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From: Jerome Brunet <jbrunet@baylibre.com>
To: Vladimir Zapolskiy <vz@mleia.com>,
	Stephen Boyd <sboyd@codeaurora.org>,
	Michael Turquette <mturquette@baylibre.com>,
	linux-clk@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-arm-msm@vger.kernel.org,
	Sylvain Lemieux <slemieux.tyco@gmail.com>,
	Andy Gross <andy.gross@linaro.org>,
	David Brown <david.brown@linaro.org>
Subject: Re: [PATCH 2/5] clk: lpc32xx: read-only divider can propagate rate change
Date: Mon, 08 Jan 2018 10:10:39 +0100	[thread overview]
Message-ID: <1515402639.5048.82.camel@baylibre.com> (raw)
In-Reply-To: <54782a8f-9735-a574-d8e1-7ff3e9173229@mleia.com>

On Sat, 2018-01-06 at 16:04 +0200, Vladimir Zapolskiy wrote:
> > I added the fix to LPC32xx because it looks like the generic divider (a lot) and
> 
> right, the relevant divider operations were copied, however the difference
> is important, unfortunately there is no simple option to get rid of regmap,
> because System Control Block registers are shared with a number of other
> device drivers.

I have the same issue ;)

> 
> > appears to support CLK_DIVIDER_READ_ONLY. If it does not, could you please kill
> > the related code ?
> 
> The driver supports CLK_DIVIDER_READ_ONLY clocks, and it should not be
> changed, but all such clocks don't have children with CLK_SET_RATE_PARENT
> property, which invalidates your fix for LPC32xx. Please let me know,
> if I missed something.

You did not miss anything. I understand your choice.
I just have different approach and usually prefer to avoid these particularity
which may catch you later on. 

At least, the fact that propagation would stop with CLK_DIVIDER_READ_ONLY on
LPC32xx, even with CLK_SET_RATE_PARENT, is now known.

Adding a comment in the code to make this explicit would be nice though.

Regards
Jerome

WARNING: multiple messages have this Message-ID (diff)
From: jbrunet@baylibre.com (Jerome Brunet)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/5] clk: lpc32xx: read-only divider can propagate rate change
Date: Mon, 08 Jan 2018 10:10:39 +0100	[thread overview]
Message-ID: <1515402639.5048.82.camel@baylibre.com> (raw)
In-Reply-To: <54782a8f-9735-a574-d8e1-7ff3e9173229@mleia.com>

On Sat, 2018-01-06 at 16:04 +0200, Vladimir Zapolskiy wrote:
> > I added the fix to LPC32xx because it looks like the generic divider (a lot) and
> 
> right, the relevant divider operations were copied, however the difference
> is important, unfortunately there is no simple option to get rid of regmap,
> because System Control Block registers are shared with a number of other
> device drivers.

I have the same issue ;)

> 
> > appears to support CLK_DIVIDER_READ_ONLY. If it does not, could you please kill
> > the related code ?
> 
> The driver supports CLK_DIVIDER_READ_ONLY clocks, and it should not be
> changed, but all such clocks don't have children with CLK_SET_RATE_PARENT
> property, which invalidates your fix for LPC32xx. Please let me know,
> if I missed something.

You did not miss anything. I understand your choice.
I just have different approach and usually prefer to avoid these particularity
which may catch you later on. 

At least, the fact that propagation would stop with CLK_DIVIDER_READ_ONLY on
LPC32xx, even with CLK_SET_RATE_PARENT, is now known.

Adding a comment in the code to make this explicit would be nice though.

Regards
Jerome

  reply	other threads:[~2018-01-08  9:10 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-05 17:09 [PATCH 0/5] clk: read-only dividers and rate propagation fixup Jerome Brunet
2018-01-05 17:09 ` Jerome Brunet
2018-01-05 17:09 ` [PATCH 1/5] clk: divider: read-only divider can propagate rate change Jerome Brunet
2018-01-05 17:09   ` Jerome Brunet
2018-01-05 17:09   ` Jerome Brunet
2018-01-11 22:55   ` [1/5] " David Lechner
2018-01-11 22:55     ` David Lechner
2018-01-17 16:39     ` Jerome Brunet
2018-01-17 16:39       ` Jerome Brunet
2018-01-05 17:09 ` [PATCH 2/5] clk: lpc32xx: " Jerome Brunet
2018-01-05 17:09   ` Jerome Brunet
2018-01-05 18:12   ` Vladimir Zapolskiy
2018-01-05 18:12     ` Vladimir Zapolskiy
2018-01-05 19:40     ` Jerome Brunet
2018-01-05 19:40       ` Jerome Brunet
2018-01-06 14:04       ` Vladimir Zapolskiy
2018-01-06 14:04         ` Vladimir Zapolskiy
2018-01-08  9:10         ` Jerome Brunet [this message]
2018-01-08  9:10           ` Jerome Brunet
2018-01-05 17:09 ` [PATCH 3/5] clk: divider: add divider_ro_round_rate helper Jerome Brunet
2018-01-05 17:09   ` Jerome Brunet
2018-01-11 23:08   ` [3/5] " David Lechner
2018-01-11 23:08     ` David Lechner
2018-01-17 17:47     ` Jerome Brunet
2018-01-17 17:47       ` Jerome Brunet
2018-01-17 17:55       ` David Lechner
2018-01-17 17:55         ` David Lechner
2018-01-05 17:09 ` [PATCH 4/5] clk: lpc32xx: use " Jerome Brunet
2018-01-05 17:09   ` Jerome Brunet
2018-01-05 17:09 ` [PATCH 5/5] clk: qcom: " Jerome Brunet
2018-01-05 17:09   ` Jerome Brunet
2018-01-08 10:04   ` Jerome Brunet
2018-01-08 10:04     ` Jerome Brunet

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