1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Backlight driver for Marvell Semiconductor 88PM8606 4 * 5 * Copyright (C) 2009 Marvell International Ltd. 6 * Haojian Zhuang <haojian.zhuang@marvell.com> 7 */ 8 9 #include <linux/init.h> 10 #include <linux/kernel.h> 11 #include <linux/of.h> 12 #include <linux/platform_device.h> 13 #include <linux/slab.h> 14 #include <linux/i2c.h> 15 #include <linux/backlight.h> 16 #include <linux/mfd/88pm860x.h> 17 #include <linux/module.h> 18 19 #define MAX_BRIGHTNESS (0xFF) 20 #define MIN_BRIGHTNESS (0) 21 22 #define CURRENT_BITMASK (0x1F << 1) 23 24 struct pm860x_backlight_data { 25 struct pm860x_chip *chip; 26 struct i2c_client *i2c; 27 int current_brightness; 28 int port; 29 int pwm; 30 int iset; 31 int reg_duty_cycle; 32 int reg_always_on; 33 int reg_current; 34 }; 35 36 static int backlight_power_set(struct pm860x_chip *chip, int port, 37 int on) 38 { 39 int ret = -EINVAL; 40 41 switch (port) { 42 case 0: 43 ret = on ? pm8606_osc_enable(chip, WLED1_DUTY) : 44 pm8606_osc_disable(chip, WLED1_DUTY); 45 break; 46 case 1: 47 ret = on ? pm8606_osc_enable(chip, WLED2_DUTY) : 48 pm8606_osc_disable(chip, WLED2_DUTY); 49 break; 50 case 2: 51 ret = on ? pm8606_osc_enable(chip, WLED3_DUTY) : 52 pm8606_osc_disable(chip, WLED3_DUTY); 53 break; 54 } 55 return ret; 56 } 57 58 static int pm860x_backlight_set(struct backlight_device *bl, int brightness) 59 { 60 struct pm860x_backlight_data *data = bl_get_data(bl); 61 struct pm860x_chip *chip = data->chip; 62 unsigned char value; 63 int ret; 64 65 if (brightness > MAX_BRIGHTNESS) 66 value = MAX_BRIGHTNESS; 67 else 68 value = brightness; 69 70 if (brightness) 71 backlight_power_set(chip, data->port, 1); 72 73 ret = pm860x_reg_write(data->i2c, data->reg_duty_cycle, value); 74 if (ret < 0) 75 goto out; 76 77 if ((data->current_brightness == 0) && brightness) { 78 if (data->iset) { 79 ret = pm860x_set_bits(data->i2c, data->reg_current, 80 CURRENT_BITMASK, data->iset); 81 if (ret < 0) 82 goto out; 83 } 84 if (data->pwm) { 85 ret = pm860x_set_bits(data->i2c, PM8606_PWM, 86 PM8606_PWM_FREQ_MASK, data->pwm); 87 if (ret < 0) 88 goto out; 89 } 90 if (brightness == MAX_BRIGHTNESS) { 91 /* set WLED_ON bit as 100% */ 92 ret = pm860x_set_bits(data->i2c, data->reg_always_on, 93 PM8606_WLED_ON, PM8606_WLED_ON); 94 } 95 } else { 96 if (brightness == MAX_BRIGHTNESS) { 97 /* set WLED_ON bit as 100% */ 98 ret = pm860x_set_bits(data->i2c, data->reg_always_on, 99 PM8606_WLED_ON, PM8606_WLED_ON); 100 } else { 101 /* clear WLED_ON bit since it's not 100% */ 102 ret = pm860x_set_bits(data->i2c, data->reg_always_on, 103 PM8606_WLED_ON, 0); 104 } 105 } 106 if (ret < 0) 107 goto out; 108 109 if (brightness == 0) 110 backlight_power_set(chip, data->port, 0); 111 112 dev_dbg(chip->dev, "set brightness %d\n", value); 113 data->current_brightness = value; 114 return 0; 115 out: 116 dev_dbg(chip->dev, "set brightness %d failure with return value: %d\n", 117 value, ret); 118 return ret; 119 } 120 121 static int pm860x_backlight_update_status(struct backlight_device *bl) 122 { 123 return pm860x_backlight_set(bl, backlight_get_brightness(bl)); 124 } 125 126 static int pm860x_backlight_get_brightness(struct backlight_device *bl) 127 { 128 struct pm860x_backlight_data *data = bl_get_data(bl); 129 struct pm860x_chip *chip = data->chip; 130 int ret; 131 132 ret = pm860x_reg_read(data->i2c, data->reg_duty_cycle); 133 if (ret < 0) 134 goto out; 135 data->current_brightness = ret; 136 dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness); 137 return data->current_brightness; 138 out: 139 return -EINVAL; 140 } 141 142 static const struct