1/*
2 * SuperH Timer Support - MTU2
3 *
4 *  Copyright (C) 2009 Magnus Damm
5 *
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
9 *
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.
14 */
15
16#include <linux/clk.h>
17#include <linux/clockchips.h>
18#include <linux/delay.h>
19#include <linux/err.h>
20#include <linux/init.h>
21#include <linux/interrupt.h>
22#include <linux/io.h>
23#include <linux/ioport.h>
24#include <linux/irq.h>
25#include <linux/module.h>
26#include <linux/of.h>
27#include <linux/platform_device.h>
28#include <linux/pm_domain.h>
29#include <linux/pm_runtime.h>
30#include <linux/sh_timer.h>
31#include <linux/slab.h>
32#include <linux/spinlock.h>
33
34struct sh_mtu2_device;
35
36struct sh_mtu2_channel {
37	struct sh_mtu2_device *mtu;
38	unsigned int index;
39
40	void __iomem *base;
41
42	struct clock_event_device ced;
43};
44
45struct sh_mtu2_device {
46	struct platform_device *pdev;
47
48	void __iomem *mapbase;
49	struct clk *clk;
50
51	raw_spinlock_t lock; /* Protect the shared registers */
52
53	struct sh_mtu2_channel *channels;
54	unsigned int num_channels;
55
56	bool has_clockevent;
57};
58
59#define TSTR -1 /* shared register */
60#define TCR  0 /* channel register */
61#define TMDR 1 /* channel register */
62#define TIOR 2 /* channel register */
63#define TIER 3 /* channel register */
64#define TSR  4 /* channel register */
65#define TCNT 5 /* channel register */
66#define TGR  6 /* channel register */
67
68#define TCR_CCLR_NONE		(0 << 5)
69#define TCR_CCLR_TGRA		(1 << 5)
70#define TCR_CCLR_TGRB		(2 << 5)
71#define TCR_CCLR_SYNC		(3 << 5)
72#define TCR_CCLR_TGRC		(5 << 5)
73#define TCR_CCLR_TGRD		(6 << 5)
74#define TCR_CCLR_MASK		(7 << 5)
75#define TCR_CKEG_RISING		(0 << 3)
76#define TCR_CKEG_FALLING	(1 << 3)
77#define TCR_CKEG_BOTH		(2 << 3)
78#define TCR_CKEG_MASK		(3 << 3)
79/* Values 4 to 7 are channel-dependent */
80#define TCR_TPSC_P1		(0 << 0)
81#define TCR_TPSC_P4		(1 << 0)
82#define TCR_TPSC_P16		(2 << 0)
83#define TCR_TPSC_P64		(3 << 0)
84#define TCR_TPSC_CH0_TCLKA	(4 << 0)
85#define TCR_TPSC_CH0_TCLKB	(5 << 0)
86#define TCR_TPSC_CH0_TCLKC	(6 << 0)
87#define TCR_TPSC_CH0_TCLKD	(7 << 0)
88#define TCR_TPSC_CH1_TCLKA	(4 << 0)
89#define TCR_TPSC_CH1_TCLKB	(5 << 0)
90#define TCR_TPSC_CH1_P256	(6 << 0)
91#define TCR_TPSC_CH1_TCNT2	(7 << 0)
92#define TCR_TPSC_CH2_TCLKA	(4 << 0)
93#define TCR_TPSC_CH2_TCLKB	(5 << 0)
94#define TCR_TPSC_CH2_TCLKC	(6 << 0)
95#define TCR_TPSC_CH2_P1024	(7 << 0)
96#define TCR_TPSC_CH34_P256	(4 << 0)
97#define TCR_TPSC_CH34_P1024	(5 << 0)
98#define TCR_TPSC_CH34_TCLKA	(6 << 0)
99#define TCR_TPSC_CH34_TCLKB	(7 << 0)
100#define TCR_TPSC_MASK		(7 << 0)
101
102#define TMDR_BFE		(1 << 6)
103#define TMDR_BFB		(1 << 5)
104#define TMDR_BFA		(1 << 4)
