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linux/drivers/rtc/rtc-ds1343.c
Bartosz Golaszewski fdcfd85433 rtc: rework rtc_register_device() resource management 
rtc_register_device() is a managed interface but it doesn't use devres
by itself - instead it marks an rtc_device as "registered" and the devres
callback for devm_rtc_allocate_device() takes care of resource release.

This doesn't correspond with the design behind devres where managed
structures should not be aware of being managed. The correct solution
here is to register a separate devres callback for unregistering the
device.

While at it: rename rtc_register_device() to devm_rtc_register_device()
and add it to the list of managed interfaces in devres.rst. This way we
can avoid any potential confusion of driver developers who may expect
there to exist a corresponding unregister function.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201109163409.24301-8-brgl@bgdev.pl
2020-11-19 12:50:12 +01:00

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// SPDX-License-Identifier: GPL-2.0-only
/* rtc-ds1343.c
*
* Driver for Dallas Semiconductor DS1343 Low Current, SPI Compatible
* Real Time Clock
*
* Author : Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
* Ankur Srivastava <sankurece@gmail.com> : DS1343 Nvram Support
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/spi/spi.h>
#include <linux/regmap.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/pm.h>
#include <linux/pm_wakeirq.h>
#include <linux/slab.h>
#define DALLAS_MAXIM_DS1343 0
#define DALLAS_MAXIM_DS1344 1
/* RTC DS1343 Registers */
#define DS1343_SECONDS_REG 0x00
#define DS1343_MINUTES_REG 0x01
#define DS1343_HOURS_REG 0x02
#define DS1343_DAY_REG 0x03
#define DS1343_DATE_REG 0x04
#define DS1343_MONTH_REG 0x05
#define DS1343_YEAR_REG 0x06
#define DS1343_ALM0_SEC_REG 0x07
#define DS1343_ALM0_MIN_REG 0x08
#define DS1343_ALM0_HOUR_REG 0x09
#define DS1343_ALM0_DAY_REG 0x0A
#define DS1343_ALM1_SEC_REG 0x0B
#define DS1343_ALM1_MIN_REG 0x0C
#define DS1343_ALM1_HOUR_REG 0x0D
#define DS1343_ALM1_DAY_REG 0x0E
#define DS1343_CONTROL_REG 0x0F
#define DS1343_STATUS_REG 0x10
#define DS1343_TRICKLE_REG 0x11
#define DS1343_NVRAM 0x20
#define DS1343_NVRAM_LEN 96
/* DS1343 Control Registers bits */
#define DS1343_EOSC 0x80
#define DS1343_DOSF 0x20
#define DS1343_EGFIL 0x10
#define DS1343_SQW 0x08
#define DS1343_INTCN 0x04
#define DS1343_A1IE 0x02
#define DS1343_A0IE 0x01
/* DS1343 Status Registers bits */
#define DS1343_OSF 0x80
#define DS1343_IRQF1 0x02
#define DS1343_IRQF0 0x01
/* DS1343 Trickle Charger Registers bits */
#define DS1343_TRICKLE_MAGIC 0xa0
#define DS1343_TRICKLE_DS1 0x08
#define DS1343_TRICKLE_1K 0x01
#define DS1343_TRICKLE_2K 0x02
#define DS1343_TRICKLE_4K 0x03
static const struct spi_device_id ds1343_id[] = {
{ "ds1343", DALLAS_MAXIM_DS1343 },
{ "ds1344", DALLAS_MAXIM_DS1344 },
{ }
};
MODULE_DEVICE_TABLE(spi, ds1343_id);
struct ds1343_priv {
struct rtc_device *rtc;
struct regmap *map;
int irq;
};
static ssize_t ds1343_show_glitchfilter(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
int glitch_filt_status, data;
int res;
res = regmap_read(priv->map, DS1343_CONTROL_REG, &data);
if (res)
return res;
glitch_filt_status = !!(data & DS1343_EGFIL);
if (glitch_filt_status)
return sprintf(buf, "enabled\n");
else
return sprintf(buf, "disabled\n");
}
static ssize_t ds1343_store_glitchfilter(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
int data = 0;
int res;
if (strncmp(buf, "enabled", 7) == 0)
data = DS1343_EGFIL;
else if (strncmp(buf, "disabled", 8))
return -EINVAL;
res = regmap_update_bits(priv->map, DS1343_CONTROL_REG,
DS1343_EGFIL, data);
if (res)
return res;
return count;
}
static DEVICE_ATTR(glitch_filter, S_IRUGO | S_IWUSR, ds1343_show_glitchfilter,
ds1343_store_glitchfilter);
static int ds1343_nvram_write(void *priv, unsigned int off, void *val,
size_t bytes)
{
