From: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
To: Fugang Duan <b38611-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org,
B20596-KZfg59tc24xl57MIdRCFDg@public.gmane.org
Subject: Re: [PATCH] i2c: imx: update i2c clock divider for each transaction
Date: Mon, 2 Jun 2014 18:03:45 +0200 [thread overview]
Message-ID: <20140602160345.GE2654@katana> (raw)
In-Reply-To: <1400552505-22954-1-git-send-email-b38611-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
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On Tue, May 20, 2014 at 10:21:45AM +0800, Fugang Duan wrote:
> Since IMX serial SOCs support low bus freq mode, some clocks freq
> may change to save power. I2C needs to check the clock source and
> update the divider.
>
> For example:
> i.MX6SL I2C clk is from IPG_PERCLK which is sourced from IPG_CLK.
> Under normal operation, IPG_CLK is 66MHz, ipg_perclk is at 22MHz.
> In low bus freq mode, IPG_CLK is at 12MHz and IPG_PERCLK is down
> to 4MHz. So the I2C driver must update the divider register for
> each transaction when the current IPG_PERCLK is not equal to the
> clock of previous transaction.
>
> Signed-off-by: Fugang Duan <B38611-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
> ---
Applied to for-next, thanks!
One change, though:
> + /* dev_dbg() can't be used, because adapter is not yet registered */
This comment is outdated. I removed it and the __func__ printout.
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prev parent reply other threads:[~2014-06-02 16:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-20 2:21 [PATCH] i2c: imx: update i2c clock divider for each transaction Fugang Duan
[not found] ` <1400552505-22954-1-git-send-email-b38611-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
2014-05-22 13:26 ` Frank.Li-KZfg59tc24xl57MIdRCFDg
2014-06-02 16:03 ` Wolfram Sang [this message]
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