summaryrefslogtreecommitdiffstats
path: root/drivers/leds/leds-renesas-tpu.c
blob: 771ea067e680f8b64e9cd54672007a5d66091d9c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
/*
 * LED control using Renesas TPU
 *
 *  Copyright (C) 2011 Magnus Damm
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/printk.h>
#include <linux/ioport.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/leds.h>
#include <linux/platform_data/leds-renesas-tpu.h>
#include <linux/gpio.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/pm_runtime.h>
#include <linux/workqueue.h>

enum r_tpu_pin { R_TPU_PIN_UNUSED, R_TPU_PIN_GPIO, R_TPU_PIN_GPIO_FN };
enum r_tpu_timer { R_TPU_TIMER_UNUSED, R_TPU_TIMER_ON };

struct r_tpu_priv {
	struct led_classdev ldev;
	void __iomem *mapbase;
	struct clk *clk;
	struct platform_device *pdev;
	enum r_tpu_pin pin_state;
	enum r_tpu_timer timer_state;
	unsigned long min_rate;
	unsigned int refresh_rate;
	struct work_struct work;
	enum led_brightness new_brightness;
};

static DEFINE_SPINLOCK(r_tpu_lock);

#define TSTR -1 /* Timer start register (shared register) */
#define TCR  0 /* Timer control register (+0x00) */
#define TMDR 1 /* Timer mode register (+0x04) */
#define TIOR 2 /* Timer I/O control register (+0x08) */
#define TIER 3 /* Timer interrupt enable register (+0x0c) */
#define TSR  4 /* Timer status register (+0x10) */
#define TCNT 5 /* Timer counter (+0x14) */
#define TGRA 6 /* Timer general register A (+0x18) */
#define TGRB 7 /* Timer general register B (+0x1c) */
#define TGRC 8 /* Timer general register C (+0x20) */
#define TGRD 9 /* Timer general register D (+0x24) */

static inline unsigned short r_tpu_read(struct r_tpu_priv *p, int reg_nr)
{
	struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
	void __iomem *base = p->mapbase;
	unsigned long offs = reg_nr << 2;

	if (reg_nr == TSTR)
		return ioread16(base - cfg->channel_offset);

	return ioread16(base + offs);
}

static inline void r_tpu_write(struct r_tpu_priv *p, int reg_nr,
			       unsigned short value)
{
	struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
	void __iomem *base = p->mapbase;
	unsigned long offs = reg_nr << 2;

	if (reg_nr == TSTR) {
		iowrite16(value, base - cfg->channel_offset);
		return;
	}

	iowrite16(value, base + offs);
}

static void r_tpu_start_stop_ch(struct r_tpu_priv *p, int start)
{
	struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
	unsigned long flags, value;

	/* start stop register shared by multiple timer channels */
	spin_lock_irqsave(&r_tpu_lock, flags);
	value = r_tpu_read(p, TSTR);

	if (start)
		value |= 1 << cfg->timer_bit;
	else
		value &= ~(1 << cfg->timer_bit);

	r_tpu_write(p, TSTR, value);
	spin_unlock_irqrestore(&r_tpu_lock, flags);
}

static int r_tpu_enable(struct r_tpu_priv *p, enum led_brightness brightness)
{
	struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
	int prescaler[] = { 1, 4, 16, 64 };
	int k, ret;
	unsigned long rate, tmp;

	if (p->timer_state == R_TPU_TIMER_ON)
		return 0;

	/* wake up device and enable clock */
	pm_runtime_get_sync(&p->pdev->dev);
	ret = clk_enable(p->clk);
	if (ret) {
		dev_err(&p->pdev->dev, "cannot enable clock\n");
		return ret;
	}

	/* make sure channel is disabled */
	r_tpu_start_stop_ch(p, 0);

	/* get clock rate after enabling it */
	rate = clk_get_rate(p->clk);

	/* pick the lowest acceptable rate */
	for (k = 0; k < ARRAY_SIZE(prescaler); k++)
		if ((rate / prescaler[k]) < p->min_rate)
			break;

	if (!k) {
		dev_err(&p->pdev->dev, "clock rate mismatch\n");
		goto err0;
	}
	dev_dbg(&p->pdev->dev, "rate = %lu, prescaler %u\n",
		rate, prescaler[k - 1]);

	/* clear TCNT on TGRB match, count on rising edge, set prescaler */
	r_tpu_write(p, TCR, 0x0040 | (k - 1));

	/* output 0 until TGRA, output 1 until TGRB */
	r_tpu_write(p, TIOR, 0x0002);

	rate /= prescaler[k - 1] * p->refresh_rate;
	r_tpu_write(p, TGRB, rate);
	dev_dbg(&p->pdev->dev, "TRGB = 0x%04lx\n", rate);

	tmp = (cfg->max_brightness - brightness) * rate;
	r_tpu_write(p, TGRA, tmp / cfg->max_brightness);
	dev_dbg(&p->pdev->dev, "TRGA = 0x%04lx\n", tmp / cfg->max_brightness);

	/* PWM mode */
	r_tpu_write(p, TMDR, 0x0002);

	/* enable channel */
	r_tpu_start_stop_ch(p, 1);

	p->timer_state = R_TPU_TIMER_ON;
	return 0;
 err0:
	clk_disable(p->clk);
	pm_runtime_put_sync(&p->pdev->dev);
	return -ENOTSUPP;
}

static void r_tpu_disable(struct r_tpu_priv *p)
{
	if (p->timer_state == R_TPU_TIMER_UNUSED)
		return;

