387 lines
9.2 KiB
Diff
387 lines
9.2 KiB
Diff
From f803f0d079ded4272d7a1c9813bfd24c58b8ee5f Mon Sep 17 00:00:00 2001
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From: Thierry Reding <thierry.reding@avionic-design.de>
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Date: Mon, 17 Dec 2012 16:02:44 -0800
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Subject: [PATCH] rtc: add NXP PCF8523 support
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Add an RTC driver for PCF8523 chips by NXP Semiconductors. No support is
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currently provided for the alarm and interrupt functions. Only the time
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and date functionality is implemented.
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Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
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Cc: Alessandro Zummo <a.zummo@towertech.it>
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Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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---
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drivers/rtc/Kconfig | 9 ++
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drivers/rtc/Makefile | 1 +
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drivers/rtc/rtc-pcf8523.c | 326 +++++++++++++++++++++++++++++++++++++++++++++
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3 files changed, 336 insertions(+), 0 deletions(-)
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create mode 100644 drivers/rtc/rtc-pcf8523.c
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diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
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index 608a7b1..5bb0314 100644
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--- drivers/rtc/Kconfig
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+++ drivers/rtc/Kconfig
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@@ -269,6 +269,15 @@ config RTC_DRV_X1205
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This driver can also be built as a module. If so, the module
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will be called rtc-x1205.
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+config RTC_DRV_PCF8523
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+ tristate "NXP PCF8523"
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+ help
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+ If you say yes here you get support for the NXP PCF8523 RTC
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+ chips.
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+
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+ This driver can also be built as a module. If so, the module
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+ will be called rtc-pcf8523.
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+
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config RTC_DRV_PCF8563
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tristate "Philips PCF8563/Epson RTC8564"
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help
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diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
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index 56297f0..59e2132 100644
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--- drivers/rtc/Makefile
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+++ drivers/rtc/Makefile
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@@ -76,6 +76,7 @@ obj-$(CONFIG_RTC_DRV_MV) += rtc-mv.o
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obj-$(CONFIG_RTC_DRV_NUC900) += rtc-nuc900.o
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obj-$(CONFIG_RTC_DRV_OMAP) += rtc-omap.o
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obj-$(CONFIG_RTC_DRV_PCAP) += rtc-pcap.o
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+obj-$(CONFIG_RTC_DRV_PCF8523) += rtc-pcf8523.o
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obj-$(CONFIG_RTC_DRV_PCF8563) += rtc-pcf8563.o
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obj-$(CONFIG_RTC_DRV_PCF8583) += rtc-pcf8583.o
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obj-$(CONFIG_RTC_DRV_PCF2123) += rtc-pcf2123.o
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diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c
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new file mode 100644
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index 0000000..be05a64
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--- /dev/null
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+++ drivers/rtc/rtc-pcf8523.c
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@@ -0,0 +1,326 @@
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+/*
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+ * Copyright (C) 2012 Avionic Design GmbH
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License version 2 as
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+ * published by the Free Software Foundation.
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+ */
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+
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+#include <linux/bcd.h>
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+#include <linux/i2c.h>
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+#include <linux/module.h>
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+#include <linux/rtc.h>
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+#include <linux/of.h>
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+
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+#define DRIVER_NAME "rtc-pcf8523"
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+
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+#define REG_CONTROL1 0x00
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+#define REG_CONTROL1_CAP_SEL (1 << 7)
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+#define REG_CONTROL1_STOP (1 << 5)
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+
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+#define REG_CONTROL3 0x02
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+#define REG_CONTROL3_PM_BLD (1 << 7) /* battery low detection disabled */
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+#define REG_CONTROL3_PM_VDD (1 << 6) /* switch-over disabled */
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+#define REG_CONTROL3_PM_DSM (1 << 5) /* direct switching mode */
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+#define REG_CONTROL3_PM_MASK 0xe0
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+
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+#define REG_SECONDS 0x03
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+#define REG_SECONDS_OS (1 << 7)
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+
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+#define REG_MINUTES 0x04
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+#define REG_HOURS 0x05
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+#define REG_DAYS 0x06
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+#define REG_WEEKDAYS 0x07
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+#define REG_MONTHS 0x08
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+#define REG_YEARS 0x09
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+
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+struct pcf8523 {
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+ struct rtc_device *rtc;
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+};
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+
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+static int pcf8523_read(struct i2c_client *client, u8 reg, u8 *valuep)
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+{
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+ struct i2c_msg msgs[2];
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+ u8 value = 0;
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+ int err;
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+
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+ msgs[0].addr = client->addr;
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+ msgs[0].flags = 0;
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+ msgs[0].len = sizeof(reg);
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+ msgs[0].buf = ®
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+
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+ msgs[1].addr = client->addr;
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+ msgs[1].flags = I2C_M_RD;
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+ msgs[1].len = sizeof(value);
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+ msgs[1].buf = &value;
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+
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+ err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
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+ if (err < 0)
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+ return err;
