// SPDX-License-Identifier: GPL-2.0 /* * Nintendo GameCube, Wii and Wii U RTC driver * * This driver is for the MX23L4005, more specifically its real-time clock and * SRAM storage. The value returned by the RTC counter must be added with the * offset stored in a bias register in SRAM (on the GameCube and Wii) or in * /config/rtc.xml (on the Wii U). The latter being very impractical to access * from Linux, this driver assumes the bootloader has read it and stored it in * SRAM like for the other two consoles. * * This device sits on a bus named EXI (which is similar to SPI), channel 0, * device 1. This driver assumes no other user of the EXI bus, which is * currently the case but would have to be reworked to add support for other * GameCube hardware exposed on this bus. * * References: * - https://wiiubrew.org/wiki/Hardware/RTC * - https://wiibrew.org/wiki/MX23L4005 * * Copyright (C) 2018 rw-r-r-0644 * Copyright (C) 2021 Emmanuel Gil Peyrot <[email protected]> * * Based on rtc-gcn.c * Copyright (C) 2004-2009 The GameCube Linux Team * Copyright (C) 2005,2008,2009 Albert Herranz * Based on gamecube_time.c from Torben Nielsen. */ #include <linux/init.h> #include <linux/module.h> #include <linux/of.h> #include <linux/of_address.h> #include <linux/platform_device.h> #include <linux/regmap.h> #include <linux/rtc.h> #include <linux/time.h> /* EXI registers */ #define EXICSR … #define EXICR … #define EXIDATA … /* EXI register values */ #define EXICSR_DEV … #define EXICSR_DEV1 … #define EXICSR_CLK … #define EXICSR_CLK_1MHZ … #define EXICSR_CLK_2MHZ … #define EXICSR_CLK_4MHZ … #define EXICSR_CLK_8MHZ … #define EXICSR_CLK_16MHZ … #define EXICSR_CLK_32MHZ … #define EXICSR_INT … #define EXICSR_INTSET … #define EXICR_TSTART … #define EXICR_TRSMODE … #define EXICR_TRSMODE_IMM … #define EXICR_TRSTYPE … #define EXICR_TRSTYPE_R … #define EXICR_TRSTYPE_W … #define EXICR_TLEN … #define EXICR_TLEN32 … /* EXI registers values to access the RTC */ #define RTC_EXICSR … #define RTC_EXICR_W … #define RTC_EXICR_R … #define RTC_EXIDATA_W … /* RTC registers */ #define RTC_COUNTER … #define RTC_SRAM … #define RTC_SRAM_BIAS … #define RTC_SNAPSHOT … #define RTC_ONTMR … #define RTC_OFFTMR … #define RTC_TEST0 … #define RTC_TEST1 … #define RTC_TEST2 … #define RTC_TEST3 … #define RTC_CONTROL0 … #define RTC_CONTROL1 … /* RTC flags */ #define RTC_CONTROL0_UNSTABLE_POWER … #define RTC_CONTROL0_LOW_BATTERY … struct priv { … }; static int exi_read(void *context, u32 reg, u32 *data) { … } static int exi_write(void *context, u32 reg, u32 data) { … } static const struct regmap_bus exi_bus = …; static int gamecube_rtc_read_time(struct device *dev, struct rtc_time *t) { … } static int gamecube_rtc_set_time(struct device *dev, struct rtc_time *t) { … } static int gamecube_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) { … } static const struct rtc_class_ops gamecube_rtc_ops = …; static int gamecube_rtc_read_offset_from_sram(struct priv *d) { … } static const struct regmap_range rtc_rd_ranges[] = …; static const struct regmap_access_table rtc_rd_regs = …; static const struct regmap_range rtc_wr_ranges[] = …; static const struct regmap_access_table rtc_wr_regs = …; static const struct regmap_config gamecube_rtc_regmap_config = …; static int gamecube_rtc_probe(struct platform_device *pdev) { … } static const struct of_device_id gamecube_rtc_of_match[] = …; MODULE_DEVICE_TABLE(of, gamecube_rtc_of_match); static struct platform_driver gamecube_rtc_driver = …; module_platform_driver(…) …; MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
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