1 /*
2  * tps65217_bl.c
3  *
4  * TPS65217 backlight driver
5  *
6  * Copyright (C) 2012 Matthias Kaehlcke
7  * Author: Matthias Kaehlcke <matthias@kaehlcke.net>
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License as
11  * published by the Free Software Foundation version 2.
12  *
13  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
14  * kind, whether express or implied; without even the implied warranty
15  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  */
18 
19 #include <linux/kernel.h>
20 #include <linux/backlight.h>
21 #include <linux/err.h>
22 #include <linux/fb.h>
23 #include <linux/mfd/tps65217.h>
24 #include <linux/module.h>
25 #include <linux/platform_device.h>
26 #include <linux/slab.h>
27 
28 struct tps65217_bl {
29 	struct tps65217 *tps;
30 	struct device *dev;
31 	struct backlight_device *bl;
32 	bool is_enabled;
33 };
34 
35 static int tps65217_bl_enable(struct tps65217_bl *tps65217_bl)
36 {
37 	int rc;
38 
39 	rc = tps65217_set_bits(tps65217_bl->tps, TPS65217_REG_WLEDCTRL1,
40 			TPS65217_WLEDCTRL1_ISINK_ENABLE,
41 			TPS65217_WLEDCTRL1_ISINK_ENABLE, TPS65217_PROTECT_NONE);
42 	if (rc) {
43 		dev_err(tps65217_bl->dev,
44 			"failed to enable backlight: %d\n", rc);
45 		return rc;
46 	}
47 
48 	tps65217_bl->is_enabled = true;
49 
50 	dev_dbg(tps65217_bl->dev, "backlight enabled\n");
51 
52 	return 0;
53 }
54 
55 static int tps65217_bl_disable(struct tps65217_bl *tps65217_bl)
56 {
57 	int rc;
58 
59 	rc = tps65217_clear_bits(tps65217_bl->tps,
60 				TPS65217_REG_WLEDCTRL1,
61 				TPS65217_WLEDCTRL1_ISINK_ENABLE,
62 				TPS65217_PROTECT_NONE);
63 	if (rc) {
64 		dev_err(tps65217_bl->dev,
65 			"failed to disable backlight: %d\n", rc);
66 		return rc;
67 	}
68 
69 	tps65217_bl->is_enabled = false;
70 
71 	dev_dbg(tps65217_bl->dev, "backlight disabled\n");
72 
73 	return 0;
74 }
75 
76 static int tps65217_bl_update_status(struct backlight_device *bl)
77 {
78 	struct tps65217_bl *tps65217_bl = bl_get_data(bl);
79 	int rc;
80 	int brightness = bl->props.brightness;
81 
82 	if (bl->props.state & BL_CORE_SUSPENDED)
83 		brightness = 0;
84 
85 	if ((bl->props.power != FB_BLANK_UNBLANK) ||
86 		(bl->props.fb_blank != FB_BLANK_UNBLANK))
87 		/* framebuffer in low power mode or blanking active */
88 		brightness = 0;
89 
90 	if (brightness > 0) {
91 		rc = tps65217_reg_write(tps65217_bl->tps,
92 					TPS65217_REG_WLEDCTRL2,
93 					brightness - 1,
94 					TPS65217_PROTECT_NONE);
95 		if (rc) {
96 			dev_err(tps65217_bl->dev,
97 				"failed to set brightness level: %d\n", rc);
98 			return rc;
99 		}
100 
101 		dev_dbg(tps65217_bl->dev, "brightness set to %d\n", brightness);
102 
103 		if (!tps65217_bl->is_enabled)
104 			rc = tps65217_bl_enable(tps65217_bl);
105 	} else {
106 		rc = tps65217_bl_disable(tps65217_bl);
107 	}
108 
109 	return rc;
110 }
111 
112 static int tps65217_bl_get_brightness(struct backlight_device *bl)
113 {
114 	return bl->props.brightness;
115 }
116 
117 static const struct backlight_ops tps65217_bl_ops = {
118 	.options	= BL_CORE_SUSPENDRESUME,
119 	.update_status	= tps65217_bl_update_status,