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+
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+ *valuep = value;
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+
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+ return 0;
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+}
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+
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+static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value)
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+{
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+ u8 buffer[2] = { reg, value };
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+ struct i2c_msg msg;
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+ int err;
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+
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+ msg.addr = client->addr;
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+ msg.flags = 0;
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+ msg.len = sizeof(buffer);
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+ msg.buf = buffer;
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+
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+ err = i2c_transfer(client->adapter, &msg, 1);
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+ if (err < 0)
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+ return err;
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+
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+ return 0;
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+}
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+
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+static int pcf8523_select_capacitance(struct i2c_client *client, bool high)
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+{
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+ u8 value;
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+ int err;
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+
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+ err = pcf8523_read(client, REG_CONTROL1, &value);
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+ if (err < 0)
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+ return err;
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+
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+ if (!high)
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+ value &= ~REG_CONTROL1_CAP_SEL;
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+ else
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+ value |= REG_CONTROL1_CAP_SEL;
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+
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+ err = pcf8523_write(client, REG_CONTROL1, value);
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+ if (err < 0)
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+ return err;
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+
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+ return err;
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+}
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+
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+static int pcf8523_set_pm(struct i2c_client *client, u8 pm)
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+{
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+ u8 value;
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+ int err;
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+
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+ err = pcf8523_read(client, REG_CONTROL3, &value);
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+ if (err < 0)
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+ return err;
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+
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+ value = (value & ~REG_CONTROL3_PM_MASK) | pm;
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+
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+ err = pcf8523_write(client, REG_CONTROL3, value);
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+ if (err < 0)
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+ return err;
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+
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+ return 0;
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+}
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+
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+static int pcf8523_stop_rtc(struct i2c_client *client)
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+{
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+ u8 value;
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+ int err;
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+
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+ err = pcf8523_read(client, REG_CONTROL1, &value);
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+ if (err < 0)
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+ return err;
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+
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+ value |= REG_CONTROL1_STOP;
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+
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+ err = pcf8523_write(client, REG_CONTROL1, value);
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+ if (err < 0)
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+ return err;
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+
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+ return 0;
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+}
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+
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+static int pcf8523_start_rtc(struct i2c_client *client)
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+{
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+ u8 value;
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+ int err;
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+
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+ err = pcf8523_read(client, REG_CONTROL1, &value);
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+ if (err < 0)
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+ return err;
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+
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+ value &= ~REG_CONTROL1_STOP;
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+
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+ err = pcf8523_write(client, REG_CONTROL1, value);
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+ if (err < 0)
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+ return err;
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+
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+ return 0;
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+}
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+
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+static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
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+{
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+ struct i2c_client *client = to_i2c_client(dev);
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+ u8 start = REG_SECONDS, regs[7];
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+ struct i2c_msg msgs[2];
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+ int err;
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+
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+ msgs[0].addr = client->addr;
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+ msgs[0].flags = 0;
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+ msgs[0].len = 1;
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+ msgs[0].buf = &start;
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+
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+ msgs[1].addr = client->addr;
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+ msgs[1].flags = I2C_M_RD;
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+ msgs[1].len = sizeof(regs);
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+ msgs[1].buf = regs;
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+
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+ err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
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+ if (err < 0)
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+ return err;
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+
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+ if (regs[0] & REG_SECONDS_OS) {
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+ /*
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+ * If the oscillator was stopped, try to clear the flag. Upon
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+ * power-up the flag is always set, but if we cannot clear it
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+ * the oscillator isn't running properly for some reason. The
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+ * sensible thing therefore is to return an error, signalling
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+ * that the clock cannot be assumed to be correct.
