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 = 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
112static const struct backlight_ops tps65217_bl_ops = {
113	.options	= BL_CORE_SUSPENDRESUME,
114	.update_status	= tps65217_bl_update_status,
115};
116
117static 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
183static struct tps65217_bl_pdata *
184tps65217_bl_parse_dt(struct platform_device *pdev)
185{
186	struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
187	struct device_node *node = of_node_get(tps->dev->of_node);
188	struct tps65217_bl_pdata *pdata, *err;
189	u32 val;
190
191	node = of_find_node_by_name(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 < 0 ||
243			val > 100) {
244			dev_err(&pdev->dev,
245				"invalid 'default-brightness' value in the device tree\n");
246			err = ERR_PTR(-EINVAL);
247			goto err;
248		}
249
250		pdata->dft_brightness = val;
251	}
252
253	of_node_put(node);
254
255	return pdata;
256
257err:
258	of_node_put(node);
259
260	return err;
261}
262#else
263static struct tps65217_bl_pdata *
264tps65217_bl_parse_dt(struct platform_device *pdev)
265{
266	return NULL;
267}
268#endif
269
270static int tps65217_bl_probe(struct platform_device *pdev)
271{
272	int rc;
273	struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
274	struct tps65217_bl *tps65217_bl;
275	struct tps65217_bl_pdata *pdata;
276	struct backlight_properties bl_props;
277
278	if (tps->dev->of_node) {
279		pdata = tps65217_bl_parse_dt(pdev);
280		if (IS_ERR(pdata))
281			return PTR_ERR(pdata);
282	} else {
283		pdata = dev_get_platdata(&pdev->dev);
284		if (!pdata) {
285			dev_err(&pdev->dev, "no platform data provided\n");
286			return -EINVAL;
287		}
288	}
289
290	tps65217_bl = devm_kzalloc(&pdev->dev, sizeof(*tps65217_bl),
291				GFP_KERNEL);
292	if (tps65217_bl == NULL)
293		return -ENOMEM;
294
295	tps65217_bl->tps = tps;
296	tps65217_bl->dev = &pdev->dev;
297	tps65217_bl->is_enabled = false;
298
299	rc = tps65217_bl_hw_init(tps65217_bl, pdata);
300	if (rc)
301		return rc;
302
303	memset(&bl_props, 0, sizeof(struct backlight_properties));
304	bl_props.type = BACKLIGHT_RAW;
305	bl_props.max_brightness = 100;
306
307	tps65217_bl->bl = devm_backlight_device_register(&pdev->dev, pdev->name,
308						tps65217_bl->dev, tps65217_bl,
309						&tps65217_bl_ops, &bl_props);
310	if (IS_ERR(tps65217_bl->bl)) {
311		dev_err(tps65217_bl->dev,
312			"registration of backlight device failed: %d\n", rc);
313		return PTR_ERR(tps65217_bl->bl);
314	}
315
316	tps65217_bl->bl->props.brightness = pdata->dft_brightness;
317	backlight_update_status(tps65217_bl->bl);
318	platform_set_drvdata(pdev, tps65217_bl);
319
320	return 0;
321}
322
323static struct platform_driver tps65217_bl_driver = {
324	.probe		= tps65217_bl_probe,
325	.driver		= {
326		.name	= "tps65217-bl",
327	},
328};
329
330module_platform_driver(tps65217_bl_driver);
331
332MODULE_DESCRIPTION("TPS65217 Backlight driver");
333MODULE_LICENSE("GPL v2");
334MODULE_AUTHOR("Matthias Kaehlcke <matthias@kaehlcke.net>");
335