120 	.get_brightness	= tps65217_bl_get_brightness
121 };
122 
123 static int tps65217_bl_hw_init(struct tps65217_bl *tps65217_bl,
124 			struct tps65217_bl_pdata *pdata)
125 {
126 	int rc;
127 
128 	rc = tps65217_bl_disable(tps65217_bl);
129 	if (rc)
130 		return rc;
131 
132 	switch (pdata->isel) {
133 	case TPS65217_BL_ISET1:
134 		/* select ISET_1 current level */
135 		rc = tps65217_clear_bits(tps65217_bl->tps,
136 					TPS65217_REG_WLEDCTRL1,
137 					TPS65217_WLEDCTRL1_ISEL,
138 					TPS65217_PROTECT_NONE);
139 		if (rc) {
140 			dev_err(tps65217_bl->dev,
141 				"failed to select ISET1 current level: %d)\n",
142 				rc);
143 			return rc;
144 		}
145 
146 		dev_dbg(tps65217_bl->dev, "selected ISET1 current level\n");
147 
148 		break;
149 
150 	case TPS65217_BL_ISET2:
151 		/* select ISET2 current level */
152 		rc = tps65217_set_bits(tps65217_bl->tps, TPS65217_REG_WLEDCTRL1,
153 				TPS65217_WLEDCTRL1_ISEL,
154 				TPS65217_WLEDCTRL1_ISEL, TPS65217_PROTECT_NONE);
155 		if (rc) {
156 			dev_err(tps65217_bl->dev,
157 				"failed to select ISET2 current level: %d\n",
158 				rc);
159 			return rc;
160 		}
161 
162 		dev_dbg(tps65217_bl->dev, "selected ISET2 current level\n");
163 
164 		break;
165 
166 	default:
167 		dev_err(tps65217_bl->dev,
168 			"invalid value for current level: %d\n", pdata->isel);
169 		return -EINVAL;
170 	}
171 
172 	/* set PWM frequency */
173 	rc = tps65217_set_bits(tps65217_bl->tps,
174 			TPS65217_REG_WLEDCTRL1,
175 			TPS65217_WLEDCTRL1_FDIM_MASK,
176 			pdata->fdim,
177 			TPS65217_PROTECT_NONE);
178 	if (rc) {
179 		dev_err(tps65217_bl->dev,
180 			"failed to select PWM dimming frequency: %d\n",
181 			rc);
182 		return rc;
183 	}
184 
185 	return 0;
186 }
187 
188 #ifdef CONFIG_OF
189 static struct tps65217_bl_pdata *
190 tps65217_bl_parse_dt(struct platform_device *pdev)
191 {
192 	struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
193 	struct device_node *node = of_node_get(tps->dev->of_node);
194 	struct tps65217_bl_pdata *pdata, *err;
195 	u32 val;
196 
197 	node = of_find_node_by_name(node, "backlight");
198 	if (!node)
199 		return ERR_PTR(-ENODEV);
200 
201 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
202 	if (!pdata) {
203 		dev_err(&pdev->dev, "failed to allocate platform data\n");
204 		err = ERR_PTR(-ENOMEM);
205 		goto err;
206 	}
207 
208 	pdata->isel = TPS65217_BL_ISET1;
209 	if (!of_property_read_u32(node, "isel", &val)) {
210 		if (val < TPS65217_BL_ISET1 ||
211 			val > TPS65217_BL_ISET2) {
212 			dev_err(&pdev->dev,
213 				"invalid 'isel' value in the device tree\n");
214 			err = ERR_PTR(-EINVAL);
215 			goto err;
216 		}
217 
218 		pdata->isel = val;
219 	}
220 
221 	pdata->fdim = TPS65217_BL_FDIM_200HZ;
222 	if (!of_property_read_u32(node, "fdim", &val)) {
223 		switch (val) {
224 		case 100:
225 			pdata->fdim = TPS65217_BL_FDIM_100HZ;
226 			break;
227 
228 		case 200:
229 			pdata->fdim = TPS65217_BL_FDIM_200HZ;
230 			break;
231 
232 		case 500:
233 			pdata->fdim = TPS65217_BL_FDIM_500HZ;
234 			break;
235 
236 		case 1000:
237 			pdata->fdim = TPS65217_BL_FDIM_1000HZ;
