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From: "Pali Rohár" <pali.rohar@gmail.com>
To: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Anton Vorontsov <anton@enomsg.org>,
	linux-kernel@vger.kernel.org,
	David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH] bq2415x_charger: fix max battery regulation voltage
Date: Tue, 15 Oct 2013 15:56:23 +0200	[thread overview]
Message-ID: <201310151556.23557@pali> (raw)
In-Reply-To: <1380709462-860-1-git-send-email-alexandre.belloni@free-electrons.com>

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On Wednesday 02 October 2013 12:24:22 Alexandre Belloni wrote:
> As per the datasheets, maximum battery regulation voltage is
> 4440mV.
> 
> The formula is (voltage - offset) / step, so the maximum value
> is: (4440 - 3500) / 20 = 47
> 
> Signed-off-by: Alexandre Belloni
> <alexandre.belloni@free-electrons.com> ---
>  drivers/power/bq2415x_charger.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/power/bq2415x_charger.c
> b/drivers/power/bq2415x_charger.c index 0727f92..0aa643e
> 100644
> --- a/drivers/power/bq2415x_charger.c
> +++ b/drivers/power/bq2415x_charger.c
> @@ -607,7 +607,7 @@ static int
> bq2415x_set_battery_regulation_voltage(struct bq2415x_device
> *bq,
> 
>  	if (val < 0)
>  		val = 0;
> -	else if (val > 94) /* FIXME: Max is 94 or 122 ? Set max
> value ? */ +	else if (val > 47)
>  		return -EINVAL;
> 
>  	return bq2415x_i2c_write_mask(bq, BQ2415X_REG_VOLTAGE, val,

Right, max is 47 (101111) and not 94 (1011110). But if you set 
all six registers to 1 then you get 63 (111111) and not 122.

I do not know from where I got above bad values, but you should 
add comment to code that according to datasheet max value is 
4440mV (101111) and not 4760mV (111111).

-- 
Pali Rohár
pali.rohar@gmail.com

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  reply	other threads:[~2013-10-15 13:56 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-02 10:24 [PATCH] bq2415x_charger: fix max battery regulation voltage Alexandre Belloni
2013-10-15 13:56 ` Pali Rohár [this message]
2013-10-15 14:54   ` Alexandre Belloni
  -- strict thread matches above, loose matches on Subject: below --
2013-10-16 14:08 Alexandre Belloni
2013-10-16 14:09 ` Alexandre Belloni
2013-10-25 23:25   ` Anton Vorontsov

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