* [PATCH] rtc:add support for maxim rtc max6916
@ 2016-05-04 10:30 venkat.prashanth2498
2016-05-04 11:51 ` Marcus Folkesson
0 siblings, 1 reply; 5+ messages in thread
From: venkat.prashanth2498 @ 2016-05-04 10:30 UTC (permalink / raw)
To: linux-kernel; +Cc: venkat-prashanth
From: venkat-prashanth <venkat.prashanth2498@gmail.com>
This is a patch to add support for
maxim rtc max6916
Signed-off-by:Venkat Prashanth B U <venkat.prashanth2498@gmail.com>
---
Kconfig | 9 ++++
Makefile | 6 +++
rtc-max6916.c | 133 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 148 insertions(+)
create mode 100644 Kconfig
create mode 100644 Makefile
create mode 100644 rtc-max6916.c
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
new file mode 100644
index 0000000..fa7a2fa
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -0,0 +1,9 @@
+config RTC_DRV_MAX6916
+tristate "Maxim MAX6916"
+ help
+ If you say yes here you get support for the
+ Maxim MAX6916 chips.
+ This driver only supports the RTC feature, and not other chip
+ features such as alarms.
+ This driver can also be built as a module. If so, the module
+ will be called rtc‐max6916.
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
new file mode 100644
index 0000000..db34a02
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -0,0 +1,6 @@
+CONFIG_MODULE_SIG=n
+obj-m+=rtc-max6916.o
+all:
+ make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
+clean:
+ make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean
diff --git a/drivers/rtc/rtc-max6916.c b/drivers/rtc/rtc-max6916.c
new file mode 100644
index 0000000..8e9bcdc
--- a/drivers/rtc/rtc-max6916.c
+++ b/drivers/rtc/rtc-max6916.c
@@ -0,0 +1,133 @@
+/* rtc-max6916.c
+ *
+ * Driver for MAXIM max6916 Low Current, SPI Compatible
+ * Real Time Clock
+ *
+ * Author : Venkat Prashanth B U <venkat.prashanth2498@gmail.com>
+ *
+ * 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.
+ *
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/spi/spi.h>
+#include <linux/bcd.h>
+/* Registers in max6916 rtc */
+#define MAX6916_SECONDS_REG 0x01
+#define MAX6916_MINUTES_REG 0x02
+#define MAX6916_HOURS_REG 0x03
+#define MAX6916_DATE_REG 0x04
+#define MAX6916_MONTH_REG 0x05
+#define MAX6916_DAY_REG 0x06
+#define MAX6916_YEAR_REG 0x07
+#define MAX6916_CONTROL_REG 0x08
+#define MAX6916_STATUS_REG 0x0C
+#define MAX6916_CLOCK_BURST 0x00
+
+static int max6916_read_reg(struct device *dev, unsigned char address, unsigned char *data)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ *data = address | 0x80;
+ return spi_write_then_read(spi, data, 1, data, 1);
+}
+
+static int max6916_write_reg(struct device *dev, unsigned char address, unsigned char data)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ unsigned char buf[2];
+
+ buf[0] = address&0x7F;
+ buf[1] = data;
+ return spi_write_then_read(spi, buf, 2, NULL, 0);
+}
+
+static int max6916_read_time(struct device *dev, struct rtc_time *dt)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ int err;
+ unsigned char buf[8];
+
+ buf[0] = MAX6916_CLOCK_BURST | 0x80;
+ err = spi_write_then_read(spi, buf, 1, buf, 8);
+ if (err)
+ return err;
+ dt->tm_sec = bcd2bin(buf[0]);
+ dt->tm_min = bcd2bin(buf[1]);
+ dt->tm_hour = bcd2bin(buf[2] & MAX6916_CLOCK_BURST);
+ dt->tm_mday = bcd2bin(buf[3]);
+ dt->tm_mon = bcd2bin(buf[4]) - 1;
+ dt->tm_wday = bcd2bin(buf[5]) - 1;
+ dt->tm_year = bcd2bin(buf[6]) + 100;
+ return rtc_valid_tm(dt);
+}