105#define TMDR_MD_NORMAL		(0 << 0)
106#define TMDR_MD_PWM_1		(2 << 0)
107#define TMDR_MD_PWM_2		(3 << 0)
108#define TMDR_MD_PHASE_1		(4 << 0)
109#define TMDR_MD_PHASE_2		(5 << 0)
110#define TMDR_MD_PHASE_3		(6 << 0)
111#define TMDR_MD_PHASE_4		(7 << 0)
112#define TMDR_MD_PWM_SYNC	(8 << 0)
113#define TMDR_MD_PWM_COMP_CREST	(13 << 0)
114#define TMDR_MD_PWM_COMP_TROUGH	(14 << 0)
115#define TMDR_MD_PWM_COMP_BOTH	(15 << 0)
116#define TMDR_MD_MASK		(15 << 0)
117
118#define TIOC_IOCH(n)		((n) << 4)
119#define TIOC_IOCL(n)		((n) << 0)
120#define TIOR_OC_RETAIN		(0 << 0)
121#define TIOR_OC_0_CLEAR		(1 << 0)
122#define TIOR_OC_0_SET		(2 << 0)
123#define TIOR_OC_0_TOGGLE	(3 << 0)
124#define TIOR_OC_1_CLEAR		(5 << 0)
125#define TIOR_OC_1_SET		(6 << 0)
126#define TIOR_OC_1_TOGGLE	(7 << 0)
127#define TIOR_IC_RISING		(8 << 0)
128#define TIOR_IC_FALLING		(9 << 0)
129#define TIOR_IC_BOTH		(10 << 0)
130#define TIOR_IC_TCNT		(12 << 0)
131#define TIOR_MASK		(15 << 0)
132
133#define TIER_TTGE		(1 << 7)
134#define TIER_TTGE2		(1 << 6)
135#define TIER_TCIEU		(1 << 5)
136#define TIER_TCIEV		(1 << 4)
137#define TIER_TGIED		(1 << 3)
138#define TIER_TGIEC		(1 << 2)
139#define TIER_TGIEB		(1 << 1)
140#define TIER_TGIEA		(1 << 0)
141
142#define TSR_TCFD		(1 << 7)
143#define TSR_TCFU		(1 << 5)
144#define TSR_TCFV		(1 << 4)
145#define TSR_TGFD		(1 << 3)
146#define TSR_TGFC		(1 << 2)
147#define TSR_TGFB		(1 << 1)
148#define TSR_TGFA		(1 << 0)
149
150static unsigned long mtu2_reg_offs[] = {
151	[TCR] = 0,
152	[TMDR] = 1,
153	[TIOR] = 2,
154	[TIER] = 4,
155	[TSR] = 5,
156	[TCNT] = 6,
157	[TGR] = 8,
158};
159
160static inline unsigned long sh_mtu2_read(struct sh_mtu2_channel *ch, int reg_nr)
161{
162	unsigned long offs;
163
164	if (reg_nr == TSTR)
165		return ioread8(ch->mtu->mapbase + 0x280);
166
167	offs = mtu2_reg_offs[reg_nr];
168
169	if ((reg_nr == TCNT) || (reg_nr == TGR))
170		return ioread16(ch->base + offs);
171	else
172		return ioread8(ch->base + offs);
173}
174
175static inline void sh_mtu2_write(struct sh_mtu2_channel *ch, int reg_nr,
176				unsigned long value)
177{
178	unsigned long offs;
179
180	if (reg_nr == TSTR)
181		return iowrite8(value, ch->mtu->mapbase + 0x280);
182
183	offs = mtu2_reg_offs[reg_nr];
184
185	if ((reg_nr == TCNT) || (reg_nr == TGR))
186		iowrite16(value, ch->base + offs);
187	else
188		iowrite8(value, ch->base + offs);
189}
190
191static void sh_mtu2_start_stop_ch(struct sh_mtu2_channel *ch, int start)
192{
193	unsigned long flags, value;
194
195	/* start stop register shared by multiple timer channels */
196	raw_spin_lock_irqsave(&ch->mtu->lock, flags);
197	value = sh_mtu2_read(ch, TSTR);
198
199	if (start)
200		value |= 1 << ch->index;
201	else
202		value &= ~(1 << ch->index);
203
