1/* 2 * Backlight driver for Wolfson Microelectronics WM831x PMICs 3 * 4 * Copyright 2009 Wolfson Microelectonics plc 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 */ 10 11#include <linux/kernel.h> 12#include <linux/init.h> 13#include <linux/platform_device.h> 14#include <linux/fb.h> 15#include <linux/backlight.h> 16#include <linux/slab.h> 17 18#include <linux/mfd/wm831x/core.h> 19#include <linux/mfd/wm831x/pdata.h> 20#include <linux/mfd/wm831x/regulator.h> 21 22struct wm831x_backlight_data { 23 struct wm831x *wm831x; 24 int isink_reg; 25 int current_brightness; 26}; 27 28static int wm831x_backlight_set(struct backlight_device *bl, int brightness) 29{ 30 struct wm831x_backlight_data *data = bl_get_data(bl); 31 struct wm831x *wm831x = data->wm831x; 32 int power_up = !data->current_brightness && brightness; 33 int power_down = data->current_brightness && !brightness; 34 int ret; 35 36 if (power_up) { 37 /* Enable the ISINK */ 38 ret = wm831x_set_bits(wm831x, data->isink_reg, 39 WM831X_CS1_ENA, WM831X_CS1_ENA); 40 if (ret < 0) 41 goto err; 42 43 /* Enable the DC-DC */ 44 ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, 45 WM831X_DC4_ENA, WM831X_DC4_ENA); 46 if (ret < 0) 47 goto err; 48 } 49 50 if (power_down) { 51 /* DCDC first */ 52 ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, 53 WM831X_DC4_ENA, 0); 54 if (ret < 0) 55 goto err; 56 57 /* ISINK */ 58 ret = wm831x_set_bits(wm831x, data->isink_reg, 59 WM831X_CS1_DRIVE | WM831X_CS1_ENA, 0); 60 if (ret < 0) 61 goto err; 62 } 63 64 /* Set the new brightness */ 65 ret = wm831x_set_bits(wm831x, data->isink_reg, 66 WM831X_CS1_ISEL_MASK, brightness); 67 if (ret < 0) 68 goto err; 69 70 if (power_up) { 71 /* Drive current through the ISINK */ 72 ret = wm831x_set_bits(wm831x, data->isink_reg, 73 WM831X_CS1_DRIVE, WM831X_CS1_DRIVE); 74 if (ret < 0) 75 return ret; 76 } 77 78 data->current_brightness = brightness; 79 80 return 0; 81 82err: 83 /* If we were in the middle of a power transition always shut down 84 * for safety. 85 */ 86 if (power_up || power_down) { 87 wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); 88 wm831x_set_bits(wm831x, data->isink_reg, WM831X_CS1_ENA, 0); 89 } 90 91 return ret; 92} 93 94static int wm831x_backlight_update_status(struct backlight_device *bl) 95{ 96 int brightness = bl->props.brightness; 97 98 if (bl->props.power != FB_BLANK_UNBLANK) 99 brightness = 0; 100 101 if (bl->props.fb_blank != FB_BLANK_UNBLANK) 102 brightness = 0; 103 104 if (bl->props.state & BL_CORE_SUSPENDED) 105 brightness = 0; 106 107 return wm831x_backlight_set(bl, brightness); 108} 109 110static int wm831x_backlight_get_brightness(struct backlight_device *bl) 111{ 112 struct wm831x_backlight_data *data = bl_get_data(bl); 113 return data->current_brightness; 114} 115 116static const struct backlight_ops wm831x_backlight_ops = { 117 .options = BL_CORE_SUSPENDRESUME, 118 .update_status = wm831x_backlight_update_status, 119 .get_brightness = wm831x_backlight_get_brightness, 120}; 121 122static int wm831x_backlight_probe(struct platform_device *pdev) 123{ 124 struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent); 125 struct wm831x_pdata *wm831x_pdata; 126 struct wm831x_backlight_pdata *pdata; 127 struct wm831x_backlight_data *data; 128 