	/* disable channel */
	r_tpu_start_stop_ch(p, 0);

	/* stop clock and mark device as idle */
	clk_disable(p->clk);
	pm_runtime_put_sync(&p->pdev->dev);

	p->timer_state = R_TPU_TIMER_UNUSED;
}

static void r_tpu_set_pin(struct r_tpu_priv *p, enum r_tpu_pin new_state,
			  enum led_brightness brightness)
{
	struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;

	if (p->pin_state == new_state) {
		if (p->pin_state == R_TPU_PIN_GPIO)
			gpio_set_value(cfg->pin_gpio, brightness);
		return;
	}

	if (p->pin_state == R_TPU_PIN_GPIO)
		gpio_free(cfg->pin_gpio);

	if (p->pin_state == R_TPU_PIN_GPIO_FN)
		gpio_free(cfg->pin_gpio_fn);

	if (new_state == R_TPU_PIN_GPIO) {
		gpio_request(cfg->pin_gpio, cfg->name);
		gpio_direction_output(cfg->pin_gpio, !!brightness);
	}
	if (new_state == R_TPU_PIN_GPIO_FN)
		gpio_request(cfg->pin_gpio_fn, cfg->name);

	p->pin_state = new_state;
}

static void r_tpu_work(struct work_struct *work)
{
	struct r_tpu_priv *p = container_of(work, struct r_tpu_priv, work);
	enum led_brightness brightness = p->new_brightness;

	r_tpu_disable(p);

	/* off and maximum are handled as GPIO pins, in between PWM */
	if ((brightness == 0) || (brightness == p->ldev.max_brightness))
		r_tpu_set_pin(p, R_TPU_PIN_GPIO, brightness);
	else {
		r_tpu_set_pin(p, R_TPU_PIN_GPIO_FN, 0);
		r_tpu_enable(p, brightness);
	}
}

static void r_tpu_set_brightness(struct led_classdev *ldev,
				 enum led_brightness brightness)
{
	struct r_tpu_priv *p = container_of(ldev, struct r_tpu_priv, ldev);
	p->new_brightness = brightness;
	schedule_work(&p->work);
}

static int __devinit r_tpu_probe(struct platform_device *pdev)
{
	struct led_renesas_tpu_config *cfg = pdev->dev.platform_data;
	struct r_tpu_priv *p;
	struct resource *res;
	int ret;

	if (!cfg) {
		dev_err(&pdev->dev, "missing platform data\n");
		return -ENODEV;
	}

	p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
	if (p == NULL) {
		dev_err(&pdev->dev, "failed to allocate driver data\n");
		return -ENOMEM;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(&pdev->dev, "failed to get I/O memory\n");
		return -ENXIO;
	}

	/* map memory, let mapbase point to our channel */
	p->mapbase = ioremap_nocache(res->start, resource_size(res));
	if (p->mapbase == NULL) {
		dev_err(&pdev->dev, "failed to remap I/O memory\n");
		return -ENXIO;
	}

	/* get hold of clock */
	p->clk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(p->clk)) {
		dev_err(&pdev->dev, "cannot get clock\n");
		ret = PTR_ERR(p->clk);
		goto err0;
	}

	p->pdev = pdev;
	p->pin_state = R_TPU_PIN_UNUSED;
	p->timer_state = R_TPU_TIMER_UNUSED;
	p->refresh_rate = cfg->refresh_rate ? cfg->refresh_rate : 100;
	r_tpu_set_pin(p, R_TPU_PIN_GPIO, LED_OFF);
	platform_set_drvdata(pdev, p);

	INIT_WORK(&p->work, r_tpu_work);

	p->ldev.name = cfg->name;
	p->ldev.brightness = LED_OFF;
	p->ldev.max_brightness = cfg->max_brightness;
	p->ldev.brightness_set = r_tpu_set_brightness;
	p->ldev.flags |= LED_CORE_SUSPENDRESUME;
	ret = led_classdev_register(&pdev->dev, &p->ldev);
	if (ret < 0)
		goto err1;

	/* max_brightness may be updated by the LED core code */
	p->min_rate = p->ldev.max_brightness * p->refresh_rate;

	pm_runtime_enable(&pdev->dev);
	return 0;

 err1:
	r_tpu_set_pin(p, R_TPU_PIN_UNUSED, LED_OFF);
	clk_put(p->clk);
 err0:
	iounmap(p->mapbase);
	return ret;
}

static int __devexit r_tpu_remove(struct platform_device *pdev)
{
	struct r_tpu_priv *p = platform_get_drvdata(pdev);

	r_tpu_set_brightness(&p->ldev, LED_OFF);
	led_classdev_unregister(&p->ldev);
	cancel_work_sync(&p->work);
	r_tpu_disable(p);
	r_tpu_set_pin(p, R_TPU_PIN_UNUSED, LED_OFF);

	pm_runtime_disable(&pdev->dev);
	clk_put(p->clk);

	iounmap(p->mapbase);
	return 0;
}

static struct platform_driver r_tpu_device_driver = {
	.probe		= r_tpu_probe,
	.remove		= __devexit_p(r_tpu_remove),
	.driver		= {
		.name	= "leds-renesas-tpu",
	}
};

module_platform_driver(r_tpu_device_driver);

MODULE_AUTHOR("Magnus Damm");
MODULE_DESCRIPTION("Renesas TPU LED Driver");
MODULE_LICENSE("GPL v2");