forked from Minki/linux
673536cc5f
Use the BIT macro to define register bits. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20201118002747.1346504-3-alexandre.belloni@bootlin.com
387 lines
8.0 KiB
C
387 lines
8.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Copyright (C) 2012 Avionic Design GmbH
|
|
*/
|
|
|
|
#include <linux/bcd.h>
|
|
#include <linux/i2c.h>
|
|
#include <linux/module.h>
|
|
#include <linux/rtc.h>
|
|
#include <linux/of.h>
|
|
|
|
#define DRIVER_NAME "rtc-pcf8523"
|
|
|
|
#define REG_CONTROL1 0x00
|
|
#define REG_CONTROL1_CAP_SEL BIT(7)
|
|
#define REG_CONTROL1_STOP BIT(5)
|
|
|
|
#define REG_CONTROL3 0x02
|
|
#define REG_CONTROL3_PM_BLD BIT(7) /* battery low detection disabled */
|
|
#define REG_CONTROL3_PM_VDD BIT(6) /* switch-over disabled */
|
|
#define REG_CONTROL3_PM_DSM BIT(5) /* direct switching mode */
|
|
#define REG_CONTROL3_PM_MASK 0xe0
|
|
#define REG_CONTROL3_BLF BIT(2) /* battery low bit, read-only */
|
|
|
|
#define REG_SECONDS 0x03
|
|
#define REG_SECONDS_OS BIT(7)
|
|
|
|
#define REG_MINUTES 0x04
|
|
#define REG_HOURS 0x05
|
|
#define REG_DAYS 0x06
|
|
#define REG_WEEKDAYS 0x07
|
|
#define REG_MONTHS 0x08
|
|
#define REG_YEARS 0x09
|
|
|
|
#define REG_OFFSET 0x0e
|
|
#define REG_OFFSET_MODE BIT(7)
|
|
|
|
static int pcf8523_read(struct i2c_client *client, u8 reg, u8 *valuep)
|
|
{
|
|
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_voltage_low(struct i2c_client *client)
|
|
{
|
|
u8 value;
|
|
int err;
|
|
|
|
err = pcf8523_read(client, REG_CONTROL3, &value);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
return !!(value & REG_CONTROL3_BLF);
|
|
}
|
|
|
|
static int pcf8523_load_capacitance(struct i2c_client *client)
|
|
{
|
|
u32 load;
|
|
u8 value;
|
|
int err;
|
|
|
|
err = pcf8523_read(client, REG_CONTROL1, &value);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
load = 12500;
|
|
of_property_read_u32(client->dev.of_node, "quartz-load-femtofarads",
|
|
&load);
|
|
|
|
switch (load) {
|
|
default:
|
|
dev_warn(&client->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500",
|
|
load);
|
|
fallthrough;
|
|
case 12500:
|
|
value |= REG_CONTROL1_CAP_SEL;
|
|
break;
|
|
case 7000:
|
|
value &= ~REG_CONTROL1_CAP_SEL;
|
|
break;
|
|
}
|
|
|
|
err = pcf8523_write(client, REG_CONTROL1, value);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int pcf8523_set_pm(struct i2c_client *client, u8 pm)
|
|
{
|
|
u8 value;
|
|
int err;
|
|
|
|
err = pcf8523_read(client, REG_CONTROL3, &value);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
value = (value & ~REG_CONTROL3_PM_MASK) | pm;
|
|
|
|
err = pcf8523_write(client, REG_CONTROL3, value);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pcf8523_stop_rtc(struct i2c_client *client)
|
|
{
|
|
u8 value;
|
|
int err;
|
|
|
|
err = pcf8523_read(client, REG_CONTROL1, &value);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
value |= REG_CONTROL1_STOP;
|
|
|
|
err = pcf8523_write(client, 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, REG_CONTROL1, &value);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
value &= ~REG_CONTROL1_STOP;
|
|
|
|
err = pcf8523_write(client, 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 = REG_SECONDS, regs[7];
|
|
struct i2c_msg msgs[2];
|
|
int err;
|
|
|
|
err = pcf8523_voltage_low(client);
|
|
if (err < 0) {
|
|
return err;
|
|
} else if (err > 0) {
|
|
dev_err(dev, "low voltage detected, time is unreliable\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
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));
|
|
if (err < 0)
|
|
return err;
|
|
|
|
if (regs[0] & REG_SECONDS_OS)
|
|
return -EINVAL;
|
|
|
|
