1d2912cb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 2a4f3d55cSMark Brown /* 3a4f3d55cSMark Brown * Backlight driver for Wolfson Microelectronics WM831x PMICs 4a4f3d55cSMark Brown * 5a4f3d55cSMark Brown * Copyright 2009 Wolfson Microelectonics plc 6a4f3d55cSMark Brown */ 7a4f3d55cSMark Brown 8a4f3d55cSMark Brown #include <linux/kernel.h> 9a4f3d55cSMark Brown #include <linux/init.h> 10a4f3d55cSMark Brown #include <linux/platform_device.h> 11355b200bSPaul Gortmaker #include <linux/module.h> 12a4f3d55cSMark Brown #include <linux/fb.h> 13a4f3d55cSMark Brown #include <linux/backlight.h> 145a0e3ad6STejun Heo #include <linux/slab.h> 15a4f3d55cSMark Brown 16a4f3d55cSMark Brown #include <linux/mfd/wm831x/core.h> 17a4f3d55cSMark Brown #include <linux/mfd/wm831x/pdata.h> 18a4f3d55cSMark Brown #include <linux/mfd/wm831x/regulator.h> 19a4f3d55cSMark Brown 20a4f3d55cSMark Brown struct wm831x_backlight_data { 21a4f3d55cSMark Brown struct wm831x *wm831x; 22a4f3d55cSMark Brown int isink_reg; 23a4f3d55cSMark Brown int current_brightness; 24a4f3d55cSMark Brown }; 25a4f3d55cSMark Brown 26a4f3d55cSMark Brown static int wm831x_backlight_set(struct backlight_device *bl, int brightness) 27a4f3d55cSMark Brown { 28a4f3d55cSMark Brown struct wm831x_backlight_data *data = bl_get_data(bl); 29a4f3d55cSMark Brown struct wm831x *wm831x = data->wm831x; 30a4f3d55cSMark Brown int power_up = !data->current_brightness && brightness; 31a4f3d55cSMark Brown int power_down = data->current_brightness && !brightness; 32a4f3d55cSMark Brown int ret; 33a4f3d55cSMark Brown 34a4f3d55cSMark Brown if (power_up) { 35a4f3d55cSMark Brown /* Enable the ISINK */ 36a4f3d55cSMark Brown ret = wm831x_set_bits(wm831x, data->isink_reg, 37a4f3d55cSMark Brown WM831X_CS1_ENA, WM831X_CS1_ENA); 38a4f3d55cSMark Brown if (ret < 0) 39a4f3d55cSMark Brown goto err; 40a4f3d55cSMark Brown 41a4f3d55cSMark Brown /* Enable the DC-DC */ 42a4f3d55cSMark Brown ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, 43a4f3d55cSMark Brown WM831X_DC4_ENA, WM831X_DC4_ENA); 44a4f3d55cSMark Brown if (ret < 0) 45a4f3d55cSMark Brown goto err; 46a4f3d55cSMark Brown } 47a4f3d55cSMark Brown 48a4f3d55cSMark Brown if (power_down) { 49a4f3d55cSMark Brown /* DCDC first */ 50a4f3d55cSMark Brown ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, 51a4f3d55cSMark Brown WM831X_DC4_ENA, 0); 52a4f3d55cSMark Brown if (ret < 0) 53a4f3d55cSMark Brown goto err; 54a4f3d55cSMark Brown 55a4f3d55cSMark Brown /* ISINK */ 56a4f3d55cSMark Brown ret = wm831x_set_bits(wm831x, data->isink_reg, 57a4f3d55cSMark Brown WM831X_CS1_DRIVE | WM831X_CS1_ENA, 0); 58a4f3d55cSMark Brown if (ret < 0) 59a4f3d55cSMark Brown goto err; 60a4f3d55cSMark Brown } 61a4f3d55cSMark Brown 62a4f3d55cSMark Brown /* Set the new brightness */ 63a4f3d55cSMark Brown ret = wm831x_set_bits(wm831x, data->isink_reg, 64a4f3d55cSMark Brown WM831X_CS1_ISEL_MASK, brightness); 65a4f3d55cSMark Brown if (ret < 0) 66a4f3d55cSMark Brown goto err; 67a4f3d55cSMark Brown 68a4f3d55cSMark Brown if (power_up) { 69a4f3d55cSMark Brown /* Drive current through the ISINK */ 70a4f3d55cSMark Brown ret = wm831x_set_bits(wm831x, data->isink_reg, 71a4f3d55cSMark Brown WM831X_CS1_DRIVE, WM831X_CS1_DRIVE); 72a4f3d55cSMark Brown if (ret < 0) 73a4f3d55cSMark Brown return ret; 74a4f3d55cSMark Brown } 75a4f3d55cSMark Brown 76a4f3d55cSMark Brown data->current_brightness = brightness; 77a4f3d55cSMark Brown 78a4f3d55cSMark Brown return 0; 79a4f3d55cSMark Brown 80a4f3d55cSMark Brown err: 81a4f3d55cSMark Brown /* If we were in the middle of a power transition always shut down 82a4f3d55cSMark Brown * for safety. 