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authorSergey Yanovich <ynvich@gmail.com>2016-02-23 13:54:57 +0300
committerAlexandre Belloni <alexandre.belloni@free-electrons.com>2016-05-20 12:33:51 +0200
commitd25a5ed37d5fdd25f3cfbffc2f9a0f62e58f884c (patch)
treeab7921d55bcb2c297b7ee375ceef35da9ebd26ac
parent2dcd0af568b0cf583645c8a317dd12e344b1c72a (diff)
downloadlinux-d25a5ed37d5fdd25f3cfbffc2f9a0f62e58f884c.tar.gz
rtc: ds1302: rewrite using SPI
DS1302 is an half-duplex SPI device. The driver respects this fact now. Pin configurations should be implemented using SPI subsystem. Signed-off-by: Sergei Ianovich <ynvich@gmail.com> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
-rw-r--r--Documentation/devicetree/bindings/rtc/maxim-ds1302.txt46
-rw-r--r--drivers/rtc/Kconfig15
-rw-r--r--drivers/rtc/rtc-ds1302.c348
3 files changed, 212 insertions, 197 deletions
diff --git a/Documentation/devicetree/bindings/rtc/maxim-ds1302.txt b/Documentation/devicetree/bindings/rtc/maxim-ds1302.txt
new file mode 100644
index 000000000000..ba470c56cdec
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/maxim-ds1302.txt
@@ -0,0 +1,46 @@
+* Maxim/Dallas Semiconductor DS-1302 RTC
+
+Simple device which could be used to store date/time between reboots.
+
+The device uses the standard MicroWire half-duplex transfer timing.
+Master output is set on low clock and sensed by the RTC on the rising
+edge. Master input is set by the RTC on the trailing edge and is sensed
+by the master on low clock.
+
+Required properties:
+
+- compatible : Should be "maxim,ds1302"
+
+Required SPI properties:
+
+- reg : Should be address of the device chip select within
+ the controller.
+
+- spi-max-frequency : DS-1302 has 500 kHz if powered at 2.2V,
+ and 2MHz if powered at 5V.
+
+- spi-3wire : The device has a shared signal IN/OUT line.
+
+- spi-lsb-first : DS-1302 requires least significant bit first
+ transfers.
+
+- spi-cs-high: DS-1302 has active high chip select line. This is
+ required unless inverted in hardware.
+
+Example:
+
+spi@901c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ compatible = "icpdas,lp8841-spi-rtc";
+ reg = <0x901c 0x1>;
+
+ rtc@0 {
+ compatible = "maxim,ds1302";
+ reg = <0>;
+ spi-max-frequency = <500000>;
+ spi-3wire;
+ spi-lsb-first;
+ spi-cs-high;
+ };
+};
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 3e84315c6f12..f1e1f502be5d 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -634,6 +634,15 @@ config RTC_DRV_M41T94
This driver can also be built as a module. If so, the module
will be called rtc-m41t94.
+config RTC_DRV_DS1302
+ tristate "Dallas/Maxim DS1302"
+ depends on SPI
+ help
+ If you say yes here you get support for the Dallas DS1302 RTC chips.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-ds1302.
+
config RTC_DRV_DS1305
tristate "Dallas/Maxim DS1305/DS1306"
help
@@ -834,12 +843,6 @@ config RTC_DRV_DS1286
help
If you say yes here you get support for the Dallas DS1286 RTC chips.
-config RTC_DRV_DS1302
- tristate "Dallas DS1302"
- depends on SH_SECUREEDGE5410
- help
- If you say yes here you get support for the Dallas DS1302 RTC chips.
-
config RTC_DRV_DS1511
tristate "Dallas DS1511"
depends on HAS_IOMEM
diff --git a/drivers/rtc/rtc-ds1302.c b/drivers/rtc/rtc-ds1302.c
index 6bef7a5233c4..5cdc0f201b34 100644
--- a/drivers/rtc/rtc-ds1302.c
+++ b/drivers/rtc/rtc-ds1302.c
@@ -9,16 +9,17 @@
* this archive for more details.
