1a4f3d55cSMark Brown /* 2a4f3d55cSMark Brown * Backlight driver for Wolfson Microelectronics WM831x PMICs 3a4f3d55cSMark Brown * 4a4f3d55cSMark Brown * Copyright 2009 Wolfson Microelectonics plc 5a4f3d55cSMark Brown * 6a4f3d55cSMark Brown * This program is free software; you can redistribute it and/or modify 7a4f3d55cSMark Brown * it under the terms of the GNU General Public License version 2 as 8a4f3d55cSMark Brown * published by the Free Software Foundation. 9a4f3d55cSMark Brown */ 10a4f3d55cSMark Brown 11a4f3d55cSMark Brown #include <linux/kernel.h> 12a4f3d55cSMark Brown #include <linux/init.h> 13a4f3d55cSMark Brown #include <linux/platform_device.h> 14355b200bSPaul Gortmaker #include <linux/module.h> 15a4f3d55cSMark Brown #include <linux/fb.h> 16a4f3d55cSMark Brown #include <linux/backlight.h> 175a0e3ad6STejun Heo #include <linux/slab.h> 18a4f3d55cSMark Brown 19a4f3d55cSMark Brown #include <linux/mfd/wm831x/core.h> 20a4f3d55cSMark Brown #include <linux/mfd/wm831x/pdata.h> 21a4f3d55cSMark Brown #include <linux/mfd/wm831x/regulator.h> 22a4f3d55cSMark Brown 23a4f3d55cSMark Brown struct wm831x_backlight_data { 24a4f3d55cSMark Brown struct wm831x *wm831x; 25a4f3d55cSMark Brown int isink_reg; 26a4f3d55cSMark Brown int current_brightness; 27a4f3d55cSMark Brown }; 28a4f3d55cSMark Brown 29a4f3d55cSMark Brown static int wm831x_backlight_set(struct backlight_device *bl, int brightness) 30a4f3d55cSMark Brown { 31a4f3d55cSMark Brown struct wm831x_backlight_data *data = bl_get_data(bl); 32a4f3d55cSMark Brown struct wm831x *wm831x = data->wm831x; 33a4f3d55cSMark Brown int power_up = !data->current_brightness && brightness; 34a4f3d55cSMark Brown int power_down = data->current_brightness && !brightness; 35a4f3d55cSMark Brown int ret; 36a4f3d55cSMark Brown 37a4f3d55cSMark Brown if (power_up) { 38a4f3d55cSMark Brown /* Enable the ISINK */ 39a4f3d55cSMark Brown ret = wm831x_set_bits(wm831x, data->isink_reg, 40a4f3d55cSMark Brown WM831X_CS1_ENA, WM831X_CS1_ENA); 41a4f3d55cSMark Brown if (ret < 0) 42a4f3d55cSMark Brown goto err; 43a4f3d55cSMark Brown 44a4f3d55cSMark Brown /* Enable the DC-DC */ 45a4f3d55cSMark Brown ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, 46a4f3d55cSMark Brown WM831X_DC4_ENA, WM831X_DC4_ENA); 47a4f3d55cSMark Brown if (ret < 0) 48a4f3d55cSMark Brown goto err; 49a4f3d55cSMark Brown } 50a4f3d55cSMark Brown 51a4f3d55cSMark Brown if (power_down) { 52a4f3d55cSMark Brown /* DCDC first */ 53a4f3d55cSMark Brown ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, 54a4f3d55cSMark Brown WM831X_DC4_ENA, 0); 55a4f3d55cSMark Brown if (ret < 0) 56a4f3d55cSMark Brown goto err; 57a4f3d55cSMark Brown 58a4f3d55cSMark Brown /* ISINK */ 59a4f3d55cSMark Brown ret = wm831x_set_bits(wm831x, data->isink_reg, 60a4f3d55cSMark Brown WM831X_CS1_DRIVE | WM831X_CS1_ENA, 0); 61a4f3d55cSMark Brown if (ret < 0) 62a4f3d55cSMark Brown goto err; 63a4f3d55cSMark Brown } 64a4f3d55cSMark Brown 65a4f3d55cSMark Brown /* Set the new brightness */ 66a4f3d55cSMark Brown ret = wm831x_set_bits(wm831x, data->isink_reg, 67a4f3d55cSMark Brown WM831X_CS1_ISEL_MASK, brightness); 68a4f3d55cSMark Brown if (ret < 0) 69a4f3d55cSMark Brown goto err; 70a4f3d55cSMark Brown 71a4f3d55cSMark Brown if (power_up) { 72a4f3d55cSMark Brown /* Drive current through the ISINK */ 73a4f3d55cSMark Brown ret = wm831x_set_bits(wm831x, data->isink_reg, 74a4f3d55cSMark Brown WM831X_CS1_DRIVE, WM831X_CS1_DRIVE); 75a4f3d55cSMark Brown if (ret < 0) 76a4f3d55cSMark Brown return ret; 77a4f3d55cSMark Brown } 78a4f3d55cSMark Brown 79a4f3d55cSMark Brown data->current_brightness = brightness; 80a4f3d55cSMark Brown 81a4f3d55cSMark Brown return 0; 82a4f3d55cSMark Brown 83a4f3d55cSMark Brown err: 84a4f3d55cSMark Brown /* If we were in the middle of a power transition always shut down 85a4f3d55cSMark Brown * for safety. 