204	sh_mtu2_write(ch, TSTR, value);
205	raw_spin_unlock_irqrestore(&ch->mtu->lock, flags);
206}
207
208static int sh_mtu2_enable(struct sh_mtu2_channel *ch)
209{
210	unsigned long periodic;
211	unsigned long rate;
212	int ret;
213
214	pm_runtime_get_sync(&ch->mtu->pdev->dev);
215	dev_pm_syscore_device(&ch->mtu->pdev->dev, true);
216
217	/* enable clock */
218	ret = clk_enable(ch->mtu->clk);
219	if (ret) {
220		dev_err(&ch->mtu->pdev->dev, "ch%u: cannot enable clock\n",
221			ch->index);
222		return ret;
223	}
224
225	/* make sure channel is disabled */
226	sh_mtu2_start_stop_ch(ch, 0);
227
228	rate = clk_get_rate(ch->mtu->clk) / 64;
229	periodic = (rate + HZ/2) / HZ;
230
231	/*
232	 * "Periodic Counter Operation"
233	 * Clear on TGRA compare match, divide clock by 64.
234	 */
235	sh_mtu2_write(ch, TCR, TCR_CCLR_TGRA | TCR_TPSC_P64);
236	sh_mtu2_write(ch, TIOR, TIOC_IOCH(TIOR_OC_0_CLEAR) |
237		      TIOC_IOCL(TIOR_OC_0_CLEAR));
238	sh_mtu2_write(ch, TGR, periodic);
239	sh_mtu2_write(ch, TCNT, 0);
240	sh_mtu2_write(ch, TMDR, TMDR_MD_NORMAL);
241	sh_mtu2_write(ch, TIER, TIER_TGIEA);
242
243	/* enable channel */
244	sh_mtu2_start_stop_ch(ch, 1);
245
246	return 0;
247}
248
249static void sh_mtu2_disable(struct sh_mtu2_channel *ch)
250{
251	/* disable channel */
252	sh_mtu2_start_stop_ch(ch, 0);
253
254	/* stop clock */
255	clk_disable(ch->mtu->clk);
256
257	dev_pm_syscore_device(&ch->mtu->pdev->dev, false);
258	pm_runtime_put(&ch->mtu->pdev->dev);
259}
260
261static irqreturn_t sh_mtu2_interrupt(int irq, void *dev_id)
262{
263	struct sh_mtu2_channel *ch = dev_id;
264
265	/* acknowledge interrupt */
266	sh_mtu2_read(ch, TSR);
267	sh_mtu2_write(ch, TSR, ~TSR_TGFA);
268
269	/* notify clockevent layer */
270	ch->ced.event_handler(&ch->ced);
271	return IRQ_HANDLED;
272}
273
274static struct sh_mtu2_channel *ced_to_sh_mtu2(struct clock_event_device *ced)
275{
276	return container_of(ced, struct sh_mtu2_channel, ced);
277}
278
279static int sh_mtu2_clock_event_shutdown(struct clock_event_device *ced)
280{
281	struct sh_mtu2_channel *ch = ced_to_sh_mtu2(ced);
282
283	if (clockevent_state_periodic(ced))
284		sh_mtu2_disable(ch);
285
286	return 0;
287}
288
289static int sh_mtu2_clock_event_set_periodic(struct clock_event_device *ced)
290{
291	struct sh_mtu2_channel *ch = ced_to_sh_mtu2(ced);
292
293	if (clockevent_state_periodic(ced))
294		sh_mtu2_disable(ch);
295
296	dev_info(&ch->mtu->pdev->dev, "ch%u: used for periodic clock events\n",
297		 ch->index);
298	sh_mtu2_enable(ch);
299	return 0;
300}
301
302static void sh_mtu2_clock_event_suspend(struct clock_event_device *ced)
303{
304	pm_genpd_syscore_poweroff(&ced_to_sh_mtu2(ced)->mtu->pdev->dev);
305}
306
307static void sh_mtu2_clock_event_resume(struct clock_event_device *ced)
308{
