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Date: Sun, 30 Oct 2016 01:03:06 -0700
From: VENKAT PRASHANTH B U <venkat.prashanth2498@...il.com>
To: alexandre.belloni@...e-electrons.com
Cc: a.zummo@...ertech.it, rtc-linux@...glegroups.com,
linux-kernel@...r.kernel.org,
VENKAT PRASHANTH B U <venkat.prashanth2498@...il.com>
Subject: [PATCH] rtc: add support for rtc NXP pca8565
This is a patch to add support for
NXP rtc pca8565
Signed-off-by: Venkat Prashanth B U <venkat.prashanth2498@...il.com>
---
---
drivers/rtc/Kconfig | 9 ++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-pca8565.c | 221 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 231 insertions(+)
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index e215f50..f28b569 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -392,6 +392,15 @@ config RTC_DRV_PCF8523
This driver can also be built as a module. If so, the module
will be called rtc-pcf8523.
+config RTC_DRV_PCA8565
+ tristate "NXP PCA8565"
+ help
+ If you say yes here you get support for the NXP PCA8565 RTC
+ chips.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-pca8565.
+
config RTC_DRV_PCF85063
tristate "NXP PCF85063"
help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 7cf7ad5..ec709a4 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -106,6 +106,7 @@ 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_PCAP) += rtc-pcap.o
+obj-$(CONFIG_RTC_DRV_PCA8565) += rtc-pca8565.o
obj-$(CONFIG_RTC_DRV_PCF2123) += rtc-pcf2123.o
obj-$(CONFIG_RTC_DRV_PCF2127) += rtc-pcf2127.o
obj-$(CONFIG_RTC_DRV_PCF50633) += rtc-pcf50633.o
diff --git a/drivers/rtc/rtc-pca8565.c b/drivers/rtc/rtc-pca8565.c
index e69de29..ec678ee 100644
--- a/drivers/rtc/rtc-pca8565.c
+++ b/drivers/rtc/rtc-pca8565.c
@@ -0,0 +1,221 @@
+/*
+ * An I2C driver for the PCA8565 RTC
+ *
+ * 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/i2c.h>
+#include <linux/bcd.h>
+#include <linux/rtc.h>
+#include <linux/module.h>
+
+#define PCA8565_REG_CTRL1 0x00 /* status */
+#define PCA8565_REG_CTRL1_STOP BIT(5)
+#define PCA8565_REG_CTRL2 0x01
+#define PCA8565_REG_SC 0x02 /* datetime */
+#define PCA8565_REG_SC_OS 0x80
+#define PCA8565_REG_MN 0x03
+#define PCA8565_REG_HR 0x04
+#define PCA8565_REG_DM 0x05
+#define PCA8565_REG_DW 0x06
+#define PCA8565_REG_MO 0x07
+#define PCA8565_REG_YR 0x08
+
+static struct i2c_driver pca8565_driver;
+
+static int pca8565_stop_clock(struct i2c_client *client, u8 *ctrl1)
+{
+ s32 ret;
+
+ ret = i2c_smbus_read_byte_data(client, PCA8565_REG_CTRL1);
+ if (ret < 0) {
+ dev_err(&client->dev, "Failing to stop the clock\n");
+ return -EIO;
+ }
+
+ /* stop the clock */
+ ret |= PCA8565_REG_CTRL1_STOP;
+
+ ret = i2c_smbus_write_byte_data(client, PCA8565_REG_CTRL1, ret);
+ if (ret < 0) {
+ dev_err(&client->dev, "Failing to stop the clock\n");
+ return -EIO;
+ }
+
+ *ctrl1 = ret;
+
+ return 0;
+}
+
+static int pca8565_start_clock(struct i2c_client *client, u8 ctrl1)
+{
+ s32 ret;
+
+ /* start the clock */
+ ctrl1 &= PCA8565_REG_CTRL1_STOP;
+
+ ret = i2c_smbus_write_byte_data(client, PCA8565_REG_CTRL1, ctrl1);
+ if (ret < 0) {
+ dev_err(&client->dev, "Failing to start the clock\n");
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int pca8565_get_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ int rc;
+ u8 regs[7];
+
+ /*
+ * while reading, the time/date registers are blocked and not updated
+ * anymore until the access is finished. To not lose a second
+ * event, the access must be finished within one second. So, read all
+ * time/date registers in one turn.