struct ds1343_priv *ds1343 = priv;
return regmap_bulk_write(ds1343->map, DS1343_NVRAM + off, val, bytes);
}
static int ds1343_nvram_read(void *priv, unsigned int off, void *val,
size_t bytes)
{
struct ds1343_priv *ds1343 = priv;
return regmap_bulk_read(ds1343->map, DS1343_NVRAM + off, val, bytes);
}
static ssize_t ds1343_show_tricklecharger(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
int res, data;
char *diodes = "disabled", *resistors = " ";
res = regmap_read(priv->map, DS1343_TRICKLE_REG, &data);
if (res)
return res;
if ((data & 0xf0) == DS1343_TRICKLE_MAGIC) {
switch (data & 0x0c) {
case DS1343_TRICKLE_DS1:
diodes = "one diode,";
break;
default:
diodes = "no diode,";
break;
}
switch (data & 0x03) {
case DS1343_TRICKLE_1K:
resistors = "1k Ohm";
break;
case DS1343_TRICKLE_2K:
resistors = "2k Ohm";
break;
case DS1343_TRICKLE_4K:
resistors = "4k Ohm";
break;
default:
diodes = "disabled";
break;
}
}
return sprintf(buf, "%s %s\n", diodes, resistors);
}
static DEVICE_ATTR(trickle_charger, S_IRUGO, ds1343_show_tricklecharger, NULL);
static struct attribute *ds1343_attrs[] = {
&dev_attr_glitch_filter.attr,
&dev_attr_trickle_charger.attr,
NULL
};
static const struct attribute_group ds1343_attr_group = {
.attrs = ds1343_attrs,
};
static int ds1343_read_time(struct device *dev, struct rtc_time *dt)
{
struct ds1343_priv *priv = dev_get_drvdata(dev);
unsigned char buf[7];
int res;
res = regmap_bulk_read(priv->map, DS1343_SECONDS_REG, buf, 7);
if (res)
return res;
dt->tm_sec = bcd2bin(buf[0]);
dt->tm_min = bcd2bin(buf[1]);
dt->tm_hour = bcd2bin(buf[2] & 0x3F);
dt->tm_wday = bcd2bin(buf[3]) - 1;
dt->tm_mday = bcd2bin(buf[4]);
dt->tm_mon = bcd2bin(buf[5] & 0x1F) - 1;
dt->tm_year = bcd2bin(buf[6]) + 100; /* year offset from 1900 */
return 0;
}
static int ds1343_set_time(struct device *dev, struct rtc_time *dt)
{
struct ds1343_priv *priv = dev_get_drvdata(dev);
u8 buf[7];
buf[0] = bin2bcd(dt->tm_sec);
buf[1] = bin2bcd(dt->tm_min);
buf[2] = bin2bcd(dt->tm_hour) & 0x3F;
buf[3] = bin2bcd(dt->tm_wday + 1);
buf[4] = bin2bcd(dt->tm_mday);
buf[5] = bin2bcd(dt->tm_mon + 1);
buf[6] = bin2bcd(dt->tm_year - 100);
return regmap_bulk_write(priv->map, DS1343_SECONDS_REG,
buf, sizeof(buf));
}
static int ds1343_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct ds1343_priv *priv = dev_get_drvdata(dev);
unsigned char buf[4];
unsigned int val;
int res;
if (priv->irq <= 0)
return -EINVAL;
res = regmap_read(priv->map, DS1343_STATUS_REG, &val);
if (res)
return res;
alarm->pending = !!(val & DS1343_IRQF0);
res = regmap_read(priv->map, DS1343_CONTROL_REG, &val);
if (res)
return res;
alarm->enabled = !!(val & DS1343_A0IE);
res = regmap_bulk_read(priv->map, DS1343_ALM0_SEC_REG, buf, 4);
if (res)
return res;
alarm->time.tm_sec = bcd2bin(buf[0]) & 0x7f;
alarm->time.tm_min = bcd2bin(buf[1]) & 0x7f;
alarm->time.tm_hour = bcd2bin(buf[2]) & 0x3f;
alarm->time.tm_mday = bcd2bin(buf[3]) & 0x3f;
return 0;
}
static int ds1343_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct ds1343_priv *priv = dev_get_drvdata(dev);
unsigned char buf[4];
int res = 0;
if (priv->irq <= 0)
return -EINVAL;
res = regmap_update_bits(priv->map, DS1343_CONTROL_REG, DS1343_A0IE, 0);
if (res)
return res;
buf[0] = bin2bcd(alarm->time.tm_sec);
buf[1] = bin2bcd(alarm->time.tm_min);
buf[2] = bin2bcd(alarm->time.tm_hour);
buf[3] = bin2bcd(alarm->time.tm_mday);
res = regmap_bulk_write(priv->map, DS1343_ALM0_SEC_REG, buf, 4);
if (res)
return res;
if (alarm->enabled)
res = regmap_update_bits(priv->map, DS1343_CONTROL_REG,
DS1343_A0IE, DS1343_A0IE);
return res;
}
static int ds1343_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct ds1343_priv *priv = dev_get_drvdata(dev);
if (priv->irq <= 0)
return -EINVAL;
return regmap_update_bits(priv->map, DS1343_CONTROL_REG,
DS1343_A0IE, enabled ? DS1343_A0IE : 0);
}
static irqreturn_t ds1343_thread(int irq, void *dev_id)
{
struct ds1343_priv *priv = dev_id;
