linux-kernel - Re: [PATCH 1/3] clk: mux: Add regmap support for simple mux

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Message-ID: <CABuKBeL3U2kdVCVHDKJp+K91K3CUF=XEuDUhfwjqWVEhFNFVcA@mail.gmail.com>
Date:	Fri, 29 May 2015 17:24:58 +0200
From:	Matthias Brugger <matthias.bgg@...il.com>
To:	Sascha Hauer <s.hauer@...gutronix.de>
Cc:	Mike Turquette <mturquette@...aro.org>,
	Stephen Boyd <sboyd@...eaurora.org>,
	HenryC Chen <henryc.chen@...iatek.com>,
	James Liao <jamesjj.liao@...iatek.com>,
	Philipp Zabel <p.zabel@...gutronix.de>,
	linux-clk@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"moderated list:ARM/Mediatek SoC..." 
	<linux-mediatek@...ts.infradead.org>
Subject: Re: [PATCH 1/3] clk: mux: Add regmap support for simple mux

2015-05-29 8:40 GMT+02:00 Sascha Hauer <s.hauer@...gutronix.de>:
> On Thu, May 28, 2015 at 08:41:46PM +0200, Matthias Brugger wrote:
>> Some devices like SoCs from Mediatek need to use the clock muxes
>> through a regmap interface.
>> This patch adds regmap support for simple the simple multiplexer
>> clock code.
>>
>> Signed-off-by: Matthias Brugger <matthias.bgg@...il.com>
>> ---
>>  drivers/clk/clk-mux.c        | 103 ++++++++++++++++++++++++++++++++++++++-----
>>  include/linux/clk-provider.h |  40 +++++++++++++++++
>>  2 files changed, 132 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/clk/clk-mux.c b/drivers/clk/clk-mux.c
>> index 1fa2a8d..c7c692a 100644
>> --- a/drivers/clk/clk-mux.c
>> +++ b/drivers/clk/clk-mux.c
>> @@ -29,6 +29,26 @@
>>
>>  #define to_clk_mux(_hw) container_of(_hw, struct clk_mux, hw)
>>
>> +static void clk_mux_writel(struct clk_mux *mux, u32 val)
>> +{
>> +     if (mux->flags && CLK_MUX_USE_REGMAP)
>> +             regmap_write(mux->regmap, mux->offset, val);
>> +     else
>> +             clk_writel(val, mux->reg);
>> +}
>> +
>> +static u32 clk_mux_readl(struct clk_mux *mux)
>> +{
>> +     u32 val;
>> +
>> +     if (mux->flags && CLK_MUX_USE_REGMAP)
>> +             regmap_read(mux->regmap, mux->offset, &val);
>> +     else
>> +             val = clk_readl(mux->reg);
>> +
>> +     return val;
>> +}
>> +
>>  static u8 clk_mux_get_parent(struct clk_hw *hw)
>>  {
>>       struct clk_mux *mux = to_clk_mux(hw);
>> @@ -42,7 +62,10 @@ static u8 clk_mux_get_parent(struct clk_hw *hw)
>>        * OTOH, pmd_trace_clk_mux_ck uses a separate bit for each clock, so
>>        * val = 0x4 really means "bit 2, index starts at bit 0"
>>        */
>> -     val = clk_readl(mux->reg) >> mux->shift;
>> +
>> +     val = clk_mux_readl(mux);
>> +
>> +     val >>= mux->shift;
>>       val &= mux->mask;
>>
>>       if (mux->table) {
>> @@ -89,11 +112,11 @@ static int clk_mux_set_parent(struct clk_hw *hw, u8 index)
>>       if (mux->flags & CLK_MUX_HIWORD_MASK) {
>>               val = mux->mask << (mux->shift + 16);
>>       } else {
>> -             val = clk_readl(mux->reg);
>> +             val = clk_mux_readl(mux);
>>               val &= ~(mux->mask << mux->shift);
>>       }
>>       val |= index << mux->shift;
>> -     clk_writel(val, mux->reg);
>> +     clk_mux_writel(mux, val);
>
> With regmap the register lock is inside the regmap, you must hold it
> during read/modify/write operations which means you have to use
> regmap_update_bits rather than regmap_read followed by regmap_write.

Fixed in next version.
Thanks for reviewing.

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