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
28struct tps65217_bl {
29	struct tps65217 *tps;
30	struct device *dev;
31	struct backlight_device *bl;
32	bool is_enabled;
33};
34
35static 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
55static 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
76static 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 = backlight_get_brightness(bl);
81
82	if (brightness > 0) {
83		rc = tps65217_reg_write(tps65217_bl->tps,
84					TPS65217_REG_WLEDCTRL2,
85					brightness - 1,
86					TPS65217_PROTECT_NONE);
87		if (rc) {
88			dev_err(tps65217_bl->dev,
89				"failed to set brightness level: %d\n", rc);
90			return rc;
91		}
92
93		dev_dbg(tps65217_bl->dev, "brightness set to %d\n", brightness);
94
95		if (!tps65217_bl->is_enabled)
96			rc = tps65217_bl_enable(tps65217_bl);
97	} else {
98		rc = tps65217_bl_disable(tps65217_bl);
99	}
100
101	return rc;
102}
103
104static const struct backlight_ops tps65217_bl_ops = {
105	.options	= BL_CORE_SUSPENDRESUME,
106	.update_status	= tps65217_bl_update_status,
107};
108
109static int tps65217_bl_hw_init(struct tps65217_bl *tps65217_bl,
110			struct tps65217_bl_pdata *pdata)
111{
112	int rc;
113
114	rc = tps65217_bl_disable(tps65217_bl);
115	if (rc)
116		return rc;
117
118	switch (pdata->isel) {
119	case TPS65217_BL_ISET1:
120		/* select ISET_1 current level */
121		rc = tps65217_clear_bits(tps65217_bl->tps,
122					TPS65217_REG_WLEDCTRL1,
123					TPS65217_WLEDCTRL1_ISEL,
124					TPS65217_PROTECT_NONE);
125		if (rc) {
126			dev_err(tps65217_bl->dev,
127				"failed to select ISET1 current level: %d)\n",
128				rc);
129			return rc;
130		}
131
132		dev_dbg(tps65217_bl->dev, "selected ISET1 current level\n");
133
134		break;
135
136	case TPS65217_BL_ISET2:
137		/* select ISET2 current level */
138		rc = tps65217_set_bits(tps65217_bl->tps, TPS65217_REG_WLEDCTRL1,
139				TPS65217_WLEDCTRL1_ISEL,
140				TPS65217_WLEDCTRL1_ISEL, TPS65217_PROTECT_NONE);
141		if (rc) {
142			dev_err(tps65217_bl->dev,
143				"failed to select ISET2 current level: %d\n",
144				rc);
145			return rc;
146		}
147
148		dev_dbg(tps65217_bl->dev, "selected ISET2 current level\n");
149
150		break;
151
152	default:
153		dev_err(tps65217_bl->dev,
154			"invalid value for current level: %d\n", pdata->isel);
155		return -EINVAL;
156	}
157
158	/* set PWM frequency */
159	rc = tps65217_set_bits(tps65217_bl->tps,
160			TPS65217_REG_WLEDCTRL1,
161			TPS65217_WLEDCTRL1_FDIM_MASK,
162			pdata->fdim,
163			TPS65217_PROTECT_NONE);
164	if (rc) {
165		dev_err(tps65217_bl->dev,
166			"failed to select PWM dimming frequency: %d\n",
167			rc);
168		return rc;
169	}
170
171	return 0;
172}
173
174#ifdef CONFIG_OF
175static struct tps65217_bl_pdata *
176tps65217_bl_parse_dt(struct platform_device *pdev)
177{
178	struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
179	struct device_node *node;
180	struct tps65217_bl_pdata *pdata, *err;
181	u32 val;
182
183	node = of_get_child_by_name(tps->dev->of_node, "backlight");
184	if (!node)
185		return ERR_PTR(-ENODEV);
186
187	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
188	if (!pdata) {
189		err = ERR_PTR(-ENOMEM);
190		goto err;
191	}
192
193	pdata->isel = TPS65217_BL_ISET1;
194	if (!of_property_read_u32(node, "isel", &val)) {
