1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2022 Richtek Technology Corp. 4 * 5 * Author: ChiaEn Wu <chiaen_wu@richtek.com> 6 */ 7 8 #include <linux/backlight.h> 9 #include <linux/bitfield.h> 10 #include <linux/bits.h> 11 #include <linux/gpio/consumer.h> 12 #include <linux/kernel.h> 13 #include <linux/minmax.h> 14 #include <linux/mod_devicetable.h> 15 #include <linux/module.h> 16 #include <linux/platform_device.h> 17 #include <linux/property.h> 18 #include <linux/regmap.h> 19 20 #define MT6370_REG_DEV_INFO 0x100 21 #define MT6370_REG_BL_EN 0x1A0 22 #define MT6370_REG_BL_BSTCTRL 0x1A1 23 #define MT6370_REG_BL_PWM 0x1A2 24 #define MT6370_REG_BL_DIM2 0x1A4 25 26 #define MT6370_VENID_MASK GENMASK(7, 4) 27 #define MT6370_BL_EXT_EN_MASK BIT(7) 28 #define MT6370_BL_EN_MASK BIT(6) 29 #define MT6370_BL_CODE_MASK BIT(0) 30 #define MT6370_BL_CH_MASK GENMASK(5, 2) 31 #define MT6370_BL_CH_SHIFT 2 32 #define MT6370_BL_DIM2_COMMON_MASK GENMASK(2, 0) 33 #define MT6370_BL_DIM2_COMMON_SHIFT 3 34 #define MT6370_BL_DIM2_6372_MASK GENMASK(5, 0) 35 #define MT6370_BL_DIM2_6372_SHIFT 6 36 #define MT6370_BL_PWM_EN_MASK BIT(7) 37 #define MT6370_BL_PWM_HYS_EN_MASK BIT(2) 38 #define MT6370_BL_PWM_HYS_SEL_MASK GENMASK(1, 0) 39 #define MT6370_BL_OVP_EN_MASK BIT(7) 40 #define MT6370_BL_OVP_SEL_MASK GENMASK(6, 5) 41 #define MT6370_BL_OVP_SEL_SHIFT 5 42 #define MT6370_BL_OC_EN_MASK BIT(3) 43 #define MT6370_BL_OC_SEL_MASK GENMASK(2, 1) 44 #define MT6370_BL_OC_SEL_SHIFT 1 45 46 #define MT6370_BL_PWM_HYS_TH_MIN_STEP 1 47 #define MT6370_BL_PWM_HYS_TH_MAX_STEP 64 48 #define MT6370_BL_OVP_MIN_UV 17000000 49 #define MT6370_BL_OVP_MAX_UV 29000000 50 #define MT6370_BL_OVP_STEP_UV 4000000 51 #define MT6370_BL_OCP_MIN_UA 900000 52 #define MT6370_BL_OCP_MAX_UA 1800000 53 #define MT6370_BL_OCP_STEP_UA 300000 54 #define MT6370_BL_MAX_COMMON_BRIGHTNESS 2048 55 #define MT6370_BL_MAX_6372_BRIGHTNESS 16384 56 #define MT6370_BL_MAX_CH 15 57 58 enum { 59 MT6370_VID_COMMON = 1, 60 MT6370_VID_6372, 61 }; 62 63 struct mt6370_priv { 64 u8 dim2_mask; 65 u8 dim2_shift; 66 int def_max_brightness; 67 struct backlight_device *bl; 68 struct device *dev; 69 struct gpio_desc *enable_gpio; 70 struct regmap *regmap; 71 }; 72 73 static int mt6370_bl_update_status(struct backlight_device *bl_dev) 74 { 75 struct mt6370_priv *priv = bl_get_data(bl_dev); 76 int brightness = backlight_get_brightness(bl_dev); 77 unsigned int enable_val; 78 u8 brightness_val[2]; 79 int ret; 80 81 if (brightness) { 82 brightness_val[0] = (brightness - 1) & priv->dim2_mask; 83 brightness_val[1] = (brightness - 1) >> priv->dim2_shift; 84 85 ret = regmap_raw_write(priv->regmap, MT6370_REG_BL_DIM2, 86 brightness_val, sizeof(brightness_val)); 87 if (ret) 88 return ret; 89 } 90 91 gpiod_set_value(priv->enable_gpio, !!brightness); 92 93 enable_val = brightness ? MT6370_BL_EN_MASK : 0; 94 return regmap_update_bits(priv->regmap, MT6370_REG_BL_EN, 95 MT6370_BL_EN_MASK, enable_val); 96 } 97 98 static int mt6370_bl_get_brightness(struct backlight_device *bl_dev) 99 { 100 struct mt6370_priv *priv = bl_get_data(bl_dev); 101 unsigned int enable; 102 u8 brightness_val[2]; 103 int brightness, ret; 104 105 ret = regmap_read(priv->regmap, MT6370_REG_BL_EN, &enable); 106 if (ret) 107 return ret; 108 109 if (!