This patch adds support for the Dallas DS1390 SPI RTC chip.
Signed-off-by: M.Jackson <[email protected]>
---
drivers/rtc/Kconfig | 14 +++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-ds1390.c | 283 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 298 insertions(+), 0 deletions(-)
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 9a9755c..7ec6abb 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -292,6 +292,20 @@ config RTC_DRV_DS1305
This driver can also be built as a module. If so, the module
will be called rtc-ds1305.
+config RTC_DRV_DS1390
+ tristate "Dallas/Maxim DS1390"
+ help
+ If you say yes here you get support for the DS1390 and probably
+ other chips connected with SPI.
+
+ The first seven registers on these chips hold an RTC, and other
+ registers may add features such as NVRAM, a trickle charger for
+ the RTC/NVRAM backup power, and alarms. This driver may not
+ expose all those available chip features.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-ds1390.
+
config RTC_DRV_MAX6902
tristate "Maxim MAX6902"
help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 18622ef..6306900 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_RTC_DRV_DS1302) += rtc-ds1302.o
obj-$(CONFIG_RTC_DRV_DS1305) += rtc-ds1305.o
obj-$(CONFIG_RTC_DRV_DS1307) += rtc-ds1307.o
obj-$(CONFIG_RTC_DRV_DS1374) += rtc-ds1374.o
+obj-$(CONFIG_RTC_DRV_DS1390) += rtc-ds1390.o
obj-$(CONFIG_RTC_DRV_DS1511) += rtc-ds1511.o
obj-$(CONFIG_RTC_DRV_DS1553) += rtc-ds1553.o
obj-$(CONFIG_RTC_DRV_DS1672) += rtc-ds1672.o
diff --git a/drivers/rtc/rtc-ds1390.c b/drivers/rtc/rtc-ds1390.c
new file mode 100644
index 0000000..57fb215
--- /dev/null
+++ b/drivers/rtc/rtc-ds1390.c
@@ -0,0 +1,283 @@
+/* drivers/rtc/rtc-ds1390.c
+ *
+ * Copyright (C) 2008 Mercury IMC Ltd
+ *
+ * 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.
+ *
+ * Driver for DS1390 spi RTC
+ *
+ * Changelog:
+ *
+ * 04-Apr-2008: Mark Jackson <[email protected]>
+ * - Initial version based on rtc-max6902
+ * - No alarm support though !!
+ */
+
+#include <linux/module.h>
+#include <linux/version.h>
+
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/init.h>
+#include <linux/rtc.h>
+#include <linux/spi/spi.h>
+#include <linux/bcd.h>
+#include <linux/delay.h>
+
+#define DS1390_REG_100THS 0x00
+#define DS1390_REG_SECONDS 0x01
+#define DS1390_REG_MINUTES 0x02
+#define DS1390_REG_HOURS 0x03
+#define DS1390_REG_DAY 0x04
+#define DS1390_REG_DATE 0x05
+#define DS1390_REG_MONTH_CENT 0x06
+#define DS1390_REG_YEAR 0x07
+
+#define DS1390_REG_ALARM_100THS 0x08
+#define DS1390_REG_ALARM_SECONDS 0x09
+#define DS1390_REG_ALARM_MINUTES 0x0A
+#define DS1390_REG_ALARM_HOURS 0x0B
+#define DS1390_REG_ALARM_DAY_DATE 0x0C
+
+#define DS1390_REG_CONTROL 0x0D
+#define DS1390_REG_STATUS 0x0E
+#define DS1390_REG_TRICKLE 0x0F
+
+struct ds1390
+{
+ struct rtc_device *rtc;
+ u8 buf[9]; /* cmd + 8 registers */
+ u8 tx_buf[2];
+ u8 rx_buf[2];
+};
+
+static void ds1390_set_reg(struct device *dev, unsigned char address,
+ unsigned char data)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ unsigned char buf[2];
+
+ /* MSB must be '1' to write */
+ buf[0] = address | 0x80;
+ buf[1] = data;
+
+ spi_write(spi, buf, 2);
+}
+
+static int ds1390_get_reg(struct device *dev, unsigned char address,
