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Message-ID: <CAJKOXPfRUePLAjiFU_V0p1n0sfJXqmk0dUBbq16nfFJeJai+Ww@mail.gmail.com>
Date: Tue, 19 May 2015 19:03:40 +0900
From: Krzysztof Kozlowski <k.kozlowski@...sung.com>
To: Laurentiu Palcu <laurentiu.palcu@...el.com>
Cc: Krzysztof Kozlowski <k.kozlowski@...sung.com>,
Rob Herring <robh+dt@...nel.org>,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>,
Sebastian Reichel <sre@...nel.org>,
Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
David Woodhouse <dwmw2@...radead.org>,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-pm@...r.kernel.org
Subject: Re: [PATCH 2/2] power_supply: Add support for TI BQ25890 charger chip
2015-05-19 18:14 GMT+09:00 Laurentiu Palcu <laurentiu.palcu@...el.com>:
> Hi Krzysztof,
>
> On Tue, May 19, 2015 at 05:40:25PM +0900, Krzysztof Kozlowski wrote:
>> > +
>> > +static int bq25890_chip_reset(struct bq25890_device *bq)
>> > +{
>> > + int ret;
>> > +
>> > + ret = bq25890_field_write(bq, F_REG_RST, 1);
>> > + if (ret < 0)
>> > + return ret;
>> > +
>> > + do {
>> > + ret = bq25890_field_read(bq, F_REG_RST);
>> > + if (ret < 0)
>> > + return ret;
>> > +
>> > + usleep_range(5, 10);
>> > + } while (ret == 1);
>>
>> Is it possible to loop here indefinetely?
> According to specifications, this field is "Reset to 0 after register
> reset is completed", so I'm trusting the chip will behave as advertised!
> :) We could implement a safety mechanism to avoid looping in case the
> chip misbehaves but I don't think it's worth it. What do you think?
I just prefer to use some retry counter because it would be better to
fail the reset instead of being stuck here. The chip may behave
correctly but still a bug could exist in the driver. The retry counter
won't be much complicated here also. But I do not insist so if you
really think it is not worth it then I am fine.
Best regards,
Krzysztof
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