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

From: Alexandre Belloni
Date: Mon Oct 18 2021 - 11:37:32 EST

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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@xxxxxxxxxxx>
---
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 = ®
-
- 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

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