rtc: cros-ec: add cros-ec-rtc driver.
On platforms with a Chrome OS EC, the EC can function as a simple RTC. Add a basic driver with this functionality. Signed-off-by: Stephen Barber <smbarber@chromium.org> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Acked-by: Benson Leung <bleung@chromium.org> Reviewed-by: Brian Norris <briannorris@chromium.org> Tested-by: Brian Norris <briannorris@chromium.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
Stephen Barber
Alexandre Belloni
parent
3eff6d2cc9
commit
6f2a71a31a
3 changed files with 424 additions and 0 deletions
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@ -1255,6 +1255,16 @@ config RTC_DRV_ZYNQMP
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If you say yes here you get support for the RTC controller found on
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Xilinx Zynq Ultrascale+ MPSoC.
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config RTC_DRV_CROS_EC
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tristate "Chrome OS EC RTC driver"
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depends on MFD_CROS_EC
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help
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If you say yes here you will get support for the
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Chrome OS Embedded Controller's RTC.
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This driver can also be built as a module. If so, the module
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will be called rtc-cros-ec.
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comment "on-CPU RTC drivers"
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config RTC_DRV_ASM9260
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@ -44,6 +44,7 @@ obj-$(CONFIG_RTC_DRV_BQ4802) += rtc-bq4802.o
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obj-$(CONFIG_RTC_DRV_CMOS) += rtc-cmos.o
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obj-$(CONFIG_RTC_DRV_COH901331) += rtc-coh901331.o
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obj-$(CONFIG_RTC_DRV_CPCAP) += rtc-cpcap.o
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obj-$(CONFIG_RTC_DRV_CROS_EC) += rtc-cros-ec.o
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obj-$(CONFIG_RTC_DRV_DA9052) += rtc-da9052.o
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obj-$(CONFIG_RTC_DRV_DA9055) += rtc-da9055.o
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obj-$(CONFIG_RTC_DRV_DA9063) += rtc-da9063.o
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413
drivers/rtc/rtc-cros-ec.c
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413
drivers/rtc/rtc-cros-ec.c
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@ -0,0 +1,413 @@
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/*
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* RTC driver for Chrome OS Embedded Controller
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*
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* Copyright (c) 2017, Google, Inc
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*
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* Author: Stephen Barber <smbarber@chromium.org>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*/
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#include <linux/kernel.h>
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#include <linux/mfd/cros_ec.h>
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#include <linux/mfd/cros_ec_commands.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/rtc.h>
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#include <linux/slab.h>
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#define DRV_NAME "cros-ec-rtc"
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/**
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* struct cros_ec_rtc - Driver data for EC RTC
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*
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* @cros_ec: Pointer to EC device
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* @rtc: Pointer to RTC device
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* @notifier: Notifier info for responding to EC events
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* @saved_alarm: Alarm to restore when interrupts are reenabled
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*/
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struct cros_ec_rtc {
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struct cros_ec_device *cros_ec;
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struct rtc_device *rtc;
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struct notifier_block notifier;
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u32 saved_alarm;
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};
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static int cros_ec_rtc_get(struct cros_ec_device *cros_ec, u32 command,
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u32 *response)
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{
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int ret;
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struct {
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struct cros_ec_command msg;
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struct ec_response_rtc data;
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} __packed msg;
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memset(&msg, 0, sizeof(msg));
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msg.msg.command = command;
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msg.msg.insize = sizeof(msg.data);
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ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
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if (ret < 0) {
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dev_err(cros_ec->dev,
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"error getting %s from EC: %d\n",
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command == EC_CMD_RTC_GET_VALUE ? "time" : "alarm",
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ret);
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return ret;
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}
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*response = msg.data.time;
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return 0;
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}
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static int cros_ec_rtc_set(struct cros_ec_device *cros_ec, u32 command,
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u32 param)
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{
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int ret = 0;
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struct {
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struct cros_ec_command msg;
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struct ec_response_rtc data;
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} __packed msg;
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memset(&msg, 0, sizeof(msg));
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msg.msg.command = command;
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msg.msg.outsize = sizeof(msg.data);
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msg.data.time = param;
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ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
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if (ret < 0) {
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dev_err(cros_ec->dev, "error setting %s on EC: %d\n",
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command == EC_CMD_RTC_SET_VALUE ? "time" : "alarm",
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ret);
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return ret;
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}
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return 0;
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}
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/* Read the current time from the EC. */
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static int cros_ec_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
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struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
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int ret;
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u32 time;
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ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &time);
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if (ret) {
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dev_err(dev, "error getting time: %d\n", ret);
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return ret;
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}
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rtc_time64_to_tm(time, tm);
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return 0;
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}
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/* Set the current EC time. */
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static int cros_ec_rtc_set_time(struct device *dev, struct rtc_time *tm)
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{
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struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
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struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
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int ret;
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time64_t time;
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time = rtc_tm_to_time64(tm);
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if (time < 0 || time > U32_MAX)
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return -EINVAL;
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ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_VALUE, (u32)time);
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if (ret < 0) {
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dev_err(dev, "error setting time: %d\n", ret);
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return ret;
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}
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return 0;
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}
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/* Read alarm time from RTC. */
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static int cros_ec_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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{
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struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
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struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
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int ret;
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u32 current_time, alarm_offset;
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/*
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* The EC host command for getting the alarm is relative (i.e. 5
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* seconds from now) whereas rtc_wkalrm is absolute. Get the current
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* RTC time first so we can calculate the relative time.
