/* * An SPI driver for the Philips PCF2123 RTC * Copyright 2009 Cyber Switching, Inc. * * Author: Chris Verges <chrisv@cyberswitching.com> * Maintainers: http://www.cyberswitching.com * * based on the RS5C348 driver in this same directory. * * Thanks to Christian Pellegrin <chripell@fsfe.org> for * the sysfs contributions to this driver. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * Please note that the CS is active high, so platform data * should look something like: * * static struct spi_board_info ek_spi_devices[] = { * ... * { * .modalias = "rtc-pcf2123", * .chip_select = 1, * .controller_data = (void *)AT91_PIN_PA10, * .max_speed_hz = 1000 * 1000, * .mode = SPI_CS_HIGH, * .bus_num = 0, * }, * ... *}; * */ #include <linux/bcd.h> #include <linux/delay.h> #include <linux/device.h> #include <linux/errno.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/of.h> #include <linux/string.h> #include <linux/slab.h> #include <linux/rtc.h> #include <linux/spi/spi.h> #include <linux/module.h> #include <linux/sysfs.h> #define DRV_VERSION "0.6" #define PCF2123_REG_CTRL1 (0x00) /* Control Register 1 */ #define PCF2123_REG_CTRL2 (0x01) /* Control Register 2 */ #define PCF2123_REG_SC (0x02) /* datetime */ #define PCF2123_REG_MN (0x03) #define PCF2123_REG_HR (0x04) #define PCF2123_REG_DM (0x05) #define PCF2123_REG_DW (0x06) #define PCF2123_REG_MO (0x07) #define PCF2123_REG_YR (0x08) #define PCF2123_SUBADDR (1 << 4) #define PCF2123_WRITE ((0 << 7) | PCF2123_SUBADDR) #define PCF2123_READ ((1 << 7) | PCF2123_SUBADDR) static struct spi_driver pcf2123_driver; struct pcf2123_sysfs_reg { struct device_attribute attr; char name[2]; }; struct pcf2123_plat_data { struct rtc_device *rtc; struct pcf2123_sysfs_reg regs[16]; }; /* * Causes a 30 nanosecond delay to ensure that the PCF2123 chip select * is released properly after an SPI write. This function should be * called after EVERY read/write call over SPI. */ static inline void pcf2123_delay_trec(void) { ndelay(30); } static ssize_t pcf2123_show(struct device *dev, struct device_attribute *attr, char *buffer) { struct spi_device *spi = to_spi_device(dev); struct pcf2123_sysfs_reg *r; u8 txbuf[1], rxbuf[1]; unsigned long reg; int ret; r = container_of(attr, struct pcf2123_sysfs_reg, attr); ret = kstrtoul(r->name, 16, ®); if (ret) return ret; txbuf[0] = PCF2123_READ | reg; ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1); if (ret < 0) return -EIO; pcf2123_delay_trec(); return sprintf(buffer, "0x%x\n", rxbuf[0]); } static ssize_t pcf2123_store(struct device *dev, struct device_attribute *attr, const char *buffer, size_t count) { struct spi_device *spi = to_spi_device(dev); struct pcf2123_sysfs_reg *r; u8 txbuf[2]; unsigned long reg; unsigned long val; int ret; r = container_of(attr, struct pcf2123_sysfs_reg, attr); ret = kstrtoul(r->name, 16, ®); if (ret) return ret; ret = kstrtoul(buffer, 10, &val); if (ret) return ret; txbuf[0] = PCF2123_WRITE | reg; txbuf[1] = val; ret = spi_write(spi, txbuf, sizeof(txbuf)); if (ret < 0) return -EIO; pcf2123_delay_trec(); return count; } static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct spi_device *spi = to_spi_device(dev); u8 txbuf[1], rxbuf[7]; int ret; txbuf[0] = PCF2123_READ | PCF2123_REG_SC; ret = spi_write_then_read(spi, txbuf, sizeof(txbuf), rxbuf, sizeof(rxbuf)); if (ret < 0) return ret; pcf2123_delay_trec(); tm->tm_sec = bcd2bin(rxbuf[0] & 0x7F); tm->tm_min = bcd2bin(rxbuf[1] & 0x7F); tm->tm_hour = bcd2bin(rxbuf[2] & 0x3F); /* rtc hr 0-23 */ tm->tm_mday = bcd2bin(rxbuf[3] & 0x3F); tm->tm_wday = rxbuf[4] & 0x07; tm->tm_mon = bcd2bin(rxbuf[5] & 0x1F) - 1; /* rtc mn 1-12 */ tm->tm_year = bcd2bin(rxbuf[6]); if (tm->tm_year < 70) tm->tm_year += 100; /* assume we are in 1970...2069 */ dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " "mday=%d, mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); /* the clock can give out invalid datetime, but we cannot return * -EINVAL otherwise hwclock will refuse to set the time on bootup. */ if (rtc_valid_tm(tm) < 0) dev_err(dev, "retrieved date/time is not valid.