diff options
Diffstat (limited to 'drivers/rtc/rtc-pcf2123.c')
| -rw-r--r-- | drivers/rtc/rtc-pcf2123.c | 344 |
1 files changed, 344 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-pcf2123.c b/drivers/rtc/rtc-pcf2123.c new file mode 100644 index 00000000000..d07b199a0c9 --- /dev/null +++ b/drivers/rtc/rtc-pcf2123.c @@ -0,0 +1,344 @@ +/* + * 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/string.h> +#include <linux/rtc.h> +#include <linux/spi/spi.h> + +#define DRV_VERSION "0.5" + +#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; /* must be first */ + 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 = (struct pcf2123_sysfs_reg *) attr; + u8 txbuf[1], rxbuf[1]; + int ret; + + txbuf[0] = PCF2123_READ | simple_strtoul(r->name, NULL, 16); + ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1); + if (ret < 0) + return sprintf(buffer, "error: %d", ret); + pcf2123_delay_trec(); + return sprintf(buffer, "0x%x", 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 = (struct pcf2123_sysfs_reg *) attr; + u8 txbuf[2]; + int ret; + + txbuf[0] = PCF2123_WRITE | simple_strtoul(r->name, NULL, 16); + txbuf[1] = simple_strtoul(buffer, NULL, 0); + 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 __devinit pcf2123_probe(struct spi_device *spi) +{ + struct rtc_device *rtc; + struct pcf2123_plat_data *pdata; + u8 txbuf[2], rxbuf[2]; + int ret, i; + + pdata = kzalloc(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) + return ret; + 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) + return ret; + 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"); + 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 = rtc_device_register(pcf2123_driver.driver.name, &spi->dev, + &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++) { + 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); + pdata->regs[i].name[0] = '\0'; + } + } + + return 0; +kfree_exit: + kfree(pdata); + spi->dev.platform_data = NULL; + return ret; +} + +static int pcf2123_remove(struct spi_device *spi) +{ + struct pcf2123_plat_data *pdata = spi->dev.platform_data; + int i; + + if (pdata) { + struct rtc_device *rtc = pdata->rtc; + + if (rtc) + rtc_device_unregister(rtc); + for (i = 0; i < 16; i++) + if (pdata->regs[i].name[0]) + device_remove_file(&spi->dev, + &pdata->regs[i].attr); + kfree(pdata); + } + + return 0; +} + +static struct spi_driver pcf2123_driver = { + .driver = { + .name = "rtc-pcf2123", + .bus = &spi_bus_type, + .owner = THIS_MODULE, + }, + .probe = pcf2123_probe, + .remove = __devexit_p(pcf2123_remove), +}; + +static int __init pcf2123_init(void) +{ + return spi_register_driver(&pcf2123_driver); +} + +static void __exit pcf2123_exit(void) +{ + spi_unregister_driver(&pcf2123_driver); +} + +MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>"); +MODULE_DESCRIPTION("NXP PCF2123 RTC driver"); +MODULE_LICENSE("GPL"); +MODULE_VERSION(DRV_VERSION); + +module_init(pcf2123_init); +module_exit(pcf2123_exit); |