*/
+#include <linux/bcd.h>
#include <linux/init.h>
-#include <linux/module.h>
+#include <linux/io.h>
#include <linux/kernel.h>
-#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/of.h>
#include <linux/rtc.h>
-#include <linux/io.h>
-#include <linux/bcd.h>
+#include <linux/spi/spi.h>
#define DRV_NAME "rtc-ds1302"
-#define DRV_VERSION "0.1.1"
+#define DRV_VERSION "1.0.0"
#define RTC_CMD_READ 0x81 /* Read command */
#define RTC_CMD_WRITE 0x80 /* Write command */
@@ -28,6 +29,8 @@
#define RTC_ADDR_RAM0 0x20 /* Address of RAM0 */
#define RTC_ADDR_TCR 0x08 /* Address of trickle charge register */
+#define RTC_CLCK_BURST 0x1F /* Address of clock burst */
+#define RTC_CLCK_LEN 0x08 /* Size of clock burst */
#define RTC_ADDR_CTRL 0x07 /* Address of control register */
#define RTC_ADDR_YEAR 0x06 /* Address of year register */
#define RTC_ADDR_DAY 0x05 /* Address of day of week register */
@@ -37,217 +40,180 @@
#define RTC_ADDR_MIN 0x01 /* Address of minute register */
#define RTC_ADDR_SEC 0x00 /* Address of second register */
-#ifdef CONFIG_SH_SECUREEDGE5410
-#include <asm/rtc.h>
-#include <mach/secureedge5410.h>
-
-#define RTC_RESET 0x1000
-#define RTC_IODATA 0x0800
-#define RTC_SCLK 0x0400
-
-#define set_dp(x) SECUREEDGE_WRITE_IOPORT(x, 0x1c00)
-#define get_dp() SECUREEDGE_READ_IOPORT()
-#define ds1302_set_tx()
-#define ds1302_set_rx()
-
-static inline int ds1302_hw_init(void)
+static int ds1302_rtc_set_time(struct device *dev, struct rtc_time *time)
{
- return 0;
+ struct spi_device *spi = dev_get_drvdata(dev);
+ u8 buf[1 + RTC_CLCK_LEN];
+ u8 *bp = buf;
+ int status;
+
+ /* Enable writing */
+ bp = buf;
+ *bp++ = RTC_ADDR_CTRL << 1 | RTC_CMD_WRITE;
+ *bp++ = RTC_CMD_WRITE_ENABLE;
+
+ status = spi_write_then_read(spi, buf, 2,
+ NULL, 0);
+ if (!status)
+ return status;
+
+ /* Write registers starting at the first time/date address. */
+ bp = buf;
+ *bp++ = RTC_CLCK_BURST << 1 | RTC_CMD_WRITE;
+
+ *bp++ = bin2bcd(time->tm_sec);
+ *bp++ = bin2bcd(time->tm_min);
+ *bp++ = bin2bcd(time->tm_hour);
+ *bp++ = bin2bcd(time->tm_mday);
+ *bp++ = bin2bcd(time->tm_mon + 1);
+ *bp++ = time->tm_wday;
+ *bp++ = bin2bcd(time->tm_year % 100);
+ *bp++ = RTC_CMD_WRITE_DISABLE;
+
+ /* use write-then-read since dma from stack is nonportable */
+ return spi_write_then_read(spi, buf, sizeof(buf),
+ NULL, 0);
}
-static inline void ds1302_reset(void)
+static int ds1302_rtc_get_time(struct device *dev, struct rtc_time *time)
{
- set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));
+ struct spi_device *spi = dev_get_drvdata(dev);
+ u8 addr = RTC_CLCK_BURST << 1 | RTC_CMD_READ;
+ u8 buf[RTC_CLCK_LEN - 1];
+ int status;
+
+ /* Use write-then-read to get all the date/time registers
+ * since dma from stack is nonportable
+ */
+ status = spi_write_then_read(spi, &addr, sizeof(addr),
+ buf, sizeof(buf));
+ if (status < 0)
+ return status;
+
+ /* Decode the registers */
+ time->tm_sec = bcd2bin(buf[RTC_ADDR_SEC]);
+ time->tm_min = bcd2bin(buf[RTC_ADDR_MIN]);
+ time->tm_hour = bcd2bin(buf[RTC_ADDR_HOUR]);
+ time->tm_wday = buf[RTC_ADDR_DAY] - 1;
+ time->tm_mday = bcd2bin(buf[RTC_ADDR_DATE]);
+ time->tm_mon = bcd2bin(buf[RTC_ADDR_MON]) - 1;
+ time->tm_year = bcd2bin(buf[RTC_ADDR_YEAR]) + 100;
+
+ /* Time may not be set */
+ return rtc_valid_tm(time);
}
-static inline void ds1302_clock(void)
-{
- set_dp(get_dp() | RTC_SCLK); /* clock high */
- set_dp(get_dp() & ~RTC_SCLK); /* clock low */
-}
-
-static inline void ds1302_start(void)
-{
- set_dp(get_dp() | RTC_RESET);
-}
-
-static inline void ds1302_stop(void)
-{
- set_dp(get_dp() & ~RTC_RESET);
-}
-
-static inline void ds1302_txbit(int bit)
-{
- set_dp((get_dp() & ~RTC_IODATA) | (bit ? RTC_IODATA : 0));
-}
-
-static inline int ds1302_rxbit(void)
-{
- return !!(get_dp() & RTC_IODATA);
-}
-
-#else
-#error "Add support for your platform"
-#endif
+static struct rtc_class_ops ds1302_rtc_ops = {
+ .read_time = ds1302_rtc_get_time,
+ .set_time = ds1302_rtc_set_time,
+};
-static void ds1302_sendbits(unsigned int val)
+static int ds1302_probe(struct spi_device *spi)
{
- int i;
-
- ds1302_set_tx();
-
- for (i = 8; (i); i--, val >>= 1) {
- ds1302_txbit(val & 0x1);
- ds1302_clock();
+ struct rtc_device *rtc;
+ u8 addr;
+ u8 buf[4];
+ u8 *bp = buf;
+ int status;
+
+ /* Sanity check board setup data. This may be hooked up
+ * in 3wire mode, but we don't care. Note that unless
+ * there's an inverter in place, this needs SPI_CS_HIGH!
