Commit a39a6405 authored by Heiko Schocher's avatar Heiko Schocher Committed by Alexandre Belloni
Browse files

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: default avatarHeiko Schocher <hs@denx.de>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
parent dbb812b1

Documentation/devicetree/bindings/rtc/pcf8563.txt

0 → 100644
+25 −0
Original line number Diff line number Diff line 
* 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 0.

- clock-output-names:

  overwrite the default clock name "pcf8563-clkout"



Example:



pcf8563: pcf8563@51 {

	compatible = "nxp,pcf8563";

	reg = <0x51>;

	#clock-cells = <0>;

};



device {

...

	clocks = <&pcf8563>;

...

};

drivers/rtc/rtc-pcf8563.c

+169 −1
Original line number Diff line number Diff line
@@ -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>
@@ -41,6 +42,13 @@ 
#define PCF8563_REG_AMN		0x09 /* alarm */



#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 +84,9 @@ struct pcf8563 { 
	int voltage_low; /* incicates if a low_voltage was detected */



	struct i2c_client *client;

#ifdef CONFIG_COMMON_CLK

	struct clk_hw		clkout_hw;

#endif

};



static int pcf8563_read_block_data(struct i2c_client *client, unsigned char reg,
@@ -390,6 +401,158 @@ static int pcf8563_irq_enable(struct device *dev, unsigned int enabled) 
	return pcf8563_set_alarm_mode(to_i2c_client(dev), !!enabled);

}



#ifdef CONFIG_COMMON_CLK

/*

 * 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 = devm_clk_register(&client->dev, &pcf8563->clkout_hw);



	if (!IS_ERR(clk))

		of_clk_add_provider(node, of_clk_src_simple_get, clk);



	return clk;

}

#endif



static const struct rtc_class_ops pcf8563_rtc_ops = {

	.ioctl		= pcf8563_rtc_ioctl,

	.read_time	= pcf8563_rtc_read_time,
@@ -459,6 +622,11 @@ static int pcf8563_probe(struct i2c_client *client, 


	}



#ifdef CONFIG_COMMON_CLK

	/* register clk in common clk framework */

	pcf8563_clkout_register_clk(pcf8563);

#endif



	/* the pcf8563 alarm only supports a minute accuracy */

	pcf8563->rtc->uie_unsupported = 1;

CRA Git | Maintained and supported by SUSTech CRA and CCSE