(enable & MT6370_BL_EN_MASK)) 110 return 0; 111 112 ret = regmap_raw_read(priv->regmap, MT6370_REG_BL_DIM2, 113 brightness_val, sizeof(brightness_val)); 114 if (ret) 115 return ret; 116 117 brightness = brightness_val[1] << priv->dim2_shift; 118 brightness += brightness_val[0] & priv->dim2_mask; 119 120 return brightness + 1; 121 } 122 123 static const struct backlight_ops mt6370_bl_ops = { 124 .options = BL_CORE_SUSPENDRESUME, 125 .update_status = mt6370_bl_update_status, 126 .get_brightness = mt6370_bl_get_brightness, 127 }; 128 129 static int mt6370_init_backlight_properties(struct mt6370_priv *priv, 130 struct backlight_properties *props) 131 { 132 struct device *dev = priv->dev; 133 u8 prop_val; 134 u32 brightness, ovp_uV, ocp_uA; 135 unsigned int mask, val; 136 int ret; 137 138 /* Vendor optional properties */ 139 val = 0; 140 if (device_property_read_bool(dev, "mediatek,bled-pwm-enable")) 141 val |= MT6370_BL_PWM_EN_MASK; 142 143 if (device_property_read_bool(dev, "mediatek,bled-pwm-hys-enable")) 144 val |= MT6370_BL_PWM_HYS_EN_MASK; 145 146 ret = device_property_read_u8(dev, 147 "mediatek,bled-pwm-hys-input-th-steps", 148 &prop_val); 149 if (!ret) { 150 prop_val = clamp_val(prop_val, 151 MT6370_BL_PWM_HYS_TH_MIN_STEP, 152 MT6370_BL_PWM_HYS_TH_MAX_STEP); 153 prop_val = prop_val <= 1 ? 0 : 154 prop_val <= 4 ? 1 : 155 prop_val <= 16 ? 2 : 3; 156 val |= prop_val; 157 } 158 159 ret = regmap_update_bits(priv->regmap, MT6370_REG_BL_PWM, 160 val, val); 161 if (ret) 162 return ret; 163 164 val = 0; 165 if (device_property_read_bool(dev, "mediatek,bled-ovp-shutdown")) 166 val |= MT6370_BL_OVP_EN_MASK; 167 168 ret = device_property_read_u32(dev, "mediatek,bled-ovp-microvolt", 169 &ovp_uV); 170 if (!ret) { 171 ovp_uV = clamp_val(ovp_uV, MT6370_BL_OVP_MIN_UV, 172 MT6370_BL_OVP_MAX_UV); 173 ovp_uV = DIV_ROUND_UP(ovp_uV - MT6370_BL_OVP_MIN_UV, 174 MT6370_BL_OVP_STEP_UV); 175 val |= ovp_uV << MT6370_BL_OVP_SEL_SHIFT; 176 } 177 178 if (device_property_read_bool(dev, "mediatek,bled-ocp-shutdown")) 179 val |= MT6370_BL_OC_EN_MASK; 180 181 ret = device_property_read_u32(dev, "mediatek,bled-ocp-microamp", 182 &ocp_uA); 183 if (!ret) { 184 ocp_uA = clamp_val(ocp_uA, MT6370_BL_OCP_MIN_UA, 185 MT6370_BL_OCP_MAX_UA); 186 ocp_uA = DIV_ROUND_UP(ocp_uA - MT6370_BL_OCP_MIN_UA, 187 MT6370_BL_OCP_STEP_UA); 188 val |= ocp_uA << MT6370_BL_OC_SEL_SHIFT; 189 } 190 191 ret = regmap_update_bits(priv->regmap, MT6370_REG_BL_BSTCTRL, 192 val, val); 193 if (ret) 194 return ret; 195 196 /* Common properties */ 197 ret = device_property_read_u32(dev, "max-brightness", &brightness); 198 if (ret) 199 brightness = priv->def_max_brightness; 200 201 props->max_brightness = min_t(u32, brightness, priv->def_max_brightness); 202 203 ret = device_property_read_u32(dev, "default-brightness", &brightness); 204 if (ret) 205 brightness = props->max_brightness; 206 207 props->brightness = min_t(u32, brightness, props->max_brightness); 208 209 val = 0; 210 if (device_property_read_bool(dev, "mediatek,bled-exponential-mode-enable")) { 211 val |= MT6370_BL_CODE_MASK; 212 props->scale = BACKLIGHT_SCALE_NON_LINEAR; 213 } else 214 props->scale = BACKLIGHT_SCALE_LINEAR; 215 216 ret = device_property_read_u8(dev, "mediatek,bled-channel-use", 217 &prop_val); 218 if (ret) { 219 dev_err(dev, "mediatek,bled-channel-use DT property missing\n"); 220 return ret; 221 } 222 223 if (!prop_val || prop_val > MT6370_BL_MAX_CH) { 224 dev_err(dev, 225 "No channel specified or over than upper bound (%d)\n", 226 prop_val); 227 return -EINVAL; 228 } 229 230 mask = MT6370_BL_EXT_EN_MASK | MT6370_BL_CH_MASK; 231 val |= prop_val << MT6370_BL_CH_SHIFT; 232 233 if (priv->enable_gpio) 234 val |= MT6370_BL_EXT_EN_MASK; 235 236 return regmap_update_bits(priv->regmap, MT6370_REG_BL_EN, mask, val); 237 } 238 239 static