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android_kernel_xiaomi_sm7250/drivers/rtc/rtc-pcf2127.c
Bruno Thomsen 630c20f52a rtc: pcf2127: bugfix: read rtc disables watchdog 
[ Upstream commit 7f43020e3bdb63d65661ed377682702f8b34d3ea ]

The previous fix listed bulk read of registers as root cause of
accendential disabling of watchdog, since the watchdog counter
register (WD_VAL) was zeroed.

Fixes: 3769a375ab rtc: pcf2127: bulk read only date and time registers.

Tested with the same PCF2127 chip as Sean reveled root cause
of WD_VAL register value zeroing was caused by reading CTRL2
register which is one of the watchdog feature control registers.

So the solution is to not read the first two control registers
(CTRL1 and CTRL2) in pcf2127_rtc_read_time as they are not
needed anyway. Size of local buf variable is kept to allow
easy usage of register defines to improve readability of code.

Debug trace line was updated after CTRL1 and CTRL2 are no longer
read from the chip. Also replaced magic numbers in buf access
with register defines.

Signed-off-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Link: https://lore.kernel.org/r/20190822131936.18772-3-bruno.thomsen@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-27 14:51:07 +01:00

498 lines
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/*
* An I2C and SPI driver for the NXP PCF2127/29 RTC
* Copyright 2013 Til-Technologies
*
* Author: Renaud Cerrato <r.cerrato@til-technologies.fr>
*
* based on the other drivers in this same directory.
*
* Datasheet: http://cache.nxp.com/documents/data_sheet/PCF2127.pdf
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/i2c.h>
#include <linux/spi/spi.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/regmap.h>
#define PCF2127_REG_CTRL1 (0x00) /* Control Register 1 */
#define PCF2127_REG_CTRL2 (0x01) /* Control Register 2 */
#define PCF2127_REG_CTRL3 (0x02) /* Control Register 3 */
#define PCF2127_REG_CTRL3_BLF BIT(2)
#define PCF2127_REG_SC (0x03) /* datetime */
#define PCF2127_REG_MN (0x04)
#define PCF2127_REG_HR (0x05)
#define PCF2127_REG_DM (0x06)
#define PCF2127_REG_DW (0x07)
#define PCF2127_REG_MO (0x08)
#define PCF2127_REG_YR (0x09)
/* the pcf2127 has 512 bytes nvmem, pcf2129 doesn't */
#define PCF2127_REG_RAM_addr_MSB 0x1a
#define PCF2127_REG_RAM_wrt_cmd 0x1c
#define PCF2127_REG_RAM_rd_cmd 0x1d
#define PCF2127_OSF BIT(7) /* Oscillator Fail flag */
struct pcf2127 {
struct rtc_device *rtc;
struct regmap *regmap;
};
/*
* In the routines that deal directly with the pcf2127 hardware, we use
* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
*/
static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
unsigned char buf[10];
int ret;
/*
* Avoid reading CTRL2 register as it causes WD_VAL register
* value to reset to 0 which means watchdog is stopped.
*/
ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_CTRL3,
(buf + PCF2127_REG_CTRL3),
ARRAY_SIZE(buf) - PCF2127_REG_CTRL3);
if (ret) {
dev_err(dev, "%s: read error\n", __func__);
return ret;
}
if (buf[PCF2127_REG_CTRL3] & PCF2127_REG_CTRL3_BLF)
dev_info(dev,
"low voltage detected, check/replace RTC battery.\n");
if (buf[PCF2127_REG_SC] & PCF2127_OSF) {
/*
* no need clear the flag here,
* it will be cleared once the new date is saved
*/
dev_warn(dev,
"oscillator stop detected, date/time is not reliable\n");
return -EINVAL;
}
dev_dbg(dev,
"%s: raw data is cr3=%02x, sec=%02x, min=%02x, hr=%02x, "
"mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
__func__, buf[PCF2127_REG_CTRL3], buf[PCF2127_REG_SC],
buf[PCF2127_REG_MN], buf[PCF2127_REG_HR],
buf[PCF2127_REG_DM], buf[PCF2127_REG_DW],
buf[PCF2127_REG_MO], buf[PCF2127_REG_YR]);
tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F);
tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F);
tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */
tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F);
tm->tm_wday = buf[PCF2127_REG_DW] & 0x07;
tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]);
if (tm->tm_year < 70)
