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rtc: pcf8563: add CLKOUT to common clock framework
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@denx.de> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
Heiko Schocher
Alexandre Belloni
parent
dbb812b141
commit
a39a6405d5
2 changed files with 194 additions and 1 deletions
25
Documentation/devicetree/bindings/rtc/pcf8563.txt
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25
Documentation/devicetree/bindings/rtc/pcf8563.txt
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@ -0,0 +1,25 @@
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* Philips PCF8563/Epson RTC8564 Real Time Clock
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Philips PCF8563/Epson RTC8564 Real Time Clock
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Required properties:
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see: Documentation/devicetree/bindings/i2c/trivial-devices.txt
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Optional property:
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- #clock-cells: Should be 0.
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- clock-output-names:
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overwrite the default clock name "pcf8563-clkout"
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Example:
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pcf8563: pcf8563@51 {
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compatible = "nxp,pcf8563";
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reg = <0x51>;
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#clock-cells = <0>;
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};
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device {
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...
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clocks = <&pcf8563>;
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...
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};
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@ -14,6 +14,7 @@
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* published by the Free Software Foundation.
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*/
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#include <linux/clk-provider.h>
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#include <linux/i2c.h>
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#include <linux/bcd.h>
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#include <linux/rtc.h>
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@ -40,7 +41,14 @@
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#define PCF8563_REG_AMN 0x09 /* alarm */
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#define PCF8563_REG_CLKO 0x0D /* clock out */
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#define PCF8563_REG_CLKO 0x0D /* clock out */
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#define PCF8563_REG_CLKO_FE 0x80 /* clock out enabled */
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#define PCF8563_REG_CLKO_F_MASK 0x03 /* frequenc mask */
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#define PCF8563_REG_CLKO_F_32768HZ 0x00
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#define PCF8563_REG_CLKO_F_1024HZ 0x01
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#define PCF8563_REG_CLKO_F_32HZ 0x02
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#define PCF8563_REG_CLKO_F_1HZ 0x03
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#define PCF8563_REG_TMRC 0x0E /* timer control */
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#define PCF8563_TMRC_ENABLE BIT(7)
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#define PCF8563_TMRC_4096 0
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@ -76,6 +84,9 @@ struct pcf8563 {
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int voltage_low; /* incicates if a low_voltage was detected */
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struct i2c_client *client;
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#ifdef CONFIG_COMMON_CLK
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struct clk_hw clkout_hw;
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#endif
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};
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static int pcf8563_read_block_data(struct i2c_client *client, unsigned char reg,
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@ -390,6 +401,158 @@ static int pcf8563_irq_enable(struct device *dev, unsigned int enabled)
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return pcf8563_set_alarm_mode(to_i2c_client(dev), !!enabled);
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}
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#ifdef CONFIG_COMMON_CLK
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/*
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* Handling of the clkout
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*/
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#define clkout_hw_to_pcf8563(_hw) container_of(_hw, struct pcf8563, clkout_hw)
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static int clkout_rates[] = {
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32768,
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1024,
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32,
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1,
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};
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static unsigned long pcf8563_clkout_recalc_rate(struct clk_hw *hw,
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unsigned long parent_rate)
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{
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struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
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struct i2c_client *client = pcf8563->client;
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unsigned char buf;
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int ret = pcf8563_read_block_data(client, PCF8563_REG_CLKO, 1, &buf);
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if (ret < 0)
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return 0;
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buf &= PCF8563_REG_CLKO_F_MASK;
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return clkout_rates[ret];
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}
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static long pcf8563_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long *prate)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
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if (clkout_rates[i] <= rate)
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return clkout_rates[i];
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return 0;
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}
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static int pcf8563_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long parent_rate)
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{
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struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
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struct i2c_client *client = pcf8563->client;
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unsigned char buf;
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int ret = pcf8563_read_block_data(client, PCF8563_REG_CLKO, 1, &buf);
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int i;
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if (ret < 0)
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return ret;
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for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
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if (clkout_rates[i] == rate) {
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buf &= ~PCF8563_REG_CLKO_F_MASK;
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buf |= i;
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ret = pcf8563_write_block_data(client,
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PCF8563_REG_CLKO, 1,
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&buf);
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return ret;
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}
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return -EINVAL;
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}
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static int pcf8563_clkout_control(struct clk_hw *hw, bool enable)
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{
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struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
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struct i2c_client *client = pcf8563->client;
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unsigned char buf;
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int ret = pcf8563_read_block_data(client, PCF8563_REG_CLKO, 1, &buf);
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if (ret < 0)
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return ret;
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if (enable)
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buf |= PCF8563_REG_CLKO_FE;
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else
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buf &= ~PCF8563_REG_CLKO_FE;
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ret = pcf8563_write_block_data(client, PCF8563_REG_CLKO, 1, &buf);
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return ret;
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}
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static int pcf8563_clkout_prepare(struct clk_hw *hw)
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{
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return pcf8563_clkout_control(hw, 1);
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}
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static void pcf8563_clkout_unprepare(struct clk_hw *hw)
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{
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pcf8563_clkout_control(hw, 0);
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}
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static int pcf8563_clkout_is_prepared(struct clk_hw *hw)
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{
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struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
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struct i2c_client *client = pcf8563->client;
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unsigned char buf;
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int ret = pcf8563_read_block_data(client, PCF8563_REG_CLKO, 1, &buf);
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if (ret < 0)
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return ret;
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return !!(buf & PCF8563_REG_CLKO_FE);
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}
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static const struct clk_ops pcf8563_clkout_ops = {
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.prepare = pcf8563_clkout_prepare,
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.unprepare = pcf8563_clkout_unprepare,
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.is_prepared = pcf8563_clkout_is_prepared,
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.recalc_rate = pcf8563_clkout_recalc_rate,
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.round_rate = pcf8563_clkout_round_rate,
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.set_rate = pcf8563_clkout_set_rate,
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};
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static struct clk *pcf8563_clkout_register_clk(struct pcf8563 *pcf8563)
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{
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struct i2c_client *client = pcf8563->client;
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struct device_node *node = client->dev.of_node;
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struct clk *clk;
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struct clk_init_data init;
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int ret;
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unsigned char buf;
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/* disable the clkout output */
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buf = 0;
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ret = pcf8563_write_block_data(client, PCF8563_REG_CLKO, 1, &buf);
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if (ret < 0)
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return ERR_PTR(ret);
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init.name = "pcf8563-clkout";
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init.ops = &pcf8563_clkout_ops;
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init.flags = CLK_IS_ROOT;
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init.parent_names = NULL;
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init.num_parents = 0;
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pcf8563->clkout_hw.init = &init;
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/* optional override of the clockname */
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of_property_read_string(node, "clock-output-names", &init.name);
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/* register the clock */
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clk = devm_clk_register(&client->dev, &pcf8563->clkout_hw);
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if (!IS_ERR(clk))
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of_clk_add_provider(node, of_clk_src_simple_get, clk);
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return clk;
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}
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#endif
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static const struct rtc_class_ops pcf8563_rtc_ops = {
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.ioctl = pcf8563_rtc_ioctl,
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.read_time = pcf8563_rtc_read_time,
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@ -459,6 +622,11 @@ static int pcf8563_probe(struct i2c_client *client,
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}
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#ifdef CONFIG_COMMON_CLK
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/* register clk in common clk framework */
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pcf8563_clkout_register_clk(pcf8563);
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#endif
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/* the pcf8563 alarm only supports a minute accuracy */
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pcf8563->rtc->uie_unsupported = 1;
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