rtc: Philips PCF2123 RTC SPI driver
authorChris Verges <chrisv@cyberswitching.com>
Tue, 22 Sep 2009 23:46:20 +0000 (16:46 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 23 Sep 2009 14:39:44 +0000 (07:39 -0700)
Add support for the Philips/NXP PCF2123 RTC.

Signed-off: Chris Verges <chrisv@cyberswitching.com>
Tested-by: Chris Verges <chrisv@cyberswitching.com>
Signed-off: Christian Pellegrin <chripell@fsfe.org>
Tested-by: Christian Pellegrin <chripell@fsfe.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/rtc/Kconfig
drivers/rtc/Makefile
drivers/rtc/rtc-pcf2123.c [new file with mode: 0644]

index 73771b09fbd37dd0ab2a757ecb317ec818501c78..2ccd351c52eda50f6941f8a91f05460ac9a08743 100644 (file)
@@ -378,6 +378,15 @@ config RTC_DRV_DS3234
          This driver can also be built as a module. If so, the module
          will be called rtc-ds3234.
 
+config RTC_DRV_PCF2123
+       tristate "NXP PCF2123"
+       help
+         If you say yes here you get support for the NXP PCF2123
+         RTC chip.
+
+         This driver can also be built as a module. If so, the module
+         will be called rtc-pcf2123.
+
 endif # SPI_MASTER
 
 comment "Platform RTC drivers"
index 5e152ffe505819291917118a511c4ee56d053f9f..0e9414995caeba662703cfebc0a2d4a9e9488cd3 100644 (file)
@@ -55,6 +55,7 @@ obj-$(CONFIG_RTC_DRV_MV)      += rtc-mv.o
 obj-$(CONFIG_RTC_DRV_OMAP)     += rtc-omap.o
 obj-$(CONFIG_RTC_DRV_PCF8563)  += rtc-pcf8563.o
 obj-$(CONFIG_RTC_DRV_PCF8583)  += rtc-pcf8583.o
+obj-$(CONFIG_RTC_DRV_PCF2123)  += rtc-pcf2123.o
 obj-$(CONFIG_RTC_DRV_PL030)    += rtc-pl030.o
 obj-$(CONFIG_RTC_DRV_PL031)    += rtc-pl031.o
 obj-$(CONFIG_RTC_DRV_GENERIC)  += rtc-generic.o
diff --git a/drivers/rtc/rtc-pcf2123.c b/drivers/rtc/rtc-pcf2123.c
new file mode 100644 (file)
index 0000000..d07b199
--- /dev/null
@@ -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);