1F << 1) 27 28struct pm860x_backlight_data { 29 struct pm860x_chip *chip; 30 struct i2c_client *i2c; 31 int current_brightness; 32 int port; 33 int pwm; 34 int iset; 35 int reg_duty_cycle; 36 int reg_always_on; 37 int reg_current; 38}; 39 40static int backlight_power_set(struct pm860x_chip *chip, int port, 41 int on) 42{ 43 int ret = -EINVAL; 44 45 switch (port) { 46 case 0: 47 ret = on ? pm8606_osc_enable(chip, WLED1_DUTY) : 48 pm8606_osc_disable(chip, WLED1_DUTY); 49 break; 50 case 1: 51 ret = on ? pm8606_osc_enable(chip, WLED2_DUTY) : 52 pm8606_osc_disable(chip, WLED2_DUTY); 53 break; 54 case 2: 55 ret = on ? pm8606_osc_enable(chip, WLED3_DUTY) : 56 pm8606_osc_disable(chip, WLED3_DUTY); 57 break; 58 } 59 return ret; 60} 61 62static int pm860x_backlight_set(struct backlight_device *bl, int brightness) 63{ 64 struct pm860x_backlight_data *data = bl_get_data(bl); 65 struct pm860x_chip *chip = data->chip; 66 unsigned char value; 67 int ret; 68 69 if (brightness > MAX_BRIGHTNESS) 70 value = MAX_BRIGHTNESS; 71 else 72 value = brightness; 73 74 if (brightness) 75 backlight_power_set(chip, data->port, 1); 76 77 ret = pm860x_reg_write(data->i2c, data->reg_duty_cycle, value); 78 if (ret < 0) 79 goto out; 80 81 if ((data->current_brightness == 0) && brightness) { 82 if (data->iset) { 83 ret = pm860x_set_bits(data->i2c, data->reg_current, 84 CURRENT_BITMASK, data->iset); 85 if (ret < 0) 86 goto out; 87 } 88 if (data->pwm) { 89 ret = pm860x_set_bits(data->i2c, PM8606_PWM, 90 PM8606_PWM_FREQ_MASK, data->pwm); 91 if (ret < 0) 92 goto out; 93 } 94 if (brightness == MAX_BRIGHTNESS) { 95 /* set WLED_ON bit as 100% */ 96 ret = pm860x_set_bits(data->i2c, data->reg_always_on, 97 PM8606_WLED_ON, PM8606_WLED_ON); 98 } 99 } else { 100 if (brightness == MAX_BRIGHTNESS) { 101 /* set WLED_ON bit as 100% */ 102 ret = pm860x_set_bits(data->i2c, data->reg_always_on, 103 PM8606_WLED_ON, PM8606_WLED_ON); 104 } else { 105 /* clear WLED_ON bit since it's not 100% */ 106 ret = pm860x_set_bits(data->i2c, data->reg_always_on, 107 PM8606_WLED_ON, 0); 108 } 109 } 110 if (ret < 0) 111 goto out; 112 113 if (brightness == 0) 114 backlight_power_set(chip, data->port, 0); 115 116 dev_dbg(chip->dev, "set brightness %d\n", value); 117 data->current_brightness = value; 118 return 0; 119out: 120 dev_dbg(chip->dev, "set brightness %d failure with return value: %d\n", 121 value, ret); 122 return ret; 123} 124 125static int pm860x_backlight_update_status(struct backlight_device *bl) 126{ 127 int brightness = bl->props.brightness; 128 129 if (bl->props.power != FB_BLANK_UNBLANK) 130 brightness = 0; 131 132 if (bl->props.fb_blank != FB_BLANK_UNBLANK) 133 brightness = 0; 134 135 if (bl->props.state & BL_CORE_SUSPENDED) 136 brightness = 0; 137 138 return pm860x_backlight_set(bl, brightness); 139} 140 141static int pm860x_backlight_get_brightness(struct backlight_device *bl) 142{ 143 struct pm860x_backlight_data *data = bl_get_data(bl); 144 struct pm860x_chip *chip = data->chip; 145 int ret; 146 147 ret = pm860x_reg_read(data->i2c, data->reg_duty_cycle); 148 if (ret < 0) 149 goto out; 150 data->current_brightness = ret; 151 dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness); 152 return data->current_brightness; 153out: 154 return -EINVAL; 155} 156 157static const struct backlight_ops pm860x_backlight_ops = { 158 .options = BL_CORE_SUSPENDRESUME, 159 .update_status = pm860x_backlight_update_status, 160 .get_brightness = pm860x_backlight_get_brightness, 