From mboxrd@z Thu Jan  1 00:00:00 1970
From: wellsk40@gmail.com (Kevin Wells)
Date: Tue, 3 Aug 2010 13:36:25 -0700
Subject: [PATCH v4] GPIO PL061: Adding Clk framework support
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	<20100713182644.GC30142@n2100.arm.linux.org.uk>
	<4C3EA46B.1000709@st.com>
	<20100715083032.GA26212@n2100.arm.linux.org.uk>
	<4C3ED678.7010308@st.com>
	<20100715095637.GF26212@n2100.arm.linux.org.uk>
	<083DF309106F364B939360100EC290F80AC392ACFC@eu1rdcrdc1wx030.exi.nxp.com>
	<20100730070943.GA29746@n2100.arm.linux.org.uk>
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Message-ID: <AANLkTimcunSmSiV2+N19RPbZ_AwfzEnAMyO74Zh+N6h7@mail.gmail.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

> 2010/8/3 Kevin Wells <kevin.wells@nxp.com>:
>
>> Wouldn't drivers that use clk_disable in their xxx_suspend functions
>> have some problems with this as multiple clk_enables have been called?
>
> Russell already answered that, all drivers have to be augmented
> in the following way (this is for PL011, the same will be valid for
> any other PrimeCell with aggressive clocking):
>
> [Russell King]
>> 1. add an amba_bus_clk_disable() at the end of the successful probe
>> ?function
>> 2. add amba_bus_clk_enable() at the beginning of the remove function.
>> 3. add amba_bus_clk_enable()/amba_bus_clk_disable() around each of the
>> suspend(), resume(), pl011_console_write(), and
>> ?pl011_console_get_options() functions.
>> 4. amba_bus_clk_enable() at the start of the startup method.
>> 5. amba_bus_clk_disable() at the end of the shutdown method.
>
>> AMBA enables clock in amba_probe() <<< clock use count = 1
>> pl022 driver enables clock in mmci_probe <<< clock use count = 2
>> ...SPI stuff happens...
>> ...Linux enters suspend mode...
>> pl022 driver enters suspend mode, disables clock <<< clock use count = 1
>
> OK I feel some responsibility for that driver so I will try to fix it,
> maybe I can take a round at PL011 and perhaps MMCI as well.
>

Thanks for the info Linus. I'll take an initial try at the pl11x driver..

Kevin