// SPDX-License-Identifier: GPL-2.0-only /* * SPI Driver for Microchip MCP795 RTC * * Copyright (C) Josef Gajdusek <[email protected]> * * based on other Linux RTC drivers * * Device datasheet: * https://ww1.microchip.com/downloads/en/DeviceDoc/22280A.pdf */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/device.h> #include <linux/printk.h> #include <linux/spi/spi.h> #include <linux/rtc.h> #include <linux/of.h> #include <linux/bcd.h> #include <linux/delay.h> /* MCP795 Instructions, see datasheet table 3-1 */ #define MCP795_EEREAD … #define MCP795_EEWRITE … #define MCP795_EEWRDI … #define MCP795_EEWREN … #define MCP795_SRREAD … #define MCP795_SRWRITE … #define MCP795_READ … #define MCP795_WRITE … #define MCP795_UNLOCK … #define MCP795_IDWRITE … #define MCP795_IDREAD … #define MCP795_CLRWDT … #define MCP795_CLRRAM … /* MCP795 RTCC registers, see datasheet table 4-1 */ #define MCP795_REG_SECONDS … #define MCP795_REG_DAY … #define MCP795_REG_MONTH … #define MCP795_REG_CONTROL … #define MCP795_REG_ALM0_SECONDS … #define MCP795_REG_ALM0_DAY … #define MCP795_ST_BIT … #define MCP795_24_BIT … #define MCP795_LP_BIT … #define MCP795_EXTOSC_BIT … #define MCP795_OSCON_BIT … #define MCP795_ALM0_BIT … #define MCP795_ALM1_BIT … #define MCP795_ALM0IF_BIT … #define MCP795_ALM0C0_BIT … #define MCP795_ALM0C1_BIT … #define MCP795_ALM0C2_BIT … #define SEC_PER_DAY … static int mcp795_rtcc_read(struct device *dev, u8 addr, u8 *buf, u8 count) { … } static int mcp795_rtcc_write(struct device *dev, u8 addr, u8 *data, u8 count) { … } static int mcp795_rtcc_set_bits(struct device *dev, u8 addr, u8 mask, u8 state) { … } static int mcp795_stop_oscillator(struct device *dev, bool *extosc) { … } static int mcp795_start_oscillator(struct device *dev, bool *extosc) { … } /* Enable or disable Alarm 0 in RTC */ static int mcp795_update_alarm(struct device *dev, bool enable) { … } static int mcp795_set_time(struct device *dev, struct rtc_time *tim) { … } static int mcp795_read_time(struct device *dev, struct rtc_time *tim) { … } static int mcp795_set_alarm(struct device *dev, struct rtc_wkalrm *alm) { … } static int mcp795_read_alarm(struct device *dev, struct rtc_wkalrm *alm) { … } static int mcp795_alarm_irq_enable(struct device *dev, unsigned int enabled) { … } static irqreturn_t mcp795_irq(int irq, void *data) { … } static const struct rtc_class_ops mcp795_rtc_ops = …; static int mcp795_probe(struct spi_device *spi) { … } #ifdef CONFIG_OF static const struct of_device_id mcp795_of_match[] = …; MODULE_DEVICE_TABLE(of, mcp795_of_match); #endif static const struct spi_device_id mcp795_spi_ids[] = …; MODULE_DEVICE_TABLE(spi, mcp795_spi_ids); static struct spi_driver mcp795_driver = …; module_spi_driver(…) …; MODULE_DESCRIPTION(…) …; MODULE_AUTHOR(…) …; MODULE_LICENSE(…) …;
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