diff options
| -rw-r--r-- | drivers/rtc/rtc-pm8xxx.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-pm8xxx.c b/drivers/rtc/rtc-pm8xxx.c index ef47411c9429..a547729d2877 100644 --- a/drivers/rtc/rtc-pm8xxx.c +++ b/drivers/rtc/rtc-pm8xxx.c @@ -65,6 +65,7 @@ struct qcom_uefi_rtc_info { * @rtc_info: qcom uefi rtc-info structure * @nvmem_cell: nvmem cell for offset * @offset: offset from epoch in seconds + * @offset_dirty: offset needs to be stored on shutdown */ struct pm8xxx_rtc { struct rtc_device *rtc; @@ -77,6 +78,7 @@ struct pm8xxx_rtc { struct qcom_uefi_rtc_info rtc_info; struct nvmem_cell *nvmem_cell; u32 offset; + bool offset_dirty; }; #ifdef CONFIG_EFI @@ -256,6 +258,15 @@ static int pm8xxx_rtc_update_offset(struct pm8xxx_rtc *rtc_dd, u32 secs) if (offset == rtc_dd->offset) return 0; + /* + * Reduce flash wear by deferring updates due to clock drift until + * shutdown. + */ + if (abs_diff(offset, rtc_dd->offset) < 30) { + rtc_dd->offset_dirty = true; + goto out; + } + if (rtc_dd->nvmem_cell) rc = pm8xxx_rtc_write_nvmem_offset(rtc_dd, offset); else @@ -264,6 +275,8 @@ static int pm8xxx_rtc_update_offset(struct pm8xxx_rtc *rtc_dd, u32 secs) if (rc) return rc; + rtc_dd->offset_dirty = false; +out: rtc_dd->offset = offset; return 0; @@ -634,8 +647,21 @@ static int pm8xxx_rtc_probe(struct platform_device *pdev) return devm_rtc_register_device(rtc_dd->rtc); } +static void pm8xxx_shutdown(struct platform_device *pdev) +{ + struct pm8xxx_rtc *rtc_dd = platform_get_drvdata(pdev); + + if (rtc_dd->offset_dirty) { + if (rtc_dd->nvmem_cell) + pm8xxx_rtc_write_nvmem_offset(rtc_dd, rtc_dd->offset); + else + pm8xxx_rtc_write_uefi_offset(rtc_dd, rtc_dd->offset); + } +} + static struct platform_driver pm8xxx_rtc_driver = { .probe = pm8xxx_rtc_probe, + .shutdown = pm8xxx_shutdown, .driver = { .name = "rtc-pm8xxx", .of_match_table = pm8xxx_id_table, |