[PATCH 1/5] rtc: pcf8523: switch to regmap

[PATCH 1/5] rtc: pcf8523: switch to regmap

[Alexandre Belloni]

Use regmap to access the RTC registers, this is a huge reduction in code
lines and generated code. Values on ARMv7:

   text	   data	    bss	    dec	    hex
   5180	    132	      0	   5312	   14c0	before
   3900	    132	      0	   4032	    fc0	after

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/Kconfig       |   1 +
 drivers/rtc/rtc-pcf8523.c | 303 +++++++++++---------------------------
 2 files changed, 85 insertions(+), 219 deletions(-)

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 59dc1410a160..8dc92b4e042f 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -441,6 +441,7 @@ config RTC_DRV_X1205
 
 config RTC_DRV_PCF8523
 	tristate "NXP PCF8523"
+	select REGMAP_I2C
 	help
 	  If you say yes here you get support for the NXP PCF8523 RTC
 	  chips.
diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c
index 09110b3ae25f..c5d31c525997 100644
--- a/drivers/rtc/rtc-pcf8523.c
+++ b/drivers/rtc/rtc-pcf8523.c
@@ -6,6 +6,7 @@
 #include <linux/bcd.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
+#include <linux/regmap.h>
 #include <linux/rtc.h>
 #include <linux/of.h>
 #include <linux/pm_wakeirq.h>
@@ -49,115 +50,45 @@
 
 struct pcf8523 {
 	struct rtc_device *rtc;
-	struct i2c_client *client;
+	struct regmap *regmap;
 };
 
-static int pcf8523_read(struct i2c_client *client, u8 reg, u8 *valuep)
+static int pcf8523_load_capacitance(struct pcf8523 *pcf8523, struct device_node *node)
 {
-	struct i2c_msg msgs[2];
-	u8 value = 0;
-	int err;
-
-	msgs[0].addr = client->addr;
-	msgs[0].flags = 0;
-	msgs[0].len = sizeof(reg);
-	msgs[0].buf = &reg;
-
-	msgs[1].addr = client->addr;
-	msgs[1].flags = I2C_M_RD;
-	msgs[1].len = sizeof(value);
-	msgs[1].buf = &value;
-
-	err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
-	if (err < 0)
-		return err;
-
-	*valuep = value;
-
-	return 0;
-}
-
-static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value)
-{
-	u8 buffer[2] = { reg, value };
-	struct i2c_msg msg;
-	int err;
-
-	msg.addr = client->addr;
-	msg.flags = 0;
-	msg.len = sizeof(buffer);
-	msg.buf = buffer;
-
-	err = i2c_transfer(client->adapter, &msg, 1);
-	if (err < 0)
-		return err;
-
-	return 0;
-}
-
-static int pcf8523_load_capacitance(struct i2c_client *client)
-{
-	u32 load;
-	u8 value;
-	int err;
-
-	err = pcf8523_read(client, PCF8523_REG_CONTROL1, &value);
-	if (err < 0)
-		return err;
+	u32 load, value = 0;
 
 	load = 12500;
-	of_property_read_u32(client->dev.of_node, "quartz-load-femtofarads",
-			     &load);
+	of_property_read_u32(node, "quartz-load-femtofarads", &load);
 
 	switch (load) {
 	default:
-		dev_warn(&client->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500",
+		dev_warn(&pcf8523->rtc->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500",
 			 load);
 		fallthrough;
 	case 12500:
 		value |= PCF8523_CONTROL1_CAP_SEL;
 		break;
 	case 7000:
-		value &= ~PCF8523_CONTROL1_CAP_SEL;
 		break;
 	}
 
-	err = pcf8523_write(client, PCF8523_REG_CONTROL1, value);
-
-	return err;
-}
-
-static int pcf8523_set_pm(struct i2c_client *client, u8 pm)
-{
-	u8 value;
-	int err;
-
-	err = pcf8523_read(client, PCF8523_REG_CONTROL3, &value);
-	if (err < 0)
-		return err;
-
-	value = (value & ~PCF8523_CONTROL3_PM_MASK) | pm;
-
-	err = pcf8523_write(client, PCF8523_REG_CONTROL3, value);
-	if (err < 0)
-		return err;
-
-	return 0;
+	return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
+				  PCF8523_CONTROL1_CAP_SEL, value);
 }
 
 static irqreturn_t pcf8523_irq(int irq, void *dev_id)
 {
-	struct pcf8523 *pcf8523 = i2c_get_clientdata(dev_id);
-	u8 value;
+	struct pcf8523 *pcf8523 = dev_id;
+	u32 value;
 	int err;
 
