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 const struct backlight_ops tps65217_bl_ops = {
113 	.options	= BL_CORE_SUSPENDRESUME,
114 	.update_status	= tps65217_bl_update_status,
115 };
116 
117 static int tps65217_bl_hw_init(struct tps65217_bl *tps65217_bl,
118 			struct tps65217_bl_pdata *pdata)
119 {
120 	int rc;
121 
122 	rc = tps65217_bl_disable(tps65217_bl);
123 	if (rc)
124 		return rc;
125 
126 	switch (pdata->isel) {
127 	case TPS65217_BL_ISET1:
128 		/* select ISET_1 current level */
129 		rc = tps65217_clear_bits(tps65217_bl->tps,
130 					TPS65217_REG_WLEDCTRL1,
131 					TPS65217_WLEDCTRL1_ISEL,
132 					TPS65217_PROTECT_NONE);
133 		if (rc) {
134 			dev_err(tps65217_bl->dev,
135 				"failed to select ISET1 current level: %d)\n",
136 				rc);
137 			return rc;
138 		}
139 
140 		dev_dbg(tps65217_bl->dev, "selected ISET1 current level\n");
141 
142 		break;
143 
144 	case TPS65217_BL_ISET2:
145 		/* select ISET2 current level */
146 		rc = tps65217_set_bits(tps65217_bl->tps, TPS65217_REG_WLEDCTRL1,
147 				TPS65217_WLEDCTRL1_ISEL,
148 				TPS65217_WLEDCTRL1_ISEL, TPS65217_PROTECT_NONE);
149 		if (rc) {
150 			dev_err(tps65217_bl->dev,
151 				"failed to select ISET2 current level: %d\n",
152 				rc);
153 			return rc;
154 		}
155 
156 		dev_dbg(tps65217_bl->dev, "selected ISET2 current level\n");
157 
158 		break;
159 
160 	default:
161 		dev_err(tps65217_bl->dev,
162 			"invalid value for current level: %d\n", pdata->isel);
163 		return -EINVAL;
164 	}
165 
166 	/* set PWM frequency */
167 	rc = tps65217_set_bits(tps65217_bl->tps,
168 			TPS65217_REG_WLEDCTRL1,
169 			TPS65217_WLEDCTRL1_FDIM_MASK,
170 			pdata->fdim,
171 			TPS65217_PROTECT_NONE);
172 	if (rc) {
173 		dev_err(tps65217_bl->dev,
174 			"failed to select PWM dimming frequency: %d\n",
175 			rc);
176 		return rc;
177 	}
178 
179 	return 0;
180 }
181 
182 #ifdef CONFIG_OF
183 static struct tps65217_bl_pdata *
184 tps65217_bl_parse_dt(struct platform_device *pdev)
185 {
186 	struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
187 	struct device_node *node;
188 	struct tps65217_bl_pdata *pdata, *err;
189 	u32 val;
190 
191 	node = of_get_child_by_name(tps->dev->of_node, "backlight");
192 	if (!node)
193 		return ERR_PTR(-ENODEV);
194 
195 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
196 	if (!pdata) {
197 		err = ERR_PTR(-ENOMEM);
198 		goto err;
199 	}
200 
201 	pdata->isel = TPS65217_BL_ISET1;
202 	if (!of_property_read_u32(node, "isel", &val)) {
203 		if (val < TPS65217_BL_ISET1 ||
204 			val > TPS65217_BL_ISET2) {
205 			dev_err(&pdev->dev,
206 				"invalid 'isel' value in the device tree\n");
207 			err = ERR_PTR(-EINVAL);
208 			goto err;
209 		}
210 
211 		pdata->isel = val;
212 	}
213 
214 	pdata->fdim = TPS65217_BL_FDIM_200HZ;
215 	if (!of_property_read_u32(node, "fdim", &val)) {
216 		switch (val) {
217 		case 100:
218 			pdata->fdim = TPS65217_BL_FDIM_100HZ;
219 			break;
220 
221 		case 200:
222 			pdata->fdim = TPS65217_BL_FDIM_200HZ;
223 			break;
224 
225 		case 500:
226 			pdata->fdim = TPS65217_BL_FDIM_500HZ;
227 			break;
228 
229 		case 1000:
230 			pdata->fdim = TPS65217_BL_FDIM_1000HZ;
231 			break;
232 
233 		default:
234 			dev_err(&pdev->dev,
235 				"invalid 'fdim' value in the device tree\n");
236 			err = ERR_PTR(-EINVAL);
237 			goto err;
238 		}
239 	}
240 
241 	if (!of_property_read_u32(node, "default-brightness", &val)) {
242 		if (val > 100) {
243 			dev_err(&pdev->dev,
244 				"invalid 'default-brightness' value in the device tree\n");
245 			err = ERR_PTR(-EINVAL);
246 			goto err;
247 		}
248 
249 		pdata->dft_brightness = val;
250 	}
251 
252 	of_node_put(node);
253 
254 	return pdata;
255 
256 err:
257 	of_node_put(node);
258 
259 	return err;
260 }
261 #else
262 static struct tps65217_bl_pdata *
263 tps65217_bl_parse_dt(struct platform_device *pdev)
264 {
265 	return NULL;
266 }
267 #endif
268 
269 static int tps65217_bl_probe(struct platform_device *pdev)
270 {
271 	int rc;
272 	struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
273 	struct tps65217_bl *tps65217_bl;
274 	struct tps65217_bl_pdata *pdata;
275 	struct backlight_properties bl_props;
276 
277 	pdata = tps65217_bl_parse_dt(pdev);
278 	if (IS_ERR(pdata))
279 		return PTR_ERR(pdata);
280 
281 	tps65217_bl = devm_kzalloc(&pdev->dev, sizeof(*tps65217_bl),
282 				GFP_KERNEL);
283 	if (tps65217_bl == NULL)
284 		return -ENOMEM;
285 
286 	tps65217_bl->tps = tps;
287 	tps65217_bl->dev = &pdev->dev;
288 	tps65217_bl->is_enabled = false;
289 
290 	rc = tps65217_bl_hw_init(tps65217_bl, pdata);
291 	if (rc)
292 		return rc;
293 
294 	memset(&bl_props, 0, sizeof(struct backlight_properties));
295 	bl_props.type = BACKLIGHT_RAW;
296 	bl_props.max_brightness = 100;
297 
298 	tps65217_bl->bl = devm_backlight_device_register(&pdev->dev, pdev->name,
299 						tps65217_bl->dev, tps65217_bl,
300 						&tps65217_bl_ops, &bl_props);
301 	if (IS_ERR(tps65217_bl->bl)) {
302 		dev_err(tps65217_bl->dev,
303 			"registration of backlight device failed: %d\n", rc);
304 		return PTR_ERR(tps65217_bl->bl);
305 	}
306 
307 	tps65217_bl->bl->props.brightness = pdata->dft_brightness;
308 	backlight_update_status(tps65217_bl->bl);
309 	platform_set_drvdata(pdev, tps65217_bl);
310 
311 	return 0;
312 }
313 
314 #ifdef CONFIG_OF
315 static const struct of_device_id tps65217_bl_of_match[] = {
316 	{ .compatible = "ti,tps65217-bl", },
317 	{ /* sentinel */ },
318 };
319 MODULE_DEVICE_TABLE(of, tps65217_bl_of_match);
320 #endif
321 
322 static struct platform_driver tps65217_bl_driver = {
323 	.probe		= tps65217_bl_probe,
324 	.driver		= {
325 		.name	= "tps65217-bl",
326 		.of_match_table = of_match_ptr(tps65217_bl_of_match),
327 	},
328 };
329 
330 module_platform_driver(tps65217_bl_driver);
331 
332 MODULE_DESCRIPTION("TPS65217 Backlight driver");
333 MODULE_LICENSE("GPL v2");
334 MODULE_AUTHOR("Matthias Kaehlcke <matthias@kaehlcke.net>");
335