+static int max6916_set_time(struct device *dev, struct rtc_time *dt)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ unsigned char buf[9];
+
+ buf[0] = MAX6916_CLOCK_BURST & 0x7F;
+ buf[1] = bcd2bin(dt->tm_sec);
+ buf[2] = bcd2bin(dt->tm_min);
+ buf[3] = (bcd2bin(dt->tm_hour)&MAX6916_CLOCK_BURST);
+ buf[4] = bcd2bin(dt->tm_mday);
+ buf[5] = bcd2bin(dt->tm_mon + 1);
+ buf[6] = bcd2bin(dt->tm_wday + 1);
+ /* year from 1900-range of 100 in rtc from 00 to 99 */
+ dt->tm_year = dt->tm_year % 100;
+ buf[7] = bcd2bin(dt->tm_year);
+ buf[8] = bcd2bin(0x00);
+ /* write the rtc settings */
+ return spi_write_then_read(spi, buf, 9, NULL, 0);
+}
+static const struct rtc_class_ops max6916_rtc_ops = {
+ .read_time = max6916_read_time,
+ .set_time = max6916_set_time,
+};
+static int max6916_probe(struct spi_device *spi)
+{
+ struct rtc_device *rtc;
+ unsigned char data;
+ int res;
+
+ /* spi setup with max6916 in mode 3 and bits per word as 8 */
+ spi->mode = SPI_MODE_3;
+ spi->bits_per_word = 8;
+ spi_setup(spi);
+ /* RTC Settings */
+ res = max6916_read_reg(&spi->dev, MAX6916_SECONDS_REG, &data);
+ if (res)
+ return res;
+ /* Disable the write protect of rtc */
+ max6916_read_reg(&spi->dev, MAX6916_CONTROL_REG, &data);
+ data = data & ~(1<<7);
+ max6916_write_reg(&spi->dev, MAX6916_CONTROL_REG, data);
+ /* Enable the oscillator,disable the oscillator stop flag,and glitch filter to reduce current consumption */
+ max6916_read_reg(&spi->dev, MAX6916_STATUS_REG, &data);
+ data = data & 0x1B;
+ max6916_write_reg(&spi->dev, MAX6916_STATUS_REG, data);
+ /* display the settings */
+ max6916_read_reg(&spi->dev, MAX6916_CONTROL_REG, &data);
+ dev_info(&spi->dev, "MAX6916 RTC CTRL Reg = 0x%02x\n", data);
+ max6916_read_reg(&spi->dev, MAX6916_STATUS_REG, &data);
+ dev_info(&spi->dev, "MAX6916 RTC Status Reg = 0x%02x\n", data);
+ rtc = devm_rtc_device_register(&spi->dev, "max6916", &max6916_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+ spi_set_drvdata(spi, rtc);
+ return 0;
+}
+static struct spi_driver max6916_driver = {
+ .driver = {
+ .name = "max6916",
+ },
+ .probe = max6916_probe,
+};
+module_spi_driver(max6916_driver);
+MODULE_DESCRIPTION("MAX6916 SPI RTC DRIVER");
+MODULE_AUTHOR("Venkat Prashanth B U <venkat.prashanth2498@gmail.com>");
+MODULE_LICENSE("GPL v2");
--
1.9.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] rtc:add support for maxim rtc max6916
2016-05-04 10:30 [PATCH] rtc:add support for maxim rtc max6916 venkat.prashanth2498
@ 2016-05-04 11:51 ` Marcus Folkesson
0 siblings, 0 replies; 5+ messages in thread
From: Marcus Folkesson @ 2016-05-04 11:51 UTC (permalink / raw)
To: venkat.prashanth2498; +Cc: linux-kernel
[-- Attachment #1: Type: text/plain, Size: 5466 bytes --]
On Wed, May 04, 2016 at 03:30:17AM -0700, venkat.prashanth2498@gmail.com wrote:
> From: venkat-prashanth <venkat.prashanth2498@gmail.com>
>
> This is a patch to add support for
> maxim rtc max6916
> Signed-off-by:Venkat Prashanth B U <venkat.prashanth2498@gmail.com>
> ---
> Kconfig | 9 ++++
> Makefile | 6 +++
> rtc-max6916.c | 133 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 148 insertions(+)
> create mode 100644 Kconfig
> create mode 100644 Makefile
> create mode 100644 rtc-max6916.c
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> new file mode 100644
> index 0000000..fa7a2fa
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -0,0 +1,9 @@
> +config RTC_DRV_MAX6916
> +tristate "Maxim MAX6916"
> + help
> + If you say yes here you get support for the
> + Maxim MAX6916 chips.