int mt6370_check_vendor_info(struct mt6370_priv *priv) 240 { 241 /* 242 * Because MT6372 uses 14 bits to control the brightness, 243 * MT6370 and MT6371 use 11 bits. This function is used 244 * to check the vendor's ID and set the relative hardware 245 * mask, shift and default maximum brightness value that 246 * should be used. 247 */ 248 unsigned int dev_info, hw_vid, of_vid; 249 int ret; 250 251 ret = regmap_read(priv->regmap, MT6370_REG_DEV_INFO, &dev_info); 252 if (ret) 253 return ret; 254 255 of_vid = (uintptr_t)device_get_match_data(priv->dev); 256 hw_vid = FIELD_GET(MT6370_VENID_MASK, dev_info); 257 hw_vid = (hw_vid == 0x9 || hw_vid == 0xb) ? MT6370_VID_6372 : MT6370_VID_COMMON; 258 if (hw_vid != of_vid) 259 return dev_err_probe(priv->dev, -EINVAL, 260 "Buggy DT, wrong compatible string\n"); 261 262 if (hw_vid == MT6370_VID_6372) { 263 priv->dim2_mask = MT6370_BL_DIM2_6372_MASK; 264 priv->dim2_shift = MT6370_BL_DIM2_6372_SHIFT; 265 priv->def_max_brightness = MT6370_BL_MAX_6372_BRIGHTNESS; 266 } else { 267 priv->dim2_mask = MT6370_BL_DIM2_COMMON_MASK; 268 priv->dim2_shift = MT6370_BL_DIM2_COMMON_SHIFT; 269 priv->def_max_brightness = MT6370_BL_MAX_COMMON_BRIGHTNESS; 270 } 271 272 return 0; 273 } 274 275 static int mt6370_bl_probe(struct platform_device *pdev) 276 { 277 struct backlight_properties props = { 278 .type = BACKLIGHT_RAW, 279 }; 280 struct device *dev = &pdev->dev; 281 struct mt6370_priv *priv; 282 int ret; 283 284 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 285 if (!priv) 286 return -ENOMEM; 287 288 priv->dev = dev; 289 290 priv->regmap = dev_get_regmap(dev->parent, NULL); 291 if (!priv->regmap) 292 return dev_err_probe(dev, -ENODEV, "Failed to get regmap\n"); 293 294 ret = mt6370_check_vendor_info(priv); 295 if (ret) 296 return dev_err_probe(dev, ret, "Failed to check vendor info\n"); 297 298 priv->enable_gpio = devm_gpiod_get_optional(dev, "enable", 299 GPIOD_OUT_HIGH); 300 if (IS_ERR(priv->enable_gpio)) 301 return dev_err_probe(dev, PTR_ERR(priv->enable_gpio), 302 "Failed to get 'enable' gpio\n"); 303 304 ret = mt6370_init_backlight_properties(priv, &props); 305 if (ret) 306 return dev_err_probe(dev, ret, 307 "Failed to init backlight properties\n"); 308 309 priv->bl = devm_backlight_device_register(dev, pdev->name, dev, priv, 310 &mt6370_bl_ops, &props); 311 if (IS_ERR(priv->bl)) 312 return dev_err_probe(dev, PTR_ERR(priv->bl), 313 "Failed to register backlight\n"); 314 315 backlight_update_status(priv->bl); 316 platform_set_drvdata(pdev, priv); 317 318 return 0; 319 } 320 321 static void mt6370_bl_remove(struct platform_device *pdev) 322 { 323 struct mt6370_priv *priv = platform_get_drvdata(pdev); 324 struct backlight_device *bl_dev = priv->bl; 325 326 bl_dev->props.brightness = 0; 327 backlight_update_status(priv->bl); 328 } 329 330 static const struct of_device_id mt6370_bl_of_match[] = { 331 { .compatible = "mediatek,mt6370-backlight", .data = (void *)MT6370_VID_COMMON }, 332 { .compatible = "mediatek,mt6372-backlight", .data = (void *)MT6370_VID_6372 }, 333 {} 334 }; 335 MODULE_DEVICE_TABLE(of, mt6370_bl_of_match); 336 337 static struct platform_driver mt6370_bl_driver = { 338 .driver = { 339 .name = "mt6370-backlight", 340 .of_match_table = mt6370_bl_of_match, 341 }, 342 .probe = mt6370_bl_probe, 343 .remove_new = mt6370_bl_remove, 344 }; 345 module_platform_driver(mt6370_bl_driver); 346 347 MODULE_AUTHOR("ChiaEn Wu <chiaen_wu@richtek.com>"); 348 MODULE_DESCRIPTION("MediaTek MT6370 Backlight Driver"); 349 MODULE_LICENSE("GPL v2"); 350