+ unsigned char *data)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ struct ds1390 *chip = dev_get_drvdata(dev);
+ struct spi_message message;
+ struct spi_transfer xfer;
+ int status;
+
+ if (!data)
+ return -EINVAL;
+
+ /* Build our spi message */
+ spi_message_init(&message);
+ memset(&xfer, 0, sizeof(xfer));
+ xfer.len = 2;
+ /* Can tx_buf and rx_buf be equal? The doc in spi.h is not sure... */
+ xfer.tx_buf = chip->tx_buf;
+ xfer.rx_buf = chip->rx_buf;
+
+ /* Clear MSB to indicate read */
+ chip->tx_buf[0] = address & 0x7f;
+
+ spi_message_add_tail(&xfer, &message);
+
+ /* do the i/o */
+ status = spi_sync(spi, &message);
+ if (status == 0)
+ {
+ status = message.status;
+ }
+ else
+ {
+ return status;
+ }
+
+ *data = chip->rx_buf[1];
+
+ return status;
+}
+
+static int ds1390_get_datetime(struct device *dev, struct rtc_time *dt)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ struct ds1390 *chip = dev_get_drvdata(dev);
+ struct spi_message message;
+ struct spi_transfer xfer;
+ int status;
+
+ /* build the message */
+ spi_message_init(&message);
+ memset(&xfer, 0, sizeof(xfer));
+ xfer.len = 1 + 7; /* read command + 7 registers */
+ xfer.tx_buf = chip->buf;
+ xfer.rx_buf = chip->buf;
+ chip->buf[0] = DS1390_REG_SECONDS;
+ spi_message_add_tail(&xfer, &message);
+
+ /* do the i/o */
+ status = spi_sync(spi, &message);
+ if (status == 0)
+ {
+ status = message.status;
+ }
+ else
+ {
+ return status;
+ }
+
+ /* The chip sends data in this order:
+ * Seconds, Minutes, Hours, Day, Date, Month / Century, Year */
+ dt->tm_sec = BCD2BIN(chip->buf[1]);
+ dt->tm_min = BCD2BIN(chip->buf[2]);
+ dt->tm_hour = BCD2BIN(chip->buf[3]);
+ dt->tm_wday = BCD2BIN(chip->buf[4]);
+ dt->tm_mday = BCD2BIN(chip->buf[5]);
+ /* mask off century bit */
+ dt->tm_mon = BCD2BIN(chip->buf[6] & 0x7f) - 1;
+ /* adjust for century bit */
+ dt->tm_year = BCD2BIN(chip->buf[7]) + ((chip->buf[6] & 0x80) ? 100 : 0);
+
+ return 0;
+}
+
+static int ds1390_set_datetime(struct device *dev, struct rtc_time *dt)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ struct ds1390 *chip = dev_get_drvdata(dev);
+ struct spi_message message;
+ struct spi_transfer xfer;
+ int status;
+
+ /* build the message */
+ spi_message_init(&message);
+ memset(&xfer, 0, sizeof(xfer));
+ xfer.len = 1 + 8; /* write command + 8 registers */
+ xfer.tx_buf = chip->buf;
+ xfer.rx_buf = chip->buf;
+ chip->buf[0] = DS1390_REG_SECONDS | 0x80;
+ chip->buf[1] = BIN2BCD(dt->tm_sec);
+ chip->buf[2] = BIN2BCD(dt->tm_min);
+ chip->buf[3] = BIN2BCD(dt->tm_hour);
+ chip->buf[4] = BIN2BCD(dt->tm_wday);
+ chip->buf[5] = BIN2BCD(dt->tm_mday);
+ chip->buf[6] = BIN2BCD(dt->tm_mon + 1) | ((dt->tm_year > 99) ? 0x80 : 0x00);
+ chip->buf[7] = BIN2BCD(dt->tm_year % 100);
+ spi_message_add_tail(&xfer, &message);
+
+ /* do the i/o */
+ status = spi_sync(spi, &message);
+ if (status == 0)
+ {
+ status = message.status;
+ }
+ else
+ {
+ return status;
+ }
+
+ return 0;
+}
+
+static int ds1390_read_time(struct device *dev, struct rtc_time *tm)
+{
+ return ds1390_get_datetime(dev, tm);
+}
+
+static int ds1390_set_time(struct device *dev, struct rtc_time *tm)
+{
+ return ds1390_set_datetime(dev, tm);
+}
+
+static const struct rtc_class_ops ds1390_rtc_ops = {