> + This driver only supports the RTC feature, and not other chip
> + features such as alarms.
> + This driver can also be built as a module. If so, the module
> + will be called rtc‐max6916.
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> new file mode 100644
> index 0000000..db34a02
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -0,0 +1,6 @@
> +CONFIG_MODULE_SIG=n
> +obj-m+=rtc-max6916.o
> +all:
> + make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
> +clean:
> + make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean
Something is wrong here.
Kconfig and Makefile should really not be created, and the Makefile
seems like an out-of-tree-Makefile?
Clone a proper working tree and look how it should be written.
> + *
> + */
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/device.h>
> +#include <linux/platform_device.h>
> +#include <linux/rtc.h>
> +#include <linux/spi/spi.h>
> +#include <linux/bcd.h>
> +/* Registers in max6916 rtc */
> +#define MAX6916_SECONDS_REG 0x01
> +#define MAX6916_MINUTES_REG 0x02
> +#define MAX6916_HOURS_REG 0x03
> +#define MAX6916_DATE_REG 0x04
> +#define MAX6916_MONTH_REG 0x05
> +static int max6916_read_time(struct device *dev, struct rtc_time *dt)
> +{
> + struct spi_device *spi = to_spi_device(dev);
> + int err;
> + unsigned char buf[8];
> +
> + buf[0] = MAX6916_CLOCK_BURST | 0x80;
> + err = spi_write_then_read(spi, buf, 1, buf, 8);
> + if (err)
> + return err;
> + dt->tm_sec = bcd2bin(buf[0]);
> + dt->tm_min = bcd2bin(buf[1]);
> + dt->tm_hour = bcd2bin(buf[2] & MAX6916_CLOCK_BURST);
> + dt->tm_mday = bcd2bin(buf[3]);
> + dt->tm_mon = bcd2bin(buf[4]) - 1;
> + dt->tm_wday = bcd2bin(buf[5]) - 1;
> + dt->tm_year = bcd2bin(buf[6]) + 100;
> + return rtc_valid_tm(dt);
> +}
> +static int max6916_set_time(struct device *dev, struct rtc_time *dt)
> +{
> + struct spi_device *spi = to_spi_device(dev);
> + unsigned char buf[9];
> +
> + buf[0] = MAX6916_CLOCK_BURST & 0x7F;
> + buf[1] = bcd2bin(dt->tm_sec);
> + buf[2] = bcd2bin(dt->tm_min);
> + buf[3] = (bcd2bin(dt->tm_hour)&MAX6916_CLOCK_BURST);
> + buf[4] = bcd2bin(dt->tm_mday);
> + buf[5] = bcd2bin(dt->tm_mon + 1);
> + buf[6] = bcd2bin(dt->tm_wday + 1);
> + /* year from 1900-range of 100 in rtc from 00 to 99 */
> + dt->tm_year = dt->tm_year % 100;
> + buf[7] = bcd2bin(dt->tm_year);
> + buf[8] = bcd2bin(0x00);
> + /* write the rtc settings */
> + return spi_write_then_read(spi, buf, 9, NULL, 0);
> +}
> +static const struct rtc_class_ops max6916_rtc_ops = {
> + .read_time = max6916_read_time,
> + .set_time = max6916_set_time,
> +};
> +static int max6916_probe(struct spi_device *spi)
> +{
> + struct rtc_device *rtc;
> + unsigned char data;
> + int res;
> +
> + /* spi setup with max6916 in mode 3 and bits per word as 8 */
> + spi->mode = SPI_MODE_3;
> + spi->bits_per_word = 8;
> + spi_setup(spi);
> + /* RTC Settings */
> + res = max6916_read_reg(&spi->dev, MAX6916_SECONDS_REG, &data);
> + if (res)
> + return res;
> + /* Disable the write protect of rtc */
> + max6916_read_reg(&spi->dev, MAX6916_CONTROL_REG, &data);
> + data = data & ~(1<<7);
> + max6916_write_reg(&spi->dev, MAX6916_CONTROL_REG, data);
> + /* Enable the oscillator,disable the oscillator stop flag,and glitch filter to reduce current consumption */