161}; 162 163#ifdef CONFIG_OF 164static int pm860x_backlight_dt_init(struct platform_device *pdev, 165 struct pm860x_backlight_data *data, 166 char *name) 167{ 168 struct device_node *nproot, *np; 169 int iset = 0; 170 171 nproot = of_get_child_by_name(pdev->dev.parent->of_node, "backlights"); 172 if (!nproot) { 173 dev_err(&pdev->dev, "failed to find backlights node\n"); 174 return -ENODEV; 175 } 176 for_each_child_of_node(nproot, np) { 177 if (!of_node_cmp(np->name, name)) { 178 of_property_read_u32(np, "marvell,88pm860x-iset", 179 &iset); 180 data->iset = PM8606_WLED_CURRENT(iset); 181 of_property_read_u32(np, "marvell,88pm860x-pwm", 182 &data->pwm); 183 of_node_put(np); 184 break; 185 } 186 } 187 of_node_put(nproot); 188 return 0; 189} 190#else 191#define pm860x_backlight_dt_init(x, y, z) (-1) 192#endif 193 194static int pm860x_backlight_probe(struct platform_device *pdev) 195{ 196 struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent); 197 struct pm860x_backlight_pdata *pdata = dev_get_platdata(&pdev->dev); 198 struct pm860x_backlight_data *data; 199 struct backlight_device *bl; 200 struct resource *res; 201 struct backlight_properties props; 202 char name[MFD_NAME_SIZE]; 203 int ret = 0; 204 205 data = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_backlight_data), 206 GFP_KERNEL); 207 if (data == NULL) 208 return -ENOMEM; 209 res = platform_get_resource_byname(pdev, IORESOURCE_REG, "duty cycle"); 210 if (!res) { 211 dev_err(&pdev->dev, "No REG resource for duty cycle\n"); 212 return -ENXIO; 213 } 214 data->reg_duty_cycle = res->start; 215 res = platform_get_resource_byname(pdev, IORESOURCE_REG, "always on"); 216 if (!res) { 217 dev_err(&pdev->dev, "No REG resource for always on\n"); 218 return -ENXIO; 219 } 220 data->reg_always_on = res->start; 221 res = platform_get_resource_byname(pdev, IORESOURCE_REG, "current"); 222 if (!res) { 223 dev_err(&pdev->dev, "No REG resource for current\n"); 224 return -ENXIO; 225 } 226 data->reg_current = res->start; 227 228 memset(name, 0, MFD_NAME_SIZE); 229 sprintf(name, "backlight-%d", pdev->id); 230 data->port = pdev->id; 231 data->chip = chip; 232 data->i2c = (chip->id == CHIP_PM8606) ? chip->client : chip->companion; 233 data->current_brightness = MAX_BRIGHTNESS; 234 if (pm860x_backlight_dt_init(pdev, data, name)) { 235 if (pdata) { 236 data->pwm = pdata->pwm; 237 data->iset = pdata->iset; 238 } 239 } 240 241 memset(&props, 0, sizeof(struct backlight_properties)); 242 props.type = BACKLIGHT_RAW; 243 props.max_brightness = MAX_BRIGHTNESS; 244 bl = devm_backlight_device_register(&pdev->dev, name, &pdev->dev, data, 245 &pm860x_backlight_ops, &props); 246 if (IS_ERR(bl)) { 247 dev_err(&pdev->dev, "failed to register backlight\n"); 248 return PTR_ERR(bl); 249 } 250 bl->props.brightness = MAX_BRIGHTNESS; 251 252 platform_set_drvdata(pdev, bl); 253 254 /* read current backlight */ 255 ret = pm860x_backlight_get_brightness(bl); 256 if (ret < 0) 257 return ret; 258 259 backlight_update_status(bl); 260 return 0; 261} 262 263static struct platform_driver pm860x_backlight_driver = { 264 .driver = { 265 .name = "88pm860x-backlight", 266 }, 267 .probe = pm860x_backlight_probe, 268}; 269 270module_platform_driver(pm860x_backlight_driver); 271 272MODULE_DESCRIPTION("Backlight Driver for Marvell Semiconductor 88PM8606"); 273MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>"); 274MODULE_LICENSE("GPL"); 275MODULE_ALIAS("platform:88pm860x-backlight"); 276