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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 | // SPDX-License-Identifier: GPL-2.0 /* * RTC interface for Wilco Embedded Controller with R/W abilities * * Copyright 2018 Google LLC * * The corresponding platform device is typically registered in * drivers/platform/chrome/wilco_ec/core.c */ #include <linux/bcd.h> #include <linux/err.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/platform_device.h> #include <linux/platform_data/wilco-ec.h> #include <linux/rtc.h> #include <linux/timekeeping.h> #define EC_COMMAND_CMOS 0x7c #define EC_CMOS_TOD_WRITE 0x02 #define EC_CMOS_TOD_READ 0x08 /* Message sent to the EC to request the current time. */ struct ec_rtc_read_request { u8 command; u8 reserved; u8 param; } __packed; static struct ec_rtc_read_request read_rq = { .command = EC_COMMAND_CMOS, .param = EC_CMOS_TOD_READ, }; /** * struct ec_rtc_read_response - Format of RTC returned by EC. * @reserved: Unused byte * @second: Second value (0..59) * @minute: Minute value (0..59) * @hour: Hour value (0..23) * @day: Day value (1..31) * @month: Month value (1..12) * @year: Year value (full year % 100) * @century: Century value (full year / 100) * * All values are presented in binary (not BCD). */ struct ec_rtc_read_response { u8 reserved; u8 second; u8 minute; u8 hour; u8 day; u8 month; u8 year; u8 century; } __packed; /** * struct ec_rtc_write_request - Format of RTC sent to the EC. * @command: Always EC_COMMAND_CMOS * @reserved: Unused byte * @param: Always EC_CMOS_TOD_WRITE * @century: Century value (full year / 100) * @year: Year value (full year % 100) * @month: Month value (1..12) * @day: Day value (1..31) * @hour: Hour value (0..23) * @minute: Minute value (0..59) * @second: Second value (0..59) * @weekday: Day of the week (0=Saturday) * * All values are presented in BCD. */ struct ec_rtc_write_request { u8 command; u8 reserved; u8 param; u8 century; u8 year; u8 month; u8 day; u8 hour; u8 minute; u8 second; u8 weekday; } __packed; static int wilco_ec_rtc_read(struct device *dev, struct rtc_time *tm) { struct wilco_ec_device *ec = dev_get_drvdata(dev->parent); struct ec_rtc_read_response rtc; struct wilco_ec_message msg; int ret; memset(&msg, 0, sizeof(msg)); msg.type = WILCO_EC_MSG_LEGACY; msg.request_data = &read_rq; msg.request_size = sizeof(read_rq); msg.response_data = &rtc; msg.response_size = sizeof(rtc); ret = wilco_ec_mailbox(ec, &msg); if (ret < 0) return ret; tm->tm_sec = rtc.second; tm->tm_min = rtc.minute; tm->tm_hour = rtc.hour; tm->tm_mday = rtc.day; tm->tm_mon = rtc.month - 1; tm->tm_year = rtc.year + (rtc.century * 100) - 1900; /* Ignore other tm fields, man rtc says userspace shouldn't use them. */ if (rtc_valid_tm(tm)) { dev_err(dev, "Time from RTC is invalid: %ptRr\n", tm); return -EIO; } return 0; } static int wilco_ec_rtc_write(struct device *dev, struct rtc_time *tm) { struct wilco_ec_device *ec = dev_get_drvdata(dev->parent); struct ec_rtc_write_request rtc; struct wilco_ec_message msg; int year = tm->tm_year + 1900; /* * Convert from 0=Sunday to 0=Saturday for the EC * We DO need to set weekday because the EC controls battery charging * schedules that depend on the day of the week. */ int wday = tm->tm_wday == 6 ? 0 : tm->tm_wday + 1; int ret; rtc.command = EC_COMMAND_CMOS; rtc.param = EC_CMOS_TOD_WRITE; rtc.century = bin2bcd(year / 100); rtc.year = bin2bcd(year % 100); rtc.month = bin2bcd(tm->tm_mon + 1); rtc.day = bin2bcd(tm->tm_mday); rtc.hour = bin2bcd(tm->tm_hour); rtc.minute = bin2bcd(tm->tm_min); rtc.second = bin2bcd(tm->tm_sec); rtc.weekday = bin2bcd(wday); memset(&msg, 0, sizeof(msg)); msg.type = WILCO_EC_MSG_LEGACY; msg.request_data = &rtc; msg.request_size = sizeof(rtc); ret = wilco_ec_mailbox(ec, &msg); if (ret < 0) return ret; return 0; } static const struct rtc_class_ops wilco_ec_rtc_ops = { .read_time = wilco_ec_rtc_read, .set_time = wilco_ec_rtc_write, }; static int wilco_ec_rtc_probe(struct platform_device *pdev) { struct rtc_device *rtc; rtc = devm_rtc_allocate_device(&pdev->dev); if (IS_ERR(rtc)) return PTR_ERR(rtc); rtc->ops = &wilco_ec_rtc_ops; /* EC only supports this century */ rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; rtc->range_max = RTC_TIMESTAMP_END_2099; rtc->owner = THIS_MODULE; return devm_rtc_register_device(rtc); } static struct platform_driver wilco_ec_rtc_driver = { .driver = { .name = "rtc-wilco-ec", }, .probe = wilco_ec_rtc_probe, }; module_platform_driver(wilco_ec_rtc_driver); MODULE_ALIAS("platform:rtc-wilco-ec"); MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>"); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("Wilco EC RTC driver"); |