> + max6916_read_reg(&spi->dev, MAX6916_STATUS_REG, &data);
> + data = data & 0x1B;
> + max6916_write_reg(&spi->dev, MAX6916_STATUS_REG, data);
> + /* display the settings */
> + max6916_read_reg(&spi->dev, MAX6916_CONTROL_REG, &data);
> + dev_info(&spi->dev, "MAX6916 RTC CTRL Reg = 0x%02x\n", data);
> + max6916_read_reg(&spi->dev, MAX6916_STATUS_REG, &data);
> + dev_info(&spi->dev, "MAX6916 RTC Status Reg = 0x%02x\n", data);
> + rtc = devm_rtc_device_register(&spi->dev, "max6916", &max6916_rtc_ops, THIS_MODULE);
> + if (IS_ERR(rtc))
> + return PTR_ERR(rtc);
> + spi_set_drvdata(spi, rtc);
> + return 0;
> +}
> +static struct spi_driver max6916_driver = {
> + .driver = {
> + .name = "max6916",
> + },
> + .probe = max6916_probe,
> +};
> +module_spi_driver(max6916_driver);
> +MODULE_DESCRIPTION("MAX6916 SPI RTC DRIVER");
> +MODULE_AUTHOR("Venkat Prashanth B U <venkat.prashanth2498@gmail.com>");
> +MODULE_LICENSE("GPL v2");
An overall comment, the patch is hard to parse.
Please seperate logical code sections with an empty line and use
indentation after if-statements.
Cheers,
Marcus Folkesson
> --
> 1.9.2
>
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] rtc: add support for maxim rtc max6916
2016-05-05 10:09 [PATCH] rtc: add " venkat.prashanth2498
@ 2016-05-05 10:53 ` Alexandre Belloni
0 siblings, 0 replies; 5+ messages in thread
From: Alexandre Belloni @ 2016-05-05 10:53 UTC (permalink / raw)
To: venkat.prashanth2498; +Cc: a.zummo, marcus.folkesson, rtc-linux, linux-kernel
Hi,
On 05/05/2016 at 03:09:49 -0700, venkat.prashanth2498@gmail.com wrote :
> From: venkat-prashanth <venkat.prashanth2498@gmail.com>
>
> This a patch to add support for
> maxim rtc max6916
>
> Signed-off-by: Venkat Prashanth B U <venkat.prashanth2498@gmail.com>
> ---
> ---
> drivers/rtc/rtc-max6916.c | 165 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 165 insertions(+)
>
This is the second version you send since my comments. Please include
the patch version in the subject line.
Also, you need to include a changelog.
Finally, you didn't address many of my comments please do so before
submitting again.
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH] rtc: add support for maxim rtc max6916
@ 2016-05-05 10:09 venkat.prashanth2498
2016-05-05 10:53 ` Alexandre Belloni
0 siblings, 1 reply; 5+ messages in thread
From: venkat.prashanth2498 @ 2016-05-05 10:09 UTC (permalink / raw)
To: a.zummo
Cc: marcus.folkesson, alexandre.belloni, rtc-linux, linux-kernel,
venkat-prashanth
From: venkat-prashanth <venkat.prashanth2498@gmail.com>
This a patch to add support for
maxim rtc max6916
Signed-off-by: Venkat Prashanth B U <venkat.prashanth2498@gmail.com>
---
---
drivers/rtc/rtc-max6916.c | 165 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 165 insertions(+)
diff --git a/drivers/rtc/rtc-max6916.c b/drivers/rtc/rtc-max6916.c
index e69de29..2085151 100644
--- a/drivers/rtc/rtc-max6916.c
+++ b/drivers/rtc/rtc-max6916.c
@@ -0,0 +1,165 @@
+/* rtc-max6916.c
+ *
+ * Driver for MAXIM max6916 Low Current, SPI Compatible
+ * Real Time Clock
+ *
+ * Author : Venkat Prashanth B U <venkat.prashanth2498@gmail.com>
+ *
+ * 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.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/spi/spi.h>
+#include <linux/bcd.h>
+
+/* Registers in max6916 rtc */
+
