1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Backlight driver for Wolfson Microelectronics WM831x PMICs |
4 | * |
5 | * Copyright 2009 Wolfson Microelectonics plc |
6 | */ |
7 | |
8 | #include <linux/kernel.h> |
9 | #include <linux/init.h> |
10 | #include <linux/platform_device.h> |
11 | #include <linux/module.h> |
12 | #include <linux/fb.h> |
13 | #include <linux/backlight.h> |
14 | #include <linux/slab.h> |
15 | |
16 | #include <linux/mfd/wm831x/core.h> |
17 | #include <linux/mfd/wm831x/pdata.h> |
18 | #include <linux/mfd/wm831x/regulator.h> |
19 | |
20 | struct wm831x_backlight_data { |
21 | struct wm831x *wm831x; |
22 | int isink_reg; |
23 | int current_brightness; |
24 | }; |
25 | |
26 | static int wm831x_backlight_set(struct backlight_device *bl, int brightness) |
27 | { |
28 | struct wm831x_backlight_data *data = bl_get_data(bl_dev: bl); |
29 | struct wm831x *wm831x = data->wm831x; |
30 | int power_up = !data->current_brightness && brightness; |
31 | int power_down = data->current_brightness && !brightness; |
32 | int ret; |
33 | |
34 | if (power_up) { |
35 | /* Enable the ISINK */ |
36 | ret = wm831x_set_bits(wm831x, reg: data->isink_reg, |
37 | WM831X_CS1_ENA, WM831X_CS1_ENA); |
38 | if (ret < 0) |
39 | goto err; |
40 | |
41 | /* Enable the DC-DC */ |
42 | ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, |
43 | WM831X_DC4_ENA, WM831X_DC4_ENA); |
44 | if (ret < 0) |
45 | goto err; |
46 | } |
47 | |
48 | if (power_down) { |
49 | /* DCDC first */ |
50 | ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, |
51 | WM831X_DC4_ENA, val: 0); |
52 | if (ret < 0) |
53 | goto err; |
54 | |
55 | /* ISINK */ |
56 | ret = wm831x_set_bits(wm831x, reg: data->isink_reg, |
57 | WM831X_CS1_DRIVE | WM831X_CS1_ENA, val: 0); |
58 | if (ret < 0) |
59 | goto err; |
60 | } |
61 | |
62 | /* Set the new brightness */ |
63 | ret = wm831x_set_bits(wm831x, reg: data->isink_reg, |
64 | WM831X_CS1_ISEL_MASK, val: brightness); |
65 | if (ret < 0) |
66 | goto err; |
67 | |
68 | if (power_up) { |
69 | /* Drive current through the ISINK */ |
70 | ret = wm831x_set_bits(wm831x, reg: data->isink_reg, |
71 | WM831X_CS1_DRIVE, WM831X_CS1_DRIVE); |
72 | if (ret < 0) |
73 | return ret; |
74 | } |
75 | |
76 | data->current_brightness = brightness; |
77 | |
78 | return 0; |
79 | |
80 | err: |
81 | /* If we were in the middle of a power transition always shut down |
82 | * for safety. |
83 | */ |
84 | if (power_up || power_down) { |
85 | wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, val: 0); |
86 | wm831x_set_bits(wm831x, reg: data->isink_reg, WM831X_CS1_ENA, val: 0); |
87 | } |
88 | |
89 | return ret; |
90 | } |
91 | |
92 | static int wm831x_backlight_update_status(struct backlight_device *bl) |
93 | { |
94 | return wm831x_backlight_set(bl, brightness: backlight_get_brightness(bd: bl)); |
95 | } |
96 | |
97 | static int wm831x_backlight_get_brightness(struct backlight_device *bl) |
98 | { |
99 | struct wm831x_backlight_data *data = bl_get_data(bl_dev: bl); |
100 | |
101 | return data->current_brightness; |
102 | } |
103 | |
104 | static const struct backlight_ops wm831x_backlight_ops = { |
105 | .options = BL_CORE_SUSPENDRESUME, |
106 | .update_status = wm831x_backlight_update_status, |
107 | .get_brightness = wm831x_backlight_get_brightness, |
108 | }; |
109 | |
110 | static int wm831x_backlight_probe(struct platform_device *pdev) |
111 | { |