+ */
+ rc = i2c_smbus_read_i2c_block_data(client, PCA8565_REG_SC,
+ sizeof(regs), regs);
+ if (rc != sizeof(regs)) {
+ dev_err(&client->dev, "date/time register read error\n");
+ return -EIO;
+ }
+
+ /* if the clock has lost its power it makes no sense to use its time */
+ if (regs[0] & PCA8565_REG_SC_OS) {
+ dev_warn(&client->dev, "Power loss detected, invalid time\n");
+ return -EINVAL;
+ }
+
+ tm->tm_sec = bcd2bin(regs[0] & 0x7F);
+ tm->tm_min = bcd2bin(regs[1] & 0x7F);
+ tm->tm_hour = bcd2bin(regs[2] & 0x3F); /* rtc hr 0-23 */
+ tm->tm_mday = bcd2bin(regs[3] & 0x3F);
+ tm->tm_wday = regs[4] & 0x07;
+ tm->tm_mon = bcd2bin(regs[5] & 0x1F) - 1; /* rtc mn 1-12 */
+ tm->tm_year = bcd2bin(regs[6]);
+ tm->tm_year += 100;
+
+ return rtc_valid_tm(tm);
+}
+
+static int pca8565_set_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ int rc;
+ u8 regs[7];
+ u8 ctrl1;
+
+ if ((tm->tm_year < 100) || (tm->tm_year > 199))
+ return -EINVAL;
+
+ /*
+ * to accurately set the time, reset the divider chain and keep it in
+ * reset state until all time/date registers are written
+ */
+ rc = pca8565_stop_clock(client, &ctrl1);
+ if (rc != 0)
+ return rc;
+
+ /* hours, minutes and seconds */
+ regs[0] = bin2bcd(tm->tm_sec) & 0x7F; /* clear OS flag */
+
+ regs[1] = bin2bcd(tm->tm_min);
+ regs[2] = bin2bcd(tm->tm_hour);
+
+ /* Day of month, 1 - 31 */
+ regs[3] = bin2bcd(tm->tm_mday);
+
+ /* Day, 0 - 6 */
+ regs[4] = tm->tm_wday & 0x07;
+
+ /* month, 1 - 12 */
+ regs[5] = bin2bcd(tm->tm_mon + 1);
+
+ /* year and century */
+ regs[6] = bin2bcd(tm->tm_year - 100);
+
+ /* write all registers at once */
+ rc = i2c_smbus_write_i2c_block_data(client, PCA8565_REG_SC,
+ sizeof(regs), regs);
+ if (rc < 0) {
+ dev_err(&client->dev, "date/time register write error\n");
+ return rc;
+ }
+
+ /*
+ * Write the control register as a separate action since the size of
+ * the register space is different between the PCA8565TP and
+ * PCA8565A devices. The rollover point can not be used.
+ */
+ rc = pca8565_start_clock(client, ctrl1);
+ if (rc != 0)
+ return rc;
+
+ return 0;
+}
+
+static int pca8565_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ return pca8565_get_datetime(to_i2c_client(dev), tm);
+}
+
+static int pca8565_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ return pca8565_set_datetime(to_i2c_client(dev), tm);
+}
+
+static const struct rtc_class_ops pca8565_rtc_ops = {
+ .read_time = pca8565_rtc_read_time,
+ .set_time = pca8565_rtc_set_time
+};
+
+static int pca8565_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct rtc_device *rtc;
+
+ dev_dbg(&client->dev, "%s\n", __func__);
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ rtc = devm_rtc_device_register(&client->dev,
+ pca8565_driver.driver.name,
+ &pca8565_rtc_ops, THIS_MODULE);
+
+ return PTR_ERR_OR_ZERO(rtc);
+}
+
+static const struct i2c_device_id pca8565_id[] = {
+ { "pca8565", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, pca8565_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id pca8565_of_match[] = {
+ { .compatible = "nxp,pca8565" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, pca8565_of_match);
+#endif
+
+static struct i2c_driver pca8565_driver = {
+ .driver = {
+ .name = "rtc-pca8565",
+ .of_match_table = of_match_ptr(pca8565_of_match),
+ },
+ .probe = pca8565_probe,
+ .id_table = pca8565_id,
+};
+
+module_i2c_driver(pca8565_driver);
+
+MODULE_AUTHOR("Venkat Prashanth B U <venkat.prashanth2498@...il.com>");
+MODULE_DESCRIPTION("PCA8565 RTC driver");
+MODULE_LICENSE("GPL");
+
--
1.9.2
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