-	err = pcf8523_read(pcf8523->client, PCF8523_REG_CONTROL2, &value);
+	err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
 	if (err < 0)
 		return IRQ_HANDLED;
 
 	if (value & PCF8523_CONTROL2_AF) {
 		value &= ~PCF8523_CONTROL2_AF;
-		pcf8523_write(pcf8523->client, PCF8523_REG_CONTROL2, value);
+		regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, value);
 		rtc_update_irq(pcf8523->rtc, 1, RTC_IRQF | RTC_AF);
 
 		return IRQ_HANDLED;
@@ -166,60 +97,14 @@ static irqreturn_t pcf8523_irq(int irq, void *dev_id)
 	return IRQ_NONE;
 }
 
-static int pcf8523_stop_rtc(struct i2c_client *client)
-{
-	u8 value;
-	int err;
-
-	err = pcf8523_read(client, PCF8523_REG_CONTROL1, &value);
-	if (err < 0)
-		return err;
-
-	value |= PCF8523_CONTROL1_STOP;
-
-	err = pcf8523_write(client, PCF8523_REG_CONTROL1, value);
-	if (err < 0)
-		return err;
-
-	return 0;
-}
-
-static int pcf8523_start_rtc(struct i2c_client *client)
-{
-	u8 value;
-	int err;
-
-	err = pcf8523_read(client, PCF8523_REG_CONTROL1, &value);
-	if (err < 0)
-		return err;
-
-	value &= ~PCF8523_CONTROL1_STOP;
-
-	err = pcf8523_write(client, PCF8523_REG_CONTROL1, value);
-	if (err < 0)
-		return err;
-
-	return 0;
-}
-
 static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
-	struct i2c_client *client = to_i2c_client(dev);
-	u8 start = PCF8523_REG_SECONDS, regs[7];
-	struct i2c_msg msgs[2];
+	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
+	u8 regs[7];
 	int err;
 
-	msgs[0].addr = client->addr;
-	msgs[0].flags = 0;
-	msgs[0].len = 1;
-	msgs[0].buf = &start;
-
-	msgs[1].addr = client->addr;
-	msgs[1].flags = I2C_M_RD;
-	msgs[1].len = sizeof(regs);
-	msgs[1].buf = regs;
-
-	err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+	err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_SECONDS, regs,
+			       sizeof(regs));
 	if (err < 0)
 		return err;
 
@@ -239,63 +124,50 @@ static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
 
 static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
-	struct i2c_client *client = to_i2c_client(dev);
-	struct i2c_msg msg;
-	u8 regs[8];
+	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
+	u8 regs[7];
 	int err;
 
-	err = pcf8523_stop_rtc(client);
+	err = regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
+				 PCF8523_CONTROL1_STOP, PCF8523_CONTROL1_STOP);
 	if (err < 0)
 		return err;
 
-	regs[0] = PCF8523_REG_SECONDS;
 	/* This will purposely overwrite PCF8523_SECONDS_OS */
-	regs[1] = bin2bcd(tm->tm_sec);
-	regs[2] = bin2bcd(tm->tm_min);
-	regs[3] = bin2bcd(tm->tm_hour);
-	regs[4] = bin2bcd(tm->tm_mday);
-	regs[5] = tm->tm_wday;
-	regs[6] = bin2bcd(tm->tm_mon + 1);
-	regs[7] = bin2bcd(tm->tm_year - 100);
-
-	msg.addr = client->addr;
-	msg.flags = 0;
-	msg.len = sizeof(regs);
-	msg.buf = regs;
-
-	err = i2c_transfer(client->adapter, &msg, 1);
+	regs[0] = bin2bcd(tm->tm_sec);
+	regs[1] = bin2bcd(tm->tm_min);
+	regs[2] = bin2bcd(tm->tm_hour);
+	regs[3] = bin2bcd(tm->tm_mday);
+	regs[4] = tm->tm_wday;
+	regs[5] = bin2bcd(tm->tm_mon + 1);
+	regs[6] = bin2bcd(tm->tm_year - 100);
+
+	err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_SECONDS, regs,
+				sizeof(regs));
 	if (err < 0) {
 		/*
 		 * If the time cannot be set, restart the RTC anyway. Note
 		 * that errors are ignored if the RTC cannot be started so
 		 * that we have a chance to propagate the original error.
 		 */
-		pcf8523_start_rtc(client);
+		regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
+				   PCF8523_CONTROL1_STOP, 0);
 		return err;
 	}
 
