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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 2015-10-16 13:31:29 +02:00 committed by Alexandre Belloni
parent dbb812b141
commit a39a6405d5
2 changed files with 194 additions and 1 deletions
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25
Documentation/devicetree/bindings/rtc/pcf8563.txt Normal file
View File

@ -0,0 +1,25 @@
* 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>;
...
};

170
drivers/rtc/rtc-pcf8563.c
View File

@ -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 +84,9 @@ 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;