2
* LED control using Renesas TPU
4
* Copyright (C) 2011 Magnus Damm
6
* This program is free software; you can redistribute it and/or modify
7
* it under the terms of the GNU General Public License as published by
8
* the Free Software Foundation; either version 2 of the License
10
* This program is distributed in the hope that it will be useful,
11
* but WITHOUT ANY WARRANTY; without even the implied warranty of
12
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13
* GNU General Public License for more details.
15
* You should have received a copy of the GNU General Public License
16
* along with this program; if not, write to the Free Software
17
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20
#include <linux/module.h>
21
#include <linux/init.h>
22
#include <linux/platform_device.h>
23
#include <linux/spinlock.h>
24
#include <linux/printk.h>
25
#include <linux/ioport.h>
27
#include <linux/clk.h>
28
#include <linux/leds.h>
29
#include <linux/platform_data/leds-renesas-tpu.h>
30
#include <linux/gpio.h>
31
#include <linux/err.h>
32
#include <linux/slab.h>
33
#include <linux/pm_runtime.h>
34
#include <linux/workqueue.h>
36
enum r_tpu_pin { R_TPU_PIN_UNUSED, R_TPU_PIN_GPIO, R_TPU_PIN_GPIO_FN };
37
enum r_tpu_timer { R_TPU_TIMER_UNUSED, R_TPU_TIMER_ON };
40
struct led_classdev ldev;
41
void __iomem *mapbase;
43
struct platform_device *pdev;
44
enum r_tpu_pin pin_state;
45
enum r_tpu_timer timer_state;
46
unsigned long min_rate;
47
unsigned int refresh_rate;
48
struct work_struct work;
49
enum led_brightness new_brightness;
52
static DEFINE_SPINLOCK(r_tpu_lock);
54
#define TSTR -1 /* Timer start register (shared register) */
55
#define TCR 0 /* Timer control register (+0x00) */
56
#define TMDR 1 /* Timer mode register (+0x04) */
57
#define TIOR 2 /* Timer I/O control register (+0x08) */
58
#define TIER 3 /* Timer interrupt enable register (+0x0c) */
59
#define TSR 4 /* Timer status register (+0x10) */
60
#define TCNT 5 /* Timer counter (+0x14) */
61
#define TGRA 6 /* Timer general register A (+0x18) */
62
#define TGRB 7 /* Timer general register B (+0x1c) */
63
#define TGRC 8 /* Timer general register C (+0x20) */
64
#define TGRD 9 /* Timer general register D (+0x24) */
66
static inline unsigned short r_tpu_read(struct r_tpu_priv *p, int reg_nr)
68
struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
69
void __iomem *base = p->mapbase;
70
unsigned long offs = reg_nr << 2;
73
return ioread16(base - cfg->channel_offset);
75
return ioread16(base + offs);
78
static inline void r_tpu_write(struct r_tpu_priv *p, int reg_nr,
81
struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
82
void __iomem *base = p->mapbase;
83
unsigned long offs = reg_nr << 2;
86
iowrite16(value, base - cfg->channel_offset);
90
iowrite16(value, base + offs);
93
static void r_tpu_start_stop_ch(struct r_tpu_priv *p, int start)
95
struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
96
unsigned long flags, value;
98
/* start stop register shared by multiple timer channels */
99
spin_lock_irqsave(&r_tpu_lock, flags);
100
value = r_tpu_read(p, TSTR);
103
value |= 1 << cfg->timer_bit;
105
value &= ~(1 << cfg->timer_bit);
107
r_tpu_write(p, TSTR, value);
108
spin_unlock_irqrestore(&r_tpu_lock, flags);
111
static int r_tpu_enable(struct r_tpu_priv *p, enum led_brightness brightness)
113
struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
114
int prescaler[] = { 1, 4, 16, 64 };
116
unsigned long rate, tmp;
118
if (p->timer_state == R_TPU_TIMER_ON)
121
/* wake up device and enable clock */
122
pm_runtime_get_sync(&p->pdev->dev);
123
ret = clk_enable(p->clk);
125
dev_err(&p->pdev->dev, "cannot enable clock\n");
129
/* make sure channel is disabled */
130
r_tpu_start_stop_ch(p, 0);
132
/* get clock rate after enabling it */
133
rate = clk_get_rate(p->clk);
135
/* pick the lowest acceptable rate */
136
for (k = 0; k < ARRAY_SIZE(prescaler); k++)
137
if ((rate / prescaler[k]) < p->min_rate)
141
dev_err(&p->pdev->dev, "clock rate mismatch\n");
144
dev_dbg(&p->pdev->dev, "rate = %lu, prescaler %u\n",
145
rate, prescaler[k - 1]);
147
/* clear TCNT on TGRB match, count on rising edge, set prescaler */
148
r_tpu_write(p, TCR, 0x0040 | (k - 1));
150
/* output 0 until TGRA, output 1 until TGRB */
151
r_tpu_write(p, TIOR, 0x0002);
153
rate /= prescaler[k - 1] * p->refresh_rate;
154
r_tpu_write(p, TGRB, rate);
155
dev_dbg(&p->pdev->dev, "TRGB = 0x%04lx\n", rate);
