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![Bartosz Golaszewski](/assets/img/avatar_default.png)
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
194 lines
4.6 KiB
C
194 lines
4.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* RTC interface for Wilco Embedded Controller with R/W abilities
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*
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* Copyright 2018 Google LLC
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*
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* The corresponding platform device is typically registered in
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* drivers/platform/chrome/wilco_ec/core.c
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*/
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#include <linux/bcd.h>
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#include <linux/err.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/platform_data/wilco-ec.h>
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#include <linux/rtc.h>
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#include <linux/timekeeping.h>
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#define EC_COMMAND_CMOS 0x7c
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#define EC_CMOS_TOD_WRITE 0x02
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#define EC_CMOS_TOD_READ 0x08
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/* Message sent to the EC to request the current time. */
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struct ec_rtc_read_request {
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u8 command;
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u8 reserved;
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u8 param;
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} __packed;
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static struct ec_rtc_read_request read_rq = {
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.command = EC_COMMAND_CMOS,
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.param = EC_CMOS_TOD_READ,
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};
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/**
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* struct ec_rtc_read_response - Format of RTC returned by EC.
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* @reserved: Unused byte
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* @second: Second value (0..59)
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* @minute: Minute value (0..59)
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* @hour: Hour value (0..23)
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* @day: Day value (1..31)
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* @month: Month value (1..12)
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* @year: Year value (full year % 100)
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* @century: Century value (full year / 100)
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*
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* All values are presented in binary (not BCD).
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*/
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struct ec_rtc_read_response {
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u8 reserved;
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u8 second;
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u8 minute;
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u8 hour;
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u8 day;
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u8 month;
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u8 year;
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u8 century;
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} __packed;
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/**
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* struct ec_rtc_write_request - Format of RTC sent to the EC.
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* @command: Always EC_COMMAND_CMOS
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* @reserved: Unused byte
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* @param: Always EC_CMOS_TOD_WRITE
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* @century: Century value (full year / 100)
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* @year: Year value (full year % 100)
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* @month: Month value (1..12)
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* @day: Day value (1..31)
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* @hour: Hour value (0..23)
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* @minute: Minute value (0..59)
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* @second: Second value (0..59)
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* @weekday: Day of the week (0=Saturday)
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*
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* All values are presented in BCD.
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*/
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struct ec_rtc_write_request {
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u8 command;
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u8 reserved;
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u8 param;
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u8 century;
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u8 year;
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u8 month;
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u8 day;
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u8 hour;
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u8 minute;
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u8 second;
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u8 weekday;
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} __packed;
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static int wilco_ec_rtc_read(struct device *dev, struct rtc_time *tm)
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{
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struct wilco_ec_device *ec = dev_get_drvdata(dev->parent);
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struct ec_rtc_read_response rtc;
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struct wilco_ec_message msg;
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int ret;
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memset(&msg, 0, sizeof(msg));
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msg.type = WILCO_EC_MSG_LEGACY;
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msg.request_data = &read_rq;
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msg.request_size = sizeof(read_rq);
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msg.response_data = &rtc;
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msg.response_size = sizeof(rtc);
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ret = wilco_ec_mailbox(ec, &msg);
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if (ret < 0)
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return ret;
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tm->tm_sec = rtc.second;
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tm->tm_min = rtc.minute;
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tm->tm_hour = rtc.hour;
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tm->tm_mday = rtc.day;
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tm->tm_mon = rtc.month - 1;
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tm->tm_year = rtc.year + (rtc.century * 100) - 1900;
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/* Ignore other tm fields, man rtc says userspace shouldn't use them. */
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if (rtc_valid_tm(tm)) {
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dev_err(dev, "Time from RTC is invalid: %ptRr\n", tm);
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return -EIO;
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}
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return 0;
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}
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static int wilco_ec_rtc_write(struct device *dev, struct rtc_time *tm)
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{
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struct wilco_ec_device *ec = dev_get_drvdata(dev->parent);
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struct ec_rtc_write_request rtc;
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struct wilco_ec_message msg;
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int year = tm->tm_year + 1900;
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/*
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* Convert from 0=Sunday to 0=Saturday for the EC
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* We DO need to set weekday because the EC controls battery charging
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* schedules that depend on the day of the week.
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*/
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int wday = tm->tm_wday == 6 ? 0 : tm->tm_wday + 1;
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int ret;
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rtc.command = EC_COMMAND_CMOS;
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rtc.param = EC_CMOS_TOD_WRITE;
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rtc.century = bin2bcd(year / 100);
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rtc.year = bin2bcd(year % 100);
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rtc.month = bin2bcd(tm->tm_mon + 1);
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rtc.day = bin2bcd(tm->tm_mday);
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rtc.hour = bin2bcd(tm->tm_hour);
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rtc.minute = bin2bcd(tm->tm_min);
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rtc.second = bin2bcd(tm->tm_sec);
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rtc.weekday = bin2bcd(wday);
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memset(&msg, 0, sizeof(msg));
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msg.type = WILCO_EC_MSG_LEGACY;
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msg.request_data = &rtc;
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msg.request_size = sizeof(rtc);
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ret = wilco_ec_mailbox(ec, &msg);
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if (ret < 0)
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return ret;
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return 0;
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}
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static const struct rtc_class_ops wilco_ec_rtc_ops = {
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.read_time = wilco_ec_rtc_read,
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.set_time = wilco_ec_rtc_write,
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};
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static int wilco_ec_rtc_probe(struct platform_device *pdev)
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{
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struct rtc_device *rtc;
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rtc = devm_rtc_allocate_device(&pdev->dev);
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if (IS_ERR(rtc))
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return PTR_ERR(rtc);
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rtc->ops = &wilco_ec_rtc_ops;
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/* EC only supports this century */
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rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
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rtc->range_max = RTC_TIMESTAMP_END_2099;
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rtc->owner = THIS_MODULE;
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return devm_rtc_register_device(rtc);
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}
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static struct platform_driver wilco_ec_rtc_driver = {
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.driver = {
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.name = "rtc-wilco-ec",
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},
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.probe = wilco_ec_rtc_probe,
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};
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module_platform_driver(wilco_ec_rtc_driver);
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MODULE_ALIAS("platform:rtc-wilco-ec");
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MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>");
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MODULE_LICENSE("GPL v2");
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MODULE_DESCRIPTION("Wilco EC RTC driver");
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