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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141// SPDX-License-Identifier: GPL-2.0-only OR MIT/* * Apple SMC RTC driver * Copyright The Asahi Linux Contributors */
#include <linux/bitops.h>#include <linux/mfd/macsmc.h>#include <linux/module.h>#include <linux/nvmem-consumer.h>#include <linux/of.h>#include <linux/platform_device.h>#include <linux/rtc.h>#include <linux/slab.h>
/* 48-bit RTC */#define RTC_BYTES 6#define RTC_BITS (8 * RTC_BYTES)
/* 32768 Hz clock */#define RTC_SEC_SHIFT 15
struct macsmc_rtc { struct device *dev; struct apple_smc *smc; struct rtc_device *rtc_dev; struct nvmem_cell *rtc_offset;};
static int macsmc_rtc_get_time(struct device *dev, struct rtc_time *tm){ struct macsmc_rtc *rtc = dev_get_drvdata(dev); u64 ctr = 0, off = 0; time64_t now; void *p_off; size_t len; int ret;
ret = apple_smc_read(rtc->smc, SMC_KEY(CLKM), &ctr, RTC_BYTES); if (ret < 0) return ret; if (ret != RTC_BYTES) return -EIO;
p_off = nvmem_cell_read(rtc->rtc_offset, &len); if (IS_ERR(p_off)) return PTR_ERR(p_off); if (len < RTC_BYTES) { kfree(p_off); return -EIO; }
memcpy(&off, p_off, RTC_BYTES); kfree(p_off);
/* Sign extend from 48 to 64 bits, then arithmetic shift right 15 bits to get seconds */ now = sign_extend64(ctr + off, RTC_BITS - 1) >> RTC_SEC_SHIFT; rtc_time64_to_tm(now, tm);
return ret;}
static int macsmc_rtc_set_time(struct device *dev, struct rtc_time *tm){ struct macsmc_rtc *rtc = dev_get_drvdata(dev); u64 ctr = 0, off = 0; int ret;
ret = apple_smc_read(rtc->smc, SMC_KEY(CLKM), &ctr, RTC_BYTES); if (ret < 0) return ret; if (ret != RTC_BYTES) return -EIO;
/* This sets the offset such that the set second begins now */ off = (rtc_tm_to_time64(tm) << RTC_SEC_SHIFT) - ctr; return nvmem_cell_write(rtc->rtc_offset, &off, RTC_BYTES);}
static const struct rtc_class_ops macsmc_rtc_ops = { .read_time = macsmc_rtc_get_time, .set_time = macsmc_rtc_set_time,};
static int macsmc_rtc_probe(struct platform_device *pdev){ struct apple_smc *smc = dev_get_drvdata(pdev->dev.parent); struct macsmc_rtc *rtc;
/* * MFD will probe this device even without a node in the device tree, * thus bail out early if the SMC on the current machines does not * support RTC and has no node in the device tree. */ if (!pdev->dev.of_node) return -ENODEV;
rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); if (!rtc) return -ENOMEM;
rtc->dev = &pdev->dev; rtc->smc = smc;
rtc->rtc_offset = devm_nvmem_cell_get(&pdev->dev, "rtc_offset"); if (IS_ERR(rtc->rtc_offset)) return dev_err_probe(&pdev->dev, PTR_ERR(rtc->rtc_offset), "Failed to get rtc_offset NVMEM cell\n");
rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev); if (IS_ERR(rtc->rtc_dev)) return PTR_ERR(rtc->rtc_dev);
rtc->rtc_dev->ops = &macsmc_rtc_ops; rtc->rtc_dev->range_min = S64_MIN >> (RTC_SEC_SHIFT + (64 - RTC_BITS)); rtc->rtc_dev->range_max = S64_MAX >> (RTC_SEC_SHIFT + (64 - RTC_BITS));
platform_set_drvdata(pdev, rtc);
return devm_rtc_register_device(rtc->rtc_dev);}
static const struct of_device_id macsmc_rtc_of_table[] = { { .compatible = "apple,smc-rtc", }, {}};MODULE_DEVICE_TABLE(of, macsmc_rtc_of_table);
static struct platform_driver macsmc_rtc_driver = { .driver = { .name = "macsmc-rtc", .of_match_table = macsmc_rtc_of_table, }, .probe = macsmc_rtc_probe,};module_platform_driver(macsmc_rtc_driver);
MODULE_LICENSE("Dual MIT/GPL");MODULE_DESCRIPTION("Apple SMC RTC driver");MODULE_AUTHOR("Hector Martin <marcan@marcan.st>");