+ .read_time = ds1390_read_time,
+ .set_time = ds1390_set_time,
+};
+
+static int __devinit ds1390_probe(struct spi_device *spi)
+{
+ struct rtc_device *rtc;
+ unsigned char tmp;
+ struct ds1390 *chip;
+ int res;
+
+ printk("DS1390 SPI RTC driver\n");
+
+ rtc = rtc_device_register("ds1390",
+ &spi->dev, &ds1390_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc))
+ {
+ printk("RTC : unable to register device\n");
+ return PTR_ERR(rtc);
+ }
+
+ spi->mode = SPI_MODE_3;
+ spi->bits_per_word = 8;
+ spi_setup(spi);
+
+ chip = kzalloc(sizeof *chip, GFP_KERNEL);
+ if (!chip) {
+ printk("RTC : unable to allocate device memory\n");
+ rtc_device_unregister(rtc);
+ return -ENOMEM;
+ }
+ chip->rtc = rtc;
+ dev_set_drvdata(&spi->dev, chip);
+
+ res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp);
+ if (res) {
+ printk("RTC : unable to read device\n");
+ rtc_device_unregister(rtc);
+ return res;
+ }
+
+ return 0;
+}
+
+static int __devexit ds1390_remove(struct spi_device *spi)
+{
+ struct ds1390 *chip = platform_get_drvdata(spi);
+ struct rtc_device *rtc = chip->rtc;
+
+ if (rtc)
+ rtc_device_unregister(rtc);
+
+ kfree(chip);
+
+ return 0;
+}
+
+static struct spi_driver ds1390_driver = {
+ .driver = {
+ .name = "rtc-ds1390",
+ .bus = &spi_bus_type,
+ .owner = THIS_MODULE,
+ },
+ .probe = ds1390_probe,
+ .remove = __devexit_p(ds1390_remove),
+};
+
+static __init int ds1390_init(void)
+{
+ return spi_register_driver(&ds1390_driver);
+}
+module_init(ds1390_init);
+
+static __exit void ds1390_exit(void)
+{
+ spi_unregister_driver(&ds1390_driver);
+}
+module_exit(ds1390_exit);
+
+MODULE_DESCRIPTION ("DS1390 SPI RTC driver");
+MODULE_AUTHOR ("Mark Jackson");
+MODULE_LICENSE ("GPL");
On Tue, 14 Oct 2008 09:05:18 +0100
Mark Jackson <[email protected]> wrote:
Hi Mark,
a few notes below:
> +#include <linux/module.h>
> +#include <linux/version.h>
> +
> +#include <linux/kernel.h>
> +#include <linux/platform_device.h>
> +#include <linux/init.h>
> +#include <linux/rtc.h>
> +#include <linux/spi/spi.h>
> +#include <linux/bcd.h>
> +#include <linux/delay.h>
Please check that you require all of those includes.
> +struct ds1390
> +{
> + struct rtc_device *rtc;
> + u8 buf[9]; /* cmd + 8 registers */
> + u8 tx_buf[2];
> + u8 rx_buf[2];
> +};
> +
> +static void ds1390_set_reg(struct device *dev, unsigned char address,
> + unsigned char data)
> +{
> + struct spi_device *spi = to_spi_device(dev);
> + unsigned char buf[2];
> +
> + /* MSB must be '1' to write */
> + buf[0] = address | 0x80;
> + buf[1] = data;
> +
> + spi_write(spi, buf, 2);
> +}
> +
> +static int ds1390_get_reg(struct device *dev, unsigned char address,
> + unsigned char *data)
> +{
> + struct spi_device *spi = to_spi_device(dev);
> + struct ds1390 *chip = dev_get_drvdata(dev);
> + struct spi_message message;
> + struct spi_transfer xfer;
> + int status;
> +
> + if (!data)
> + return -EINVAL;
> +
> + /* Build our spi message */
> + spi_message_init(&message);
> + memset(&xfer, 0, sizeof(xfer));
> + xfer.len = 2;
> + /* Can tx_buf and rx_buf be equal? The doc in spi.h is not sure... */
> + xfer.tx_buf = chip->tx_buf;
> + xfer.rx_buf = chip->rx_buf;
you use the same buffer a few functions below. either
one way or the other. please investigate with the spi subsystem maintainer.