238 			break;
239 
240 		default:
241 			dev_err(&pdev->dev,
242 				"invalid 'fdim' value in the device tree\n");
243 			err = ERR_PTR(-EINVAL);
244 			goto err;
245 		}
246 	}
247 
248 	if (!of_property_read_u32(node, "default-brightness", &val)) {
249 		if (val < 0 ||
250 			val > 100) {
251 			dev_err(&pdev->dev,
252 				"invalid 'default-brightness' value in the device tree\n");
253 			err = ERR_PTR(-EINVAL);
254 			goto err;
255 		}
256 
257 		pdata->dft_brightness = val;
258 	}
259 
260 	of_node_put(node);
261 
262 	return pdata;
263 
264 err:
265 	of_node_put(node);
266 
267 	return err;
268 }
269 #else
270 static struct tps65217_bl_pdata *
271 tps65217_bl_parse_dt(struct platform_device *pdev)
272 {
273 	return NULL;
274 }
275 #endif
276 
277 static int tps65217_bl_probe(struct platform_device *pdev)
278 {
279 	int rc;
280 	struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
281 	struct tps65217_bl *tps65217_bl;
282 	struct tps65217_bl_pdata *pdata;
283 	struct backlight_properties bl_props;
284 
285 	if (tps->dev->of_node) {
286 		pdata = tps65217_bl_parse_dt(pdev);
287 		if (IS_ERR(pdata))
288 			return PTR_ERR(pdata);
289 	} else {
290 		if (!pdev->dev.platform_data) {
291 			dev_err(&pdev->dev, "no platform data provided\n");
292 			return -EINVAL;
293 		}
294 
295 		pdata = pdev->dev.platform_data;
296 	}
297 
298 	tps65217_bl = devm_kzalloc(&pdev->dev, sizeof(*tps65217_bl),
299 				GFP_KERNEL);
300 	if (tps65217_bl == NULL) {
301 		dev_err(&pdev->dev, "allocation of struct tps65217_bl failed\n");
302 		return -ENOMEM;
303 	}
304 
305 	tps65217_bl->tps = tps;
306 	tps65217_bl->dev = &pdev->dev;
307 	tps65217_bl->is_enabled = false;
308 
309 	rc = tps65217_bl_hw_init(tps65217_bl, pdata);
310 	if (rc)
311 		return rc;
312 
313 	memset(&bl_props, 0, sizeof(struct backlight_properties));
314 	bl_props.type = BACKLIGHT_RAW;
315 	bl_props.max_brightness = 100;
316 
317 	tps65217_bl->bl = backlight_device_register(pdev->name,
318 						tps65217_bl->dev, tps65217_bl,
319 						&tps65217_bl_ops, &bl_props);
320 	if (IS_ERR(tps65217_bl->bl)) {
321 		dev_err(tps65217_bl->dev,
322 			"registration of backlight device failed: %d\n", rc);
323 		return PTR_ERR(tps65217_bl->bl);
324 	}
325 
326 	tps65217_bl->bl->props.brightness = pdata->dft_brightness;
327 	backlight_update_status(tps65217_bl->bl);
328 	platform_set_drvdata(pdev, tps65217_bl);
329 
330 	return 0;
331 }
332 
333 static int tps65217_bl_remove(struct platform_device *pdev)
334 {
335 	struct tps65217_bl *tps65217_bl = platform_get_drvdata(pdev);
336 
337 	backlight_device_unregister(tps65217_bl->bl);
338 
339 	return 0;
340 }
341 
342 static struct platform_driver tps65217_bl_driver = {
343 	.probe		= tps65217_bl_probe,
344 	.remove		= tps65217_bl_remove,
345 	.driver		= {
346 		.owner	= THIS_MODULE,
347 		.name	= "tps65217-bl",
348 	},
349 };
350 
351 module_platform_driver(tps65217_bl_driver);
352 
353 MODULE_DESCRIPTION("TPS65217 Backlight driver");
354 MODULE_LICENSE("GPL v2");
355 MODULE_AUTHOR("Matthias Kaehlcke <matthias@kaehlcke.net>");
356