+ */
+ if (spi->bits_per_word && (spi->bits_per_word != 8)) {
+ dev_err(&spi->dev, "bad word length\n");
+ return -EINVAL;
+ } else if (spi->max_speed_hz > 2000000) {
+ dev_err(&spi->dev, "speed is too high\n");
+ return -EINVAL;
+ } else if (spi->mode & SPI_CPHA) {
+ dev_err(&spi->dev, "bad mode\n");
+ return -EINVAL;
}
-}
-
-static unsigned int ds1302_recvbits(void)
-{
- unsigned int val;
- int i;
-
- ds1302_set_rx();
- for (i = 0, val = 0; (i < 8); i++) {
- val |= (ds1302_rxbit() << i);
- ds1302_clock();
+ addr = RTC_ADDR_CTRL << 1 | RTC_CMD_READ;
+ status = spi_write_then_read(spi, &addr, sizeof(addr), buf, 1);
+ if (status < 0) {
+ dev_err(&spi->dev, "control register read error %d\n",
+ status);
+ return status;
}
- return val;
-}
-
-static unsigned int ds1302_readbyte(unsigned int addr)
-{
- unsigned int val;
-
- ds1302_reset();
-
- ds1302_start();
- ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_READ);
- val = ds1302_recvbits();
- ds1302_stop();
-
- return val;
-}
-
-static void ds1302_writebyte(unsigned int addr, unsigned int val)
-{
- ds1302_reset();
-
- ds1302_start();
- ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_WRITE);
- ds1302_sendbits(val);
- ds1302_stop();
-}
-
-static int ds1302_rtc_read_time(struct device *dev, struct rtc_time *tm)
-{
- tm->tm_sec = bcd2bin(ds1302_readbyte(RTC_ADDR_SEC));
- tm->tm_min = bcd2bin(ds1302_readbyte(RTC_ADDR_MIN));
- tm->tm_hour = bcd2bin(ds1302_readbyte(RTC_ADDR_HOUR));
- tm->tm_wday = bcd2bin(ds1302_readbyte(RTC_ADDR_DAY));
- tm->tm_mday = bcd2bin(ds1302_readbyte(RTC_ADDR_DATE));
- tm->tm_mon = bcd2bin(ds1302_readbyte(RTC_ADDR_MON)) - 1;
- tm->tm_year = bcd2bin(ds1302_readbyte(RTC_ADDR_YEAR));
-
- if (tm->tm_year < 70)
- tm->tm_year += 100;
-
- 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 + 1, tm->tm_year, tm->tm_wday);
-
- return rtc_valid_tm(tm);
-}
-
-static int ds1302_rtc_set_time(struct device *dev, struct rtc_time *tm)
-{
- ds1302_writebyte(RTC_ADDR_CTRL, RTC_CMD_WRITE_ENABLE);
- /* Stop RTC */
- ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) | 0x80);
-
- ds1302_writebyte(RTC_ADDR_SEC, bin2bcd(tm->tm_sec));
- ds1302_writebyte(RTC_ADDR_MIN, bin2bcd(tm->tm_min));
- ds1302_writebyte(RTC_ADDR_HOUR, bin2bcd(tm->tm_hour));
- ds1302_writebyte(RTC_ADDR_DAY, bin2bcd(tm->tm_wday));
- ds1302_writebyte(RTC_ADDR_DATE, bin2bcd(tm->tm_mday));
- ds1302_writebyte(RTC_ADDR_MON, bin2bcd(tm->tm_mon + 1));
- ds1302_writebyte(RTC_ADDR_YEAR, bin2bcd(tm->tm_year % 100));
+ if ((buf[0] & ~RTC_CMD_WRITE_DISABLE) != 0) {
+ status = spi_write_then_read(spi, &addr, sizeof(addr), buf, 1);
+ if (status < 0) {
+ dev_err(&spi->dev, "control register read error %d\n",
+ status);
+ return status;
+ }
+
+ if ((buf[0] & ~RTC_CMD_WRITE_DISABLE) != 0) {
+ dev_err(&spi->dev, "junk in control register\n");
+ return -ENODEV;
+ }
+ }
+ if (buf[0] == 0) {
+ bp = buf;
+ *bp++ = RTC_ADDR_CTRL << 1 | RTC_CMD_WRITE;
