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Date: Tue, 13 Oct 2015 07:08:58 +0200
From: Heiko Schocher <hs@...x.de>
To: linux-kernel@...r.kernel.org
Cc: Heiko Schocher <hs@...x.de>,
Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
Georg.Soffel@...ch-si.com, rtc-linux@...glegroups.com,
Alessandro Zummo <a.zummo@...ertech.it>,
devicetree@...r.kernel.org
Subject: [PATCH] rtc: pcf8563: disable CLKOUT
Disable the CLKOUT of the RTC after power-up.
After power-up/reset of the RTC, CLKOUT is enabled by default,
with CLKOUT enabled the RTC chip has 2-3 times higher power
consumption. If you do not need CLKOUT, you can disable the
CLKOUT with setting "disable-clkout" property.
Signed-off-by: Heiko Schocher <hs@...x.de>
---
Documentation/devicetree/bindings/rtc/pcf8563.txt | 22 ++++++++++++++
drivers/rtc/rtc-pcf8563.c | 37 +++++++++++++++++++++++
2 files changed, 59 insertions(+)
create mode 100644 Documentation/devicetree/bindings/rtc/pcf8563.txt
diff --git a/Documentation/devicetree/bindings/rtc/pcf8563.txt b/Documentation/devicetree/bindings/rtc/pcf8563.txt
new file mode 100644
index 0000000..36f49e1
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/pcf8563.txt
@@ -0,0 +1,22 @@
+* Philips PCF8563/Epson RTC8564 Real Time Clock
+
+Philips PCF8563/Epson RTC8564 Real Time Clock
+
+Required properties:
+see: Documentation/devicetree/bindings/i2c/trivial-devices.txt
+
+Optional property:
+- disable-clkout:
+ disable the CLKOUT of the RTC after power-up.
+ After power-up/reset of the RTC, CLKOUT is enabled by default,
+ with CLKOUT enabled the RTC chip has 2-3 times higher power
+ consumption. If you not need CLKOUT, you can disable the CLKOUT
+ with setting this property.
+
+Example:
+
+pcf8563@51 {
+ compatible = "nxp,pcf8563";
+ reg = <0x51>;
+ disable-clkout;
+};
diff --git a/drivers/rtc/rtc-pcf8563.c b/drivers/rtc/rtc-pcf8563.c
index e569243..fa9a412 100644
--- a/drivers/rtc/rtc-pcf8563.c
+++ b/drivers/rtc/rtc-pcf8563.c
@@ -53,6 +53,7 @@
#define PCF8563_SC_LV 0x80 /* low voltage */
#define PCF8563_MO_C 0x80 /* century */
+#define PCF8563_CLKOUT 0x80 /* CLKOUT */
static struct i2c_driver pcf8563_driver;
@@ -74,6 +75,7 @@ struct pcf8563 {
*/
int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
int voltage_low; /* incicates if a low_voltage was detected */
+ int disable_clkout;
struct i2c_client *client;
};
@@ -186,6 +188,33 @@ static irqreturn_t pcf8563_irq(int irq, void *dev_id)
return IRQ_NONE;
}
+static int pcf8563_disable_clkout(struct i2c_client *client)
+{
+ struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
+ unsigned char buf;
+ int err;
+
+ if (!pcf8563->disable_clkout)
+ return 0;
+
+ err = pcf8563_read_block_data(client, PCF8563_REG_CLKO, 1, &buf);
+ if (err)
+ return err;
+
+ if (buf & PCF8563_CLKOUT) {
+ buf = 0x00;
+ dev_warn(&client->dev, "CLKOUT enabled! Disabling it...\n");
+ err = pcf8563_write_block_data(client, PCF8563_REG_CLKO, 1,
+ &buf);
+ if (err < 0)
+ dev_err(&client->dev, "could not disable clock\n");
+ } else {
+ dev_info(&client->dev, "CLKOUT disabled.\n");
+ }
+
+ return 0;
+}
+
/*
* In the routines that deal directly with the pcf8563 hardware, we use
* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
@@ -235,6 +264,7 @@ static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
tm->tm_sec, tm->tm_min, tm->tm_hour,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
+ pcf8563_disable_clkout(client);
return 0;
}
@@ -406,6 +436,9 @@ static int pcf8563_probe(struct i2c_client *client,
int err;
unsigned char buf;
unsigned char alm_pending;
+#ifdef CONFIG_OF
+ int len;
+#endif
dev_dbg(&client->dev, "%s\n", __func__);
@@ -419,6 +452,10 @@ static int pcf8563_probe(struct i2c_client *client,
dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
+#ifdef CONFIG_OF
+ if (of_find_property(client->dev.of_node, "disable-clkout", &len))
+ pcf8563->disable_clkout = 1;
+#endif
i2c_set_clientdata(client, pcf8563);
pcf8563->client = client;
device_set_wakeup_capable(&client->dev, 1);
--
2.1.0
--
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