linux-kernel - Re: [PATCH v2 1/3] mmc: sdhci: introduce sdhci_compute_clock

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Message-ID: <20160406150445.GA32232@odux.rfo.atmel.com>
Date:	Wed, 6 Apr 2016 17:04:45 +0200
From:	Ludovic Desroches <ludovic.desroches@...el.com>
To:	Adrian Hunter <adrian.hunter@...el.com>
CC:	Ludovic Desroches <ludovic.desroches@...el.com>,
	<ulf.hansson@...aro.org>, <linux-kernel@...r.kernel.org>,
	<linux-mmc@...r.kernel.org>, <nicolas.ferre@...el.com>
Subject: Re: [PATCH v2 1/3] mmc: sdhci: introduce sdhci_compute_clock_config

On Wed, Apr 06, 2016 at 03:37:28PM +0300, Adrian Hunter wrote:
> On 04/04/16 18:27, Ludovic Desroches wrote:
> > In order to remove the SDHCI_QUIRK2_NEED_DELAY_AFTER_INT_CLK_RST and to
> > reduce code duplication, put the code relative to the SD clock
> > configuration in a function which can be used by hosts for the
> > implementation of the set_clock() callback.
> > 
> > Signed-off-by: Ludovic Desroches <ludovic.desroches@...el.com>
> > ---
> >  drivers/mmc/host/sdhci.c | 33 ++++++++++++++++++++++-----------
> >  drivers/mmc/host/sdhci.h |  1 +
> >  2 files changed, 23 insertions(+), 11 deletions(-)
> > 
> > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> > index 6bd3d17..2c3dede 100644
> > --- a/drivers/mmc/host/sdhci.c
> > +++ b/drivers/mmc/host/sdhci.c
> > @@ -1091,23 +1091,13 @@ static u16 sdhci_get_preset_value(struct sdhci_host *host)
> >  	return preset;
> >  }
> >  
> > -void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
> > +u16 sdhci_compute_clock_config(struct sdhci_host *host, unsigned int clock)
> 
> The function name 'sdhci_compute_clock_config' seems a bit long.  How about
> just sdhci_calc_clk.

Ok.

> 
> Also it needs to calculate 'actual_clock' too, so it needs to do that and
> return the value.
> 

actual_clock is updated at the end of the function.

Which value has to be returned? actual_clock or clock configuration?

Regards

Ludovic

> >  {
> >  	int div = 0; /* Initialized for compiler warning */
> >  	int real_div = div, clk_mul = 1;
> >  	u16 clk = 0;
> > -	unsigned long timeout;
> >  	bool switch_base_clk = false;
> >  
> > -	host->mmc->actual_clock = 0;
> > -
> > -	sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
> > -	if (host->quirks2 & SDHCI_QUIRK2_NEED_DELAY_AFTER_INT_CLK_RST)
> > -		mdelay(1);
> > -
> > -	if (clock == 0)
> > -		return;
> > -
> >  	if (host->version >= SDHCI_SPEC_300) {
> >  		if (host->preset_enabled) {
> >  			u16 pre_val;
> > @@ -1188,6 +1178,27 @@ clock_set:
> >  	clk |= (div & SDHCI_DIV_MASK) << SDHCI_DIVIDER_SHIFT;
> >  	clk |= ((div & SDHCI_DIV_HI_MASK) >> SDHCI_DIV_MASK_LEN)
> >  		<< SDHCI_DIVIDER_HI_SHIFT;
> > +
> > +	return clk;
> > +}
> > +EXPORT_SYMBOL_GPL(sdhci_compute_clock_config);
> > +
> > +void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
> > +{
> > +	u16 clk;
> > +	unsigned long timeout;
> > +
> > +	host->mmc->actual_clock = 0;
> > +
> > +	sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
> > +	if (host->quirks2 & SDHCI_QUIRK2_NEED_DELAY_AFTER_INT_CLK_RST)
> > +		mdelay(1);
> > +
> > +	if (clock == 0)
> > +		return;
> > +
> > +	clk = sdhci_compute_clock_config(host, clock);
> > +
> >  	clk |= SDHCI_CLOCK_INT_EN;
> >  	sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
> >  
> > diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> > index 0f39f4f..23ddd6e 100644
> > --- a/drivers/mmc/host/sdhci.h
> > +++ b/drivers/mmc/host/sdhci.h
> > @@ -661,6 +661,7 @@ static inline bool sdhci_sdio_irq_enabled(struct sdhci_host *host)
> >  	return !!(host->flags & SDHCI_SDIO_IRQ_ENABLED);
> >  }
> >  
> > +u16 sdhci_compute_clock_config(struct sdhci_host *host, unsigned int clock);
> >  void sdhci_set_clock(struct sdhci_host *host, unsigned int clock);
> >  void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
> >  		     unsigned short vdd);
> > 
>