+ *bp++ = RTC_CMD_WRITE_DISABLE;
+
+ status = spi_write_then_read(spi, buf, 2, NULL, 0);
+ if (status < 0) {
+ dev_err(&spi->dev, "control register write error %d\n",
+ status);
+ return status;
+ }
+
+ addr = RTC_ADDR_CTRL << 1 | RTC_CMD_READ;
+ status = spi_write_then_read(spi, &addr, sizeof(addr), buf, 1);
+ if (status < 0) {
+ dev_err(&spi->dev,
+ "error %d reading control register\n",
+ status);
+ return status;
+ }
+
+ if (buf[0] != RTC_CMD_WRITE_DISABLE) {
+ dev_err(&spi->dev, "failed to detect chip\n");
+ return -ENODEV;
+ }
+ }
- /* Start RTC */
- ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) & ~0x80);
+ spi_set_drvdata(spi, spi);
- ds1302_writebyte(RTC_ADDR_CTRL, RTC_CMD_WRITE_DISABLE);
+ rtc = devm_rtc_device_register(&spi->dev, "ds1302",
+ &ds1302_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc)) {
+ status = PTR_ERR(rtc);
+ dev_err(&spi->dev, "error %d registering rtc\n", status);
+ return status;
+ }
return 0;
}
-static int ds1302_rtc_ioctl(struct device *dev, unsigned int cmd,
- unsigned long arg)
+static int ds1302_remove(struct spi_device *spi)
{
- switch (cmd) {
-#ifdef RTC_SET_CHARGE
- case RTC_SET_CHARGE:
- {
- int tcs_val;
-
- if (copy_from_user(&tcs_val, (int __user *)arg, sizeof(int)))
- return -EFAULT;
-
- ds1302_writebyte(RTC_ADDR_TCR, (0xa0 | tcs_val * 0xf));
- return 0;
- }
-#endif
- }
-
- return -ENOIOCTLCMD;
+ spi_set_drvdata(spi, NULL);
+ return 0;
}
-static struct rtc_class_ops ds1302_rtc_ops = {
- .read_time = ds1302_rtc_read_time,
- .set_time = ds1302_rtc_set_time,
- .ioctl = ds1302_rtc_ioctl,
+#ifdef CONFIG_OF
+static const struct of_device_id ds1302_dt_ids[] = {
+ { .compatible = "maxim,ds1302", },
+ { /* sentinel */ }
};
+MODULE_DEVICE_TABLE(of, ds1302_dt_ids);
+#endif
-static int __init ds1302_rtc_probe(struct platform_device *pdev)
-{
- struct rtc_device *rtc;
-
- if (ds1302_hw_init()) {
- dev_err(&pdev->dev, "Failed to init communication channel");
- return -EINVAL;
- }
-
- /* Reset */
- ds1302_reset();
-
- /* Write a magic value to the DS1302 RAM, and see if it sticks. */
- ds1302_writebyte(RTC_ADDR_RAM0, 0x42);
- if (ds1302_readbyte(RTC_ADDR_RAM0) != 0x42) {
- dev_err(&pdev->dev, "Failed to probe");
- return -ENODEV;
- }
-
- rtc = devm_rtc_device_register(&pdev->dev, "ds1302",
- &ds1302_rtc_ops, THIS_MODULE);
- if (IS_ERR(rtc))
- return PTR_ERR(rtc);
-
- platform_set_drvdata(pdev, rtc);
-
- return 0;
-}
-
-static struct platform_driver ds1302_platform_driver = {
- .driver = {
- .name = DRV_NAME,
- },
+static struct spi_driver ds1302_driver = {
+ .driver.name = "rtc-ds1302",
+ .driver.of_match_table = of_match_ptr(ds1302_dt_ids),
+ .probe = ds1302_probe,
+ .remove = ds1302_remove,
};
-module_platform_driver_probe(ds1302_platform_driver, ds1302_rtc_probe);
+module_spi_driver(ds1302_driver);
MODULE_DESCRIPTION("Dallas DS1302 RTC driver");
MODULE_VERSION(DRV_VERSION);