+#define MAX6916_SECONDS_REG 0x01
+#define MAX6916_MINUTES_REG 0x02
+#define MAX6916_HOURS_REG 0x03
+#define MAX6916_DATE_REG 0x04
+#define MAX6916_MONTH_REG 0x05
+#define MAX6916_DAY_REG 0x06
+#define MAX6916_YEAR_REG 0x07
+#define MAX6916_CONTROL_REG 0x08
+#define MAX6916_STATUS_REG 0x0C
+#define MAX6916_CLOCK_BURST 0x00
+
+static int max6916_read_reg(struct device *dev, unsigned char address,
+ unsigned char *data)
+{
+ struct spi_device *spi = to_spi_device(dev);
+
+ *data = address | 0x80;
+
+ return spi_write_then_read(spi, data, 1, data, 1);
+}
+
+static int max6916_write_reg(struct device *dev, unsigned char address,
+ unsigned char data)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ unsigned char buf[2];
+
+ buf[0] = address&0x7F;
+ buf[1] = data;
+
+ return spi_write_then_read(spi, buf, 2, NULL, 0);
+}
+
+static int max6916_read_time(struct device *dev, struct rtc_time *dt)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ int err;
+ unsigned char buf[8];
+
+ buf[0] = MAX6916_CLOCK_BURST | 0x80;
+
+ err = spi_write_then_read(spi, buf, 1, buf, 8);
+ if (err)
+ return err;
+
+ dt->tm_sec = bcd2bin(buf[0]);
+ dt->tm_min = bcd2bin(buf[1]);
+ dt->tm_hour = bcd2bin(buf[2] & MAX6916_CLOCK_BURST);
+ dt->tm_mday = bcd2bin(buf[3]);
+ dt->tm_mon = bcd2bin(buf[4]) - 1;
+ dt->tm_wday = bcd2bin(buf[5]) - 1;
+ dt->tm_year = bcd2bin(buf[6]) + 100;
+
+ return rtc_valid_tm(dt);
+}
+
+static int max6916_set_time(struct device *dev, struct rtc_time *dt)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ unsigned char buf[9];
+
+ buf[0] = MAX6916_CLOCK_BURST & 0x7F;
+ buf[1] = bcd2bin(dt->tm_sec);
+ buf[2] = bcd2bin(dt->tm_min);
+ buf[3] = (bcd2bin(dt->tm_hour)&MAX6916_CLOCK_BURST);
+ buf[4] = bcd2bin(dt->tm_mday);
+ buf[5] = bcd2bin(dt->tm_mon + 1);
+ buf[6] = bcd2bin(dt->tm_wday + 1);
+
+ /* year from 1900-range of 100 in rtc from 00 to 99 */
+ dt->tm_year = dt->tm_year % 100;
+
+ buf[7] = bcd2bin(dt->tm_year);
+ buf[8] = bcd2bin(0x00);
+
+ /* write the rtc settings */
+ return spi_write_then_read(spi, buf, 9, NULL, 0);
+}
+
+static const struct rtc_class_ops max6916_rtc_ops = {
+ .read_time = max6916_read_time,
+ .set_time = max6916_set_time,
+};
+
+static int max6916_probe(struct spi_device *spi)
+{
+ struct rtc_device *rtc;
+ unsigned char data;
+ int res;
+
+ /* spi setup with max6916 in mode 3 and bits per word as 8 */
+ spi->mode = SPI_MODE_3;
+ spi->bits_per_word = 8;
+ spi_setup(spi);
+
+ /* RTC Settings */
+ res = max6916_read_reg(&spi->dev, MAX6916_SECONDS_REG, &data);
+
+ if (res)
+ return res;
+
+ /* Disable the write protect of rtc */
+ max6916_read_reg(&spi->dev, MAX6916_CONTROL_REG, &data);
+ data = data & ~(1<<7);
+ max6916_write_reg(&spi->dev, MAX6916_CONTROL_REG, data);
+
+ /* Enable the oscillator,disable the oscillator stop flag,
+ and glitch filter to reduce current consumption */
+ max6916_read_reg(&spi->dev, MAX6916_STATUS_REG, &data);
+ data = data & 0x1B;
+ max6916_write_reg(&spi->dev, MAX6916_STATUS_REG, data);
+
+ /* display the settings */
+ max6916_read_reg(&spi->dev, MAX6916_CONTROL_REG, &data);
+ dev_info(&spi->dev, "MAX6916 RTC CTRL Reg = 0x%02x\n", data);
+
+ max6916_read_reg(&spi->dev, MAX6916_STATUS_REG, &data);
+ dev_info(&spi->dev, "MAX6916 RTC Status Reg = 0x%02x\n", data);
+