83a4f3d55cSMark Brown */ 84a4f3d55cSMark Brown if (power_up || power_down) { 85a4f3d55cSMark Brown wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); 86a4f3d55cSMark Brown wm831x_set_bits(wm831x, data->isink_reg, WM831X_CS1_ENA, 0); 87a4f3d55cSMark Brown } 88a4f3d55cSMark Brown 89a4f3d55cSMark Brown return ret; 90a4f3d55cSMark Brown } 91a4f3d55cSMark Brown 92a4f3d55cSMark Brown static int wm831x_backlight_update_status(struct backlight_device *bl) 93a4f3d55cSMark Brown { 94*51d53e5bSSam Ravnborg return wm831x_backlight_set(bl, backlight_get_brightness(bl)); 95a4f3d55cSMark Brown } 96a4f3d55cSMark Brown 97a4f3d55cSMark Brown static int wm831x_backlight_get_brightness(struct backlight_device *bl) 98a4f3d55cSMark Brown { 99a4f3d55cSMark Brown struct wm831x_backlight_data *data = bl_get_data(bl); 1004876b664SJingoo Han 101a4f3d55cSMark Brown return data->current_brightness; 102a4f3d55cSMark Brown } 103a4f3d55cSMark Brown 1049905a43bSEmese Revfy static const struct backlight_ops wm831x_backlight_ops = { 105a4f3d55cSMark Brown .options = BL_CORE_SUSPENDRESUME, 106a4f3d55cSMark Brown .update_status = wm831x_backlight_update_status, 107a4f3d55cSMark Brown .get_brightness = wm831x_backlight_get_brightness, 108a4f3d55cSMark Brown }; 109a4f3d55cSMark Brown 110a4f3d55cSMark Brown static int wm831x_backlight_probe(struct platform_device *pdev) 111a4f3d55cSMark Brown { 112a4f3d55cSMark Brown struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent); 113c512794cSJingoo Han struct wm831x_pdata *wm831x_pdata = dev_get_platdata(pdev->dev.parent); 114a4f3d55cSMark Brown struct wm831x_backlight_pdata *pdata; 115a4f3d55cSMark Brown struct wm831x_backlight_data *data; 116a4f3d55cSMark Brown struct backlight_device *bl; 117a19a6ee6SMatthew Garrett struct backlight_properties props; 118a4f3d55cSMark Brown int ret, i, max_isel, isink_reg, dcdc_cfg; 119a4f3d55cSMark Brown 120a4f3d55cSMark Brown /* We need platform data */ 121c512794cSJingoo Han if (wm831x_pdata) 122a4f3d55cSMark Brown pdata = wm831x_pdata->backlight; 123c512794cSJingoo Han else 124a4f3d55cSMark Brown pdata = NULL; 125a4f3d55cSMark Brown 126a4f3d55cSMark Brown if (!pdata) { 127a4f3d55cSMark Brown dev_err(&pdev->dev, "No platform data supplied\n"); 128a4f3d55cSMark Brown return -EINVAL; 129a4f3d55cSMark Brown } 130a4f3d55cSMark Brown 131a4f3d55cSMark Brown /* Figure out the maximum current we can use */ 132a4f3d55cSMark Brown for (i = 0; i < WM831X_ISINK_MAX_ISEL; i++) { 133a4f3d55cSMark Brown if (wm831x_isinkv_values[i] > pdata->max_uA) 134a4f3d55cSMark Brown break; 135a4f3d55cSMark Brown } 136a4f3d55cSMark Brown 137a4f3d55cSMark Brown if (i == 0) { 138a4f3d55cSMark Brown dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA); 139a4f3d55cSMark Brown return -EINVAL; 140a4f3d55cSMark Brown } 141a4f3d55cSMark Brown max_isel = i - 1; 142a4f3d55cSMark Brown 143a4f3d55cSMark Brown if (pdata->max_uA != wm831x_isinkv_values[max_isel]) 144a4f3d55cSMark Brown dev_warn(&pdev->dev, 145a4f3d55cSMark