Mark Brown | a4f3d55 | 2009-09-05 14:09:20 +0100 | [diff] [blame^] | 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 | |
| 17 | #include <linux/mfd/wm831x/core.h> |
| 18 | #include <linux/mfd/wm831x/pdata.h> |
| 19 | #include <linux/mfd/wm831x/regulator.h> |
| 20 | |
| 21 | struct wm831x_backlight_data { |
| 22 | struct wm831x *wm831x; |
| 23 | int isink_reg; |
| 24 | int current_brightness; |
| 25 | }; |
| 26 | |
| 27 | static int wm831x_backlight_set(struct backlight_device *bl, int brightness) |
| 28 | { |
| 29 | struct wm831x_backlight_data *data = bl_get_data(bl); |
| 30 | struct wm831x *wm831x = data->wm831x; |
| 31 | int power_up = !data->current_brightness && brightness; |
| 32 | int power_down = data->current_brightness && !brightness; |
| 33 | int ret; |
| 34 | |
| 35 | if (power_up) { |
| 36 | /* Enable the ISINK */ |
| 37 | ret = wm831x_set_bits(wm831x, data->isink_reg, |
| 38 | WM831X_CS1_ENA, WM831X_CS1_ENA); |
| 39 | if (ret < 0) |
| 40 | goto err; |
| 41 | |
| 42 | /* Enable the DC-DC */ |
| 43 | ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, |
| 44 | WM831X_DC4_ENA, WM831X_DC4_ENA); |
| 45 | if (ret < 0) |
| 46 | goto err; |
| 47 | } |
| 48 | |
| 49 | if (power_down) { |
| 50 | /* DCDC first */ |
| 51 | ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, |
| 52 | WM831X_DC4_ENA, 0); |
| 53 | if (ret < 0) |
| 54 | goto err; |
| 55 | |
| 56 | /* ISINK */ |
| 57 | ret = wm831x_set_bits(wm831x, data->isink_reg, |
| 58 | WM831X_CS1_DRIVE | WM831X_CS1_ENA, 0); |
| 59 | if (ret < 0) |
| 60 | goto err; |
| 61 | } |
| 62 | |
| 63 | /* Set the new brightness */ |
| 64 | ret = wm831x_set_bits(wm831x, data->isink_reg, |
| 65 | WM831X_CS1_ISEL_MASK, brightness); |
| 66 | if (ret < 0) |
| 67 | goto err; |
| 68 | |
| 69 | if (power_up) { |
| 70 | /* Drive current through the ISINK */ |
| 71 | ret = wm831x_set_bits(wm831x, data->isink_reg, |
| 72 | WM831X_CS1_DRIVE, WM831X_CS1_DRIVE); |
| 73 | if (ret < 0) |
| 74 | return ret; |
| 75 | } |
| 76 | |
| 77 | data->current_brightness = brightness; |
| 78 | |
| 79 | return 0; |
| 80 | |
| 81 | err: |
| 82 | /* If we were in the middle of a power transition always shut down |
| 83 | * for safety. |
| 84 | */ |
| 85 | if (power_up || power_down) { |
| 86 | wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); |
| 87 | wm831x_set_bits(wm831x, data->isink_reg, WM831X_CS1_ENA, 0); |
| 88 | } |
| 89 | |
| 90 | return ret; |
| 91 | } |
| 92 | |
| 93 | static int wm831x_backlight_update_status(struct backlight_device *bl) |
| 94 | { |
| 95 | int brightness = bl->props.brightness; |
| 96 | |
| 97 | if (bl->props.power != FB_BLANK_UNBLANK) |
| 98 | brightness = 0; |
| 99 | |
| 100 | if (bl->props.fb_blank != FB_BLANK_UNBLANK) |
| 101 | brightness = 0; |
| 102 | |
| 103 | if (bl->props.state & BL_CORE_SUSPENDED) |
| 104 | brightness = 0; |
| 105 | |
| 106 | return wm831x_backlight_set(bl, brightness); |
| 107 | } |
| 108 | |
| 109 | static int wm831x_backlight_get_brightness(struct backlight_device *bl) |
| 110 | { |
| 111 | struct wm831x_backlight_data *data = bl_get_data(bl); |
| 112 | return data->current_brightness; |
| 113 | } |
| 114 | |
| 115 | static struct backlight_ops wm831x_backlight_ops = { |
| 116 | .options = BL_CORE_SUSPENDRESUME, |
| 117 | .update_status = wm831x_backlight_update_status, |
| 118 | .get_brightness = wm831x_backlight_get_brightness, |
| 119 | }; |
| 120 | |
| 121 | static int wm831x_backlight_probe(struct platform_device *pdev) |
| 122 | { |
| 123 | struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent); |
| 124 | struct wm831x_pdata *wm831x_pdata; |
| 125 | struct wm831x_backlight_pdata *pdata; |
| 126 | struct wm831x_backlight_data *data; |
| 127 | struct backlight_device *bl; |
| 128 | int ret, i, max_isel, isink_reg, dcdc_cfg; |
| 129 | |
| 130 | /* We need platform data */ |