+ rtc = devm_rtc_device_register(&spi->dev, "max6916",
+ &max6916_rtc_ops, THIS_MODULE);
+
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+
+ spi_set_drvdata(spi, rtc);
+
+ return 0;
+}
+
+static struct spi_driver max6916_driver = {
+ .driver = {
+ .name = "max6916",
+ },
+ .probe = max6916_probe,
+};
+
+module_spi_driver(max6916_driver);
+
+MODULE_DESCRIPTION("MAX6916 SPI RTC DRIVER");
+MODULE_AUTHOR("Venkat Prashanth B U <venkat.prashanth2498@gmail.com>");
+MODULE_LICENSE("GPL v2");
--
1.9.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH] rtc: add support for maxim rtc max6916
@ 2016-05-03 11:07 venkat.prashanth2498
0 siblings, 0 replies; 5+ messages in thread
From: venkat.prashanth2498 @ 2016-05-03 11:07 UTC (permalink / raw)
To: linux-kernel; +Cc: venkat-prashanth
From: venkat-prashanth <venkat.prashanth2498@gmail.com>
This is a patch to add support for
maxim rtc max6916
Signed-off-by:Venkat Prashanth B U <venkat.prashanth2498@gmail.com>
---
---
rtc-max6916.c | 157 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
txtfile | 11 ++++
2 files changed, 168 insertions(+)
create mode 100644 rtc-max6916.c
create mode 100644 txtfile
diff --git a/rtc-max6916.c b/rtc-max6916.c
new file mode 100644
index 0000000..7fabaa2
--- /dev/null
+++ b/rtc-max6916.c
@@ -0,0 +1,157 @@
+/* rtc-max6916.c
+ *
+ * Driver for MAXIM max6916 Low Current, SPI Compatible
+ * Real Time Clock
+ *
+ * Author : Venkat Prashanth B U <venkat.prashanth2498@gmail.com>
+ *
+ * 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.
+ *
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/spi/spi.h>
+#include <linux/bcd.h>
+
+/* Registers in max6916 rtc */
+
+#define MAX6916_SECONDS_REG 0x01
+#define MAX6916_MINUTES_REG 0x02
+#define MAX6916_HOURS_REG 0x03
+#define MAX6916_DATE_REG 0x04
+#define MAX6916_MONTH_REG 0x05
+#define MAX6916_DAY_REG 0x06
+#define MAX6916_YEAR_REG 0x07
+#define MAX6916_CONTROL_REG 0x08
+#define MAX6916_STATUS_REG 0x0C
+#define MAX6916_CLOCK_BURST 0x00
+#define ADDRESS_REG 0x70
+#define DATA_REG 0x71
+#define ADDRESS_REG_MASK 0xe0
+
+static unsigned char get_rtc(unsigned char addr)
+{
+ outb(addr, ADDRESS_REG);
+ return inb(DATA_REG);
+}
+
+static int max6916_read_reg(struct device *dev, unsigned char address,unsigned char *data)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ *data = address | 0x80;
+ return spi_write_then_read(spi, data, 1, data, 1);
+}
+
+static int max6916_write_reg(struct device *dev, unsigned char address,unsigned char data)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ unsigned char buf[2];
+ buf[0] = address & 0x7F;
+ buf[1] = data;
+ return spi_write_then_read(spi, buf, 2, NULL, 0);
+}
+
+static int max6916_read_time(struct device *dev, struct rtc_time *dt)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ int err;
+ unsigned char buf[8];
+ buf[0] = MAX6916_CLOCK_BURST | 0x80;
+ err = spi_write_then_read(spi, buf, 1, buf, 8);
+ if (err)
+ return err;
+ dt->tm_sec = get_rtc(buf[0]);
+ dt->tm_min = get_rtc(buf[1]);
+ dt->tm_hour = get_rtc(buf[2] & 0x00);
+ dt->tm_mday = get_rtc(buf[3]);
+ dt->tm_mon = get_rtc(buf[4]) - 1;
+ dt->tm_wday = get_rtc(buf[5]) - 1;
+ dt->tm_year = get_rtc(buf[6]) + 100;
+ return rtc_valid_tm(dt);
+}
+
+static int max6916_set_time(struct device *dev, struct rtc_time *dt)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ unsigned char buf[9];