86a4f3d55cSMark Brown */ 87a4f3d55cSMark Brown if (power_up || power_down) { 88a4f3d55cSMark Brown wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); 89a4f3d55cSMark Brown wm831x_set_bits(wm831x, data->isink_reg, WM831X_CS1_ENA, 0); 90a4f3d55cSMark Brown } 91a4f3d55cSMark Brown 92a4f3d55cSMark Brown return ret; 93a4f3d55cSMark Brown } 94a4f3d55cSMark Brown 95a4f3d55cSMark Brown static int wm831x_backlight_update_status(struct backlight_device *bl) 96a4f3d55cSMark Brown { 97a4f3d55cSMark Brown int brightness = bl->props.brightness; 98a4f3d55cSMark Brown 99a4f3d55cSMark Brown if (bl->props.power != FB_BLANK_UNBLANK) 100a4f3d55cSMark Brown brightness = 0; 101a4f3d55cSMark Brown 102a4f3d55cSMark Brown if (bl->props.fb_blank != FB_BLANK_UNBLANK) 103a4f3d55cSMark Brown brightness = 0; 104a4f3d55cSMark Brown 105a4f3d55cSMark Brown if (bl->props.state & BL_CORE_SUSPENDED) 106a4f3d55cSMark Brown brightness = 0; 107a4f3d55cSMark Brown 108a4f3d55cSMark Brown return wm831x_backlight_set(bl, brightness); 109a4f3d55cSMark Brown } 110a4f3d55cSMark Brown 111a4f3d55cSMark Brown static int wm831x_backlight_get_brightness(struct backlight_device *bl) 112a4f3d55cSMark Brown { 113a4f3d55cSMark Brown struct wm831x_backlight_data *data = bl_get_data(bl); 114*4876b664SJingoo Han 115a4f3d55cSMark Brown return data->current_brightness; 116a4f3d55cSMark Brown } 117a4f3d55cSMark Brown 1189905a43bSEmese Revfy static const struct backlight_ops wm831x_backlight_ops = { 119a4f3d55cSMark Brown .options = BL_CORE_SUSPENDRESUME, 120a4f3d55cSMark Brown .update_status = wm831x_backlight_update_status, 121a4f3d55cSMark Brown .get_brightness = wm831x_backlight_get_brightness, 122a4f3d55cSMark Brown }; 123a4f3d55cSMark Brown 124a4f3d55cSMark Brown static int wm831x_backlight_probe(struct platform_device *pdev) 125a4f3d55cSMark Brown { 126a4f3d55cSMark Brown struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent); 127c512794cSJingoo Han struct wm831x_pdata *wm831x_pdata = dev_get_platdata(pdev->dev.parent); 128a4f3d55cSMark Brown struct wm831x_backlight_pdata *pdata; 129a4f3d55cSMark Brown struct wm831x_backlight_data *data; 130a4f3d55cSMark Brown struct backlight_device *bl; 131a19a6ee6SMatthew Garrett struct backlight_properties props; 132a4f3d55cSMark Brown int ret, i, max_isel, isink_reg, dcdc_cfg; 133a4f3d55cSMark Brown 134a4f3d55cSMark Brown /* We need platform data */ 135c512794cSJingoo Han if (wm831x_pdata) 136a4f3d55cSMark Brown pdata = wm831x_pdata->backlight; 137c512794cSJingoo Han else 138a4f3d55cSMark Brown pdata = NULL; 139a4f3d55cSMark Brown 140a4f3d55cSMark Brown if (!pdata) { 141a4f3d55cSMark Brown dev_err(&pdev->dev, "No platform data supplied\n"); 142a4f3d55cSMark Brown return -EINVAL; 143a4f3d55cSMark Brown } 144a4f3d55cSMark Brown 145a4f3d55cSMark Brown /* Figure out the maximum current we can use */ 146a4f3d55cSMark Brown for (i = 0; i < WM831X_ISINK_MAX_ISEL; i++) { 147a4f3d55cSMark Brown if (wm831x_isinkv_values[i] > pdata->max_uA) 148a4f3d55cSMark Brown break; 149a4f3d55cSMark Brown } 150a4f3d55cSMark Brown 151a4f3d55cSMark Brown if (i == 0) { 152a4f3d55cSMark Brown dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA); 153a4f3d55cSMark Brown return -EINVAL; 