From: Philipp Rosenberger <p.rosenberger@kunbus.com>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: dan.carpenter@oracle.com, biwen.li@nxp.com, lvb@xiphos.com,
bruno.thomsen@gmail.com, l.sanfilippo@kunbus.com,
Alessandro Zummo <a.zummo@towertech.it>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] rtc: pcf2127: Run a OTP refresh if not done before
Date: Thu, 14 Jan 2021 10:15:29 +0100 [thread overview]
Message-ID: <3ee1bb68-7fab-7921-f713-66f7f931d941@kunbus.com> (raw)
In-Reply-To: <20210114080656.ee7fdqufu2biyy4y@pengutronix.de>
On 14.01.21 09:06, Uwe Kleine-König wrote:
> On Wed, Jan 13, 2021 at 12:27:42PM +0100, Philipp Rosenberger wrote:
>> The datasheet of the PCF2127 states,it is recommended to process an OTP
>
> s/,/, /
ACK
>
>> refresh once the power is up and the oscillator is operating stable. The
>> OTP refresh takes less than 100 ms to complete.
>>
>> Signed-off-by: Philipp Rosenberger <p.rosenberger@kunbus.com>
>> ---
>> drivers/rtc/rtc-pcf2127.c | 16 ++++++++++++++++
>> 1 file changed, 16 insertions(+)
>>
>> diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
>> index 378b1ce812d6..ca56dba64e79 100644
>> --- a/drivers/rtc/rtc-pcf2127.c
>> +++ b/drivers/rtc/rtc-pcf2127.c
>> @@ -58,6 +58,9 @@
>> #define PCF2127_REG_ALARM_DM 0x0D
>> #define PCF2127_REG_ALARM_DW 0x0E
>> #define PCF2127_BIT_ALARM_AE BIT(7)
>> +/* CLKOUT control register */
>> +#define PCF2127_REG_CLKOUT 0x0f
>> +#define PCF2127_BIT_CLKOUT_OTPR BIT(5)
>> /* Watchdog registers */
>> #define PCF2127_REG_WD_CTL 0x10
>> #define PCF2127_BIT_WD_CTL_TF0 BIT(0)
>> @@ -630,6 +633,19 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
>> dev_warn(dev, "Watchdog and alarm functions might not work properly\n");
>> }
>>
>> + /*
>> + * Set the OTP refresh bit unconditionally. If an OTP refresh was
>> + * already done the bit is already set and will not rerun the refresh
>> + * operation.
>> + */
>> + ret = regmap_set_bits(pcf2127->regmap, PCF2127_REG_CLKOUT,
>> + PCF2127_BIT_CLKOUT_OTPR);
>> + if (ret < 0) {
>> + dev_err(dev, "%s: OTP refresh (clkout_ctrl) failed.\n", __func__);
>> + return ret;
>> + }
>> + msleep(100);
>
> This unconditional sleep isn't so nice. Maybe it makes sense to only do
> this when the chip reports a power loss?
Right, will change that
> Best regards
> Uwe
>
Best Regards,
Philipp
next prev parent reply other threads:[~2021-01-14 9:16 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-13 11:27 [PATCH v2 0/2] rtc: pcf2127: proper initialization after power loss Philipp Rosenberger
2021-01-13 11:27 ` [PATCH v2 1/2] rtc: pcf2127: Disable Power-On Reset Override Philipp Rosenberger
2021-01-14 8:05 ` Uwe Kleine-König
2021-01-14 9:10 ` Philipp Rosenberger
2021-01-14 9:33 ` Alexandre Belloni
2021-01-14 10:43 ` Philipp Rosenberger
2021-01-14 10:53 ` Alexandre Belloni
2021-01-14 11:11 ` Philipp Rosenberger
2021-01-13 11:27 ` [PATCH v2 2/2] rtc: pcf2127: Run a OTP refresh if not done before Philipp Rosenberger
2021-01-14 8:06 ` Uwe Kleine-König
2021-01-14 9:15 ` Philipp Rosenberger [this message]
2021-01-14 9:50 ` Alexandre Belloni
2021-01-14 10:30 ` Philipp Rosenberger
2021-01-14 11:11 ` Alexandre Belloni
2021-01-14 11:18 ` Philipp Rosenberger
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