-	return pcf8523_start_rtc(client);
+	return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
+				 PCF8523_CONTROL1_STOP, 0);
 }
 
 static int pcf8523_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
 {
-	struct i2c_client *client = to_i2c_client(dev);
-	u8 start = PCF8523_REG_MINUTE_ALARM, regs[4];
-	struct i2c_msg msgs[2];
-	u8 value;
+	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
+	u8 regs[4];
+	u32 value;
 	int err;
 
-	msgs[0].addr = client->addr;
-	msgs[0].flags = 0;
-	msgs[0].len = 1;
-	msgs[0].buf = &start;
-
-	msgs[1].addr = client->addr;
-	msgs[1].flags = I2C_M_RD;
-	msgs[1].len = sizeof(regs);
-	msgs[1].buf = regs;
-
-	err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+	err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
+			       sizeof(regs));
 	if (err < 0)
 		return err;
 
@@ -305,12 +177,12 @@ static int pcf8523_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
 	tm->time.tm_mday = bcd2bin(regs[2] & 0x3F);
 	tm->time.tm_wday = bcd2bin(regs[3] & 0x7);
 
-	err = pcf8523_read(client, PCF8523_REG_CONTROL1, &value);
+	err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL1, &value);
 	if (err < 0)
 		return err;
 	tm->enabled = !!(value & PCF8523_CONTROL1_AIE);
 
-	err = pcf8523_read(client, PCF8523_REG_CONTROL2, &value);
+	err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
 	if (err < 0)
 		return err;
 	tm->pending = !!(value & PCF8523_CONTROL2_AF);
@@ -320,30 +192,16 @@ static int pcf8523_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
 
 static int pcf8523_irq_enable(struct device *dev, unsigned int enabled)
 {
-	struct i2c_client *client = to_i2c_client(dev);
-	u8 value;
-	int err;
+	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
 
-	err = pcf8523_read(client, PCF8523_REG_CONTROL1, &value);
-	if (err < 0)
-		return err;
-
-	value &= PCF8523_CONTROL1_AIE;
-
-	if (enabled)
-		value |= PCF8523_CONTROL1_AIE;
-
-	err = pcf8523_write(client, PCF8523_REG_CONTROL1, value);
-	if (err < 0)
-		return err;
-
-	return 0;
+	return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
+				  PCF8523_CONTROL1_AIE, enabled ?
+				  PCF8523_CONTROL1_AIE : 0);
 }
 
 static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
 {
-	struct i2c_client *client = to_i2c_client(dev);
-	struct i2c_msg msg;
+	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
 	u8 regs[5];
 	int err;
 
@@ -351,7 +209,7 @@ static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
 	if (err)
 		return err;
 
-	err = pcf8523_write(client, PCF8523_REG_CONTROL2, 0);
+	err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, 0);
 	if (err < 0)
 		return err;
 
@@ -363,16 +221,13 @@ static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
 		rtc_time64_to_tm(alarm_time, &tm->time);
 	}
 
-	regs[0] = PCF8523_REG_MINUTE_ALARM;
-	regs[1] = bin2bcd(tm->time.tm_min);
-	regs[2] = bin2bcd(tm->time.tm_hour);
-	regs[3] = bin2bcd(tm->time.tm_mday);
-	regs[4] = ALARM_DIS;
-	msg.addr = client->addr;
-	msg.flags = 0;
-	msg.len = sizeof(regs);
-	msg.buf = regs;
-	err = i2c_transfer(client->adapter, &msg, 1);
+	regs[0] = bin2bcd(tm->time.tm_min);
+	regs[1] = bin2bcd(tm->time.tm_hour);
+	regs[2] = bin2bcd(tm->time.tm_mday);
+	regs[3] = ALARM_DIS;
+
+	err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
+				sizeof(regs));
 	if (err < 0)
 		return err;
 