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+ */
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+
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+ regs[0] &= ~REG_SECONDS_OS;
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+
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+ err = pcf8523_write(client, REG_SECONDS, regs[0]);
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+ if (err < 0)
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+ return err;
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+
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+ err = pcf8523_read(client, REG_SECONDS, ®s[0]);
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+ if (err < 0)
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+ return err;
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+
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+ if (regs[0] & REG_SECONDS_OS)
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+ return -EAGAIN;
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+ }
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+
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+ tm->tm_sec = bcd2bin(regs[0] & 0x7f);
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+ tm->tm_min = bcd2bin(regs[1] & 0x7f);
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+ tm->tm_hour = bcd2bin(regs[2] & 0x3f);
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+ tm->tm_mday = bcd2bin(regs[3] & 0x3f);
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+ tm->tm_wday = regs[4] & 0x7;
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+ tm->tm_mon = bcd2bin(regs[5] & 0x1f);
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+ tm->tm_year = bcd2bin(regs[6]) + 100;
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+
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+ return rtc_valid_tm(tm);
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+}
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+
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+static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
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+{
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+ struct i2c_client *client = to_i2c_client(dev);
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+ struct i2c_msg msg;
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+ u8 regs[8];
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+ int err;
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+
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+ err = pcf8523_stop_rtc(client);
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+ if (err < 0)
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+ return err;
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+
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+ regs[0] = REG_SECONDS;
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+ regs[1] = bin2bcd(tm->tm_sec);
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+ regs[2] = bin2bcd(tm->tm_min);
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+ regs[3] = bin2bcd(tm->tm_hour);
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+ regs[4] = bin2bcd(tm->tm_mday);
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+ regs[5] = tm->tm_wday;
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+ regs[6] = bin2bcd(tm->tm_mon);
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+ regs[7] = bin2bcd(tm->tm_year - 100);
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+
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+ msg.addr = client->addr;
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+ msg.flags = 0;
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+ msg.len = sizeof(regs);
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+ msg.buf = regs;
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+
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+ err = i2c_transfer(client->adapter, &msg, 1);
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+ if (err < 0) {
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+ /*
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+ * If the time cannot be set, restart the RTC anyway. Note
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+ * that errors are ignored if the RTC cannot be started so
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+ * that we have a chance to propagate the original error.
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+ */
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+ pcf8523_start_rtc(client);
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+ return err;
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+ }
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+
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+ return pcf8523_start_rtc(client);
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+}
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+
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+static const struct rtc_class_ops pcf8523_rtc_ops = {
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+ .read_time = pcf8523_rtc_read_time,
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+ .set_time = pcf8523_rtc_set_time,
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+};
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+
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+static int pcf8523_probe(struct i2c_client *client,
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+ const struct i2c_device_id *id)
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+{
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+ struct pcf8523 *pcf;
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+ int err;
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+
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+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
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+ return -ENODEV;
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+
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+ pcf = devm_kzalloc(&client->dev, sizeof(*pcf), GFP_KERNEL);
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+ if (!pcf)
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+ return -ENOMEM;
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+
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+ err = pcf8523_select_capacitance(client, true);
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+ if (err < 0)
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+ return err;
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+
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+ err = pcf8523_set_pm(client, 0);
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+ if (err < 0)
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+ return err;
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+
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+ pcf->rtc = rtc_device_register(DRIVER_NAME, &client->dev,
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+ &pcf8523_rtc_ops, THIS_MODULE);
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+ if (IS_ERR(pcf->rtc))
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+ return PTR_ERR(pcf->rtc);
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+
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+ i2c_set_clientdata(client, pcf);
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+
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+ return 0;
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+}
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+
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+static int pcf8523_remove(struct i2c_client *client)
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+{
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+ struct pcf8523 *pcf = i2c_get_clientdata(client);
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+
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+ rtc_device_unregister(pcf->rtc);
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+
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+ return 0;
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+}
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+
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+static const struct i2c_device_id pcf8523_id[] = {
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+ { "pcf8523", 0 },
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+ { }
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+};
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+MODULE_DEVICE_TABLE(i2c, pcf8523_id);
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+
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+#ifdef CONFIG_OF
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+static const struct of_device_id pcf8523_of_match[] = {
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+ { .compatible = "nxp,pcf8523" },
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+ { }
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+};
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+MODULE_DEVICE_TABLE(of, pcf8523_of_match);
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+#endif
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+
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+static struct i2c_driver pcf8523_driver = {
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+ .driver = {
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+ .name = DRIVER_NAME,
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+ .owner = THIS_MODULE,
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+ .of_match_table = of_match_ptr(pcf8523_of_match),
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+ },
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+ .probe = pcf8523_probe,
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+ .remove = pcf8523_remove,
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+ .id_table = pcf8523_id,
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+};
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+module_i2c_driver(pcf8523_driver);
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+
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+MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
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+MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
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+MODULE_LICENSE("GPL v2");
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--
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1.7.6.5
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