| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Josef Gajdusek | 1149 | 50.15% | 1 | 5.88% |
| Emil Bartczak | 1102 | 48.10% | 8 | 47.06% |
| Mark Brown | 23 | 1.00% | 1 | 5.88% |
| Andy Shevchenko | 8 | 0.35% | 1 | 5.88% |
| Alexandre Belloni | 5 | 0.22% | 2 | 11.76% |
| Gustavo A. R. Silva | 1 | 0.04% | 1 | 5.88% |
| Thomas Gleixner | 1 | 0.04% | 1 | 5.88% |
| Julia Lawall | 1 | 0.04% | 1 | 5.88% |
| Alexander A. Klimov | 1 | 0.04% | 1 | 5.88% |
| Total | 2291 | 17 |
// SPDX-License-Identifier: GPL-2.0-only /* * SPI Driver for Microchip MCP795 RTC * * Copyright (C) Josef Gajdusek <atx@atx.name> * * 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 0x03 #define MCP795_EEWRITE 0x02 #define MCP795_EEWRDI 0x04 #define MCP795_EEWREN 0x06 #define MCP795_SRREAD 0x05 #define MCP795_SRWRITE 0x01 #define MCP795_READ 0x13 #define MCP795_WRITE 0x12 #define MCP795_UNLOCK 0x14 #define MCP795_IDWRITE 0x32 #define MCP795_IDREAD 0x33 #define MCP795_CLRWDT 0x44 #define MCP795_CLRRAM 0x54 /* MCP795 RTCC registers, see datasheet table 4-1 */ #define MCP795_REG_SECONDS 0x01 #define MCP795_REG_DAY 0x04 #define MCP795_REG_MONTH 0x06 #define MCP795_REG_CONTROL 0x08 #define MCP795_REG_ALM0_SECONDS 0x0C #define MCP795_REG_ALM0_DAY 0x0F #define MCP795_ST_BIT BIT(7) #define MCP795_24_BIT BIT(6) #define MCP795_LP_BIT BIT(5) #define MCP795_EXTOSC_BIT BIT(3) #define MCP795_OSCON_BIT BIT(5) #define MCP795_ALM0_BIT BIT(4) #define MCP795_ALM1_BIT BIT(5) #define MCP795_ALM0IF_BIT BIT(3) #define MCP795_ALM0C0_BIT BIT(4) #define MCP795_ALM0C1_BIT BIT(5) #define MCP795_ALM0C2_BIT BIT(6) #define SEC_PER_DAY (24 * 60 * 60) static int mcp795_rtcc_read(struct device *dev, u8 addr, u8 *buf, u8 count) { struct spi_device *spi = to_spi_device(dev); int ret; u8 tx[2]; tx[0] = MCP795_READ; tx[1] = addr; ret = spi_write_then_read(spi, tx, sizeof(tx), buf, count); if (ret) dev_err(dev, "Failed reading %d bytes from address %x.\n", count, addr); return ret; } static int mcp795_rtcc_write(struct device *dev, u8 addr, u8 *data, u8 count) { struct spi_device *spi = to_spi_device(dev); int ret; u8 tx[257]; tx[0] = MCP795_WRITE; tx[1] = addr; memcpy(&tx[2], data, count); ret = spi_write(spi, tx, 2 + count); if (ret) dev_err(dev, "Failed to write %d bytes to address %x.\n", count, addr); return ret; } static int mcp795_rtcc_set_bits(struct device *dev, u8 addr, u8 mask, u8 state) { int ret; u8 tmp; ret = mcp795_rtcc_read(dev, addr, &tmp, 1); if (ret) return ret; if ((tmp & mask) != state) { tmp = (tmp & ~mask) | state; ret = mcp795_rtcc_write(dev, addr, &tmp, 1); } return ret; } static int mcp795_stop_oscillator(struct device *dev, bool *extosc) { int retries = 5; int ret; u8 data; ret = mcp795_rtcc_set_bits(dev, MCP795_REG_SECONDS, MCP795_ST_BIT, 0); if (ret) return ret; ret = mcp795_rtcc_read(dev, MCP795_REG_CONTROL, &data, 1); if (ret) return ret; *extosc = !!(data & MCP795_EXTOSC_BIT); ret = mcp795_rtcc_set_bits( dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, 0); if (ret) return ret; /* wait for the OSCON bit to clear */ do { usleep_range(700, 800); ret = mcp795_rtcc_read(dev, MCP795_REG_DAY, &data, 1); if (ret) break; if (!