tm->tm_sec = bcd2bin(regs[0] & 0x7f);
|
|
tm->tm_min = bcd2bin(regs[1] & 0x7f);
|
|
tm->tm_hour = bcd2bin(regs[2] & 0x3f);
|
|
tm->tm_mday = bcd2bin(regs[3] & 0x3f);
|
|
tm->tm_wday = regs[4] & 0x7;
|
|
tm->tm_mon = bcd2bin(regs[5] & 0x1f) - 1;
|
|
tm->tm_year = bcd2bin(regs[6]) + 100;
|
|
|
|
return 0;
|
|
}
|
|
|
|
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];
|
|
int err;
|
|
|
|
err = pcf8523_stop_rtc(client);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
regs[0] = REG_SECONDS;
|
|
/* This will purposely overwrite REG_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);
|
|
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);
|
|
return err;
|
|
}
|
|
|
|
return pcf8523_start_rtc(client);
|
|
}
|
|
|
|
#ifdef CONFIG_RTC_INTF_DEV
|
|
static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
struct i2c_client *client = to_i2c_client(dev);
|
|
int ret;
|
|
|
|
switch (cmd) {
|
|
case RTC_VL_READ:
|
|
ret = pcf8523_voltage_low(client);
|
|
if (ret < 0)
|
|
return ret;
|
|
if (ret)
|
|
ret = RTC_VL_BACKUP_LOW;
|
|
|
|
return put_user(ret, (unsigned int __user *)arg);
|
|
|
|
default:
|
|
return -ENOIOCTLCMD;
|
|
}
|
|
}
|
|
#else
|
|
#define pcf8523_rtc_ioctl NULL
|
|
#endif
|
|
|
|
static int pcf8523_rtc_read_offset(struct device *dev, long *offset)
|
|
{
|
|
struct i2c_client *client = to_i2c_client(dev);
|
|
int err;
|
|
u8 value;
|
|
s8 val;
|
|
|
|
err = pcf8523_read(client, REG_OFFSET, &value);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
/* sign extend the 7-bit offset value */
|
|
val = value << 1;
|
|
*offset = (value & REG_OFFSET_MODE ? 4069 : 4340) * (val >> 1);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pcf8523_rtc_set_offset(struct device *dev, long offset)
|
|
{
|
|
struct i2c_client *client = to_i2c_client(dev);
|
|
long reg_m0, reg_m1;
|
|
u8 value;
|
|
|
|
reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);
|
|
reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);
|
|
|
|
if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset))
|
|
value = reg_m0 & 0x7f;
|
|
else
|
|
value = (reg_m1 & 0x7f) | REG_OFFSET_MODE;
|
|
|
|
return pcf8523_write(client, REG_OFFSET, value);
|
|
}
|
|
|
|
static const struct rtc_class_ops pcf8523_rtc_ops = {
|
|
.read_time = pcf8523_rtc_read_time,
|
|
.set_time = pcf8523_rtc_set_time,
|
|
.ioctl = pcf8523_rtc_ioctl,
|
|
.read_offset = pcf8523_rtc_read_offset,
|
|
.set_offset = pcf8523_rtc_set_offset,
|
|
};
|
|
|
|
static int pcf8523_probe(struct i2c_client *client,
|
|
const struct i2c_device_id *id)
|
|
{
|
|
struct rtc_device *rtc;
|
|
int err;
|
|
|
|
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
|
|
return -ENODEV;
|
|
|
|
err = pcf8523_load_capacitance(client);
|
|
if (err < 0)
|
|
dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
|
|
err);
|
|
|
|
err = pcf8523_set_pm(client, 0);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
rtc = devm_rtc_allocate_device(&client->dev);
|
|
if (IS_ERR(rtc))
|
|
return PTR_ERR(rtc);
|
|
|
|
rtc->ops = &pcf8523_rtc_ops;
|
|
rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
|
|
rtc->range_max = RTC_TIMESTAMP_END_2099;
|
|
|
|
return devm_rtc_register_device(rtc);
|
|
}
|
|
|
|
static const struct i2c_device_id pcf8523_id[] = {
|
|
{ "pcf8523", 0 },
|
|
{ }
|
|
};
|
|
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 = DRIVER_NAME,
|
|
.of_match_table = of_match_ptr(pcf8523_of_match),
|
|
},
|
|
.probe = pcf8523_probe,
|
|
.id_table = pcf8523_id,
|
|
};
|
|
module_i2c_driver(pcf8523_driver);
|
|
|
|
MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
|
|
MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
|
|
MODULE_LICENSE("GPL v2");
|