112 | struct wm831x *wm831x = dev_get_drvdata(dev: pdev->dev.parent); |
113 | struct wm831x_pdata *wm831x_pdata = dev_get_platdata(dev: pdev->dev.parent); |
114 | struct wm831x_backlight_pdata *pdata; |
115 | struct wm831x_backlight_data *data; |
116 | struct backlight_device *bl; |
117 | struct backlight_properties props; |
118 | int ret, i, max_isel, isink_reg, dcdc_cfg; |
119 | |
120 | /* We need platform data */ |
121 | if (wm831x_pdata) |
122 | pdata = wm831x_pdata->backlight; |
123 | else |
124 | pdata = NULL; |
125 | |
126 | if (!pdata) { |
127 | dev_err(&pdev->dev, "No platform data supplied\n" ); |
128 | return -EINVAL; |
129 | } |
130 | |
131 | /* Figure out the maximum current we can use */ |
132 | for (i = 0; i < WM831X_ISINK_MAX_ISEL; i++) { |
133 | if (wm831x_isinkv_values[i] > pdata->max_uA) |
134 | break; |
135 | } |
136 | |
137 | if (i == 0) { |
138 | dev_err(&pdev->dev, "Invalid max_uA: %duA\n" , pdata->max_uA); |
139 | return -EINVAL; |
140 | } |
141 | max_isel = i - 1; |
142 | |
143 | if (pdata->max_uA != wm831x_isinkv_values[max_isel]) |
144 | dev_warn(&pdev->dev, |
145 | "Maximum current is %duA not %duA as requested\n" , |
146 | wm831x_isinkv_values[max_isel], pdata->max_uA); |
147 | |
148 | switch (pdata->isink) { |
149 | case 1: |
150 | isink_reg = WM831X_CURRENT_SINK_1; |
151 | dcdc_cfg = 0; |
152 | break; |
153 | case 2: |
154 | isink_reg = WM831X_CURRENT_SINK_2; |
155 | dcdc_cfg = WM831X_DC4_FBSRC; |
156 | break; |
157 | default: |
158 | dev_err(&pdev->dev, "Invalid ISINK %d\n" , pdata->isink); |
159 | return -EINVAL; |
160 | } |
161 | |
162 | /* Configure the ISINK to use for feedback */ |
163 | ret = wm831x_reg_unlock(wm831x); |
164 | if (ret < 0) |
165 | return ret; |
166 | |
167 | ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC, |
168 | val: dcdc_cfg); |
169 | |
170 | wm831x_reg_lock(wm831x); |
171 | if (ret < 0) |
172 | return ret; |
173 | |
174 | data = devm_kzalloc(dev: &pdev->dev, size: sizeof(*data), GFP_KERNEL); |
175 | if (data == NULL) |
176 | return -ENOMEM; |
177 | |
178 | data->wm831x = wm831x; |
179 | data->current_brightness = 0; |
180 | data->isink_reg = isink_reg; |
181 | |
182 | memset(&props, 0, sizeof(props)); |
183 | props.type = BACKLIGHT_RAW; |
184 | props.max_brightness = max_isel; |
185 | bl = devm_backlight_device_register(dev: &pdev->dev, name: "wm831x" , parent: &pdev->dev, |
186 | devdata: data, ops: &wm831x_backlight_ops, props: &props); |
187 | if (IS_ERR(ptr: bl)) { |
188 | dev_err(&pdev->dev, "failed to register backlight\n" ); |
189 | return PTR_ERR(ptr: bl); |
190 | } |
191 | |
192 | bl->props.brightness = max_isel; |
193 | |
194 | platform_set_drvdata(pdev, data: bl); |
195 | |
196 | /* Disable the DCDC if it was started so we can bootstrap */ |
197 | wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, val: 0); |
198 | |
199 | backlight_update_status(bd: bl); |
200 | |
201 | return 0; |
202 | } |
203 | |
204 | static struct platform_driver wm831x_backlight_driver = { |
205 | .driver = { |
206 | .name = "wm831x-backlight" , |
207 | }, |
208 | .probe = wm831x_backlight_probe, |
209 | }; |
210 | |
211 | module_platform_driver(wm831x_backlight_driver); |
212 | |
213 | MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs" ); |
214 | MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com" ); |
215 | MODULE_LICENSE("GPL" ); |
216 | MODULE_ALIAS("platform:wm831x-backlight" ); |
217 | |