> +
> + /* Clear MSB to indicate read */
> + chip->tx_buf[0] = address & 0x7f;
> +
> + spi_message_add_tail(&xfer, &message);
> +
> + /* do the i/o */
> + status = spi_sync(spi, &message);
> + if (status == 0)
> + {
> + status = message.status;
> + }
> + else
> + {
> + return status;
> + }
should be cleaner in this way:
if (status != 0)
return status;
*data = chip->rx_buf[1];
return message.status;
> +static int ds1390_get_datetime(struct device *dev, struct rtc_time *dt)
> +{
> + struct spi_device *spi = to_spi_device(dev);
> + struct ds1390 *chip = dev_get_drvdata(dev);
> + struct spi_message message;
> + struct spi_transfer xfer;
> + int status;
> +
> + /* build the message */
> + spi_message_init(&message);
> + memset(&xfer, 0, sizeof(xfer));
> + xfer.len = 1 + 7; /* read command + 7 registers */
> + xfer.tx_buf = chip->buf;
> + xfer.rx_buf = chip->buf;
the buffer mentioned above.
> + chip->buf[0] = DS1390_REG_SECONDS;
> + spi_message_add_tail(&xfer, &message);
> +
> + /* do the i/o */
> + status = spi_sync(spi, &message);
> + if (status == 0)
> + {
> + status = message.status;
> + }
> + else
> + {
> + return status;
> + }
ditto.
> + /* The chip sends data in this order:
> + * Seconds, Minutes, Hours, Day, Date, Month / Century, Year */
> + dt->tm_sec = BCD2BIN(chip->buf[1]);
> + dt->tm_min = BCD2BIN(chip->buf[2]);
> + dt->tm_hour = BCD2BIN(chip->buf[3]);
> + dt->tm_wday = BCD2BIN(chip->buf[4]);
> + dt->tm_mday = BCD2BIN(chip->buf[5]);
> + /* mask off century bit */
> + dt->tm_mon = BCD2BIN(chip->buf[6] & 0x7f) - 1;
> + /* adjust for century bit */
> + dt->tm_year = BCD2BIN(chip->buf[7]) + ((chip->buf[6] & 0x80) ? 100 : 0);
> +
> + return 0;
> +}
> +
> +static int ds1390_set_datetime(struct device *dev, struct rtc_time *dt)
> +{
> + struct spi_device *spi = to_spi_device(dev);
> + struct ds1390 *chip = dev_get_drvdata(dev);
> + struct spi_message message;
> + struct spi_transfer xfer;
> + int status;
> +
> + /* build the message */
> + spi_message_init(&message);
> + memset(&xfer, 0, sizeof(xfer));
> + xfer.len = 1 + 8; /* write command + 8 registers */
> + xfer.tx_buf = chip->buf;
> + xfer.rx_buf = chip->buf;
> + chip->buf[0] = DS1390_REG_SECONDS | 0x80;
> + chip->buf[1] = BIN2BCD(dt->tm_sec);
> + chip->buf[2] = BIN2BCD(dt->tm_min);
> + chip->buf[3] = BIN2BCD(dt->tm_hour);
> + chip->buf[4] = BIN2BCD(dt->tm_wday);
> + chip->buf[5] = BIN2BCD(dt->tm_mday);
> + chip->buf[6] = BIN2BCD(dt->tm_mon + 1) | ((dt->tm_year > 99) ? 0x80 : 0x00);
> + chip->buf[7] = BIN2BCD(dt->tm_year % 100);
> + spi_message_add_tail(&xfer, &message);
> +
> + /* do the i/o */
> + status = spi_sync(spi, &message);
> + if (status == 0)
> + {
> + status = message.status;
> + }
> + else
> + {
> + return status;
> + }
if status == 0, status is not used anymore, so you can
just return if != 0;
> + return 0;
> +}
> +
> +static int ds1390_read_time(struct device *dev, struct rtc_time *tm)
> +{
> + return ds1390_get_datetime(dev, tm);
> +}
> +
> +static int ds1390_set_time(struct device *dev, struct rtc_time *tm)
> +{
> + return ds1390_set_datetime(dev, tm);
> +}
> +
> +static const struct rtc_class_ops ds1390_rtc_ops = {
> + .read_time = ds1390_read_time,
> + .set_time = ds1390_set_time,
> +};
> +
> +static int __devinit ds1390_probe(struct spi_device *spi)
> +{
> + struct rtc_device *rtc;
> + unsigned char tmp;
> + struct ds1390 *chip;
> + int res;
> +
> + printk("DS1390 SPI RTC driver\n");
> +
> + rtc = rtc_device_register("ds1390",
> + &spi->dev, &ds1390_rtc_ops, THIS_MODULE);