\n"); return 0; } static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct spi_device *spi = to_spi_device(dev); u8 txbuf[8]; int ret; dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " "mday=%d, mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); /* Stop the counter first */ txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; txbuf[1] = 0x20; ret = spi_write(spi, txbuf, 2); if (ret < 0) return ret; pcf2123_delay_trec(); /* Set the new time */ txbuf[0] = PCF2123_WRITE | PCF2123_REG_SC; txbuf[1] = bin2bcd(tm->tm_sec & 0x7F); txbuf[2] = bin2bcd(tm->tm_min & 0x7F); txbuf[3] = bin2bcd(tm->tm_hour & 0x3F); txbuf[4] = bin2bcd(tm->tm_mday & 0x3F); txbuf[5] = tm->tm_wday & 0x07; txbuf[6] = bin2bcd((tm->tm_mon + 1) & 0x1F); /* rtc mn 1-12 */ txbuf[7] = bin2bcd(tm->tm_year < 100 ? tm->tm_year : tm->tm_year - 100); ret = spi_write(spi, txbuf, sizeof(txbuf)); if (ret < 0) return ret; pcf2123_delay_trec(); /* Start the counter */ txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; txbuf[1] = 0x00; ret = spi_write(spi, txbuf, 2); if (ret < 0) return ret; pcf2123_delay_trec(); return 0; } static const struct rtc_class_ops pcf2123_rtc_ops = { .read_time = pcf2123_rtc_read_time, .set_time = pcf2123_rtc_set_time, }; static int pcf2123_probe(struct spi_device *spi) { struct rtc_device *rtc; struct pcf2123_plat_data *pdata; u8 txbuf[2], rxbuf[2]; int ret, i; pdata = devm_kzalloc(&spi->dev, sizeof(struct pcf2123_plat_data), GFP_KERNEL); if (!pdata) return -ENOMEM; spi->dev.platform_data = pdata; /* Send a software reset command */ txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; txbuf[1] = 0x58; dev_dbg(&spi->dev, "resetting RTC (0x%02X 0x%02X)\n", txbuf[0], txbuf[1]); ret = spi_write(spi, txbuf, 2 * sizeof(u8)); if (ret < 0) goto kfree_exit; pcf2123_delay_trec(); /* Stop the counter */ txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; txbuf[1] = 0x20; dev_dbg(&spi->dev, "stopping RTC (0x%02X 0x%02X)\n", txbuf[0], txbuf[1]); ret = spi_write(spi, txbuf, 2 * sizeof(u8)); if (ret < 0) goto kfree_exit; pcf2123_delay_trec(); /* See if the counter was actually stopped */ txbuf[0] = PCF2123_READ | PCF2123_REG_CTRL1; dev_dbg(&spi->dev, "checking for presence of RTC (0x%02X)\n", txbuf[0]); ret = spi_write_then_read(spi, txbuf, 1 * sizeof(u8), rxbuf, 2 * sizeof(u8)); dev_dbg(&spi->dev, "received data from RTC (0x%02X 0x%02X)\n", rxbuf[0], rxbuf[1]); if (ret < 0) goto kfree_exit; pcf2123_delay_trec(); if (!(rxbuf[0] & 0x20)) { dev_err(&spi->dev, "chip not found\n"); ret = -ENODEV; goto kfree_exit; } dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n"); dev_info(&spi->dev, "spiclk %u KHz.\n", (spi->max_speed_hz + 500) / 1000); /* Start the counter */ txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; txbuf[1] = 0x00; ret = spi_write(spi, txbuf, sizeof(txbuf)); if (ret < 0) goto kfree_exit; pcf2123_delay_trec(); /* Finalize the initialization */ rtc = devm_rtc_device_register(&spi->dev, pcf2123_driver.driver.name, &pcf2123_rtc_ops, THIS_MODULE); if (IS_ERR(rtc)) { dev_err(&spi->dev, "failed to register.\n"); ret = PTR_ERR(rtc); goto kfree_exit; } pdata->rtc = rtc; for (i = 0; i < 16; i++) { sysfs_attr_init(&pdata->regs[i].attr.attr); sprintf(pdata->regs[i].name, "%1x", i); pdata->regs[i].attr.attr.mode = S_IRUGO | S_IWUSR; pdata->regs[i].attr.attr.name = pdata->regs[i].name; pdata->regs[i].attr.show = pcf2123_show; pdata->regs[i].attr.store = pcf2123_store; ret = device_create_file(&spi->dev, &pdata->regs[i].attr); if (ret) { dev_err(&spi->dev, "Unable to create sysfs %s\n", pdata->regs[i].name); goto sysfs_exit; } } return 0; sysfs_exit: for (i--; i >= 0; i--) device_remove_file(&spi->dev, &pdata->regs[i].attr); kfree_exit: spi->dev.platform_data = NULL; return ret; } static int pcf2123_remove(struct spi_device *spi) { struct pcf2123_plat_data *pdata = dev_get_platdata(&spi->dev); int i; if (pdata) { for (i = 0; i < 16; i++) if (pdata->regs[i].name[0]) device_remove_file(&spi->dev, &pdata->regs[i].attr); } return 0; } #ifdef CONFIG_OF static const struct of_device_id pcf2123_dt_ids[] = { { .compatible = "nxp,rtc-pcf2123", }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, pcf2123_dt_ids); #endif static struct spi_driver pcf2123_driver = { .driver = { .name = "rtc-pcf2123", .owner = THIS_MODULE, .of_match_table = of_match_ptr(pcf2123_dt_ids), }, .probe = pcf2123_probe, .remove = pcf2123_remove, }; module_spi_driver(pcf2123_driver); MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>"); MODULE_DESCRIPTION("NXP PCF2123 RTC driver"); MODULE_LICENSE("GPL"); MODULE_VERSION(DRV_VERSION);