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Date: Tue, 18 Oct 2016 07:47:24 -0700
From: VENKAT PRASHANTH B U <venkat.prashanth2498@...il.com>
To: alexandre.belloni@...e-electrons.com
Cc: linux-kernel@...r.kernel.org, a.zummo@...ertech.it,
VENKAT PRASHANTH B U <venkat.prashanth2498@...il.com>
Subject: [PATCH] rtc: add support for rtc NXP pca21125
This is the patch to add support for
NXP rtc pca21125
Signed-off-by: Venkat Prashanth B U <venkat.prashanth2498@...il.com>
---
---
drivers/rtc/Kconfig | 12 ++++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-pca21125.c | 164 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 177 insertions(+)
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index e215f50..df10e0e 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -686,6 +686,18 @@ config RTC_DRV_MAX6916
This driver can also be built as a module. If so, the module
will be called rtc-max6916.
+config RTC_DRV_PCA21125
+ tristate "NXP PCA21125"
+ help
+ If you say yes here you will get support for the
+ NXP PCA21125 SPI RTC chip.
+
+ 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-pca21125.
+
config RTC_DRV_R9701
tristate "Epson RTC-9701JE"
help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 7cf7ad5..2c6af37 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -105,6 +105,7 @@ obj-$(CONFIG_RTC_DRV_NUC900) += rtc-nuc900.o
obj-$(CONFIG_RTC_DRV_OMAP) += rtc-omap.o
obj-$(CONFIG_RTC_DRV_OPAL) += rtc-opal.o
obj-$(CONFIG_RTC_DRV_PALMAS) += rtc-palmas.o
+obj-$(CONFIG_RTC_DRV_PCA21125) += rtc-pca21125.o
obj-$(CONFIG_RTC_DRV_PCAP) += rtc-pcap.o
obj-$(CONFIG_RTC_DRV_PCF2123) += rtc-pcf2123.o
obj-$(CONFIG_RTC_DRV_PCF2127) += rtc-pcf2127.o
diff --git a/drivers/rtc/rtc-pca21125.c b/drivers/rtc/rtc-pca21125.c
index e69de29..8d42e4e 100644
--- a/drivers/rtc/rtc-pca21125.c
+++ b/drivers/rtc/rtc-pca21125.c
@@ -0,0 +1,164 @@
+ /* rtc-pca21125.c
+ *
+ * Driver for NXP PCA21125 CMOS, SPI Compatible
+ * Real Time Clock
+ *
+ * Author : Venkat Prashanth B U <venkat.prashanth2498@...il.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 pca21125 rtc */
+
+ #define PCA21125_SECONDS_REG 0x02
+ #define PCA21125_MINUTES_REG 0x03
+ #define PCA21125_HOURS_REG 0x04
+ #define PCA21125_DATE_REG 0x05
+ #define PCA21125_DAY_REG 0x06
+ #define PCA21125_MONTH_REG 0x07
+ #define PCA21125_YEAR_REG 0x08
+ #define PCA21125_CONTROL_REG 0x01
+ #define PCA21125_STATUS_REG 0x00
+ #define PCA21125_CLOCK_BURST 0x0D
+
+ static int pca21125_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 pca21125_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 pca21125_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] = PCA21125_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] & 0x3F);
+ 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 pca21125_set_time(struct device *dev, struct rtc_time *dt)
+ {
+ struct spi_device *spi = to_spi_device(dev);
+ unsigned char buf[9];
+
+ if (dt->tm_year < 100 || dt->tm_year > 199) {
+ dev_err(&spi->dev, "Year must be between 2000 and 2099. It's %d.\n",
+ dt->tm_year + 1900);
+ return -EINVAL;
+ }
+
+ buf[0] = bin2bcd(dt->tm_sec);
+ buf[1] = bin2bcd(dt->tm_min);
+ buf[2] = (bin2bcd(dt->tm_hour) & 0X3F);
+ buf[3] = bin2bcd(dt->tm_mday);
+ buf[4] = bin2bcd(dt->tm_mon + 1);
+ buf[5] = bin2bcd(dt->tm_wday + 1);
+ buf[6] = bin2bcd(dt->tm_year % 100);
+ buf[7] = bin2bcd(0x00);
+
+ /* write the rtc settings */
+ return spi_write_then_read(spi, buf, 9, NULL, 0);
+ }
+
+ static const struct rtc_class_ops pca21125_rtc_ops = {
+ .read_time = pca21125_read_time,
+ .set_time = pca21125_set_time,
+ };
+
+ static int pca21125_probe(struct spi_device *spi)
+ {
+ struct rtc_device *rtc;
+ unsigned char data;
+ int res;
+
+ /* spi setup with pca21125 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 = pca21125_read_reg(&spi->dev, PCA21125_SECONDS_REG, &data);
+ if (res)
+ return res;
+
+ /* Disable the write protect of rtc */
+ pca21125_read_reg(&spi->dev, PCA21125_CONTROL_REG, &data);
+ data = data & ~(1 << 7);
+ pca21125_write_reg(&spi->dev, PCA21125_CONTROL_REG, data);
+
+ /*Enable oscillator,disable oscillator stop flag, glitch filter*/
+ pca21125_read_reg(&spi->dev, PCA21125_STATUS_REG, &data);
+ data = data & 0x1B;
+ pca21125_write_reg(&spi->dev, PCA21125_STATUS_REG, data);
+
+ /* display the settings */
+ pca21125_read_reg(&spi->dev, PCA21125_CONTROL_REG, &data);
+ dev_info(&spi->dev, "PCA21125 RTC CTRL Reg = 0x%02x\n", data);
+
+ pca21125_read_reg(&spi->dev, PCA21125_STATUS_REG, &data);
+ dev_info(&spi->dev, "PCA21125 RTC Status Reg = 0x%02x\n", data);
+
+ rtc = devm_rtc_device_register(&spi->dev, "pca21125",
+ &pca21125_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+
+ spi_set_drvdata(spi, rtc);
+
+ return 0;
+ }
+
+ static struct spi_driver pca21125_driver = {
+ .driver = {
+ .name = "pca21125",
+ },
+ .probe = pca21125_probe,
+ };
+ module_spi_driver(pca21125_driver);
+
+ MODULE_DESCRIPTION("PCA21125 SPI RTC DRIVER");
+ MODULE_AUTHOR("Venkat Prashanth B U <venkat.prashanth2498@...il.com>");
+ MODULE_LICENSE("GPL v2");
+
--
1.9.2
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