309	pm_genpd_syscore_poweron(&ced_to_sh_mtu2(ced)->mtu->pdev->dev);
310}
311
312static void sh_mtu2_register_clockevent(struct sh_mtu2_channel *ch,
313					const char *name)
314{
315	struct clock_event_device *ced = &ch->ced;
316
317	ced->name = name;
318	ced->features = CLOCK_EVT_FEAT_PERIODIC;
319	ced->rating = 200;
320	ced->cpumask = cpu_possible_mask;
321	ced->set_state_shutdown = sh_mtu2_clock_event_shutdown;
322	ced->set_state_periodic = sh_mtu2_clock_event_set_periodic;
323	ced->suspend = sh_mtu2_clock_event_suspend;
324	ced->resume = sh_mtu2_clock_event_resume;
325
326	dev_info(&ch->mtu->pdev->dev, "ch%u: used for clock events\n",
327		 ch->index);
328	clockevents_register_device(ced);
329}
330
331static int sh_mtu2_register(struct sh_mtu2_channel *ch, const char *name)
332{
333	ch->mtu->has_clockevent = true;
334	sh_mtu2_register_clockevent(ch, name);
335
336	return 0;
337}
338
339static int sh_mtu2_setup_channel(struct sh_mtu2_channel *ch, unsigned int index,
340				 struct sh_mtu2_device *mtu)
341{
342	static const unsigned int channel_offsets[] = {
343		0x300, 0x380, 0x000,
344	};
345	char name[6];
346	int irq;
347	int ret;
348
349	ch->mtu = mtu;
350
351	sprintf(name, "tgi%ua", index);
352	irq = platform_get_irq_byname(mtu->pdev, name);
353	if (irq < 0) {
354		/* Skip channels with no declared interrupt. */
355		return 0;
356	}
357
358	ret = request_irq(irq, sh_mtu2_interrupt,
359			  IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
360			  dev_name(&ch->mtu->pdev->dev), ch);
361	if (ret) {
362		dev_err(&ch->mtu->pdev->dev, "ch%u: failed to request irq %d\n",
363			index, irq);
364		return ret;
365	}
366
367	ch->base = mtu->mapbase + channel_offsets[index];
368	ch->index = index;
369
370	return sh_mtu2_register(ch, dev_name(&mtu->pdev->dev));
371}
372
373static int sh_mtu2_map_memory(struct sh_mtu2_device *mtu)
374{
375	struct resource *res;
376
377	res = platform_get_resource(mtu->pdev, IORESOURCE_MEM, 0);
378	if (!res) {
379		dev_err(&mtu->pdev->dev, "failed to get I/O memory\n");
380		return -ENXIO;
381	}
382
383	mtu->mapbase = ioremap_nocache(res->start, resource_size(res));
384	if (mtu->mapbase == NULL)
385		return -ENXIO;
386
387	return 0;
388}
389
390static int sh_mtu2_setup(struct sh_mtu2_device *mtu,
391			 struct platform_device *pdev)
392{
393	unsigned int i;
394	int ret;
395
396	mtu->pdev = pdev;
397
398	raw_spin_lock_init(&mtu->lock);
399
400	/* Get hold of clock. */
401	mtu->clk = clk_get(&mtu->pdev->dev, "fck");
402	if (IS_ERR(mtu->clk)) {
403		dev_err(&mtu->pdev->dev, "cannot get clock\n");
404		return PTR_ERR(mtu->clk);
405	}
406
407	ret = clk_prepare(mtu->clk);
408	if (ret < 0)
409		goto err_clk_put;
410
411	/* Map the memory resource. */
412	ret = sh_mtu2_map_memory(mtu);
