projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| c5a51053 KM |
1 | /* |
| 2 | * TI LP8788 MFD - backlight driver | |
| 3 | * | |
| 4 | * Copyright 2012 Texas Instruments | |
| 5 | * | |
| 6 | * Author: Milo(Woogyom) Kim <milo.kim@ti.com> | |
| 7 | * | |
| 8 | * This program is free software; you can redistribute it and/or modify | |
| 9 | * it under the terms of the GNU General Public License version 2 as | |
| 10 | * published by the Free Software Foundation. | |
| 11 | * | |
| 12 | */ | |
| 13 | ||
| 14 | #include <linux/backlight.h> | |
| 15 | #include <linux/err.h> | |
| 16 | #include <linux/mfd/lp8788.h> | |
| 17 | #include <linux/module.h> | |
| 18 | #include <linux/platform_device.h> | |
| 19 | #include <linux/pwm.h> | |
| 20 | #include <linux/slab.h> | |
| 21 | ||
| 22 | /* Register address */ | |
| 23 | #define LP8788_BL_CONFIG 0x96 | |
| 24 | #define LP8788_BL_EN BIT(0) | |
| 25 | #define LP8788_BL_PWM_INPUT_EN BIT(5) | |
| 26 | #define LP8788_BL_FULLSCALE_SHIFT 2 | |
| 27 | #define LP8788_BL_DIM_MODE_SHIFT 1 | |
| 28 | #define LP8788_BL_PWM_POLARITY_SHIFT 6 | |
| 29 | ||
| 30 | #define LP8788_BL_BRIGHTNESS 0x97 | |
| 31 | ||
| 32 | #define LP8788_BL_RAMP 0x98 | |
| 33 | #define LP8788_BL_RAMP_RISE_SHIFT 4 | |
| 34 | ||
| 35 | #define MAX_BRIGHTNESS 127 | |
| 36 | #define DEFAULT_BL_NAME "lcd-backlight" | |
| 37 | ||
| 38 | struct lp8788_bl_config { | |
| 39 | enum lp8788_bl_ctrl_mode bl_mode; | |
| 40 | enum lp8788_bl_dim_mode dim_mode; | |
| 41 | enum lp8788_bl_full_scale_current full_scale; | |
| 42 | enum lp8788_bl_ramp_step rise_time; | |
| 43 | enum lp8788_bl_ramp_step fall_time; | |
| 44 | enum pwm_polarity pwm_pol; | |
| 45 | }; | |
| 46 | ||
| 47 | struct lp8788_bl { | |
| 48 | struct lp8788 *lp; | |
| 49 | struct backlight_device *bl_dev; | |
| 50 | struct lp8788_backlight_platform_data *pdata; | |
| 51 | enum lp8788_bl_ctrl_mode mode; | |
| 52 | struct pwm_device *pwm; | |
| 53 | }; | |
| 54 | ||
| 1f299997 | 55 | static struct lp8788_bl_config default_bl_config = { |
| c5a51053 KM |
56 | .bl_mode = LP8788_BL_REGISTER_ONLY, |
| 57 | .dim_mode = LP8788_DIM_EXPONENTIAL, | |
| 58 | .full_scale = LP8788_FULLSCALE_1900uA, | |
| 59 | .rise_time = LP8788_RAMP_8192us, | |
| 60 | .fall_time = LP8788_RAMP_8192us, | |
| 61 | .pwm_pol = PWM_POLARITY_NORMAL, | |
| 62 | }; | |
| 63 | ||
| 64 | static inline bool is_brightness_ctrl_by_pwm(enum lp8788_bl_ctrl_mode mode) | |
| 65 | { | |
| 68585c41 | 66 | return mode == LP8788_BL_COMB_PWM_BASED; |
| c5a51053 KM |
67 | } |
| 68 | ||
| 69 | static inline bool is_brightness_ctrl_by_register(enum lp8788_bl_ctrl_mode mode) | |
| 70 | { | |
| 68585c41 JH |
71 | return mode == LP8788_BL_REGISTER_ONLY || |
| 72 | mode == LP8788_BL_COMB_REGISTER_BASED; | |
| c5a51053 KM |
73 | } |
| 74 | ||
| 75 | static int lp8788_backlight_configure(struct lp8788_bl *bl) | |
| 76 | { | |
