1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * JZ47xx SoCs TCU Operating System Timer driver
  4 *
  5 * Copyright (C) 2016 Maarten ter Huurne <maarten@treewalker.org>
  6 * Copyright (C) 2020 Paul Cercueil <paul@crapouillou.net>
  7 */
  8
  9#include <linux/clk.h>
 10#include <linux/clocksource.h>
 11#include <linux/mfd/ingenic-tcu.h>
 12#include <linux/mfd/syscon.h>
 13#include <linux/of.h>
 14#include <linux/platform_device.h>
 15#include <linux/pm.h>
 16#include <linux/regmap.h>
 17#include <linux/sched_clock.h>
 18
 19#define TCU_OST_TCSR_MASK	0xffc0
 20#define TCU_OST_TCSR_CNT_MD	BIT(15)
 21
 22#define TCU_OST_CHANNEL		15
 23
 24/*
 25 * The TCU_REG_OST_CNT{L,R} from <linux/mfd/ingenic-tcu.h> are only for the
 26 * regmap; these are for use with the __iomem pointer.
 27 */
 28#define OST_REG_CNTL		0x4
 29#define OST_REG_CNTH		0x8
 30
 31struct ingenic_ost_soc_info {
 32	bool is64bit;
 33};
 34
 35struct ingenic_ost {
 36	void __iomem *regs;
 37	struct clk *clk;
 38
 39	struct clocksource cs;
 40};
 41
 42static struct ingenic_ost *ingenic_ost;
 43
 44static u64 notrace ingenic_ost_read_cntl(void)
 45{
 46	/* Read using __iomem pointer instead of regmap to avoid locking */
 47	return readl(ingenic_ost->regs + OST_REG_CNTL);
 48}
 49
 50static u64 notrace ingenic_ost_read_cnth(void)
 51{
 52	/* Read using __iomem pointer instead of regmap to avoid locking */
 53	return readl(ingenic_ost->regs + OST_REG_CNTH);
 54}
 55
 56static u64 notrace ingenic_ost_clocksource_readl(struct clocksource *cs)
 57{
 58	return ingenic_ost_read_cntl();
 59}
 60
 61static u64 notrace ingenic_ost_clocksource_readh(struct clocksource *cs)
 62{
 63	return ingenic_ost_read_cnth();
 64}
 65
 66static int __init ingenic_ost_probe(struct platform_device *pdev)
 67{
 68	const struct ingenic_ost_soc_info *soc_info;
 69	struct device *dev = &pdev->dev;
 70	struct ingenic_ost *ost;
 71	struct clocksource *cs;
 72	struct regmap *map;
 73	unsigned long rate;
 74	int err;
 75
 76	soc_info = device_get_match_data(dev);
 77	if (!soc_info)
 78		return -EINVAL;
 79
 80	ost = devm_kzalloc(dev, sizeof(*ost), GFP_KERNEL);
 81	if (!ost)
 82		return -ENOMEM;
 83
 84	ingenic_ost = ost;
 85
 86	ost->regs = devm_platform_ioremap_resource(pdev, 0);
 87	if (IS_ERR(ost->regs))
 88		return PTR_ERR(ost->regs);
 89
 90	map = device_node_to_regmap(dev->parent->of_node);
 91	if (!map) {
 92		dev_err(dev, "regmap not found");
 93		return -EINVAL;
 94	}
 95
 96	ost->clk = devm_clk_get(dev, "ost");
 97	if (IS_ERR(ost->clk))
 98		return PTR_ERR(ost->clk);
 99
100	err = clk_prepare_enable(ost->clk);
101	if (err)
102		return err;
103
104	/* Clear counter high/low registers */
105	if (soc_info->is64bit)
106		regmap_write(map, TCU_REG_OST_CNTL, 0);
107	regmap_write(map, TCU_REG_OST_CNTH, 0);
108
109	/* Don't reset counter at compare value. */
110	regmap_update_bits(map, TCU_REG_OST_TCSR,
111			   TCU_OST_TCSR_MASK, TCU_OST_TCSR_CNT_MD);
112
113	rate = clk_get_rate(ost->clk);
114
115	/* Enable OST TCU channel */
116	regmap_write(map, TCU_REG_TESR, BIT(TCU_OST_CHANNEL));
117
118	cs = &ost->cs;
119	cs->name	= "ingenic-ost";
120	cs->rating	= 320;
121	cs->flags	= CLOCK_SOURCE_IS_CONTINUOUS;
122	cs->mask	= CLOCKSOURCE_MASK(32);
123
124	if (soc_info->is64bit)
125		cs->read = ingenic_ost_clocksource_readl;
126	else
127		cs->read = ingenic_ost_clocksource_readh;
128
129	err = clocksource_register_hz(cs, rate);
130	if (err) {
131		dev_err(dev, "clocksource registration failed");
132		clk_disable_unprepare(ost->clk);
133		return err;
134	}
135
136	if (soc_info->is64bit)
137		sched_clock_register(ingenic_ost_read_cntl, 32, rate);
138	else
139		sched_clock_register(ingenic_ost_read_cnth, 32, rate);
140
141	return 0;
142}
143
144static int __maybe_unused ingenic_ost_suspend(struct device *dev)
145{
146	struct ingenic_ost *ost = dev_get_drvdata(dev);
147
148	clk_disable(ost->clk);
149
150	return 0;
151}
152
153static int __maybe_unused ingenic_ost_resume(struct device *dev)
154{
155	struct ingenic_ost *ost = dev_get_drvdata(dev);
156
157	return clk_enable(ost->clk);
158}
159
160static const struct dev_pm_ops __maybe_unused ingenic_ost_pm_ops = {
161	/* _noirq: We want the OST clock to be gated last / ungated first */
162	.suspend_noirq = ingenic_ost_suspend,
163	.resume_noirq  = ingenic_ost_resume,
164};
165
166static const struct ingenic_ost_soc_info jz4725b_ost_soc_info = {
167	.is64bit = false,
168};
169
170static const struct ingenic_ost_soc_info jz4770_ost_soc_info = {
171	.is64bit = true,
172};
173
174static const struct of_device_id ingenic_ost_of_match[] = {
175	{ .compatible = "ingenic,jz4725b-ost", .data = &jz4725b_ost_soc_info, },
176	{ .compatible = "ingenic,jz4770-ost", .data = &jz4770_ost_soc_info, },
177	{ }
178};
179
180static struct platform_driver ingenic_ost_driver = {
181	.driver = {
182		.name = "ingenic-ost",
183#ifdef CONFIG_PM_SUSPEND
184		.pm = &ingenic_ost_pm_ops,
185#endif
186		.of_match_table = ingenic_ost_of_match,
187	},
188};
189builtin_platform_driver_probe(ingenic_ost_driver, ingenic_ost_probe);