backlight_ops pm860x_backlight_ops = { 143 .options = BL_CORE_SUSPENDRESUME, 144 .update_status = pm860x_backlight_update_status, 145 .get_brightness = pm860x_backlight_get_brightness, 146 }; 147 148 #ifdef CONFIG_OF 149 static int pm860x_backlight_dt_init(struct platform_device *pdev, 150 struct pm860x_backlight_data *data, 151 char *name) 152 { 153 struct device_node *nproot; 154 int iset = 0; 155 156 nproot = of_get_child_by_name(pdev->dev.parent->of_node, "backlights"); 157 if (!nproot) { 158 dev_err(&pdev->dev, "failed to find backlights node\n"); 159 return -ENODEV; 160 } 161 for_each_child_of_node_scoped(nproot, np) { 162 if (of_node_name_eq(np, name)) { 163 of_property_read_u32(np, "marvell,88pm860x-iset", 164 &iset); 165 data->iset = PM8606_WLED_CURRENT(iset); 166 of_property_read_u32(np, "marvell,88pm860x-pwm", 167 &data->pwm); 168 break; 169 } 170 } 171 of_node_put(nproot); 172 return 0; 173 } 174 #else 175 #define pm860x_backlight_dt_init(x, y, z) (-1) 176 #endif 177 178 static int pm860x_backlight_probe(struct platform_device *pdev) 179 { 180 struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent); 181 struct pm860x_backlight_pdata *pdata = dev_get_platdata(&pdev->dev); 182 struct pm860x_backlight_data *data; 183 struct backlight_device *bl; 184 struct resource *res; 185 struct backlight_properties props; 186 char name[MFD_NAME_SIZE]; 187 int ret = 0; 188 189 data = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_backlight_data), 190 GFP_KERNEL); 191 if (data == NULL) 192 return -ENOMEM; 193 res = platform_get_resource_byname(pdev, IORESOURCE_REG, "duty cycle"); 194 if (!res) { 195 dev_err(&pdev->dev, "No REG resource for duty cycle\n"); 196 return -ENXIO; 197 } 198 data->reg_duty_cycle = res->start; 199 res = platform_get_resource_byname(pdev, IORESOURCE_REG, "always on"); 200 if (!res) { 201 dev_err(&pdev->dev, "No REG resource for always on\n"); 202 return -ENXIO; 203 } 204 data->reg_always_on = res->start; 205 res = platform_get_resource_byname(pdev, IORESOURCE_REG, "current"); 206 if (!res) { 207 dev_err(&pdev->dev, "No REG resource for current\n"); 208 return -ENXIO; 209 } 210 data->reg_current = res->start; 211 212 memset(name, 0, MFD_NAME_SIZE); 213 sprintf(name, "backlight-%d", pdev->id); 214 data->port = pdev->id; 215 data->chip = chip; 216 data->i2c = (chip->id == CHIP_PM8606) ? chip->client : chip->companion; 217 data->current_brightness = MAX_BRIGHTNESS; 218 if (pm860x_backlight_dt_init(pdev, data, name)) { 219 if (pdata) { 220 data->pwm = pdata->pwm; 221 data->iset = pdata->iset; 222 } 223 } 224 225 memset(&props, 0, sizeof(struct backlight_properties)); 226 props.type = BACKLIGHT_RAW; 227 props.max_brightness = MAX_BRIGHTNESS; 228 bl = devm_backlight_device_register(&pdev->dev, name, &pdev->dev, data, 229 &pm860x_backlight_ops, &props); 230 if (IS_ERR(bl)) { 231 dev_err(&pdev->dev, "failed to register backlight\n"); 232 return PTR_ERR(bl); 233 } 234 bl->props.brightness = MAX_BRIGHTNESS; 235 236 platform_set_drvdata(pdev, bl); 237 238 /* read current backlight */ 239 ret = pm860x_backlight_get_brightness(bl); 240 if (ret < 0) 241 return ret; 242 243 backlight_update_status(bl); 244 return 0; 245 } 246 247 static struct platform_driver pm860x_backlight_driver = { 248 .driver = { 249 .name = "88pm860x-backlight", 250 }, 251 .probe = pm860x_backlight_probe, 252 }; 253 254 module_platform_driver(pm860x_backlight_driver); 255 256 MODULE_DESCRIPTION("Backlight Driver for Marvell Semiconductor 88PM8606"); 257 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>"); 258 MODULE_LICENSE("GPL"); 259 MODULE_ALIAS("platform:88pm860x-backlight"); 260