[{"id":3685028,"web_url":"http://patchwork.ozlabs.org/comment/3685028/","msgid":"<18e8ff9e-5bb9-423b-91c6-5e4b37ef4455@alliedtelesis.co.nz>","list_archive_url":null,"date":"2026-05-01T05:14:33","subject":"Re: [PATCH] rtc: ds1307: handle oscillator stop flag for\n ds1337/ds1339/ds3231","submitter":{"id":27499,"url":"http://patchwork.ozlabs.org/api/people/27499/","name":"Chris Packham","email":"chris.packham@alliedtelesis.co.nz"},"content":"Hi Ronan\n\nOn 01/05/2026 16:46, Ronan Dalton wrote:\n> Prior to commit 6cb0d8587b96 (\"rtc: ds1307: remove clear of oscillator\n> stop flag (OSF) in probe\"), the oscillator stop flag (OSF) bit was\n> checked during device probe for the ds1337, ds1339, ds1341, and ds3231\n> chips; if it was set, it would be cleared and a warning would be logged\n> saying \"SET TIME!\". Since that commit, the OSF bit is no longer cleared,\n> but the warning is still printed.\n>\n> Directly following that commit, there was no way to get rid of this\n> warning because nothing cleared the OSF bit on these chips.\n>\n> The commit associated with the previous commit, ae03a28e12a7 (\"rtc:\n> ds1307: handle oscillator stop flag (OSF) for ds1341\"), made proper use\n> of the OSF when getting and setting the time in the RTC. However, the\n> other RTC variants ds1337, ds1339 and ds3231 didn't have a corresponding\n> change made.\n>\n> Given that the OSF bit is no longer cleared at probe time when it is\n> set, the remaining three chips should have the same handling as the\n> ds1341 chip has for the OSF bit.\n>\n> Fix the issue on the ds1337, ds1339 and ds3231 chips by applying the\n> same logic as the ds1341 has to these chips.\n>\n> Note that any devices brought up between the first referenced commit and\n> this one may begin mistrusting the time reported by the RTC until it is\n> set again, if the bit was never explicitly cleared.\n>\n> Note that only the ds1339 was tested with this change, but the\n> datasheets for the other chips contain essentially identical\n> descriptions of the OSF bit so the same change should work.\n>\n> An alternative to this change could be just to revert the referenced two\n> commits and not use the OSF bit at all, apart from logging a warning and\n> clearing it on probe.\n>\n> Signed-off-by: Ronan Dalton \n> Cc: linux-rtc@vger.kernel.org\n> Cc: linux-kernel@vger.kernel.org\n> Cc: Alexandre Belloni \n> Cc: Tyler Hicks \n> Cc: Sasha Levin \n> Cc: Meagan Lloyd \n> Cc: Rodolfo Giometti \n> Cc: Chris Packham \n> Fixes: 6cb0d8587b96 (\"rtc: ds1307: remove clear of oscillator stop flag (OSF) in probe\")\n\nReviewed-by: Chris Packham \n\n> ---\n> drivers/rtc/rtc-ds1307.c | 28 +++++++++++++++++-----------\n> 1 file changed, 17 insertions(+), 11 deletions(-)\n>\n> diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c\n> index 7205c59ff729..edf81b975dec 100644\n> --- a/drivers/rtc/rtc-ds1307.c\n> +++ b/drivers/rtc/rtc-ds1307.c\n> @@ -269,6 +269,16 @@ static int ds1307_get_time(struct device *dev, struct rtc_time *t)\n> \t\tif (tmp & DS1338_BIT_OSF)\n> \t\t\treturn -EINVAL;\n> \t\tbreak;\n> +\tcase ds_1337:\n> +\tcase ds_1339:\n> +\tcase ds_1341:\n> +\tcase ds_3231:\n> +\t\tret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &tmp);\n> +\t\tif (ret)\n> +\t\t\treturn ret;\n> +\t\tif (tmp & DS1337_BIT_OSF)\n> +\t\t\treturn -EINVAL;\n> +\t\tbreak;\n> \tcase ds_1340:\n> \t\tif (tmp & DS1340_BIT_nEOSC)\n> \t\t\treturn -EINVAL;\n> @@ -279,13 +289,6 @@ static int ds1307_get_time(struct device *dev, struct rtc_time *t)\n> \t\tif (tmp & DS1340_BIT_OSF)\n> \t\t\treturn -EINVAL;\n> \t\tbreak;\n> -\tcase ds_1341:\n> -\t\tret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &tmp);\n> -\t\tif (ret)\n> -\t\t\treturn ret;\n> -\t\tif (tmp & DS1337_BIT_OSF)\n> -\t\t\treturn -EINVAL;\n> -\t\tbreak;\n> \tcase ds_1388:\n> \t\tret = regmap_read(ds1307->regmap, DS1388_REG_FLAG, &tmp);\n> \t\tif (ret)\n> @@ -380,14 +383,17 @@ static int ds1307_set_time(struct device *dev, struct rtc_time *t)\n> \t\tregmap_update_bits(ds1307->regmap, DS1307_REG_CONTROL,\n> \t\t\t\t DS1338_BIT_OSF, 0);\n> \t\tbreak;\n> +\tcase ds_1337:\n> +\tcase ds_1339:\n> +\tcase ds_1341:\n> +\tcase ds_3231:\n> +\t\tregmap_update_bits(ds1307->regmap, DS1337_REG_STATUS,\n> +\t\t\t\t DS1337_BIT_OSF, 0);\n> +\t\tbreak;\n> \tcase ds_1340:\n> \t\tregmap_update_bits(ds1307->regmap, DS1340_REG_FLAG,\n> \t\t\t\t DS1340_BIT_OSF, 0);\n> \t\tbreak;\n> -\tcase ds_1341:\n> -\t\tregmap_update_bits(ds1307->regmap, DS1337_REG_STATUS,\n> -\t\t\t\t DS1337_BIT_OSF, 0);\n> -\t\tbreak;\n> \tcase ds_1388:\n> \t\tregmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,\n> \t\t\t\t DS1388_BIT_OSF, 0);","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-rtc@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=alliedtelesis.co.nz header.i=@alliedtelesis.co.nz\n header.a=rsa-sha256 header.s=mail181024 header.b=m+LG91fZ;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; 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