195		if (val < TPS65217_BL_ISET1 ||
196			val > TPS65217_BL_ISET2) {
197			dev_err(&pdev->dev,
198				"invalid 'isel' value in the device tree\n");
199			err = ERR_PTR(-EINVAL);
200			goto err;
201		}
202
203		pdata->isel = val;
204	}
205
206	pdata->fdim = TPS65217_BL_FDIM_200HZ;
207	if (!of_property_read_u32(node, "fdim", &val)) {
208		switch (val) {
209		case 100:
210			pdata->fdim = TPS65217_BL_FDIM_100HZ;
211			break;
212
213		case 200:
214			pdata->fdim = TPS65217_BL_FDIM_200HZ;
215			break;
216
217		case 500:
218			pdata->fdim = TPS65217_BL_FDIM_500HZ;
219			break;
220
221		case 1000:
222			pdata->fdim = TPS65217_BL_FDIM_1000HZ;
223			break;
224
225		default:
226			dev_err(&pdev->dev,
227				"invalid 'fdim' value in the device tree\n");
228			err = ERR_PTR(-EINVAL);
229			goto err;
230		}
231	}
232
233	if (!of_property_read_u32(node, "default-brightness", &val)) {
234		if (val > 100) {
235			dev_err(&pdev->dev,
236				"invalid 'default-brightness' value in the device tree\n");
237			err = ERR_PTR(-EINVAL);
238			goto err;
239		}
240
241		pdata->dft_brightness = val;
242	}
243
244	of_node_put(node);
245
246	return pdata;
247
248err:
249	of_node_put(node);
250
251	return err;
252}
253#else
254static struct tps65217_bl_pdata *
255tps65217_bl_parse_dt(struct platform_device *pdev)
256{
257	return NULL;
258}
259#endif
260
261static int tps65217_bl_probe(struct platform_device *pdev)
262{
263	int rc;
264	struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
265	struct tps65217_bl *tps65217_bl;
266	struct tps65217_bl_pdata *pdata;
267	struct backlight_properties bl_props;
268
269	pdata = tps65217_bl_parse_dt(pdev);
270	if (IS_ERR(pdata))
271		return PTR_ERR(pdata);
272
273	tps65217_bl = devm_kzalloc(&pdev->dev, sizeof(*tps65217_bl),
274				GFP_KERNEL);
275	if (tps65217_bl == NULL)
276		return -ENOMEM;
277
278	tps65217_bl->tps = tps;
279	tps65217_bl->dev = &pdev->dev;
280	tps65217_bl->is_enabled = false;
281
282	rc = tps65217_bl_hw_init(tps65217_bl, pdata);
283	if (rc)
284		return rc;
285
286	memset(&bl_props, 0, sizeof(struct backlight_properties));
287	bl_props.type = BACKLIGHT_RAW;
288	bl_props.max_brightness = 100;
289
290	tps65217_bl->bl = devm_backlight_device_register(&pdev->dev, pdev->name,
291						tps65217_bl->dev, tps65217_bl,
292						&tps65217_bl_ops, &bl_props);
293	if (IS_ERR(tps65217_bl->bl)) {
294		dev_err(tps65217_bl->dev,
295			"registration of backlight device failed: %d\n", rc);
296		return PTR_ERR(tps65217_bl->bl);
297	}
298
299	tps65217_bl->bl->props.brightness = pdata->dft_brightness;
300	backlight_update_status(tps65217_bl->bl);
301	platform_set_drvdata(pdev, tps65217_bl);
302
303	return 0;
304}
305
306#ifdef CONFIG_OF
307static const struct of_device_id tps65217_bl_of_match[] = {
308	{ .compatible = "ti,tps65217-bl", },
309	{ /* sentinel */ },
310};
311MODULE_DEVICE_TABLE(of, tps65217_bl_of_match);
312#endif
313
314static struct platform_driver tps65217_bl_driver = {
315	.probe		= tps65217_bl_probe,
316	.driver		= {
317		.name	= "tps65217-bl",
318		.of_match_table = of_match_ptr(tps65217_bl_of_match),
319	},
320};
321
322module_platform_driver(tps65217_bl_driver);
323
324MODULE_DESCRIPTION("TPS65217 Backlight driver");
325MODULE_LICENSE("GPL v2");
326MODULE_AUTHOR("Matthias Kaehlcke <matthias@kaehlcke.net>");
327