rtc-ftrtc010.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *  Faraday Technology FTRTC010 driver
  4 *
  5 *  Copyright (C) 2009 Janos Laube <janos.dev@gmail.com>
  6 *
  7 * Original code for older kernel 2.6.15 are from Stormlinksemi
  8 * first update from Janos Laube for > 2.6.29 kernels
  9 *
 10 * checkpatch fixes and usage of rtc-lib code
 11 * Hans Ulli Kroll <ulli.kroll@googlemail.com>
 12 */
 13
 14#include <linux/rtc.h>
 15#include <linux/io.h>
 16#include <linux/slab.h>
 17#include <linux/platform_device.h>
 18#include <linux/kernel.h>
 19#include <linux/module.h>
 20#include <linux/mod_devicetable.h>
 21#include <linux/clk.h>
 22
 23#define DRV_NAME        "rtc-ftrtc010"
 24
 25MODULE_AUTHOR("Hans Ulli Kroll <ulli.kroll@googlemail.com>");
 26MODULE_DESCRIPTION("RTC driver for Gemini SoC");
 27MODULE_LICENSE("GPL");
 28MODULE_ALIAS("platform:" DRV_NAME);
 29
 30struct ftrtc010_rtc {
 31	void __iomem		*rtc_base;
 32	int			rtc_irq;
 33	struct clk		*pclk;
 34	struct clk		*extclk;
 35};
 36
 37enum ftrtc010_rtc_offsets {
 38	FTRTC010_RTC_SECOND		= 0x00,
 39	FTRTC010_RTC_MINUTE		= 0x04,
 40	FTRTC010_RTC_HOUR		= 0x08,
 41	FTRTC010_RTC_DAYS		= 0x0C,
 42	FTRTC010_RTC_ALARM_SECOND	= 0x10,
 43	FTRTC010_RTC_ALARM_MINUTE	= 0x14,
 44	FTRTC010_RTC_ALARM_HOUR		= 0x18,
 45	FTRTC010_RTC_RECORD		= 0x1C,
 46	FTRTC010_RTC_CR			= 0x20,
 47};
 48
 49static irqreturn_t ftrtc010_rtc_interrupt(int irq, void *dev)
 50{
 51	return IRQ_HANDLED;
 52}
 53
 54/*
 55 * Looks like the RTC in the Gemini SoC is (totaly) broken
 56 * We can't read/write directly the time from RTC registers.
 57 * We must do some "offset" calculation to get the real time
 58 *
 59 * This FIX works pretty fine and Stormlinksemi aka Cortina-Networks does
 60 * the same thing, without the rtc-lib.c calls.
 61 */
 62
 63static int ftrtc010_rtc_read_time(struct device *dev, struct rtc_time *tm)
 64{
 65	struct ftrtc010_rtc *rtc = dev_get_drvdata(dev);
 66
 67	u32 days, hour, min, sec, offset;
 68	timeu64_t time;
 69
 70	sec  = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
 71	min  = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
 72	hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
 73	days = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
 74	offset = readl(rtc->rtc_base + FTRTC010_RTC_RECORD);
 75
 76	time = offset + days * 86400 + hour * 3600 + min * 60 + sec;
 77
 78	rtc_time64_to_tm(time, tm);
 79
 80	return 0;
 81}
 82
 83static int ftrtc010_rtc_set_time(struct device *dev, struct rtc_time *tm)
 84{
 85	struct ftrtc010_rtc *rtc = dev_get_drvdata(dev);
 86	u32 sec, min, hour, day, offset;
 87	timeu64_t time;
 88
 89	time = rtc_tm_to_time64(tm);
 90
 91	sec = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
 92	min = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
 93	hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
 94	day = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
 95
 96	offset = time - (day * 86400 + hour * 3600 + min * 60 + sec);
 97
 98	writel(offset, rtc->rtc_base + FTRTC010_RTC_RECORD);
 99	writel(0x01, rtc->rtc_base + FTRTC010_RTC_CR);
100
101	return 0;
102}
103
104static const struct rtc_class_ops ftrtc010_rtc_ops = {