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*/
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ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time);
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if (ret < 0) {
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dev_err(dev, "error getting time: %d\n", ret);
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return ret;
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}
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ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM, &alarm_offset);
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if (ret < 0) {
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dev_err(dev, "error getting alarm: %d\n", ret);
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return ret;
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}
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rtc_time64_to_tm(current_time + alarm_offset, &alrm->time);
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return 0;
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}
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/* Set the EC's RTC alarm. */
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static int cros_ec_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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{
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struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
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struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
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int ret;
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time64_t alarm_time;
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u32 current_time, alarm_offset;
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/*
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* The EC host command for setting the alarm is relative
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* (i.e. 5 seconds from now) whereas rtc_wkalrm is absolute.
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* Get the current RTC time first so we can calculate the
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* relative time.
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*/
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ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time);
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if (ret < 0) {
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dev_err(dev, "error getting time: %d\n", ret);
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return ret;
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}
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alarm_time = rtc_tm_to_time64(&alrm->time);
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if (alarm_time < 0 || alarm_time > U32_MAX)
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return -EINVAL;
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if (!alrm->enabled) {
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/*
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* If the alarm is being disabled, send an alarm
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* clear command.
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*/
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alarm_offset = EC_RTC_ALARM_CLEAR;
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cros_ec_rtc->saved_alarm = (u32)alarm_time;
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} else {
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/* Don't set an alarm in the past. */
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if ((u32)alarm_time < current_time)
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alarm_offset = EC_RTC_ALARM_CLEAR;
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else
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alarm_offset = (u32)alarm_time - current_time;
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}
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ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, alarm_offset);
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if (ret < 0) {
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dev_err(dev, "error setting alarm: %d\n", ret);
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return ret;
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}
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return 0;
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}
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static int cros_ec_rtc_alarm_irq_enable(struct device *dev,
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unsigned int enabled)
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{
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struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
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struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
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int ret;
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u32 current_time, alarm_offset, alarm_value;
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ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time);
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if (ret < 0) {
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dev_err(dev, "error getting time: %d\n", ret);
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return ret;
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}
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if (enabled) {
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/* Restore saved alarm if it's still in the future. */
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if (cros_ec_rtc->saved_alarm < current_time)
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alarm_offset = EC_RTC_ALARM_CLEAR;
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else
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alarm_offset = cros_ec_rtc->saved_alarm - current_time;
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ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
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alarm_offset);
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if (ret < 0) {
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dev_err(dev, "error restoring alarm: %d\n", ret);
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return ret;
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}
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} else {
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/* Disable alarm, saving the old alarm value. */
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ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM,
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&alarm_offset);
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if (ret < 0) {
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dev_err(dev, "error saving alarm: %d\n", ret);
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return ret;
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}
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alarm_value = current_time + alarm_offset;
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/*
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* If the current EC alarm is already past, we don't want
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* to set an alarm when we go through the alarm irq enable
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* path.