| 77 | struct lp8788_backlight_platform_data *pdata = bl->pdata; | |
| 78 | struct lp8788_bl_config *cfg = &default_bl_config; | |
| 79 | int ret; | |
| 80 | u8 val; | |
| 81 | ||
| 82 | /* | |
| 83 | * Update chip configuration if platform data exists, | |
| 84 | * otherwise use the default settings. | |
| 85 | */ | |
| 86 | if (pdata) { | |
| 87 | cfg->bl_mode = pdata->bl_mode; | |
| 88 | cfg->dim_mode = pdata->dim_mode; | |
| 89 | cfg->full_scale = pdata->full_scale; | |
| 90 | cfg->rise_time = pdata->rise_time; | |
| 91 | cfg->fall_time = pdata->fall_time; | |
| 92 | cfg->pwm_pol = pdata->pwm_pol; | |
| 93 | } | |
| 94 | ||
| 95 | /* Brightness ramp up/down */ | |
| 96 | val = (cfg->rise_time << LP8788_BL_RAMP_RISE_SHIFT) | cfg->fall_time; | |
| 97 | ret = lp8788_write_byte(bl->lp, LP8788_BL_RAMP, val); | |
| 98 | if (ret) | |
| 99 | return ret; | |
| 100 | ||
| 101 | /* Fullscale current setting */ | |
| 102 | val = (cfg->full_scale << LP8788_BL_FULLSCALE_SHIFT) | | |
| 103 | (cfg->dim_mode << LP8788_BL_DIM_MODE_SHIFT); | |
| 104 | ||
| 105 | /* Brightness control mode */ | |
| 106 | switch (cfg->bl_mode) { | |
| 107 | case LP8788_BL_REGISTER_ONLY: | |
| 108 | val |= LP8788_BL_EN; | |
| 109 | break; | |
| 110 | case LP8788_BL_COMB_PWM_BASED: | |
| 111 | case LP8788_BL_COMB_REGISTER_BASED: | |
| 112 | val |= LP8788_BL_EN | LP8788_BL_PWM_INPUT_EN | | |
| 113 | (cfg->pwm_pol << LP8788_BL_PWM_POLARITY_SHIFT); | |
| 114 | break; | |
| 115 | default: | |
| 116 | dev_err(bl->lp->dev, "invalid mode: %d\n", cfg->bl_mode); | |
| 117 | return -EINVAL; | |
| 118 | } | |
| 119 | ||
| 120 | bl->mode = cfg->bl_mode; | |
| 121 | ||
| 122 | return lp8788_write_byte(bl->lp, LP8788_BL_CONFIG, val); | |
| 123 | } | |
| 124 | ||
| 125 | static void lp8788_pwm_ctrl(struct lp8788_bl *bl, int br, int max_br) | |
| 126 | { | |
| 127 | unsigned int period; | |
| 128 | unsigned int duty; | |
| 129 | struct device *dev; | |
| 130 | struct pwm_device *pwm; | |
| 131 | ||
| 132 | if (!bl->pdata) | |
| 133 | return; | |
| 134 | ||
| 135 | period = bl->pdata->period_ns; | |
| 136 | duty = br * period / max_br; | |
| 137 | dev = bl->lp->dev; | |
| 138 | ||
| 139 | /* request PWM device with the consumer name */ | |
| 140 | if (!bl->pwm) { | |
| 141 | pwm = devm_pwm_get(dev, LP8788_DEV_BACKLIGHT); | |
| 142 | if (IS_ERR(pwm)) { | |
| 143 | dev_err(dev, "can not get PWM device\n"); | |
| 144 | return; | |
| 145 | } | |
| 146 | ||
| 147 | bl->pwm = pwm; | |
| 058be4d6 BB |
148 | |
| 149 | /* | |
| 150 | * FIXME: pwm_apply_args() should be removed when switching to | |
| 151 | * the atomic PWM API. | |
| 152 | */ | |
| 153 | pwm_apply_args(pwm); | |
| c5a51053 KM |
154 | } |
| 155 | ||
| 156 | pwm_config(bl->pwm, duty, period); | |
| 157 | if (duty) | |
| 158 | pwm_enable(bl->pwm); | |
| 159 | else | |
| 160 | pwm_disable(bl->pwm); | |
| 161 | } | |
| 162 | ||