154a4f3d55cSMark Brown } 155a4f3d55cSMark Brown max_isel = i - 1; 156a4f3d55cSMark Brown 157a4f3d55cSMark Brown if (pdata->max_uA != wm831x_isinkv_values[max_isel]) 158a4f3d55cSMark Brown dev_warn(&pdev->dev, 159a4f3d55cSMark Brown "Maximum current is %duA not %duA as requested\n", 160a4f3d55cSMark Brown wm831x_isinkv_values[max_isel], pdata->max_uA); 161a4f3d55cSMark Brown 162a4f3d55cSMark Brown switch (pdata->isink) { 163a4f3d55cSMark Brown case 1: 164a4f3d55cSMark Brown isink_reg = WM831X_CURRENT_SINK_1; 165a4f3d55cSMark Brown dcdc_cfg = 0; 166a4f3d55cSMark Brown break; 167a4f3d55cSMark Brown case 2: 168a4f3d55cSMark Brown isink_reg = WM831X_CURRENT_SINK_2; 169a4f3d55cSMark Brown dcdc_cfg = WM831X_DC4_FBSRC; 170a4f3d55cSMark Brown break; 171a4f3d55cSMark Brown default: 172a4f3d55cSMark Brown dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink); 173a4f3d55cSMark Brown return -EINVAL; 174a4f3d55cSMark Brown } 175a4f3d55cSMark Brown 176a4f3d55cSMark Brown /* Configure the ISINK to use for feedback */ 177a4f3d55cSMark Brown ret = wm831x_reg_unlock(wm831x); 178a4f3d55cSMark Brown if (ret < 0) 179a4f3d55cSMark Brown return ret; 180a4f3d55cSMark Brown 181a4f3d55cSMark Brown ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC, 182a4f3d55cSMark Brown dcdc_cfg); 183a4f3d55cSMark Brown 184a4f3d55cSMark Brown wm831x_reg_lock(wm831x); 185a4f3d55cSMark Brown if (ret < 0) 186a4f3d55cSMark Brown return ret; 187a4f3d55cSMark Brown 1881107d40aSJulia Lawall data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); 189a4f3d55cSMark Brown if (data == NULL) 190a4f3d55cSMark Brown return -ENOMEM; 191a4f3d55cSMark Brown 192a4f3d55cSMark Brown data->wm831x = wm831x; 193a4f3d55cSMark Brown data->current_brightness = 0; 194a4f3d55cSMark Brown data->isink_reg = isink_reg; 195a4f3d55cSMark Brown 196f5f4fd45SCorentin Chary memset(&props, 0, sizeof(props)); 197bb7ca747SMatthew Garrett props.type = BACKLIGHT_RAW; 198a19a6ee6SMatthew Garrett props.max_brightness = max_isel; 199f369e664SJingoo Han bl = devm_backlight_device_register(&pdev->dev, "wm831x", &pdev->dev, 200f369e664SJingoo Han data, &wm831x_backlight_ops, &props); 201a4f3d55cSMark Brown if (IS_ERR(bl)) { 202a4f3d55cSMark Brown dev_err(&pdev->dev, "failed to register backlight\n"); 203a4f3d55cSMark Brown return PTR_ERR(bl); 204a4f3d55cSMark Brown } 205a4f3d55cSMark Brown 206a4f3d55cSMark Brown bl->props.brightness = max_isel; 207a4f3d55cSMark Brown 208a4f3d55cSMark Brown platform_set_drvdata(pdev, bl); 209a4f3d55cSMark Brown 210a4f3d55cSMark Brown /* Disable the DCDC if it was started so we can bootstrap */ 211a4f3d55cSMark Brown wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); 212a4f3d55cSMark Brown 213a4f3d55cSMark Brown backlight_update_status(bl); 214a4f3d55cSMark Brown 215a4f3d55cSMark Brown return 0; 216a4f3d55cSMark Brown } 217a4f3d55cSMark Brown 218a4f3d55cSMark Brown static struct platform_driver wm831x_backlight_driver = { 219a4f3d55cSMark Brown .driver = { 220a4f3d55cSMark Brown .name = "wm831x-backlight", 221a4f3d55cSMark Brown }, 222a4f3d55cSMark Brown .probe = wm831x_backlight_probe, 223a4f3d55cSMark Brown }; 224a4f3d55cSMark Brown 22581178e02SAxel Lin module_platform_driver(wm831x_backlight_driver); 226a4f3d55cSMark Brown 227a4f3d55cSMark Brown MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs"); 228a4f3d55cSMark Brown MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com"); 229a4f3d55cSMark Brown MODULE_LICENSE("GPL"); 230a4f3d55cSMark Brown MODULE_ALIAS("platform:wm831x-backlight"); 231