+
+ buf[0] = MAX6916_CLOCK_BURST & 0x7F;
+ buf[1] = bcd2bin(dt->tm_sec);
+ buf[2] = bcd2bin(dt->tm_min);
+ buf[3] = (bcd2bin(dt->tm_hour) & 0x00);
+ buf[4] = bcd2bin(dt->tm_mday);
+ buf[5] = bcd2bin(dt->tm_mon + 1);
+ buf[6] = bcd2bin(dt->tm_wday + 1);
+
+ /* year in linux is from 1900 i.e in range of 100
+ in rtc it is from 00 to 99 */
+ dt->tm_year = dt->tm_year % 100;
+
+ buf[7] = bcd2bin(dt->tm_year);
+ buf[8] = bcd2bin(0x00);
+
+ /* write the rtc settings */
+ return spi_write_then_read(spi, buf, 9, NULL, 0);
+}
+
+static const struct rtc_class_ops max6916_rtc_ops = {
+ .read_time = max6916_read_time,
+ .set_time = max6916_set_time,
+};
+
+static int max6916_probe(struct spi_device *spi)
+{
+ struct rtc_device *rtc;
+ unsigned char data;
+ int res;
+
+ /* spi setup with max6916 in mode 3 and bits per word as 8 */
+ spi->mode = SPI_MODE_3;
+ spi->bits_per_word = 8;
+ spi_setup(spi);
+
+ /* RTC Settings */
+ res = max6916_read_reg(&spi->dev, MAX6916_SECONDS_REG, &data);
+ if (res)
+ return res;
+ /* Disable the write protect of rtc */
+ max6916_read_reg(&spi->dev, MAX6916_CONTROL_REG, &data);
+ data = data & ~(1<<7);
+ max6916_write_reg(&spi->dev, MAX6916_CONTROL_REG, data);
+ /* Enable the oscillator , disable the oscillator stop flag,
+ and glitch filter to reduce current consumption */
+ max6916_read_reg(&spi->dev, MAX6916_STATUS_REG, &data);
+ data = data & 0x1B;
+ max6916_write_reg(&spi->dev, MAX6916_STATUS_REG, data);
+ /* display the settings */
+ max6916_read_reg(&spi->dev, MAX6916_CONTROL_REG, &data);
+ dev_info(&spi->dev, "MAX6916 RTC CTRL Reg = 0x%02x\n", data);
+ max6916_read_reg(&spi->dev, MAX6916_STATUS_REG, &data);
+ dev_info(&spi->dev, "MAX6916 RTC Status Reg = 0x%02x\n", data);
+ rtc = devm_rtc_device_register(&spi->dev, "max6916",&max6916_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+ spi_set_drvdata(spi, rtc);
+
+ return 0;
+}
+static struct spi_driver max6916_driver = {
+ .driver = {
+ .name = "max6916",
+ },
+ .probe = max6916_probe,
+};
+static void __exit rtc_exit(void)
+{
+ pr_info("rtc module unloaded\n");
+}
+
+module_spi_driver(max6916_driver);
+MODULE_DESCRIPTION("MAX6916 SPI RTC DRIVER");
+MODULE_AUTHOR("Venkat Prashanth B U <venkat.prashanth2498@gmail.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/txtfile b/txtfile
new file mode 100644
index 0000000..1604409
--- /dev/null
+++ b/txtfile
@@ -0,0 +1,11 @@
+config RTC_DRV_MAX6916
+tristate "Maxim MAX6916"
+
+help
+ If you say yes here you get support for the
+ Maxim MAX6916 chips.
+ This driver only supports the RTC feature, and not other chip
+ features such as alarms.
+ This driver can also be built as a module. If so, the module
+ will be called rtc‐max6916.
--
1.9.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
end of thread, other threads:[~2016-05-05 10:53 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2016-05-04 10:30 [PATCH] rtc:add support for maxim rtc max6916 venkat.prashanth2498
2016-05-04 11:51 ` Marcus Folkesson
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2016-05-05 10:09 [PATCH] rtc: add " venkat.prashanth2498
2016-05-05 10:53 ` Alexandre Belloni
2016-05-03 11:07 venkat.prashanth2498
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