> + if (IS_ERR(rtc))
> + {
> + printk("RTC : unable to register device\n");
> + return PTR_ERR(rtc);
> + }
> +
> + spi->mode = SPI_MODE_3;
> + spi->bits_per_word = 8;
> + spi_setup(spi);
> +
> + chip = kzalloc(sizeof *chip, GFP_KERNEL);
> + if (!chip) {
> + printk("RTC : unable to allocate device memory\n");
> + rtc_device_unregister(rtc);
> + return -ENOMEM;
> + }
> + chip->rtc = rtc;
> + dev_set_drvdata(&spi->dev, chip);
> +
> + res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp);
> + if (res) {
> + printk("RTC : unable to read device\n");
> + rtc_device_unregister(rtc);
> + return res;
> + }
> +
> + return 0;
> +}
> +
> +static int __devexit ds1390_remove(struct spi_device *spi)
> +{
> + struct ds1390 *chip = platform_get_drvdata(spi);
> + struct rtc_device *rtc = chip->rtc;
> +
> + if (rtc)
> + rtc_device_unregister(rtc);
> +
> + kfree(chip);
> +
> + return 0;
> +}
> +
> +static struct spi_driver ds1390_driver = {
> + .driver = {
> + .name = "rtc-ds1390",
> + .bus = &spi_bus_type,
> + .owner = THIS_MODULE,
> + },
> + .probe = ds1390_probe,
> + .remove = __devexit_p(ds1390_remove),
> +};
> +
> +static __init int ds1390_init(void)
> +{
> + return spi_register_driver(&ds1390_driver);
> +}
> +module_init(ds1390_init);
> +
> +static __exit void ds1390_exit(void)
> +{
> + spi_unregister_driver(&ds1390_driver);
> +}
> +module_exit(ds1390_exit);
> +
> +MODULE_DESCRIPTION ("DS1390 SPI RTC driver");
> +MODULE_AUTHOR ("Mark Jackson");
you email here please.
> +MODULE_LICENSE ("GPL");
--
Best regards,
Alessandro Zummo,
Tower Technologies - Torino, Italy
http://www.towertech.it
David ... please see comments below regarding spi buffers ...
Regards
Mark
Alessandro Zummo wrote:
> On Tue, 14 Oct 2008 09:05:18 +0100
> Mark Jackson <[email protected]> wrote:
>
> Hi Mark,
>
> a few notes below:
>
>> +#include <linux/module.h>
>> +#include <linux/version.h>
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/init.h>
>> +#include <linux/rtc.h>
>> +#include <linux/spi/spi.h>
>> +#include <linux/bcd.h>
>> +#include <linux/delay.h>
>
> Please check that you require all of those includes.
>
>
>> +struct ds1390
>> +{
>> + struct rtc_device *rtc;
>> + u8 buf[9]; /* cmd + 8 registers */
>> + u8 tx_buf[2];
>> + u8 rx_buf[2];
>> +};
>> +
>> +static void ds1390_set_reg(struct device *dev, unsigned char address,
>> + unsigned char data)
>> +{
>> + struct spi_device *spi = to_spi_device(dev);
>> + unsigned char buf[2];
>> +
>> + /* MSB must be '1' to write */
>> + buf[0] = address | 0x80;
>> + buf[1] = data;
>> +
>> + spi_write(spi, buf, 2);
>> +}
>> +
>> +static int ds1390_get_reg(struct device *dev, unsigned char address,
>> + unsigned char *data)
>> +{
>> + struct spi_device *spi = to_spi_device(dev);
>> + struct ds1390 *chip = dev_get_drvdata(dev);
>> + struct spi_message message;
>> + struct spi_transfer xfer;
>> + int status;
>> +
>> + if (!data)
>> + return -EINVAL;
>> +
>> + /* Build our spi message */
>> + spi_message_init(&message);
>> + memset(&xfer, 0, sizeof(xfer));
>> + xfer.len = 2;
>> + /* Can tx_buf and rx_buf be equal? The doc in spi.h is not sure... */
>> + xfer.tx_buf = chip->tx_buf;
>> + xfer.rx_buf = chip->rx_buf;
>
> you use the same buffer a few functions below. either
> one way or the other. please investigate with the spi subsystem maintainer.
David,
Just to double check (as per Alessandro's suggestion), is this okay use of the
spi buffers ?
I took the code from an existing RTC driver (rtc-max6902), so I am assuming that
this code has already passed judgement.