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*/
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if (alarm_value < current_time)
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cros_ec_rtc->saved_alarm = EC_RTC_ALARM_CLEAR;
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else
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cros_ec_rtc->saved_alarm = alarm_value;
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alarm_offset = EC_RTC_ALARM_CLEAR;
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ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
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alarm_offset);
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if (ret < 0) {
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dev_err(dev, "error disabling alarm: %d\n", ret);
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return ret;
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}
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}
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return 0;
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}
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static int cros_ec_rtc_event(struct notifier_block *nb,
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unsigned long queued_during_suspend,
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void *_notify)
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{
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struct cros_ec_rtc *cros_ec_rtc;
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struct rtc_device *rtc;
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struct cros_ec_device *cros_ec;
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u32 host_event;
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cros_ec_rtc = container_of(nb, struct cros_ec_rtc, notifier);
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rtc = cros_ec_rtc->rtc;
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cros_ec = cros_ec_rtc->cros_ec;
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host_event = cros_ec_get_host_event(cros_ec);
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if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_RTC)) {
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rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
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return NOTIFY_OK;
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} else {
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return NOTIFY_DONE;
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}
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}
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static const struct rtc_class_ops cros_ec_rtc_ops = {
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.read_time = cros_ec_rtc_read_time,
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.set_time = cros_ec_rtc_set_time,
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.read_alarm = cros_ec_rtc_read_alarm,
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.set_alarm = cros_ec_rtc_set_alarm,
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.alarm_irq_enable = cros_ec_rtc_alarm_irq_enable,
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};
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#ifdef CONFIG_PM_SLEEP
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static int cros_ec_rtc_suspend(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev);
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if (device_may_wakeup(dev))
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enable_irq_wake(cros_ec_rtc->cros_ec->irq);
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return 0;
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}
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static int cros_ec_rtc_resume(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev);
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if (device_may_wakeup(dev))
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disable_irq_wake(cros_ec_rtc->cros_ec->irq);
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return 0;
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}
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#endif
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static SIMPLE_DEV_PM_OPS(cros_ec_rtc_pm_ops, cros_ec_rtc_suspend,
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cros_ec_rtc_resume);
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static int cros_ec_rtc_probe(struct platform_device *pdev)
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{
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struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
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struct cros_ec_device *cros_ec = ec_dev->ec_dev;
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struct cros_ec_rtc *cros_ec_rtc;
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struct rtc_time tm;
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int ret;
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cros_ec_rtc = devm_kzalloc(&pdev->dev, sizeof(*cros_ec_rtc),
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GFP_KERNEL);
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if (!cros_ec_rtc)
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return -ENOMEM;
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platform_set_drvdata(pdev, cros_ec_rtc);
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cros_ec_rtc->cros_ec = cros_ec;
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/* Get initial time */
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ret = cros_ec_rtc_read_time(&pdev->dev, &tm);
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if (ret) {
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dev_err(&pdev->dev, "failed to read RTC time\n");
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return ret;
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}
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ret = device_init_wakeup(&pdev->dev, 1);
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if (ret) {
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dev_err(&pdev->dev, "failed to initialize wakeup\n");
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return ret;
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}
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cros_ec_rtc->rtc = devm_rtc_device_register(&pdev->dev, DRV_NAME,
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&cros_ec_rtc_ops,
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THIS_MODULE);
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if (IS_ERR(cros_ec_rtc->rtc)) {
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ret = PTR_ERR(cros_ec_rtc->rtc);
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dev_err(&pdev->dev, "failed to register rtc device\n");
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return ret;
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}
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/* Get RTC events from the EC. */
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cros_ec_rtc->notifier.notifier_call = cros_ec_rtc_event;
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ret = blocking_notifier_chain_register(&cros_ec->event_notifier,
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&cros_ec_rtc->notifier);
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if (ret) {
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dev_err(&pdev->dev, "failed to register notifier\n");
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return ret;
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}
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return 0;
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}
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static int cros_ec_rtc_remove(struct platform_device *pdev)
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{
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struct cros_ec_rtc *cros_ec_rtc = platform_get_drvdata(pdev);
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struct device *dev = &pdev->dev;
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int ret;
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ret = blocking_notifier_chain_unregister(
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&cros_ec_rtc->cros_ec->event_notifier,
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&cros_ec_rtc->notifier);
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if (ret) {
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dev_err(dev, "failed to unregister notifier\n");
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return ret;
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}
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return 0;
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}
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static struct platform_driver cros_ec_rtc_driver = {
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.probe = cros_ec_rtc_probe,
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.remove = cros_ec_rtc_remove,
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.driver = {
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.name = DRV_NAME,
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.pm = &cros_ec_rtc_pm_ops,
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},
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};
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module_platform_driver(cros_ec_rtc_driver);
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MODULE_DESCRIPTION("RTC driver for Chrome OS ECs");
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MODULE_AUTHOR("Stephen Barber <smbarber@chromium.org>");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:" DRV_NAME);
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