| 163 | static int lp8788_bl_update_status(struct backlight_device *bl_dev) | |
| 164 | { | |
| 165 | struct lp8788_bl *bl = bl_get_data(bl_dev); | |
| 166 | enum lp8788_bl_ctrl_mode mode = bl->mode; | |
| 167 | ||
| 168 | if (bl_dev->props.state & BL_CORE_SUSPENDED) | |
| 169 | bl_dev->props.brightness = 0; | |
| 170 | ||
| 171 | if (is_brightness_ctrl_by_pwm(mode)) { | |
| 172 | int brt = bl_dev->props.brightness; | |
| 173 | int max = bl_dev->props.max_brightness; | |
| 174 | ||
| 175 | lp8788_pwm_ctrl(bl, brt, max); | |
| 176 | } else if (is_brightness_ctrl_by_register(mode)) { | |
| 177 | u8 brt = bl_dev->props.brightness; | |
| 178 | ||
| 179 | lp8788_write_byte(bl->lp, LP8788_BL_BRIGHTNESS, brt); | |
| 180 | } | |
| 181 | ||
| 182 | return 0; | |
| 183 | } | |
| 184 | ||
| c5a51053 KM |
185 | static const struct backlight_ops lp8788_bl_ops = { |
| 186 | .options = BL_CORE_SUSPENDRESUME, | |
| 187 | .update_status = lp8788_bl_update_status, | |
| c5a51053 KM |
188 | }; |
| 189 | ||
| 190 | static int lp8788_backlight_register(struct lp8788_bl *bl) | |
| 191 | { | |
| 192 | struct backlight_device *bl_dev; | |
| 193 | struct backlight_properties props; | |
| 194 | struct lp8788_backlight_platform_data *pdata = bl->pdata; | |
| 195 | int init_brt; | |
| 196 | char *name; | |
| 197 | ||
| 198 | props.type = BACKLIGHT_PLATFORM; | |
| 199 | props.max_brightness = MAX_BRIGHTNESS; | |
| 200 | ||
| 201 | /* Initial brightness */ | |
| 202 | if (pdata) | |
| 203 | init_brt = min_t(int, pdata->initial_brightness, | |
| 204 | props.max_brightness); | |
| 205 | else | |
| 206 | init_brt = 0; | |
| 207 | ||
| 208 | props.brightness = init_brt; | |
| 209 | ||
| 210 | /* Backlight device name */ | |
| 211 | if (!pdata || !pdata->name) | |
| 212 | name = DEFAULT_BL_NAME; | |
| 213 | else | |
| 214 | name = pdata->name; | |
| 215 | ||
| 216 | bl_dev = backlight_device_register(name, bl->lp->dev, bl, | |
| 217 | &lp8788_bl_ops, &props); | |
| 218 | if (IS_ERR(bl_dev)) | |
| 219 | return PTR_ERR(bl_dev); | |
| 220 | ||
| 221 | bl->bl_dev = bl_dev; | |
| 222 | ||
| 223 | return 0; | |
| 224 | } | |
| 225 | ||
| 226 | static void lp8788_backlight_unregister(struct lp8788_bl *bl) | |
| 227 | { | |
| 228 | struct backlight_device *bl_dev = bl->bl_dev; | |
| 229 | ||
| 85463d8e | 230 | backlight_device_unregister(bl_dev); |
| c5a51053 KM |
231 | } |
| 232 | ||
| 233 | static ssize_t lp8788_get_bl_ctl_mode(struct device *dev, | |
| 234 | struct device_attribute *attr, char *buf) | |
| 235 | { | |
| 236 | struct lp8788_bl *bl = dev_get_drvdata(dev); | |
| 237 | enum lp8788_bl_ctrl_mode mode = bl->mode; | |
| 238 | char *strmode; | |
| 239 | ||
| 240 | if (is_brightness_ctrl_by_pwm(mode)) | |
| 241 | strmode = "PWM based"; | |
| 242 | else if (is_brightness_ctrl_by_register(mode)) | |
| 243 | strmode = "Register based"; | |
| 244 | else | |
| 245 | strmode = "Invalid mode"; | |