>
>
>> +
>> + /* Clear MSB to indicate read */
>> + chip->tx_buf[0] = address & 0x7f;
>> +
>> + spi_message_add_tail(&xfer, &message);
>> +
>> + /* do the i/o */
>> + status = spi_sync(spi, &message);
>> + if (status == 0)
>> + {
>> + status = message.status;
>> + }
>> + else
>> + {
>> + return status;
>> + }
>
> should be cleaner in this way:
>
> if (status != 0)
> return status;
>
> *data = chip->rx_buf[1];
>
> return message.status;
>
>
>> +static int ds1390_get_datetime(struct device *dev, struct rtc_time *dt)
>> +{
>> + struct spi_device *spi = to_spi_device(dev);
>> + struct ds1390 *chip = dev_get_drvdata(dev);
>> + struct spi_message message;
>> + struct spi_transfer xfer;
>> + int status;
>> +
>> + /* build the message */
>> + spi_message_init(&message);
>> + memset(&xfer, 0, sizeof(xfer));
>> + xfer.len = 1 + 7; /* read command + 7 registers */
>> + xfer.tx_buf = chip->buf;
>> + xfer.rx_buf = chip->buf;
>
> the buffer mentioned above.
... see text above ...
>
>
>> + chip->buf[0] = DS1390_REG_SECONDS;
>> + spi_message_add_tail(&xfer, &message);
>> +
>> + /* do the i/o */
>> + status = spi_sync(spi, &message);
>> + if (status == 0)
>> + {
>> + status = message.status;
>> + }
>> + else
>> + {
>> + return status;
>> + }
>
> ditto.
>
>> + /* The chip sends data in this order:
>> + * Seconds, Minutes, Hours, Day, Date, Month / Century, Year */
>> + dt->tm_sec = BCD2BIN(chip->buf[1]);
>> + dt->tm_min = BCD2BIN(chip->buf[2]);
>> + dt->tm_hour = BCD2BIN(chip->buf[3]);
>> + dt->tm_wday = BCD2BIN(chip->buf[4]);
>> + dt->tm_mday = BCD2BIN(chip->buf[5]);
>> + /* mask off century bit */
>> + dt->tm_mon = BCD2BIN(chip->buf[6] & 0x7f) - 1;
>> + /* adjust for century bit */
>> + dt->tm_year = BCD2BIN(chip->buf[7]) + ((chip->buf[6] & 0x80) ? 100 : 0);
>> +
>> + return 0;
>> +}
>> +
>> +static int ds1390_set_datetime(struct device *dev, struct rtc_time *dt)
>> +{
>> + struct spi_device *spi = to_spi_device(dev);
>> + struct ds1390 *chip = dev_get_drvdata(dev);
>> + struct spi_message message;
>> + struct spi_transfer xfer;
>> + int status;
>> +
>> + /* build the message */
>> + spi_message_init(&message);
>> + memset(&xfer, 0, sizeof(xfer));
>> + xfer.len = 1 + 8; /* write command + 8 registers */
>> + xfer.tx_buf = chip->buf;
>> + xfer.rx_buf = chip->buf;
... and I guess here as well ... ???
