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
wm831x_backlight_set(struct backlight_device * bl,int brightness)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
wm831x_backlight_update_status(struct backlight_device * bl)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
wm831x_backlight_get_brightness(struct backlight_device * bl)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
wm831x_backlight_probe(struct platform_device * pdev)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