Add the clkout output clk to the common clock framework.
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.
Signed-off-by: Heiko Schocher <hs@xxxxxxx>
---
Changes in v2:
- add comments from Alexandre Belloni
- remove the DT property, instead
register for the CLKOUT a clk in the common
clk framework. The clk is disabled by default.
Documentation/devicetree/bindings/rtc/pcf8563.txt | 28 ++++
drivers/rtc/rtc-pcf8563.c | 164 +++++++++++++++++++++-
2 files changed, 191 insertions(+), 1 deletion(-)
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..cdb81ef
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/pcf8563.txt
@@ -0,0 +1,28 @@
+* 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:
+- #clock-cells: Should be 1.
+- clocks: Reference to the clock entry.
+- clock-output-names:
+ overwrite the default clock name "pcf8563-clkout"
+
+Example:
+
+rtcclk: rtcclk {
+ compatible = "fixed-clock";
+ #clock-cells = <1>;
+ clock-frequency = <1>;
+ clock-output-names = "rtcclk";
+};
+
+pcf8563@51 {
+ compatible = "nxp,pcf8563";
+ reg = <0x51>;
+ #clock-cells = <1>;
+ clocks = <&rtcclk 0>;
+};
diff --git a/drivers/rtc/rtc-pcf8563.c b/drivers/rtc/rtc-pcf8563.c
index e569243..0c2f85f 100644
--- a/drivers/rtc/rtc-pcf8563.c
+++ b/drivers/rtc/rtc-pcf8563.c
@@ -14,6 +14,7 @@
* published by the Free Software Foundation.
*/
+#include <linux/clk-provider.h>
#include <linux/i2c.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
@@ -40,7 +41,14 @@
#define PCF8563_REG_AMN 0x09 /* alarm */
-#define PCF8563_REG_CLKO 0x0D /* clock out */
+#define PCF8563_REG_CLKO 0x0D /* clock out */
+#define PCF8563_REG_CLKO_FE 0x80 /* clock out enabled */
+#define PCF8563_REG_CLKO_F_MASK 0x03 /* frequenc mask */
+#define PCF8563_REG_CLKO_F_32768HZ 0x00
+#define PCF8563_REG_CLKO_F_1024HZ 0x01
+#define PCF8563_REG_CLKO_F_32HZ 0x02
+#define PCF8563_REG_CLKO_F_1HZ 0x03
+
#define PCF8563_REG_TMRC 0x0E /* timer control */
#define PCF8563_TMRC_ENABLE BIT(7)
#define PCF8563_TMRC_4096 0
@@ -76,6 +84,7 @@ struct pcf8563 {
int voltage_low; /* incicates if a low_voltage was detected */
struct i2c_client *client;
+ struct clk_hw clkout_hw;
};
static int pcf8563_read_block_data(struct i2c_client *client, unsigned char reg,
@@ -390,6 +399,156 @@ static int pcf8563_irq_enable(struct device *dev, unsigned int enabled)
return pcf8563_set_alarm_mode(to_i2c_client(dev), !!enabled);
}
+/*
+ * Handling of the clkout
+ */
+
+#define clkout_hw_to_pcf8563(_hw) container_of(_hw, struct pcf8563, clkout_hw)
+
+static int clkout_rates[] = {
+ 32768,
+ 1024,
+ 32,
+ 1,
+};
+
+static unsigned long pcf8563_clkout_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
+ struct i2c_client *client = pcf8563->client;
+ unsigned char buf;
+ int ret = pcf8563_read_block_data(client, PCF8563_REG_CLKO, 1, &buf);
+
+ if (ret < 0)
+ return 0;
+
+ buf &= PCF8563_REG_CLKO_F_MASK;
+ return clkout_rates[ret];
+}
+
+static long pcf8563_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
+ if (clkout_rates[i] <= rate)
+ return clkout_rates[i];
+
+ return 0;
+}
+
+static int pcf8563_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
