Skip to content

Commit

Permalink
rtc: Philips PCF2123 RTC SPI driver
Browse files Browse the repository at this point in the history 
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>
  • Loading branch information
Chris Verges authored and Linus Torvalds committed Sep 23, 2009
1 parent 568d069 commit 7f3923a
Show file tree
Hide file tree
Showing 3 changed files with 354 additions and 0 deletions.
9 changes: 9 additions & 0 deletions drivers/rtc/Kconfig
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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"
Expand Down
1 change: 1 addition & 0 deletions drivers/rtc/Makefile
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down
344 changes: 344 additions & 0 deletions drivers/rtc/rtc-pcf2123.c
View file
Original file line number Diff line number Diff line change
@@ -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);

0 comments on commit 7f3923a

Please sign in to comment.