(data & MCP795_OSCON_BIT)) break; } while (--retries); return !retries ? -EIO : ret; } static int mcp795_start_oscillator(struct device *dev, bool *extosc) { if (extosc) { u8 data = *extosc ? MCP795_EXTOSC_BIT : 0; int ret; ret = mcp795_rtcc_set_bits( dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, data); if (ret) return ret; } return mcp795_rtcc_set_bits( dev, MCP795_REG_SECONDS, MCP795_ST_BIT, MCP795_ST_BIT); } /* Enable or disable Alarm 0 in RTC */ static int mcp795_update_alarm(struct device *dev, bool enable) { int ret; dev_dbg(dev, "%s alarm\n", enable ? "Enable" : "Disable"); if (enable) { /* clear ALM0IF (Alarm 0 Interrupt Flag) bit */ ret = mcp795_rtcc_set_bits(dev, MCP795_REG_ALM0_DAY, MCP795_ALM0IF_BIT, 0); if (ret) return ret; /* enable alarm 0 */ ret = mcp795_rtcc_set_bits(dev, MCP795_REG_CONTROL, MCP795_ALM0_BIT, MCP795_ALM0_BIT); } else { /* disable alarm 0 and alarm 1 */ ret = mcp795_rtcc_set_bits(dev, MCP795_REG_CONTROL, MCP795_ALM0_BIT | MCP795_ALM1_BIT, 0); } return ret; } static int mcp795_set_time(struct device *dev, struct rtc_time *tim) { int ret; u8 data[7]; bool extosc; /* Stop RTC and store current value of EXTOSC bit */ ret = mcp795_stop_oscillator(dev, &extosc); if (ret) return ret; /* Read first, so we can leave config bits untouched */ ret = mcp795_rtcc_read(dev, MCP795_REG_SECONDS, data, sizeof(data)); if (ret) return ret; data[0] = (data[0] & 0x80) | bin2bcd(tim->tm_sec); data[1] = (data[1] & 0x80) | bin2bcd(tim->tm_min); data[2] = bin2bcd(tim->tm_hour); data[3] = (data[3] & 0xF8) | bin2bcd(tim->tm_wday + 1); data[4] = bin2bcd(tim->tm_mday); data[5] = (data[5] & MCP795_LP_BIT) | bin2bcd(tim->tm_mon + 1); if (tim->tm_year > 100) tim->tm_year -= 100; data[6] = bin2bcd(tim->tm_year); /* Always write the date and month using a separate Write command. * This is a workaround for a know silicon issue that some combinations * of date and month values may result in the date being reset to 1. */ ret = mcp795_rtcc_write(dev, MCP795_REG_SECONDS, data, 5); if (ret) return ret; ret = mcp795_rtcc_write(dev, MCP795_REG_MONTH, &data[5], 2); if (ret) return ret; /* Start back RTC and restore previous value of EXTOSC bit. * There is no need to clear EXTOSC bit when the previous value was 0 * because it was already cleared when stopping the RTC oscillator. */ ret = mcp795_start_oscillator(dev, extosc ? &extosc : NULL); if (ret) return ret; dev_dbg(dev, "Set mcp795: %ptR\n", tim); return 0; } static int mcp795_read_time(struct device *dev, struct rtc_time *tim) { int ret; u8 data[7]; ret = mcp795_rtcc_read(dev, MCP795_REG_SECONDS, data, sizeof(data)); if (ret) return ret; tim->tm_sec = bcd2bin(data[0] & 0x7F); tim->tm_min = bcd2bin(data[1] & 0x7F); tim->tm_hour = bcd2bin(data[2] & 0x3F); tim->tm_wday = bcd2bin(data[3] & 0x07) - 1; tim->tm_mday = bcd2bin(data[4] & 0x3F); tim->tm_mon = bcd2bin(data[5] & 0x1F) - 1; tim->tm_year = bcd2bin(data[6]) + 100; /* Assume we are in 20xx */ dev_dbg(dev, "Read from mcp795: %ptR\n", tim); return 0; } static int mcp795_set_alarm(struct device *dev, struct rtc_wkalrm *alm) { struct rtc_time now_tm; time64_t now; time64_t later; u8 tmp[6]; int ret; /* Read current time from RTC hardware */ ret = mcp795_read_time(dev, &now_tm); if (ret) return ret; /* Get the number of seconds since 1970 */ now = rtc_tm_to_time64(&now_tm); later = rtc_tm_to_time64(&alm->time); if (later <= now) return -EINVAL; /* make sure alarm fires within the next one year */ if ((later - now) >= (SEC_PER_DAY * (365 + is_leap_year(alm->time.tm_year)))) return -EDOM; /* disable alarm */ ret = mcp795_update_alarm(dev, false); if (ret) return ret; /* Read registers, so we can leave configuration bits untouched */ ret = mcp795_rtcc_read(dev, MCP795_REG_ALM0_SECONDS, tmp, sizeof(tmp)); if (ret) return ret; alm->time.tm_year = -1; alm->time.tm_isdst = -1; alm->time.tm_yday = -1; tmp[0] = (tmp[0] & 0x80) | bin2bcd(alm->time.tm_sec); tmp[1] = (tmp[1] & 0x80) | bin2bcd(alm->time.tm_min); tmp[2] = (tmp[2] & 0xE0) | bin2bcd(alm->time.tm_hour); tmp[3] = (tmp[3] & 0x80) | bin2bcd(alm->time.tm_wday + 1); /* set alarm match: seconds, minutes, hour, day, date and month */ tmp[3] |= (MCP795_ALM0C2_BIT | MCP795_ALM0C1_BIT | MCP795_ALM0C0_BIT); tmp[4] = (tmp[4] & 