struct backlight_device *bl; 129 struct backlight_properties props; 130 int ret, i, max_isel, isink_reg, dcdc_cfg; 131 132 /* We need platform data */ 133 if (pdev->dev.parent->platform_data) { 134 wm831x_pdata = pdev->dev.parent->platform_data; 135 pdata = wm831x_pdata->backlight; 136 } else { 137 pdata = NULL; 138 } 139 140 if (!pdata) { 141 dev_err(&pdev->dev, "No platform data supplied\n"); 142 return -EINVAL; 143 } 144 145 /* Figure out the maximum current we can use */ 146 for (i = 0; i < WM831X_ISINK_MAX_ISEL; i++) { 147 if (wm831x_isinkv_values[i] > pdata->max_uA) 148 break; 149 } 150 151 if (i == 0) { 152 dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA); 153 return -EINVAL; 154 } 155 max_isel = i - 1; 156 157 if (pdata->max_uA != wm831x_isinkv_values[max_isel]) 158 dev_warn(&pdev->dev, 159 "Maximum current is %duA not %duA as requested\n", 160 wm831x_isinkv_values[max_isel], pdata->max_uA); 161 162 switch (pdata->isink) { 163 case 1: 164 isink_reg = WM831X_CURRENT_SINK_1; 165 dcdc_cfg = 0; 166 break; 167 case 2: 168 isink_reg = WM831X_CURRENT_SINK_2; 169 dcdc_cfg = WM831X_DC4_FBSRC; 170 break; 171 default: 172 dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink); 173 return -EINVAL; 174 } 175 176 /* Configure the ISINK to use for feedback */ 177 ret = wm831x_reg_unlock(wm831x); 178 if (ret < 0) 179 return ret; 180 181 ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC, 182 dcdc_cfg); 183 184 wm831x_reg_lock(wm831x); 185 if (ret < 0) 186 return ret; 187 188 data = kzalloc(sizeof(*data), GFP_KERNEL); 189 if (data == NULL) 190 return -ENOMEM; 191 192 data->wm831x = wm831x; 193 data->current_brightness = 0; 194 data->isink_reg = isink_reg; 195 196 props.max_brightness = max_isel; 197 bl = backlight_device_register("wm831x", &pdev->dev, data, 198 &wm831x_backlight_ops, &props); 199 if (IS_ERR(bl)) { 200 dev_err(&pdev->dev, "failed to register backlight\n"); 201 kfree(data); 202 return PTR_ERR(bl); 203 } 204 205 bl->props.brightness = max_isel; 206 207 platform_set_drvdata(pdev, bl); 208 209 /* Disable the DCDC if it was started so we can bootstrap */ 210 wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); 211 212 213 backlight_update_status(bl); 214 215 return 0; 216} 217 218static int wm831x_backlight_remove(struct platform_device *pdev) 219{ 220 struct backlight_device *bl = platform_get_drvdata(pdev); 221 struct wm831x_backlight_data *data = bl_get_data(bl); 222 223 backlight_device_unregister(bl); 224 kfree(data); 225 return 0; 226} 227 228static struct platform_driver wm831x_backlight_driver = { 229 .driver = { 230 .name = "wm831x-backlight", 231 .owner = THIS_MODULE, 232 }, 233 .probe = wm831x_backlight_probe, 234 .remove = wm831x_backlight_remove, 235}; 236 237static int __init wm831x_backlight_init(void) 238{ 239 return platform_driver_register(&wm831x_backlight_driver); 240} 241module_init(wm831x_backlight_init); 242 243static void __exit wm831x_backlight_exit(void) 244{ 245 platform_driver_unregister(&wm831x_backlight_driver); 246} 247module_exit(wm831x_backlight_exit); 248 249MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs"); 250MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com"); 251MODULE_LICENSE("GPL"); 252MODULE_ALIAS("platform:wm831x-backlight"); 253