105	.read_time     = ftrtc010_rtc_read_time,
106	.set_time      = ftrtc010_rtc_set_time,
107};
108
109static int ftrtc010_rtc_probe(struct platform_device *pdev)
110{
111	u32 days, hour, min, sec;
112	struct ftrtc010_rtc *rtc;
113	struct device *dev = &pdev->dev;
114	struct resource *res;
115	struct rtc_device *rtc_dev;
116	int ret;
117
118	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
119	if (unlikely(!rtc))
120		return -ENOMEM;
121	platform_set_drvdata(pdev, rtc);
122
123	rtc->pclk = devm_clk_get(dev, "PCLK");
124	if (IS_ERR(rtc->pclk)) {
125		dev_err(dev, "could not get PCLK\n");
126	} else {
127		ret = clk_prepare_enable(rtc->pclk);
128		if (ret) {
129			dev_err(dev, "failed to enable PCLK\n");
130			return ret;
131		}
132	}
133	rtc->extclk = devm_clk_get(dev, "EXTCLK");
134	if (IS_ERR(rtc->extclk)) {
135		dev_err(dev, "could not get EXTCLK\n");
136	} else {
137		ret = clk_prepare_enable(rtc->extclk);
138		if (ret) {
139			dev_err(dev, "failed to enable EXTCLK\n");
140			goto err_disable_pclk;
141		}
142	}
143
144	rtc->rtc_irq = platform_get_irq(pdev, 0);
145	if (rtc->rtc_irq < 0) {
146		ret = rtc->rtc_irq;
147		goto err_disable_extclk;
148	}
149
150	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
151	if (!res) {
152		ret = -ENODEV;
153		goto err_disable_extclk;
154	}
155
156	rtc->rtc_base = devm_ioremap(dev, res->start,
157				     resource_size(res));
158	if (!rtc->rtc_base) {
159		ret = -ENOMEM;
160		goto err_disable_extclk;
161	}
162
163	rtc_dev = devm_rtc_allocate_device(dev);
164	if (IS_ERR(rtc_dev)) {
165		ret = PTR_ERR(rtc_dev);
166		goto err_disable_extclk;
167	}
168
169	rtc_dev->ops = &ftrtc010_rtc_ops;
170
171	sec  = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
172	min  = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
173	hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
174	days = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
175
176	rtc_dev->range_min = (u64)days * 86400 + hour * 3600 + min * 60 + sec;
177	rtc_dev->range_max = U32_MAX + rtc_dev->range_min;
178
179	ret = devm_request_irq(dev, rtc->rtc_irq, ftrtc010_rtc_interrupt,
180			       IRQF_SHARED, pdev->name, dev);
181	if (unlikely(ret))
182		goto err_disable_extclk;
183
184	return devm_rtc_register_device(rtc_dev);
185
186err_disable_extclk:
187	clk_disable_unprepare(rtc->extclk);
188err_disable_pclk:
189	clk_disable_unprepare(rtc->pclk);
190	return ret;
191}
192
193static void ftrtc010_rtc_remove(struct platform_device *pdev)
194{
195	struct ftrtc010_rtc *rtc = platform_get_drvdata(pdev);
196
197	if (!IS_ERR(rtc->extclk))
198		clk_disable_unprepare(rtc->extclk);
199	if (!IS_ERR(rtc->pclk))
200		clk_disable_unprepare(rtc->pclk);
201}
202
203static const struct of_device_id ftrtc010_rtc_dt_match[] = {
204	{ .compatible = "cortina,gemini-rtc" },
205	{ .compatible = "faraday,ftrtc010" },
206	{ }
207};
208MODULE_DEVICE_TABLE(of, ftrtc010_rtc_dt_match);
209
210static struct platform_driver ftrtc010_rtc_driver = {
211	.driver		= {
212		.name	= DRV_NAME,
213		.of_match_table = ftrtc010_rtc_dt_match,
214	},
215	.probe		= ftrtc010_rtc_probe,
216	.remove		= ftrtc010_rtc_remove,
217};
218
219module_platform_driver_probe(ftrtc010_rtc_driver, ftrtc010_rtc_probe);