unsigned int stat;
int res = 0;
rtc_lock(priv->rtc);
res = regmap_read(priv->map, DS1343_STATUS_REG, &stat);
if (res)
goto out;
if (stat & DS1343_IRQF0) {
stat &= ~DS1343_IRQF0;
regmap_write(priv->map, DS1343_STATUS_REG, stat);
rtc_update_irq(priv->rtc, 1, RTC_AF | RTC_IRQF);
regmap_update_bits(priv->map, DS1343_CONTROL_REG,
DS1343_A0IE, 0);
}
out:
rtc_unlock(priv->rtc);
return IRQ_HANDLED;
}
static const struct rtc_class_ops ds1343_rtc_ops = {
.read_time = ds1343_read_time,
.set_time = ds1343_set_time,
.read_alarm = ds1343_read_alarm,
.set_alarm = ds1343_set_alarm,
.alarm_irq_enable = ds1343_alarm_irq_enable,
};
static int ds1343_probe(struct spi_device *spi)
{
struct ds1343_priv *priv;
struct regmap_config config = { .reg_bits = 8, .val_bits = 8,
.write_flag_mask = 0x80, };
unsigned int data;
int res;
struct nvmem_config nvmem_cfg = {
.name = "ds1343-",
.word_size = 1,
.stride = 1,
.size = DS1343_NVRAM_LEN,
.reg_read = ds1343_nvram_read,
.reg_write = ds1343_nvram_write,
};
priv = devm_kzalloc(&spi->dev, sizeof(struct ds1343_priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
/* RTC DS1347 works in spi mode 3 and
* its chip select is active high. Active high should be defined as
* "inverse polarity" as GPIO-based chip selects can be logically
* active high but inverted by the GPIO library.
*/
spi->mode |= SPI_MODE_3;
spi->mode ^= SPI_CS_HIGH;
spi->bits_per_word = 8;
res = spi_setup(spi);
if (res)
return res;
spi_set_drvdata(spi, priv);
priv->map = devm_regmap_init_spi(spi, &config);
if (IS_ERR(priv->map)) {
dev_err(&spi->dev, "spi regmap init failed for rtc ds1343\n");
return PTR_ERR(priv->map);
}
res = regmap_read(priv->map, DS1343_SECONDS_REG, &data);
if (res)
return res;
regmap_read(priv->map, DS1343_CONTROL_REG, &data);
data |= DS1343_INTCN;
data &= ~(DS1343_EOSC | DS1343_A1IE | DS1343_A0IE);
regmap_write(priv->map, DS1343_CONTROL_REG, data);
regmap_read(priv->map, DS1343_STATUS_REG, &data);
data &= ~(DS1343_OSF | DS1343_IRQF1 | DS1343_IRQF0);
regmap_write(priv->map, DS1343_STATUS_REG, data);
priv->rtc = devm_rtc_allocate_device(&spi->dev);
if (IS_ERR(priv->rtc))
return PTR_ERR(priv->rtc);
priv->rtc->ops = &ds1343_rtc_ops;
priv->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
priv->rtc->range_max = RTC_TIMESTAMP_END_2099;
res = rtc_add_group(priv->rtc, &ds1343_attr_group);
if (res)
dev_err(&spi->dev,
"unable to create sysfs entries for rtc ds1343\n");
res = devm_rtc_register_device(priv->rtc);
if (res)
return res;
nvmem_cfg.priv = priv;
devm_rtc_nvmem_register(priv->rtc, &nvmem_cfg);
priv->irq = spi->irq;
if (priv->irq >= 0) {
res = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
ds1343_thread, IRQF_ONESHOT,
"ds1343", priv);
if (res) {
priv->irq = -1;
dev_err(&spi->dev,
"unable to request irq for rtc ds1343\n");
} else {
device_init_wakeup(&spi->dev, true);
dev_pm_set_wake_irq(&spi->dev, spi->irq);
}
}
return 0;
}
static int ds1343_remove(struct spi_device *spi)
{
dev_pm_clear_wake_irq(&spi->dev);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int ds1343_suspend(struct device *dev)
{
struct spi_device *spi = to_spi_device(dev);
if (spi->irq >= 0 && device_may_wakeup(dev))
enable_irq_wake(spi->irq);
return 0;
}
static int ds1343_resume(struct device *dev)
{
struct spi_device *spi = to_spi_device(dev);
if (spi->irq >= 0 && device_may_wakeup(dev))
disable_irq_wake(spi->irq);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(ds1343_pm, ds1343_suspend, ds1343_resume);
static struct spi_driver ds1343_driver = {
.driver = {
.name = "ds1343",
.pm = &ds1343_pm,
},
.probe = ds1343_probe,
.remove = ds1343_remove,
.id_table = ds1343_id,
};
module_spi_driver(ds1343_driver);
MODULE_DESCRIPTION("DS1343 RTC SPI Driver");
MODULE_AUTHOR("Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>,"
"Ankur Srivastava <sankurece@gmail.com>");
MODULE_LICENSE("GPL v2");
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