0xC0) | bin2bcd(alm->time.tm_mday); tmp[5] = (tmp[5] & 0xE0) | bin2bcd(alm->time.tm_mon + 1); ret = mcp795_rtcc_write(dev, MCP795_REG_ALM0_SECONDS, tmp, sizeof(tmp)); if (ret) return ret; /* enable alarm if requested */ if (alm->enabled) { ret = mcp795_update_alarm(dev, true); if (ret) return ret; dev_dbg(dev, "Alarm IRQ armed\n"); } dev_dbg(dev, "Set alarm: %ptRdr(%d) %ptRt\n", &alm->time, alm->time.tm_wday, &alm->time); return 0; } static int mcp795_read_alarm(struct device *dev, struct rtc_wkalrm *alm) { u8 data[6]; int ret; ret = mcp795_rtcc_read( dev, MCP795_REG_ALM0_SECONDS, data, sizeof(data)); if (ret) return ret; alm->time.tm_sec = bcd2bin(data[0] & 0x7F); alm->time.tm_min = bcd2bin(data[1] & 0x7F); alm->time.tm_hour = bcd2bin(data[2] & 0x1F); alm->time.tm_wday = bcd2bin(data[3] & 0x07) - 1; alm->time.tm_mday = bcd2bin(data[4] & 0x3F); alm->time.tm_mon = bcd2bin(data[5] & 0x1F) - 1; alm->time.tm_year = -1; alm->time.tm_isdst = -1; alm->time.tm_yday = -1; dev_dbg(dev, "Read alarm: %ptRdr(%d) %ptRt\n", &alm->time, alm->time.tm_wday, &alm->time); return 0; } static int mcp795_alarm_irq_enable(struct device *dev, unsigned int enabled) { return mcp795_update_alarm(dev, !!enabled); } static irqreturn_t mcp795_irq(int irq, void *data) { struct spi_device *spi = data; struct rtc_device *rtc = spi_get_drvdata(spi); int ret; rtc_lock(rtc); /* Disable alarm. * There is no need to clear ALM0IF (Alarm 0 Interrupt Flag) bit, * because it is done every time when alarm is enabled. */ ret = mcp795_update_alarm(&spi->dev, false); if (ret) dev_err(&spi->dev, "Failed to disable alarm in IRQ (ret=%d)\n", ret); rtc_update_irq(rtc, 1, RTC_AF | RTC_IRQF); rtc_unlock(rtc); return IRQ_HANDLED; } static const struct rtc_class_ops mcp795_rtc_ops = { .read_time = mcp795_read_time, .set_time = mcp795_set_time, .read_alarm = mcp795_read_alarm, .set_alarm = mcp795_set_alarm, .alarm_irq_enable = mcp795_alarm_irq_enable }; static int mcp795_probe(struct spi_device *spi) { struct rtc_device *rtc; int ret; spi->mode = SPI_MODE_0; spi->bits_per_word = 8; ret = spi_setup(spi); if (ret) { dev_err(&spi->dev, "Unable to setup SPI\n"); return ret; } /* Start the oscillator but don't set the value of EXTOSC bit */ mcp795_start_oscillator(&spi->dev, NULL); /* Clear the 12 hour mode flag*/ mcp795_rtcc_set_bits(&spi->dev, 0x03, MCP795_24_BIT, 0); rtc = devm_rtc_device_register(&spi->dev, "rtc-mcp795", &mcp795_rtc_ops, THIS_MODULE); if (IS_ERR(rtc)) return PTR_ERR(rtc); spi_set_drvdata(spi, rtc); if (spi->irq > 0) { dev_dbg(&spi->dev, "Alarm support enabled\n"); /* Clear any pending alarm (ALM0IF bit) before requesting * the interrupt. */ mcp795_rtcc_set_bits(&spi->dev, MCP795_REG_ALM0_DAY, MCP795_ALM0IF_BIT, 0); ret = devm_request_threaded_irq(&spi->dev, spi->irq, NULL, mcp795_irq, IRQF_TRIGGER_FALLING | IRQF_ONESHOT, dev_name(&rtc->dev), spi); if (ret) dev_err(&spi->dev, "Failed to request IRQ: %d: %d\n", spi->irq, ret); else device_init_wakeup(&spi->dev, true); } return 0; } #ifdef CONFIG_OF static const struct of_device_id mcp795_of_match[] = { { .compatible = "maxim,mcp795" }, { } }; MODULE_DEVICE_TABLE(of, mcp795_of_match); #endif static const struct spi_device_id mcp795_spi_ids[] = { { .name = "mcp795" }, { } }; MODULE_DEVICE_TABLE(spi, mcp795_spi_ids); static struct spi_driver mcp795_driver = { .driver = { .name = "rtc-mcp795", .of_match_table = of_match_ptr(mcp795_of_match), }, .probe = mcp795_probe, .id_table = mcp795_spi_ids, }; module_spi_driver(mcp795_driver); MODULE_DESCRIPTION("MCP795 RTC SPI Driver"); MODULE_AUTHOR("Josef Gajdusek <atx@atx.name>"); MODULE_LICENSE("GPL"); MODULE_ALIAS("spi:mcp795");
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