linux-kernel - Re: [PATCH 2/3] memory: samsung: exynos5422-dmc: remove unused exynos5

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Date:   Mon, 24 Aug 2020 14:01:39 +0200
From:   Krzysztof Kozlowski <krzk@...nel.org>
To:     Lukasz Luba <lukasz.luba@....com>
Cc:     Kukjin Kim <kgene@...nel.org>, linux-pm@...r.kernel.org,
        linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 2/3] memory: samsung: exynos5422-dmc: remove unused
 exynos5_dmc members

On Mon, Aug 24, 2020 at 12:43:33PM +0100, Lukasz Luba wrote:
> Hi Krzysztof,
> 
> On 8/22/20 5:32 PM, Krzysztof Kozlowski wrote:
> > The struct exynos5_dmc members bypass_rate, mx_mspll_ccore_phy,
> > mout_mx_mspll_ccore_phy and opp_bypass are not actually used.
> > 
> > Apparently there was a plan to store the OPP for the bypass mode in
> > opp_bypass member, but drivers fails to do it and instead always sets
> > target voltage during bypass mode.
> > 
> > Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
> > ---
> >   drivers/memory/samsung/exynos5422-dmc.c | 9 ---------
> >   1 file changed, 9 deletions(-)
> > 
> > diff --git a/drivers/memory/samsung/exynos5422-dmc.c b/drivers/memory/samsung/exynos5422-dmc.c
> > index 31864ce59b25..df02afa8aa90 100644
> > --- a/drivers/memory/samsung/exynos5422-dmc.c
> > +++ b/drivers/memory/samsung/exynos5422-dmc.c
> > @@ -123,9 +123,7 @@ struct exynos5_dmc {
> >   	struct mutex lock;
> >   	unsigned long curr_rate;
> >   	unsigned long curr_volt;
> > -	unsigned long bypass_rate;
> >   	struct dmc_opp_table *opp;
> > -	struct dmc_opp_table opp_bypass;
> >   	int opp_count;
> >   	u32 timings_arr_size;
> >   	u32 *timing_row;
> > @@ -143,8 +141,6 @@ struct exynos5_dmc {
> >   	struct clk *mout_bpll;
> >   	struct clk *mout_mclk_cdrex;
> >   	struct clk *mout_mx_mspll_ccore;
> > -	struct clk *mx_mspll_ccore_phy;
> > -	struct clk *mout_mx_mspll_ccore_phy;
> >   	struct devfreq_event_dev **counter;
> >   	int num_counters;
> >   	u64 last_overflow_ts[2];
> > @@ -455,9 +451,6 @@ static int exynos5_dmc_align_bypass_voltage(struct exynos5_dmc *dmc,
> >   					    unsigned long target_volt)
> >   {
> >   	int ret = 0;
> > -	unsigned long bypass_volt = dmc->opp_bypass.volt_uv;
> > -
> > -	target_volt = max(bypass_volt, target_volt);
> 
> 
> Could you explain which use cases you considered when you decided to
> remove these lines?

There are no use cases attached to these. These are simply not used,
never assigned a value. For example max(0, target_volt) is always equal
to target_volt for unsigned numbers...

Best regards,
Krzysztof