157
tmp = (cfg->max_brightness - brightness) * rate;
158
r_tpu_write(p, TGRA, tmp / cfg->max_brightness);
159
dev_dbg(&p->pdev->dev, "TRGA = 0x%04lx\n", tmp / cfg->max_brightness);
162
r_tpu_write(p, TMDR, 0x0002);
165
r_tpu_start_stop_ch(p, 1);
167
p->timer_state = R_TPU_TIMER_ON;
171
pm_runtime_put_sync(&p->pdev->dev);
175
static void r_tpu_disable(struct r_tpu_priv *p)
177
if (p->timer_state == R_TPU_TIMER_UNUSED)
180
/* disable channel */
181
r_tpu_start_stop_ch(p, 0);
183
/* stop clock and mark device as idle */
185
pm_runtime_put_sync(&p->pdev->dev);
187
p->timer_state = R_TPU_TIMER_UNUSED;
190
static void r_tpu_set_pin(struct r_tpu_priv *p, enum r_tpu_pin new_state,
191
enum led_brightness brightness)
193
struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
195
if (p->pin_state == new_state) {
196
if (p->pin_state == R_TPU_PIN_GPIO)
197
gpio_set_value(cfg->pin_gpio, brightness);
201
if (p->pin_state == R_TPU_PIN_GPIO)
202
gpio_free(cfg->pin_gpio);
204
if (p->pin_state == R_TPU_PIN_GPIO_FN)
205
gpio_free(cfg->pin_gpio_fn);
207
if (new_state == R_TPU_PIN_GPIO) {
208
gpio_request(cfg->pin_gpio, cfg->name);
209
gpio_direction_output(cfg->pin_gpio, !!brightness);
211
if (new_state == R_TPU_PIN_GPIO_FN)
212
gpio_request(cfg->pin_gpio_fn, cfg->name);
214
p->pin_state = new_state;
217
static void r_tpu_work(struct work_struct *work)
219
struct r_tpu_priv *p = container_of(work, struct r_tpu_priv, work);
220
enum led_brightness brightness = p->new_brightness;
224
/* off and maximum are handled as GPIO pins, in between PWM */
225
if ((brightness == 0) || (brightness == p->ldev.max_brightness))
226
r_tpu_set_pin(p, R_TPU_PIN_GPIO, brightness);
228
r_tpu_set_pin(p, R_TPU_PIN_GPIO_FN, 0);
229
r_tpu_enable(p, brightness);
233
static void r_tpu_set_brightness(struct led_classdev *ldev,
234
enum led_brightness brightness)
236
struct r_tpu_priv *p = container_of(ldev, struct r_tpu_priv, ldev);
237
p->new_brightness = brightness;
238
schedule_work(&p->work);
241
static int __devinit r_tpu_probe(struct platform_device *pdev)
243
struct led_renesas_tpu_config *cfg = pdev->dev.platform_data;
244
struct r_tpu_priv *p;
245
struct resource *res;
249
dev_err(&pdev->dev, "missing platform data\n");
253
p = kzalloc(sizeof(*p), GFP_KERNEL);
255
dev_err(&pdev->dev, "failed to allocate driver data\n");
260
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
262
dev_err(&pdev->dev, "failed to get I/O memory\n");
266
/* map memory, let mapbase point to our channel */
267
p->mapbase = ioremap_nocache(res->start, resource_size(res));
268
if (p->mapbase == NULL) {
269
dev_err(&pdev->dev, "failed to remap I/O memory\n");
273
/* get hold of clock */
274
p->clk = clk_get(&pdev->dev, NULL);
275
if (IS_ERR(p->clk)) {
276
dev_err(&pdev->dev, "cannot get clock\n");
277
ret = PTR_ERR(p->clk);
282
p->pin_state = R_TPU_PIN_UNUSED;
283
p->timer_state = R_TPU_TIMER_UNUSED;
284
p->refresh_rate = cfg->refresh_rate ? cfg->refresh_rate : 100;
285
r_tpu_set_pin(p, R_TPU_PIN_GPIO, LED_OFF);
286
platform_set_drvdata(pdev, p);
288
INIT_WORK(&p->work, r_tpu_work);
290
p->ldev.name = cfg->name;
291
p->ldev.brightness = LED_OFF;
292
p->ldev.max_brightness = cfg->max_brightness;
293
p->ldev.brightness_set = r_tpu_set_brightness;
294
p->ldev.flags |= LED_CORE_SUSPENDRESUME;
295
ret = led_classdev_register(&pdev->dev, &p->ldev);
299
/* max_brightness may be updated by the LED core code */
300
p->min_rate = p->ldev.max_brightness * p->refresh_rate;
302
pm_runtime_enable(&pdev->dev);
306
r_tpu_set_pin(p, R_TPU_PIN_UNUSED, LED_OFF);
316
static int __devexit r_tpu_remove(struct platform_device *pdev)
318
struct r_tpu_priv *p = platform_get_drvdata(pdev);
320
r_tpu_set_brightness(&p->ldev, LED_OFF);
321
led_classdev_unregister(&p->ldev);
322
cancel_work_sync(&p->work);
324
r_tpu_set_pin(p, R_TPU_PIN_UNUSED, LED_OFF);
326
pm_runtime_disable(&pdev->dev);
334
static struct platform_driver r_tpu_device_driver = {
335
.probe = r_tpu_probe,
336
.remove = __devexit_p(r_tpu_remove),
338
.name = "leds-renesas-tpu",
342
static int __init r_tpu_init(void)
344
return platform_driver_register(&r_tpu_device_driver);
347
static void __exit r_tpu_exit(void)
349
platform_driver_unregister(&r_tpu_device_driver);
352
module_init(r_tpu_init);
353
module_exit(r_tpu_exit);
355
MODULE_AUTHOR("Magnus Damm");
356
MODULE_DESCRIPTION("Renesas TPU LED Driver");
357
MODULE_LICENSE("GPL v2");