@@ -386,21 +241,21 @@ static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
 static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
 			     unsigned long arg)
 {
-	struct i2c_client *client = to_i2c_client(dev);
+	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
 	unsigned int flags = 0;
-	u8 value;
+	u32 value;
 	int ret;
 
 	switch (cmd) {
 	case RTC_VL_READ:
-		ret = pcf8523_read(client, PCF8523_REG_CONTROL3, &value);
+		ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
 		if (ret < 0)
 			return ret;
 
 		if (value & PCF8523_CONTROL3_BLF)
 			flags |= RTC_VL_BACKUP_LOW;
 
-		ret = pcf8523_read(client, PCF8523_REG_SECONDS, &value);
+		ret = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
 		if (ret < 0)
 			return ret;
 
@@ -419,12 +274,12 @@ static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
 
 static int pcf8523_rtc_read_offset(struct device *dev, long *offset)
 {
-	struct i2c_client *client = to_i2c_client(dev);
+	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
 	int err;
-	u8 value;
+	u32 value;
 	s8 val;
 
-	err = pcf8523_read(client, PCF8523_REG_OFFSET, &value);
+	err = regmap_read(pcf8523->regmap, PCF8523_REG_OFFSET, &value);
 	if (err < 0)
 		return err;
 
@@ -437,9 +292,9 @@ static int pcf8523_rtc_read_offset(struct device *dev, long *offset)
 
 static int pcf8523_rtc_set_offset(struct device *dev, long offset)
 {
-	struct i2c_client *client = to_i2c_client(dev);
+	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
 	long reg_m0, reg_m1;
-	u8 value;
+	u32 value;
 
 	reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);
 	reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);
@@ -449,7 +304,7 @@ static int pcf8523_rtc_set_offset(struct device *dev, long offset)
 	else
 		value = (reg_m1 & 0x7f) | PCF8523_OFFSET_MODE;
 
-	return pcf8523_write(client, PCF8523_REG_OFFSET, value);
+	return regmap_write(pcf8523->regmap, PCF8523_REG_OFFSET, value);
 }
 
 static const struct rtc_class_ops pcf8523_rtc_ops = {
@@ -463,6 +318,12 @@ static const struct rtc_class_ops pcf8523_rtc_ops = {
 	.set_offset = pcf8523_rtc_set_offset,
 };
 
+static const struct regmap_config regmap_config = {
+        .reg_bits = 8,
+        .val_bits = 8,
+        .max_register = 0x13,
+};
+
 static int pcf8523_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
@@ -478,37 +339,41 @@ static int pcf8523_probe(struct i2c_client *client,
 	if (!pcf8523)
 		return -ENOMEM;
 
+	pcf8523->regmap = devm_regmap_init_i2c(client, &regmap_config);
+	if (IS_ERR(pcf8523->regmap))
+		return PTR_ERR(pcf8523->regmap);
+
 	i2c_set_clientdata(client, pcf8523);
-	pcf8523->client = client;
 
-	err = pcf8523_load_capacitance(client);
+	rtc = devm_rtc_allocate_device(&client->dev);
+	if (IS_ERR(rtc))
+		return PTR_ERR(rtc);
+	pcf8523->rtc = rtc;
+
+	err = pcf8523_load_capacitance(pcf8523, client->dev.of_node);
 	if (err < 0)
 		dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
 			 err);
 
-	err = pcf8523_set_pm(client, 0);
+	err = regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL3,
+				 PCF8523_CONTROL3_PM_MASK, 0);
 	if (err < 0)
 		return err;
 
