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 28 struct 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 40 static 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 62 static 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; 119 out: 120 dev_dbg(chip->dev, "set brightness %d failure with return value: %d\n", 121 value, ret); 122 return ret; 123 } 124 125 static 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 } 140 141 static 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; 153 out: 154 return -EINVAL; 155 } 156 157 static 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 164 static 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_node_get(pdev->dev.parent->of_node); 172 if (!nproot) 173 return -ENODEV; 174 nproot = of_find_node_by_name(nproot, "backlights"); 175 if (!nproot) { 176 dev_err(&pdev->dev, "failed to find backlights node\n"); 177 return -ENODEV; 178 } 179 for_each_child_of_node(nproot, np) { 180 if (!of_node_cmp(np->name, name)) { 181 of_property_read_u32(np, "marvell,88pm860x-iset", 182 &iset); 183 data->iset = PM8606_WLED_CURRENT(iset); 184 of_property_read_u32(np, "marvell,88pm860x-pwm", 185 &data->pwm); 186 break; 187 } 188 } 189 of_node_put(nproot); 190 return 0; 191 } 192 #else 193 #define pm860x_backlight_dt_init(x, y, z) (-1) 194 #endif 195 196 static int pm860x_backlight_probe(struct platform_device *pdev) 197 { 198 struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent); 199 struct pm860x_backlight_pdata *pdata = pdev->dev.platform_data; 200 struct pm860x_backlight_data *data; 201 struct backlight_device *bl; 202 struct resource *res; 203 struct backlight_properties props; 204 char name[MFD_NAME_SIZE]; 205 int ret = 0; 206 207 data = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_backlight_data), 208 GFP_KERNEL); 209 if (data == NULL) 210 return -ENOMEM; 211 res = platform_get_resource_byname(pdev, IORESOURCE_REG, "duty cycle"); 212 if (!res) { 213 dev_err(&pdev->dev, "No REG resource for duty cycle\n"); 214 return -ENXIO; 215 } 216 data->reg_duty_cycle = res->start; 217 res = platform_get_resource_byname(pdev, IORESOURCE_REG, "always on"); 218 if (!res) { 219 dev_err(&pdev->dev, "No REG resorce for always on\n"); 220 return -ENXIO; 221 } 222 data->reg_always_on = res->start; 223 res = platform_get_resource_byname(pdev, IORESOURCE_REG, "current"); 224 if (!res) { 225 dev_err(&pdev->dev, "No REG resource for current\n"); 226 return -ENXIO; 227 } 228 data->reg_current = res->start; 229 230 memset(name, 0, MFD_NAME_SIZE); 231 sprintf(name, "backlight-%d", pdev->id); 232 data->port = pdev->id; 233 data->chip = chip; 234 data->i2c = (chip->id == CHIP_PM8606) ? chip->client : chip->companion; 235 data->current_brightness = MAX_BRIGHTNESS; 236 if (pm860x_backlight_dt_init(pdev, data, name)) { 237 if (pdata) { 238 data->pwm = pdata->pwm; 239 data->iset = pdata->iset; 240 } 241 } 242 243 memset(&props, 0, sizeof(struct backlight_properties)); 244 props.type = BACKLIGHT_RAW; 245 props.max_brightness = MAX_BRIGHTNESS; 246 bl = backlight_device_register(name, &pdev->dev, data, 247 &pm860x_backlight_ops, &props); 248 if (IS_ERR(bl)) { 249 dev_err(&pdev->dev, "failed to register backlight\n"); 250 return PTR_ERR(bl); 251 } 252 bl->props.brightness = MAX_BRIGHTNESS; 253 254 platform_set_drvdata(pdev, bl); 255 256 /* read current backlight */ 257 ret = pm860x_backlight_get_brightness(bl); 258 if (ret < 0) 259 goto out_brt; 260 261 backlight_update_status(bl); 262 return 0; 263 out_brt: 264 backlight_device_unregister(bl); 265 return ret; 266 } 267 268 static int pm860x_backlight_remove(struct platform_device *pdev) 269 { 270 struct backlight_device *bl = platform_get_drvdata(pdev); 271 272 backlight_device_unregister(bl); 273 return 0; 274 } 275 276 static struct platform_driver pm860x_backlight_driver = { 277 .driver = { 278 .name = "88pm860x-backlight", 279 .owner = THIS_MODULE, 280 }, 281 .probe = pm860x_backlight_probe, 282 .remove = pm860x_backlight_remove, 283 }; 284 285 module_platform_driver(pm860x_backlight_driver); 286 287 MODULE_DESCRIPTION("Backlight Driver for Marvell Semiconductor 88PM8606"); 288 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>"); 289 MODULE_LICENSE("GPL"); 290 MODULE_ALIAS("platform:88pm860x-backlight"); 291