413	if (ret < 0) {
414		dev_err(&mtu->pdev->dev, "failed to remap I/O memory\n");
415		goto err_clk_unprepare;
416	}
417
418	/* Allocate and setup the channels. */
419	mtu->num_channels = 3;
420
421	mtu->channels = kzalloc(sizeof(*mtu->channels) * mtu->num_channels,
422				GFP_KERNEL);
423	if (mtu->channels == NULL) {
424		ret = -ENOMEM;
425		goto err_unmap;
426	}
427
428	for (i = 0; i < mtu->num_channels; ++i) {
429		ret = sh_mtu2_setup_channel(&mtu->channels[i], i, mtu);
430		if (ret < 0)
431			goto err_unmap;
432	}
433
434	platform_set_drvdata(pdev, mtu);
435
436	return 0;
437
438err_unmap:
439	kfree(mtu->channels);
440	iounmap(mtu->mapbase);
441err_clk_unprepare:
442	clk_unprepare(mtu->clk);
443err_clk_put:
444	clk_put(mtu->clk);
445	return ret;
446}
447
448static int sh_mtu2_probe(struct platform_device *pdev)
449{
450	struct sh_mtu2_device *mtu = platform_get_drvdata(pdev);
451	int ret;
452
453	if (!is_early_platform_device(pdev)) {
454		pm_runtime_set_active(&pdev->dev);
455		pm_runtime_enable(&pdev->dev);
456	}
457
458	if (mtu) {
459		dev_info(&pdev->dev, "kept as earlytimer\n");
460		goto out;
461	}
462
463	mtu = kzalloc(sizeof(*mtu), GFP_KERNEL);
464	if (mtu == NULL)
465		return -ENOMEM;
466
467	ret = sh_mtu2_setup(mtu, pdev);
468	if (ret) {
469		kfree(mtu);
470		pm_runtime_idle(&pdev->dev);
471		return ret;
472	}
473	if (is_early_platform_device(pdev))
474		return 0;
475
476 out:
477	if (mtu->has_clockevent)
478		pm_runtime_irq_safe(&pdev->dev);
479	else
480		pm_runtime_idle(&pdev->dev);
481
482	return 0;
483}
484
485static int sh_mtu2_remove(struct platform_device *pdev)
486{
487	return -EBUSY; /* cannot unregister clockevent */
488}
489
490static const struct platform_device_id sh_mtu2_id_table[] = {
491	{ "sh-mtu2", 0 },
492	{ },
493};
494MODULE_DEVICE_TABLE(platform, sh_mtu2_id_table);
495
496static const struct of_device_id sh_mtu2_of_table[] __maybe_unused = {
497	{ .compatible = "renesas,mtu2" },
498	{ }
499};
500MODULE_DEVICE_TABLE(of, sh_mtu2_of_table);
501
502static struct platform_driver sh_mtu2_device_driver = {
503	.probe		= sh_mtu2_probe,
504	.remove		= sh_mtu2_remove,
505	.driver		= {
506		.name	= "sh_mtu2",
507		.of_match_table = of_match_ptr(sh_mtu2_of_table),
508	},
509	.id_table	= sh_mtu2_id_table,
510};
511
512static int __init sh_mtu2_init(void)
513{
514	return platform_driver_register(&sh_mtu2_device_driver);
515}
516
517static void __exit sh_mtu2_exit(void)
518{
519	platform_driver_unregister(&sh_mtu2_device_driver);
520}
521
522early_platform_init("earlytimer", &sh_mtu2_device_driver);
523subsys_initcall(sh_mtu2_init);
524module_exit(sh_mtu2_exit);
525
526MODULE_AUTHOR("Magnus Damm");
527MODULE_DESCRIPTION("SuperH MTU2 Timer Driver");
528MODULE_LICENSE("GPL v2");
529