From: Alexandre Belloni <alexandre.belloni@bootlin.com>
To: Biwen Li <biwen.li@nxp.com>
Cc: a.zummo@towertech.it, leoyang.li@nxp.com, broonie@kernel.org,
nandor.han@vaisala.com, linux-rtc@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [v5] rtc: pcf85363/pcf85263: fix error that failed to run hwclock -w
Date: Thu, 29 Aug 2019 23:05:54 +0200 [thread overview]
Message-ID: <20190829210554.GN21922@piout.net> (raw)
In-Reply-To: <20190829021418.4607-1-biwen.li@nxp.com>
On 29/08/2019 10:14:18+0800, Biwen Li wrote:
> Issue:
> - # hwclock -w
> hwclock: RTC_SET_TIME: Invalid argument
>
> Why:
> - Relative commit: 8b9f9d4dc511309918c4f6793bae7387c0c638af, this patch
> will always check for unwritable registers, it will compare reg
> with max_register in regmap_writeable.
>
> - The pcf85363/pcf85263 has the capability of address wrapping
> which means if you access an address outside the allowed range
> (0x00-0x2f) hardware actually wraps the access to a lower address.
> The rtc-pcf85363 driver will use this feature to configure the time
> and execute 2 actions in the same i2c write operation (stopping the
> clock and configure the time). However the driver has also
> configured the `regmap maxregister` protection mechanism that will
> block accessing addresses outside valid range (0x00-0x2f).
>
> How:
> - Split of writing regs to two parts, first part writes control
> registers about stop_enable and resets, second part writes
> RTC time and date registers.
>
> Signed-off-by: Biwen Li <biwen.li@nxp.com>
> ---
> Change in v5:
> - drop robust explanation
>
> Change in v4:
> - use old scheme
> - replace link to lkml.org with commit
> - add proper explanation
>
> Change in v3:
> - replace old scheme with new scheme:
> increase max_register.
>
> Change in v2:
> - add Why and How into commit message.
>
> drivers/rtc/rtc-pcf85363.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
Applied, thanks.
--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
prev parent reply other threads:[~2019-08-29 21:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-29 2:14 [v5] rtc: pcf85363/pcf85263: fix error that failed to run hwclock -w Biwen Li
2019-08-29 6:45 ` Nandor Han
2019-08-29 21:05 ` Alexandre Belloni [this message]
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