-	rtc = devm_rtc_allocate_device(&client->dev);
-	if (IS_ERR(rtc))
-		return PTR_ERR(rtc);
-
-	pcf8523->rtc = rtc;
 	rtc->ops = &pcf8523_rtc_ops;
 	rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 	rtc->range_max = RTC_TIMESTAMP_END_2099;
 	rtc->uie_unsupported = 1;
 
 	if (client->irq > 0) {
-		err = pcf8523_write(client, PCF8523_TMR_CLKOUT_CTRL, 0x38);
+		err = regmap_write(pcf8523->regmap, PCF8523_TMR_CLKOUT_CTRL, 0x38);
 		if (err < 0)
 			return err;
 
 		err = devm_request_threaded_irq(&client->dev, client->irq,
 						NULL, pcf8523_irq,
 						IRQF_SHARED | IRQF_ONESHOT | IRQF_TRIGGER_LOW,
-						dev_name(&rtc->dev), client);
+						dev_name(&rtc->dev), pcf8523);
 		if (err)
 			return err;
 
-- 
2.31.1

[PATCH 2/5] rtc: pcf8523: always compile pcf8523_rtc_ioctl

[Alexandre Belloni]

Compiling out pcf8523_rtc_ioctl saves about 5% of the generated machine
code. However, it certainly never happens as the RTC character device
interface is the most useful one and is probably always compiled in.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-pcf8523.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c
index c5d31c525997..103557f48409 100644
--- a/drivers/rtc/rtc-pcf8523.c
+++ b/drivers/rtc/rtc-pcf8523.c
@@ -237,7 +237,6 @@ static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
 	return 0;
 }
 
-#ifdef CONFIG_RTC_INTF_DEV
 static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
 			     unsigned long arg)
 {
@@ -268,9 +267,6 @@ static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
 		return -ENOIOCTLCMD;
 	}
 }
-#else
-#define pcf8523_rtc_ioctl NULL
-#endif
 
 static int pcf8523_rtc_read_offset(struct device *dev, long *offset)
 {
-- 
2.31.1

[PATCH 3/5] rtc: pcf8523: remove unecessary ifdefery

[Alexandre Belloni]

If CONFIG_OF is not defined, of_property_read_bool will return false which
is our default value

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-pcf8523.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c
index 103557f48409..79a571db803b 100644
--- a/drivers/rtc/rtc-pcf8523.c
+++ b/drivers/rtc/rtc-pcf8523.c
@@ -376,9 +376,7 @@ static int pcf8523_probe(struct i2c_client *client,
 		dev_pm_set_wake_irq(&client->dev, client->irq);
 	}
 
-#ifdef CONFIG_OF
 	wakeup_source = of_property_read_bool(client->dev.of_node, "wakeup-source");
-#endif
 	if (client->irq > 0 || wakeup_source)
 		device_init_wakeup(&client->dev, true);
 
-- 
2.31.1

[PATCH 4/5] rtc: pcf8523: allow usage on ACPI platforms

[Alexandre Belloni]

Always provide an OF table to ensure ACPI platforms can also use this
driver.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-pcf8523.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c
index 79a571db803b..181c3425d6c7 100644
--- a/drivers/rtc/rtc-pcf8523.c
+++ b/drivers/rtc/rtc-pcf8523.c
@@ -389,19 +389,17 @@ static const struct i2c_device_id pcf8523_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, pcf8523_id);
 
-#ifdef CONFIG_OF
 static const struct of_device_id pcf8523_of_match[] = {
 	{ .compatible = "nxp,pcf8523" },
 	{ .compatible = "microcrystal,rv8523" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, pcf8523_of_match);
-#endif
 
 static struct i2c_driver pcf8523_driver = {
 	.driver = {
 		.name = "rtc-pcf8523",
-		.of_match_table = of_match_ptr(pcf8523_of_match),
+		.of_match_table = pcf8523_of_match,
 	},
 	.probe = pcf8523_probe,
 	.id_table = pcf8523_id,
-- 
2.31.1

[PATCH 5/5] rtc: pcf8523: add BSM support

[Alexandre Belloni]

Backup Switch Mode allows to select the strategy to use to switch from the
main power supply to the backup power supply. As before, the driver will
switch from standby mode to level mode but now only when it has never been
set.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-pcf8523.c | 103 +++++++++++++++++++++++++++++++++++---
 1 file changed, 97 insertions(+), 6 deletions(-)

diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c
index 181c3425d6c7..c93acade7205 100644
--- a/drivers/rtc/rtc-pcf8523.c
+++ b/drivers/rtc/rtc-pcf8523.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/bcd.h>
+#include <linux/bitfield.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/regmap.h>
@@ -20,10 +21,8 @@
 #define PCF8523_CONTROL2_AF BIT(3)
 