tm->tm_year += 100; /* assume we are in 1970...2069 */
dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n",
__func__,
tm->tm_sec, tm->tm_min, tm->tm_hour,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
return 0;
}
static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
unsigned char buf[7];
int i = 0, err;
dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n",
__func__,
tm->tm_sec, tm->tm_min, tm->tm_hour,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
/* hours, minutes and seconds */
buf[i++] = bin2bcd(tm->tm_sec); /* this will also clear OSF flag */
buf[i++] = bin2bcd(tm->tm_min);
buf[i++] = bin2bcd(tm->tm_hour);
buf[i++] = bin2bcd(tm->tm_mday);
buf[i++] = tm->tm_wday & 0x07;
/* month, 1 - 12 */
buf[i++] = bin2bcd(tm->tm_mon + 1);
/* year */
buf[i++] = bin2bcd(tm->tm_year % 100);
/* write register's data */
err = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_SC, buf, i);
if (err) {
dev_err(dev,
"%s: err=%d", __func__, err);
return err;
}
return 0;
}
#ifdef CONFIG_RTC_INTF_DEV
static int pcf2127_rtc_ioctl(struct device *dev,
unsigned int cmd, unsigned long arg)
{
struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
int touser;
int ret;
switch (cmd) {
case RTC_VL_READ:
ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &touser);
if (ret)
return ret;
touser = touser & PCF2127_REG_CTRL3_BLF ? 1 : 0;
if (copy_to_user((void __user *)arg, &touser, sizeof(int)))
return -EFAULT;
return 0;
default:
return -ENOIOCTLCMD;
}
}
#else
#define pcf2127_rtc_ioctl NULL
#endif
static const struct rtc_class_ops pcf2127_rtc_ops = {
.ioctl = pcf2127_rtc_ioctl,
.read_time = pcf2127_rtc_read_time,
.set_time = pcf2127_rtc_set_time,
};
static int pcf2127_nvmem_read(void *priv, unsigned int offset,
void *val, size_t bytes)
{
struct pcf2127 *pcf2127 = priv;
int ret;
unsigned char offsetbuf[] = { offset >> 8, offset };
ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_addr_MSB,
offsetbuf, 2);
if (ret)
return ret;
ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_RAM_rd_cmd,
val, bytes);
return ret ?: bytes;
}
static int pcf2127_nvmem_write(void *priv, unsigned int offset,
void *val, size_t bytes)
{
struct pcf2127 *pcf2127 = priv;
int ret;
unsigned char offsetbuf[] = { offset >> 8, offset };
ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_addr_MSB,
offsetbuf, 2);
if (ret)
return ret;
ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_wrt_cmd,
val, bytes);
return ret ?: bytes;
}
static int pcf2127_probe(struct device *dev, struct regmap *regmap,
const char *name, bool has_nvmem)
{
struct pcf2127 *pcf2127;
int ret = 0;
dev_dbg(dev, "%s\n", __func__);
pcf2127 = devm_kzalloc(dev, sizeof(*pcf2127), GFP_KERNEL);
if (!pcf2127)
return -ENOMEM;
pcf2127->regmap = regmap;
dev_set_drvdata(dev, pcf2127);
pcf2127->rtc = devm_rtc_device_register(dev, name, &pcf2127_rtc_ops,
THIS_MODULE);
if (IS_ERR(pcf2127->rtc))
return PTR_ERR(pcf2127->rtc);
if (has_nvmem) {
struct nvmem_config nvmem_cfg = {
.priv = pcf2127,
.reg_read = pcf2127_nvmem_read,
.reg_write = pcf2127_nvmem_write,
.size = 512,
};
ret = rtc_nvmem_register(pcf2127->rtc, &nvmem_cfg);
}
return ret;
}
#ifdef CONFIG_OF
static const struct of_device_id pcf2127_of_match[] = {
{ .compatible = "nxp,pcf2127" },
{ .compatible = "nxp,pcf2129" },
{}
};
MODULE_DEVICE_TABLE(of, pcf2127_of_match);
#endif
#if IS_ENABLED(CONFIG_I2C)
static int pcf2127_i2c_write(void *context, const void *data, size_t count)
{
struct device *dev = context;
struct i2c_client *client = to_i2c_client(dev);
int ret;
ret = i2c_master_send(client, data, count);
if (ret != count)
return ret < 0 ? ret : -EIO;
return 0;
}
static int pcf2127_i2c_gather_write(void *context,
const void *reg, size_t reg_size,
const void *val, size_t val_size)
{
struct device *dev = context;
struct i2c_client *client = to_i2c_client(dev);
int ret;
void *buf;
if (WARN_ON(reg_size != 1))
return -EINVAL;
buf = kmalloc(val_size + 1, GFP_KERNEL);
if (!buf)
return -ENOMEM;
memcpy(buf, reg, 1);
memcpy(buf + 1, val, val_size);
ret = i2c_master_send(client, buf, val_size + 1);