| 246 | ||
| 247 | return scnprintf(buf, PAGE_SIZE, "%s\n", strmode); | |
| 248 | } | |
| 249 | ||
| 250 | static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp8788_get_bl_ctl_mode, NULL); | |
| 251 | ||
| 252 | static struct attribute *lp8788_attributes[] = { | |
| 253 | &dev_attr_bl_ctl_mode.attr, | |
| 254 | NULL, | |
| 255 | }; | |
| 256 | ||
| 257 | static const struct attribute_group lp8788_attr_group = { | |
| 258 | .attrs = lp8788_attributes, | |
| 259 | }; | |
| 260 | ||
| 261 | static int lp8788_backlight_probe(struct platform_device *pdev) | |
| 262 | { | |
| 263 | struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent); | |
| 264 | struct lp8788_bl *bl; | |
| 265 | int ret; | |
| 266 | ||
| 267 | bl = devm_kzalloc(lp->dev, sizeof(struct lp8788_bl), GFP_KERNEL); | |
| 268 | if (!bl) | |
| 269 | return -ENOMEM; | |
| 270 | ||
| 271 | bl->lp = lp; | |
| 272 | if (lp->pdata) | |
| 273 | bl->pdata = lp->pdata->bl_pdata; | |
| 274 | ||
| 275 | platform_set_drvdata(pdev, bl); | |
| 276 | ||
| 277 | ret = lp8788_backlight_configure(bl); | |
| 278 | if (ret) { | |
| 279 | dev_err(lp->dev, "backlight config err: %d\n", ret); | |
| 280 | goto err_dev; | |
| 281 | } | |
| 282 | ||
| 283 | ret = lp8788_backlight_register(bl); | |
| 284 | if (ret) { | |
| 285 | dev_err(lp->dev, "register backlight err: %d\n", ret); | |
| 286 | goto err_dev; | |
| 287 | } | |
| 288 | ||
| 289 | ret = sysfs_create_group(&pdev->dev.kobj, &lp8788_attr_group); | |
| 290 | if (ret) { | |
| 291 | dev_err(lp->dev, "register sysfs err: %d\n", ret); | |
| 292 | goto err_sysfs; | |
| 293 | } | |
| 294 | ||
| 295 | backlight_update_status(bl->bl_dev); | |
| 296 | ||
| 297 | return 0; | |
| 298 | ||
| 299 | err_sysfs: | |
| 300 | lp8788_backlight_unregister(bl); | |
| 301 | err_dev: | |
| 302 | return ret; | |
| 303 | } | |
| 304 | ||
| 305 | static int lp8788_backlight_remove(struct platform_device *pdev) | |
| 306 | { | |
| 307 | struct lp8788_bl *bl = platform_get_drvdata(pdev); | |
| 308 | struct backlight_device *bl_dev = bl->bl_dev; | |
| 309 | ||
| 310 | bl_dev->props.brightness = 0; | |
| 311 | backlight_update_status(bl_dev); | |
| 312 | sysfs_remove_group(&pdev->dev.kobj, &lp8788_attr_group); | |
| 313 | lp8788_backlight_unregister(bl); | |
| c5a51053 KM |
314 | |
| 315 | return 0; | |
| 316 | } | |
| 317 | ||
| 318 | static struct platform_driver lp8788_bl_driver = { | |
| 319 | .probe = lp8788_backlight_probe, | |
| 320 | .remove = lp8788_backlight_remove, | |
| 321 | .driver = { | |
| 322 | .name = LP8788_DEV_BACKLIGHT, | |
| c5a51053 KM |
323 | }, |
| 324 | }; | |
| 325 | module_platform_driver(lp8788_bl_driver); | |
| 326 | ||
| 327 | MODULE_DESCRIPTION("Texas Instruments LP8788 Backlight Driver"); | |
| 328 | MODULE_AUTHOR("Milo Kim"); | |
| 329 | MODULE_LICENSE("GPL"); | |
| 330 | MODULE_ALIAS("platform:lp8788-backlight"); |