| 131 | if (pdev->dev.parent->platform_data) { |
| 132 | wm831x_pdata = pdev->dev.parent->platform_data; |
| 133 | pdata = wm831x_pdata->backlight; |
| 134 | } else { |
| 135 | pdata = NULL; |
| 136 | } |
| 137 | |
| 138 | if (!pdata) { |
| 139 | dev_err(&pdev->dev, "No platform data supplied\n"); |
| 140 | return -EINVAL; |
| 141 | } |
| 142 | |
| 143 | /* Figure out the maximum current we can use */ |
| 144 | for (i = 0; i < WM831X_ISINK_MAX_ISEL; i++) { |
| 145 | if (wm831x_isinkv_values[i] > pdata->max_uA) |
| 146 | break; |
| 147 | } |
| 148 | |
| 149 | if (i == 0) { |
| 150 | dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA); |
| 151 | return -EINVAL; |
| 152 | } |
| 153 | max_isel = i - 1; |
| 154 | |
| 155 | if (pdata->max_uA != wm831x_isinkv_values[max_isel]) |
| 156 | dev_warn(&pdev->dev, |
| 157 | "Maximum current is %duA not %duA as requested\n", |
| 158 | wm831x_isinkv_values[max_isel], pdata->max_uA); |
| 159 | |
| 160 | switch (pdata->isink) { |
| 161 | case 1: |
| 162 | isink_reg = WM831X_CURRENT_SINK_1; |
| 163 | dcdc_cfg = 0; |
| 164 | break; |
| 165 | case 2: |
| 166 | isink_reg = WM831X_CURRENT_SINK_2; |
| 167 | dcdc_cfg = WM831X_DC4_FBSRC; |
| 168 | break; |
| 169 | default: |
| 170 | dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink); |
| 171 | return -EINVAL; |
| 172 | } |
| 173 | |
| 174 | /* Configure the ISINK to use for feedback */ |
| 175 | ret = wm831x_reg_unlock(wm831x); |
| 176 | if (ret < 0) |
| 177 | return ret; |
| 178 | |
| 179 | ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC, |
| 180 | dcdc_cfg); |
| 181 | |
| 182 | wm831x_reg_lock(wm831x); |
| 183 | if (ret < 0) |
| 184 | return ret; |
| 185 | |
| 186 | data = kzalloc(sizeof(*data), GFP_KERNEL); |
| 187 | if (data == NULL) |
| 188 | return -ENOMEM; |
| 189 | |
| 190 | data->wm831x = wm831x; |
| 191 | data->current_brightness = 0; |
| 192 | data->isink_reg = isink_reg; |
| 193 | |
| 194 | bl = backlight_device_register("wm831x", &pdev->dev, |
| 195 | data, &wm831x_backlight_ops); |
| 196 | if (IS_ERR(bl)) { |
| 197 | dev_err(&pdev->dev, "failed to register backlight\n"); |
| 198 | kfree(data); |
| 199 | return PTR_ERR(bl); |
| 200 | } |
| 201 | |
| 202 | bl->props.max_brightness = max_isel; |
| 203 | bl->props.brightness = max_isel; |
| 204 | |
| 205 | platform_set_drvdata(pdev, bl); |
| 206 | |
| 207 | /* Disable the DCDC if it was started so we can bootstrap */ |
| 208 | wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); |
| 209 | |
| 210 | |
| 211 | backlight_update_status(bl); |
| 212 | |
| 213 | return 0; |
| 214 | } |
| 215 | |
| 216 | static int wm831x_backlight_remove(struct platform_device *pdev) |
| 217 | { |
| 218 | struct backlight_device *bl = platform_get_drvdata(pdev); |
| 219 | struct wm831x_backlight_data *data = bl_get_data(bl); |
| 220 | |
| 221 | backlight_device_unregister(bl); |
| 222 | kfree(data); |
| 223 | return 0; |
| 224 | } |
| 225 | |
| 226 | static struct platform_driver wm831x_backlight_driver = { |
| 227 | .driver = { |
| 228 | .name = "wm831x-backlight", |
| 229 | .owner = THIS_MODULE, |
| 230 | }, |
| 231 | .probe = wm831x_backlight_probe, |
| 232 | .remove = wm831x_backlight_remove, |
| 233 | }; |
| 234 | |
| 235 | static int __init wm831x_backlight_init(void) |
| 236 | { |
| 237 | return platform_driver_register(&wm831x_backlight_driver); |
| 238 | } |
| 239 | module_init(wm831x_backlight_init); |
| 240 | |
| 241 | static void __exit wm831x_backlight_exit(void) |
| 242 | { |
| 243 | platform_driver_unregister(&wm831x_backlight_driver); |
| 244 | } |
| 245 | module_exit(wm831x_backlight_exit); |
| 246 | |
| 247 | MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs"); |
| 248 | MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com"); |
| 249 | MODULE_LICENSE("GPL"); |
| 250 | MODULE_ALIAS("platform:wm831x-backlight"); |