 #define PCF8523_REG_CONTROL3 0x02
-#define PCF8523_CONTROL3_PM_BLD BIT(7) /* battery low detection disabled */
-#define PCF8523_CONTROL3_PM_VDD BIT(6) /* switch-over disabled */
-#define PCF8523_CONTROL3_PM_DSM BIT(5) /* direct switching mode */
-#define PCF8523_CONTROL3_PM_MASK 0xe0
+#define PCF8523_CONTROL3_PM  GENMASK(7,5)
+#define PCF8523_PM_STANDBY   0x7
 #define PCF8523_CONTROL3_BLF BIT(2) /* battery low bit, read-only */
 #define PCF8523_CONTROL3_BSF BIT(3)
 
@@ -237,6 +236,83 @@ static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
 	return 0;
 }
 
+static int pcf8523_param_get(struct device *dev, struct rtc_param *param)
+{
+	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
+	int ret;
+
+	switch(param->param) {
+		u32 value;
+
+	case RTC_PARAM_BACKUP_SWITCH_MODE:
+		ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
+		if (ret < 0)
+			return ret;
+
+		value = FIELD_GET(PCF8523_CONTROL3_PM, value);
+
+		switch(value) {
+		case 0x0:
+		case 0x4:
+			param->uvalue = RTC_BSM_LEVEL;
+			break;
+		case 0x1:
+		case 0x5:
+			param->uvalue = RTC_BSM_DIRECT;
+			break;
+		case PCF8523_PM_STANDBY:
+			param->uvalue = RTC_BSM_STANDBY;
+			break;
+		default:
+			param->uvalue = RTC_BSM_DISABLED;
+		}
+
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int pcf8523_param_set(struct device *dev, struct rtc_param *param)
+{
+	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
+
+	switch(param->param) {
+		u8 mode;
+	case RTC_PARAM_BACKUP_SWITCH_MODE:
+		switch (param->uvalue) {
+		case RTC_BSM_DISABLED:
+			mode = 0x2;
+			break;
+		case RTC_BSM_DIRECT:
+			mode = 0x1;
+			break;
+		case RTC_BSM_LEVEL:
+			mode = 0x0;
+			break;
+		case RTC_BSM_STANDBY:
+			mode = PCF8523_PM_STANDBY;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL3,
+					  PCF8523_CONTROL3_PM,
+					  FIELD_PREP(PCF8523_CONTROL3_PM, mode));
+
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
 			     unsigned long arg)
 {
@@ -312,6 +388,8 @@ static const struct rtc_class_ops pcf8523_rtc_ops = {
 	.ioctl = pcf8523_rtc_ioctl,
 	.read_offset = pcf8523_rtc_read_offset,
 	.set_offset = pcf8523_rtc_set_offset,
+	.param_get = pcf8523_param_get,
+	.param_set = pcf8523_param_set,
 };
 
 static const struct regmap_config regmap_config = {
@@ -326,6 +404,7 @@ static int pcf8523_probe(struct i2c_client *client,
 	struct pcf8523 *pcf8523;
 	struct rtc_device *rtc;
 	bool wakeup_source = false;
+	u32 value;
 	int err;
 
 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
@@ -351,11 +430,23 @@ static int pcf8523_probe(struct i2c_client *client,
 		dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
 			 err);
 
-	err = regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL3,
-				 PCF8523_CONTROL3_PM_MASK, 0);
+	err = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
 	if (err < 0)
 		return err;
 
+	if (value & PCF8523_SECONDS_OS) {
+		err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
+		if (err < 0)
+			return err;
+
+		if (FIELD_GET(PCF8523_CONTROL3_PM, value) == PCF8523_PM_STANDBY) {
+			err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL3,
+					   value & ~PCF8523_CONTROL3_PM);
+			if (err < 0)
+				return err;
+		}
+	}
+
 	rtc->ops = &pcf8523_rtc_ops;
 	rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 	rtc->range_max = RTC_TIMESTAMP_END_2099;
-- 
2.31.1