+ struct i2c_client *client = pcf8563->client;
+ unsigned char buf;
+ int ret = pcf8563_read_block_data(client, PCF8563_REG_CLKO, 1, &buf);
+ int i;
+
+ if (ret < 0)
+ return ret;
+
+ for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
+ if (clkout_rates[i] == rate) {
+ buf &= ~PCF8563_REG_CLKO_F_MASK;
+ buf |= i;
+ ret = pcf8563_write_block_data(client,
+ PCF8563_REG_CLKO, 1,
+ &buf);
+ return ret;
+ }
+
+ return -EINVAL;
+}
+
+static int pcf8563_clkout_control(struct clk_hw *hw, bool enable)
+{
+ struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
+ struct i2c_client *client = pcf8563->client;
+ unsigned char buf;
+ int ret = pcf8563_read_block_data(client, PCF8563_REG_CLKO, 1, &buf);
+
+ if (ret < 0)
+ return ret;
+
+ if (enable)
+ buf |= PCF8563_REG_CLKO_FE;
+ else
+ buf &= ~PCF8563_REG_CLKO_FE;
+
+ ret = pcf8563_write_block_data(client, PCF8563_REG_CLKO, 1, &buf);
+ return ret;
+}
+
+static int pcf8563_clkout_prepare(struct clk_hw *hw)
+{
+ return pcf8563_clkout_control(hw, 1);
+}
+
+static void pcf8563_clkout_unprepare(struct clk_hw *hw)
+{
+ pcf8563_clkout_control(hw, 0);
+}
+
+static int pcf8563_clkout_is_prepared(struct clk_hw *hw)
+{
+ struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
+ struct i2c_client *client = pcf8563->client;
+ unsigned char buf;
+ int ret = pcf8563_read_block_data(client, PCF8563_REG_CLKO, 1, &buf);
+
+ if (ret < 0)
+ return ret;
+
+ return !!(buf & PCF8563_REG_CLKO_FE);
+}
+
+static const struct clk_ops pcf8563_clkout_ops = {
+ .prepare = pcf8563_clkout_prepare,
+ .unprepare = pcf8563_clkout_unprepare,
+ .is_prepared = pcf8563_clkout_is_prepared,
+ .recalc_rate = pcf8563_clkout_recalc_rate,
+ .round_rate = pcf8563_clkout_round_rate,
+ .set_rate = pcf8563_clkout_set_rate,
+};
+
+static struct clk *pcf8563_clkout_register_clk(struct pcf8563 *pcf8563)
+{
+ struct i2c_client *client = pcf8563->client;
+ struct device_node *node = client->dev.of_node;
+ struct clk *clk;
+ struct clk_init_data init;
+ int ret;
+ unsigned char buf;
+
+ /* disable the clkout output */
+ buf = 0;
+ ret = pcf8563_write_block_data(client, PCF8563_REG_CLKO, 1, &buf);
+ if (ret < 0)
+ return ERR_PTR(ret);
+
+ init.name = "pcf8563-clkout";
+ init.ops = &pcf8563_clkout_ops;
+ init.flags = CLK_IS_ROOT;
+ init.parent_names = NULL;
+ init.num_parents = 0;
+ pcf8563->clkout_hw.init = &init;
+
+ /* optional override of the clockname */
+ of_property_read_string(node, "clock-output-names", &init.name);
+
+ /* register the clock */
+ clk = clk_register(&client->dev, &pcf8563->clkout_hw);
+
+ if (!IS_ERR(clk))
+ of_clk_add_provider(node, of_clk_src_simple_get, clk);
+
+ return clk;
+}
+
static const struct rtc_class_ops pcf8563_rtc_ops = {
.ioctl = pcf8563_rtc_ioctl,
.read_time = pcf8563_rtc_read_time,
@@ -459,6 +618,9 @@ static int pcf8563_probe(struct i2c_client *client,
}
+ /* register clk in common clk framework */
+ pcf8563_clkout_register_clk(pcf8563);
+
/* the pcf8563 alarm only supports a minute accuracy */
pcf8563->rtc->uie_unsupported = 1;
--
2.1.0
--
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