>> + chip->buf[0] = DS1390_REG_SECONDS | 0x80;
>> + chip->buf[1] = BIN2BCD(dt->tm_sec);
>> + chip->buf[2] = BIN2BCD(dt->tm_min);
>> + chip->buf[3] = BIN2BCD(dt->tm_hour);
>> + chip->buf[4] = BIN2BCD(dt->tm_wday);
>> + chip->buf[5] = BIN2BCD(dt->tm_mday);
>> + chip->buf[6] = BIN2BCD(dt->tm_mon + 1) | ((dt->tm_year > 99) ? 0x80 : 0x00);
>> + chip->buf[7] = BIN2BCD(dt->tm_year % 100);
>> + spi_message_add_tail(&xfer, &message);
>> +
>> + /* do the i/o */
>> + status = spi_sync(spi, &message);
>> + if (status == 0)
>> + {
>> + status = message.status;
>> + }
>> + else
>> + {
>> + return status;
>> + }
>
> if status == 0, status is not used anymore, so you can
> just return if != 0;
>
>> + return 0;
>> +}
>> +
>> +static int ds1390_read_time(struct device *dev, struct rtc_time *tm)
>> +{
>> + return ds1390_get_datetime(dev, tm);
>> +}
>> +
>> +static int ds1390_set_time(struct device *dev, struct rtc_time *tm)
>> +{
>> + return ds1390_set_datetime(dev, tm);
>> +}
>> +
>> +static const struct rtc_class_ops ds1390_rtc_ops = {
>> + .read_time = ds1390_read_time,
>> + .set_time = ds1390_set_time,
>> +};
>> +
>> +static int __devinit ds1390_probe(struct spi_device *spi)
>> +{
>> + struct rtc_device *rtc;
>> + unsigned char tmp;
>> + struct ds1390 *chip;
>> + int res;
>> +
>> + printk("DS1390 SPI RTC driver\n");
>> +
>> + rtc = rtc_device_register("ds1390",
>> + &spi->dev, &ds1390_rtc_ops, THIS_MODULE);
>> + if (IS_ERR(rtc))
>> + {
>> + printk("RTC : unable to register device\n");
>> + return PTR_ERR(rtc);
>> + }
>> +
>> + spi->mode = SPI_MODE_3;
>> + spi->bits_per_word = 8;
>> + spi_setup(spi);
>> +
>> + chip = kzalloc(sizeof *chip, GFP_KERNEL);
>> + if (!chip) {
>> + printk("RTC : unable to allocate device memory\n");
>> + rtc_device_unregister(rtc);
>> + return -ENOMEM;
>> + }
>> + chip->rtc = rtc;
>> + dev_set_drvdata(&spi->dev, chip);
>> +
>> + res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp);
>> + if (res) {
>> + printk("RTC : unable to read device\n");
>> + rtc_device_unregister(rtc);
>> + return res;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int __devexit ds1390_remove(struct spi_device *spi)
>> +{
>> + struct ds1390 *chip = platform_get_drvdata(spi);
>> + struct rtc_device *rtc = chip->rtc;
>> +
>> + if (rtc)
>> + rtc_device_unregister(rtc);
>> +
>> + kfree(chip);
>> +
>> + return 0;
>> +}
>> +
>> +static struct spi_driver ds1390_driver = {
>> + .driver = {
>> + .name = "rtc-ds1390",
>> + .bus = &spi_bus_type,
>> + .owner = THIS_MODULE,
>> + },
>> + .probe = ds1390_probe,
>> + .remove = __devexit_p(ds1390_remove),
>> +};
>> +
>> +static __init int ds1390_init(void)
>> +{
>> + return spi_register_driver(&ds1390_driver);
>> +}
>> +module_init(ds1390_init);
>> +
>> +static __exit void ds1390_exit(void)
>> +{
>> + spi_unregister_driver(&ds1390_driver);
>> +}
>> +module_exit(ds1390_exit);
>> +
>> +MODULE_DESCRIPTION ("DS1390 SPI RTC driver");
>> +MODULE_AUTHOR ("Mark Jackson");
>
> you email here please.
>
>> +MODULE_LICENSE ("GPL");
>
>
On Friday 17 October 2008, Mark Jackson wrote:
> >> +????/* Can tx_buf and rx_buf be equal? The doc in spi.h is not sure... */
> >> +????xfer.tx_buf = chip->tx_buf;
> >> +????xfer.rx_buf = chip->rx_buf;
> >
> > ?you use the same buffer a few functions below. either
> > ?one way or the other. please investigate with the spi subsystem maintainer.
>
> David,
>
> Just to double check (as per Alessandro's suggestion), is this okay use of the
> spi buffers ?
Yes. That comment deserves to be updated.
SPI does bi-directional I/O, and the underlying controller
should be able to just replace the contents of a buffer
with a spi_transfer that uses the same rx and tx buffers.
- Dave
David Brownell wrote:
> On Friday 17 October 2008, Mark Jackson wrote:
>>>> + /* Can tx_buf and rx_buf be equal? The doc in spi.h is not sure... */
>>>> + xfer.tx_buf = chip->tx_buf;
>>>> + xfer.rx_buf = chip->rx_buf;
>>> you use the same buffer a few functions below. either
>>> one way or the other. please investigate with the spi subsystem maintainer.
>> David,
>>
>> Just to double check (as per Alessandro's suggestion), is this okay use of the
>> spi buffers ?
>
> Yes. That comment deserves to be updated.
>
> SPI does bi-directional I/O, and the underlying controller
> should be able to just replace the contents of a buffer
> with a spi_transfer that uses the same rx and tx buffers.
Excellent. Thanks for the confirmation.
Regards
Mark