Brown "Maximum current is %duA not %duA as requested\n", 146a4f3d55cSMark Brown wm831x_isinkv_values[max_isel], pdata->max_uA); 147a4f3d55cSMark Brown 148a4f3d55cSMark Brown switch (pdata->isink) { 149a4f3d55cSMark Brown case 1: 150a4f3d55cSMark Brown isink_reg = WM831X_CURRENT_SINK_1; 151a4f3d55cSMark Brown dcdc_cfg = 0; 152a4f3d55cSMark Brown break; 153a4f3d55cSMark Brown case 2: 154a4f3d55cSMark Brown isink_reg = WM831X_CURRENT_SINK_2; 155a4f3d55cSMark Brown dcdc_cfg = WM831X_DC4_FBSRC; 156a4f3d55cSMark Brown break; 157a4f3d55cSMark Brown default: 158a4f3d55cSMark Brown dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink); 159a4f3d55cSMark Brown return -EINVAL; 160a4f3d55cSMark Brown } 161a4f3d55cSMark Brown 162a4f3d55cSMark Brown /* Configure the ISINK to use for feedback */ 163a4f3d55cSMark Brown ret = wm831x_reg_unlock(wm831x); 164a4f3d55cSMark Brown if (ret < 0) 165a4f3d55cSMark Brown return ret; 166a4f3d55cSMark Brown 167a4f3d55cSMark Brown ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC, 168a4f3d55cSMark Brown dcdc_cfg); 169a4f3d55cSMark Brown 170a4f3d55cSMark Brown wm831x_reg_lock(wm831x); 171a4f3d55cSMark Brown if (ret < 0) 172a4f3d55cSMark Brown return ret; 173a4f3d55cSMark Brown 1741107d40aSJulia Lawall data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); 175a4f3d55cSMark Brown if (data == NULL) 176a4f3d55cSMark Brown return -ENOMEM; 177a4f3d55cSMark Brown 178a4f3d55cSMark Brown data->wm831x = wm831x; 179a4f3d55cSMark Brown data->current_brightness = 0; 180a4f3d55cSMark Brown data->isink_reg = isink_reg; 181a4f3d55cSMark Brown 182f5f4fd45SCorentin Chary memset(&props, 0, sizeof(props)); 183bb7ca747SMatthew Garrett props.type = BACKLIGHT_RAW; 184a19a6ee6SMatthew Garrett props.max_brightness = max_isel; 185f369e664SJingoo Han bl = devm_backlight_device_register(&pdev->dev, "wm831x", &pdev->dev, 186f369e664SJingoo Han data, &wm831x_backlight_ops, &props); 187a4f3d55cSMark Brown if (IS_ERR(bl)) { 188a4f3d55cSMark Brown dev_err(&pdev->dev, "failed to register backlight\n"); 189a4f3d55cSMark Brown return PTR_ERR(bl); 190a4f3d55cSMark Brown } 191a4f3d55cSMark Brown 192a4f3d55cSMark Brown bl->props.brightness = max_isel; 193a4f3d55cSMark Brown 194a4f3d55cSMark Brown platform_set_drvdata(pdev, bl); 195a4f3d55cSMark Brown 196a4f3d55cSMark Brown /* Disable the DCDC if it was started so we can bootstrap */ 197a4f3d55cSMark Brown wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); 198a4f3d55cSMark Brown 199a4f3d55cSMark Brown backlight_update_status(bl); 200a4f3d55cSMark Brown 201a4f3d55cSMark Brown return 0; 202a4f3d55cSMark Brown } 203a4f3d55cSMark Brown 204a4f3d55cSMark Brown static struct platform_driver wm831x_backlight_driver = { 205a4f3d55cSMark Brown .driver = { 206a4f3d55cSMark Brown .name = "wm831x-backlight", 207a4f3d55cSMark Brown }, 208a4f3d55cSMark Brown .probe = wm831x_backlight_probe, 209a4f3d55cSMark Brown }; 210a4f3d55cSMark Brown 21181178e02SAxel Lin module_platform_driver(wm831x_backlight_driver); 212a4f3d55cSMark Brown 213a4f3d55cSMark Brown MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs"); 214a4f3d55cSMark Brown MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com"); 215a4f3d55cSMark Brown MODULE_LICENSE("GPL"); 216a4f3d55cSMark Brown MODULE_ALIAS("platform:wm831x-backlight"); 217