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tps65217_bl.c
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1 /*
2  * tps65217_bl.c
3  *
4  * TPS65217 backlight driver
5  *
6  * Copyright (C) 2012 Matthias Kaehlcke
7  * Author: Matthias Kaehlcke <[email protected]>
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  of_node_put(node);
249 
250  return pdata;
251 
252 err:
253  of_node_put(node);
254 
255  return err;
256 }
257 #else
258 static struct tps65217_bl_pdata *
259 tps65217_bl_parse_dt(struct platform_device *pdev)
260 {
261  return NULL;
262 }
263 #endif
264 
265 static int tps65217_bl_probe(struct platform_device *pdev)
266 {
267  int rc;
268  struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
269  struct tps65217_bl *tps65217_bl;
270  struct tps65217_bl_pdata *pdata;
271  struct backlight_properties bl_props;
272 
273  if (tps->dev->of_node) {
274  pdata = tps65217_bl_parse_dt(pdev);
275  if (IS_ERR(pdata))
276  return PTR_ERR(pdata);
277  } else {
278  if (!pdev->dev.platform_data) {
279  dev_err(&pdev->dev, "no platform data provided\n");
280  return -EINVAL;
281  }
282 
283  pdata = pdev->dev.platform_data;
284  }
285 
286  tps65217_bl = devm_kzalloc(&pdev->dev, sizeof(*tps65217_bl),
287  GFP_KERNEL);
288  if (tps65217_bl == NULL) {
289  dev_err(&pdev->dev, "allocation of struct tps65217_bl failed\n");
290  return -ENOMEM;
291  }
292 
293  tps65217_bl->tps = tps;
294  tps65217_bl->dev = &pdev->dev;
295  tps65217_bl->is_enabled = false;
296 
297  rc = tps65217_bl_hw_init(tps65217_bl, pdata);
298  if (rc)
299  return rc;
300 
301  memset(&bl_props, 0, sizeof(struct backlight_properties));
302  bl_props.type = BACKLIGHT_RAW;
303  bl_props.max_brightness = 100;
304 
305  tps65217_bl->bl = backlight_device_register(pdev->name,
306  tps65217_bl->dev, tps65217_bl,
307  &tps65217_bl_ops, &bl_props);
308  if (IS_ERR(tps65217_bl->bl)) {
309  dev_err(tps65217_bl->dev,
310  "registration of backlight device failed: %d\n", rc);
311  return PTR_ERR(tps65217_bl->bl);
312  }
313 
314  tps65217_bl->bl->props.brightness = 0;
315  platform_set_drvdata(pdev, tps65217_bl);
316 
317  return 0;
318 }
319 
320 static int tps65217_bl_remove(struct platform_device *pdev)
321 {
322  struct tps65217_bl *tps65217_bl = platform_get_drvdata(pdev);
323 
324  backlight_device_unregister(tps65217_bl->bl);
325 
326  return 0;
327 }
328 
329 static struct platform_driver tps65217_bl_driver = {
330  .probe = tps65217_bl_probe,
331  .remove = tps65217_bl_remove,
332  .driver = {
333  .owner = THIS_MODULE,
334  .name = "tps65217-bl",
335  },
336 };
337 
338 module_platform_driver(tps65217_bl_driver);
339 
340 MODULE_DESCRIPTION("TPS65217 Backlight driver");
341 MODULE_LICENSE("GPL v2");
342 MODULE_AUTHOR("Matthias Kaehlcke <[email protected]>");
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