kfree(buf);
if (ret != val_size + 1)
return ret < 0 ? ret : -EIO;
return 0;
}
static int pcf2127_i2c_read(void *context, const void *reg, size_t reg_size,
void *val, size_t val_size)
{
struct device *dev = context;
struct i2c_client *client = to_i2c_client(dev);
int ret;
if (WARN_ON(reg_size != 1))
return -EINVAL;
ret = i2c_master_send(client, reg, 1);
if (ret != 1)
return ret < 0 ? ret : -EIO;
ret = i2c_master_recv(client, val, val_size);
if (ret != val_size)
return ret < 0 ? ret : -EIO;
return 0;
}
/*
* The reason we need this custom regmap_bus instead of using regmap_init_i2c()
* is that the STOP condition is required between set register address and
* read register data when reading from registers.
*/
static const struct regmap_bus pcf2127_i2c_regmap = {
.write = pcf2127_i2c_write,
.gather_write = pcf2127_i2c_gather_write,
.read = pcf2127_i2c_read,
};
static struct i2c_driver pcf2127_i2c_driver;
static int pcf2127_i2c_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct regmap *regmap;
static const struct regmap_config config = {
.reg_bits = 8,
.val_bits = 8,
};
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
regmap = devm_regmap_init(&client->dev, &pcf2127_i2c_regmap,
&client->dev, &config);
if (IS_ERR(regmap)) {
dev_err(&client->dev, "%s: regmap allocation failed: %ld\n",
__func__, PTR_ERR(regmap));
return PTR_ERR(regmap);
}
return pcf2127_probe(&client->dev, regmap,
pcf2127_i2c_driver.driver.name, id->driver_data);
}
static const struct i2c_device_id pcf2127_i2c_id[] = {
{ "pcf2127", 1 },
{ "pcf2129", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, pcf2127_i2c_id);
static struct i2c_driver pcf2127_i2c_driver = {
.driver = {
.name = "rtc-pcf2127-i2c",
.of_match_table = of_match_ptr(pcf2127_of_match),
},
.probe = pcf2127_i2c_probe,
.id_table = pcf2127_i2c_id,
};
static int pcf2127_i2c_register_driver(void)
{
return i2c_add_driver(&pcf2127_i2c_driver);
}
static void pcf2127_i2c_unregister_driver(void)
{
i2c_del_driver(&pcf2127_i2c_driver);
}
#else
static int pcf2127_i2c_register_driver(void)
{
return 0;
}
static void pcf2127_i2c_unregister_driver(void)
{
}
#endif
#if IS_ENABLED(CONFIG_SPI_MASTER)
static struct spi_driver pcf2127_spi_driver;
static int pcf2127_spi_probe(struct spi_device *spi)
{
static const struct regmap_config config = {
.reg_bits = 8,
.val_bits = 8,
.read_flag_mask = 0xa0,
.write_flag_mask = 0x20,
};
struct regmap *regmap;
regmap = devm_regmap_init_spi(spi, &config);
if (IS_ERR(regmap)) {
dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
__func__, PTR_ERR(regmap));
return PTR_ERR(regmap);
}
return pcf2127_probe(&spi->dev, regmap, pcf2127_spi_driver.driver.name,
spi_get_device_id(spi)->driver_data);
}
static const struct spi_device_id pcf2127_spi_id[] = {
{ "pcf2127", 1 },
{ "pcf2129", 0 },
{ }
};
MODULE_DEVICE_TABLE(spi, pcf2127_spi_id);
static struct spi_driver pcf2127_spi_driver = {
.driver = {
.name = "rtc-pcf2127-spi",
.of_match_table = of_match_ptr(pcf2127_of_match),
},
.probe = pcf2127_spi_probe,
.id_table = pcf2127_spi_id,
};
static int pcf2127_spi_register_driver(void)
{
return spi_register_driver(&pcf2127_spi_driver);
}
static void pcf2127_spi_unregister_driver(void)
{
spi_unregister_driver(&pcf2127_spi_driver);
}
#else
static int pcf2127_spi_register_driver(void)
{
return 0;
}
static void pcf2127_spi_unregister_driver(void)
{
}
#endif
static int __init pcf2127_init(void)
{
int ret;
ret = pcf2127_i2c_register_driver();
if (ret) {
pr_err("Failed to register pcf2127 i2c driver: %d\n", ret);
return ret;
}
ret = pcf2127_spi_register_driver();
if (ret) {
pr_err("Failed to register pcf2127 spi driver: %d\n", ret);
pcf2127_i2c_unregister_driver();
}
return ret;
}
module_init(pcf2127_init)
static void __exit pcf2127_exit(void)
{
pcf2127_spi_unregister_driver();
pcf2127_i2c_unregister_driver();
}
module_exit(pcf2127_exit)
MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
MODULE_DESCRIPTION("NXP PCF2127/29 RTC driver");
MODULE_LICENSE("GPL v2");
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