1 // SPDX-License-Identifier: GPL-2.0
5  * This driver is for the MX23L4005, more specifically its real-time clock and
6  * SRAM storage.  The value returned by the RTC counter must be added with the
7  * offset stored in a bias register in SRAM (on the GameCube and Wii) or in
10  * SRAM like for the other two consoles.
12  * This device sits on a bus named EXI (which is similar to SPI), channel 0,
13  * device 1.  This driver assumes no other user of the EXI bus, which is
18  * - https://wiiubrew.org/wiki/Hardware/RTC
19  * - https://wiibrew.org/wiki/MX23L4005
21  * Copyright (C) 2018 rw-r-r-0644
24  * Based on rtc-gcn.c
25  * Copyright (C) 2004-2009 The GameCube Linux Team
99 	void __iomem *iob = d->iob;  in exi_read()
128 	void __iomem *iob = d->iob;  in exi_write()
161 static int gamecube_rtc_read_time(struct device *dev, struct rtc_time *t)  in gamecube_rtc_read_time()
168 	ret = regmap_read(d->regmap, RTC_COUNTER, &counter);  in gamecube_rtc_read_time()
173 	timestamp = (time64_t)d->rtc_bias + counter;  in gamecube_rtc_read_time()
179 static int gamecube_rtc_set_time(struct device *dev, struct rtc_time *t)  in gamecube_rtc_set_time()
186 	return regmap_write(d->regmap, RTC_COUNTER, timestamp - d->rtc_bias);  in gamecube_rtc_set_time()
189 static int gamecube_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)  in gamecube_rtc_ioctl()
198 		ret = regmap_read(d->regmap, RTC_CONTROL0, &control0);  in gamecube_rtc_ioctl()
210 		return -ENOIOCTLCMD;  in gamecube_rtc_ioctl()
228 	np = of_find_compatible_node(NULL, NULL, "nintendo,latte-srnprot");  in gamecube_rtc_read_offset_from_sram()
231 					     "nintendo,hollywood-srnprot");  in gamecube_rtc_read_offset_from_sram()
234 		return regmap_read(d->regmap, RTC_SRAM_BIAS, &d->rtc_bias);  in gamecube_rtc_read_offset_from_sram()
241 		return -1;  in gamecube_rtc_read_offset_from_sram()
258 	/* Get the offset from RTC SRAM.  in gamecube_rtc_read_offset_from_sram()
260 	 * Its default location on the GameCube and on the Wii is in the SRAM,  in gamecube_rtc_read_offset_from_sram()
265 	 * SRAM address as on previous consoles.  in gamecube_rtc_read_offset_from_sram()
267 	ret = regmap_read(d->regmap, RTC_SRAM_BIAS, &d->rtc_bias);  in gamecube_rtc_read_offset_from_sram()
269 	/* Reset SRAM access to how it was before, our job here is done. */  in gamecube_rtc_read_offset_from_sram()
312 	.name = "gamecube-rtc",
317 	struct device *dev = &pdev->dev;  in gamecube_rtc_probe()
324 		return -ENOMEM;  in gamecube_rtc_probe()
326 	d->iob = devm_platform_ioremap_resource(pdev, 0);  in gamecube_rtc_probe()
327 	if (IS_ERR(d->iob))  in gamecube_rtc_probe()
328 		return PTR_ERR(d->iob);  in gamecube_rtc_probe()
330 	d->regmap = devm_regmap_init(dev, &exi_bus, d,  in gamecube_rtc_probe()
332 	if (IS_ERR(d->regmap))  in gamecube_rtc_probe()
333 		return PTR_ERR(d->regmap);  in gamecube_rtc_probe()
338 	dev_dbg(dev, "SRAM bias: 0x%x", d->rtc_bias);  in gamecube_rtc_probe()
350 	rtc->range_min = 0;  in gamecube_rtc_probe()
351 	rtc->range_max = U32_MAX;  in gamecube_rtc_probe()
352 	rtc->ops = &gamecube_rtc_ops;  in gamecube_rtc_probe()
360 	{.compatible = "nintendo,latte-exi" },
361 	{.compatible = "nintendo,hollywood-exi" },
362 	{.compatible = "nintendo,flipper-exi" },
370 		.name	= "rtc-gamecube",