From: <Claudiu.Beznea@microchip.com> To: <alexandre.belloni@bootlin.com> Cc: <mturquette@baylibre.com>, <sboyd@kernel.org>, <Nicolas.Ferre@microchip.com>, <Ludovic.Desroches@microchip.com>, <linux-kernel@vger.kernel.org>, <mturquette@linaro.org>, <bbrezillon@kernel.org>, <linux-clk@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org> Subject: Re: [PATCH 2/2] clk: at91: main: do not continue if oscillators already prepared Date: Wed, 1 Jul 2020 09:47:40 +0000 [thread overview] Message-ID: <0558282c-1471-84fb-d0f2-00e998db5cab@microchip.com> (raw) In-Reply-To: <20200626210357.GX131826@piout.net> On 27.06.2020 00:03, Alexandre Belloni wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > On 25/06/2020 13:09:28+0300, Claudiu Beznea wrote: >> Return in clk_main_osc_prepare()/clk_main_rc_osc_prepare() if >> oscillators are already enabled. >> >> Fixes: 27cb1c2083373 ("clk: at91: rework main clk implementation") >> Fixes: 1bdf02326b71e ("clk: at91: make use of syscon/regmap internally") > > Is this really a fix? What is the observed issue? > >> Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> >> --- >> drivers/clk/at91/clk-main.c | 18 +++++++++--------- >> 1 file changed, 9 insertions(+), 9 deletions(-) >> >> diff --git a/drivers/clk/at91/clk-main.c b/drivers/clk/at91/clk-main.c >> index 37c22667e831..46b4d2131989 100644 >> --- a/drivers/clk/at91/clk-main.c >> +++ b/drivers/clk/at91/clk-main.c >> @@ -74,13 +74,11 @@ static int clk_main_osc_prepare(struct clk_hw *hw) >> regmap_read(regmap, AT91_CKGR_MOR, &tmp); >> tmp &= ~MOR_KEY_MASK; >> >> - if (tmp & AT91_PMC_OSCBYPASS) >> + if (tmp & (AT91_PMC_OSCBYPASS | AT91_PMC_MOSCEN)) >> return 0; > > While this seems like a good optimization, it is also not correct. > Having AT91_PMC_MOSCEN set doesn't mean that the clock is ready, you > need to at least check MOSCS once. I agree! This is may introduce issues. Thank you for reviewing it. > >> >> - if (!(tmp & AT91_PMC_MOSCEN)) { >> - tmp |= AT91_PMC_MOSCEN | AT91_PMC_KEY; >> - regmap_write(regmap, AT91_CKGR_MOR, tmp); >> - } >> + tmp |= AT91_PMC_MOSCEN | AT91_PMC_KEY; >> + regmap_write(regmap, AT91_CKGR_MOR, tmp); >> >> while (!clk_main_osc_ready(regmap)) >> cpu_relax(); >> @@ -186,10 +184,12 @@ static int clk_main_rc_osc_prepare(struct clk_hw *hw) >> >> regmap_read(regmap, AT91_CKGR_MOR, &mor); >> >> - if (!(mor & AT91_PMC_MOSCRCEN)) >> - regmap_update_bits(regmap, AT91_CKGR_MOR, >> - MOR_KEY_MASK | AT91_PMC_MOSCRCEN, >> - AT91_PMC_MOSCRCEN | AT91_PMC_KEY); >> + if (mor & AT91_PMC_MOSCRCEN) >> + return 0; >> + >> + regmap_update_bits(regmap, AT91_CKGR_MOR, >> + MOR_KEY_MASK | AT91_PMC_MOSCRCEN, >> + AT91_PMC_MOSCRCEN | AT91_PMC_KEY); >> >> while (!clk_main_rc_osc_ready(regmap)) >> cpu_relax(); >> -- >> 2.7.4 >> > > -- > Alexandre Belloni, Bootlin > Embedded Linux and Kernel engineering > https://bootlin.com >
WARNING: multiple messages have this Message-ID (diff)
From: <Claudiu.Beznea@microchip.com> To: <alexandre.belloni@bootlin.com> Cc: mturquette@linaro.org, bbrezillon@kernel.org, sboyd@kernel.org, mturquette@baylibre.com, linux-kernel@vger.kernel.org, Ludovic.Desroches@microchip.com, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 2/2] clk: at91: main: do not continue if oscillators already prepared Date: Wed, 1 Jul 2020 09:47:40 +0000 [thread overview] Message-ID: <0558282c-1471-84fb-d0f2-00e998db5cab@microchip.com> (raw) In-Reply-To: <20200626210357.GX131826@piout.net> On 27.06.2020 00:03, Alexandre Belloni wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > On 25/06/2020 13:09:28+0300, Claudiu Beznea wrote: >> Return in clk_main_osc_prepare()/clk_main_rc_osc_prepare() if >> oscillators are already enabled. >> >> Fixes: 27cb1c2083373 ("clk: at91: rework main clk implementation") >> Fixes: 1bdf02326b71e ("clk: at91: make use of syscon/regmap internally") > > Is this really a fix? What is the observed issue? > >> Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> >> --- >> drivers/clk/at91/clk-main.c | 18 +++++++++--------- >> 1 file changed, 9 insertions(+), 9 deletions(-) >> >> diff --git a/drivers/clk/at91/clk-main.c b/drivers/clk/at91/clk-main.c >> index 37c22667e831..46b4d2131989 100644 >> --- a/drivers/clk/at91/clk-main.c >> +++ b/drivers/clk/at91/clk-main.c >> @@ -74,13 +74,11 @@ static int clk_main_osc_prepare(struct clk_hw *hw) >> regmap_read(regmap, AT91_CKGR_MOR, &tmp); >> tmp &= ~MOR_KEY_MASK; >> >> - if (tmp & AT91_PMC_OSCBYPASS) >> + if (tmp & (AT91_PMC_OSCBYPASS | AT91_PMC_MOSCEN)) >> return 0; > > While this seems like a good optimization, it is also not correct. > Having AT91_PMC_MOSCEN set doesn't mean that the clock is ready, you > need to at least check MOSCS once. I agree! This is may introduce issues. Thank you for reviewing it. > >> >> - if (!(tmp & AT91_PMC_MOSCEN)) { >> - tmp |= AT91_PMC_MOSCEN | AT91_PMC_KEY; >> - regmap_write(regmap, AT91_CKGR_MOR, tmp); >> - } >> + tmp |= AT91_PMC_MOSCEN | AT91_PMC_KEY; >> + regmap_write(regmap, AT91_CKGR_MOR, tmp); >> >> while (!clk_main_osc_ready(regmap)) >> cpu_relax(); >> @@ -186,10 +184,12 @@ static int clk_main_rc_osc_prepare(struct clk_hw *hw) >> >> regmap_read(regmap, AT91_CKGR_MOR, &mor); >> >> - if (!(mor & AT91_PMC_MOSCRCEN)) >> - regmap_update_bits(regmap, AT91_CKGR_MOR, >> - MOR_KEY_MASK | AT91_PMC_MOSCRCEN, >> - AT91_PMC_MOSCRCEN | AT91_PMC_KEY); >> + if (mor & AT91_PMC_MOSCRCEN) >> + return 0; >> + >> + regmap_update_bits(regmap, AT91_CKGR_MOR, >> + MOR_KEY_MASK | AT91_PMC_MOSCRCEN, >> + AT91_PMC_MOSCRCEN | AT91_PMC_KEY); >> >> while (!clk_main_rc_osc_ready(regmap)) >> cpu_relax(); >> -- >> 2.7.4 >> > > -- > Alexandre Belloni, Bootlin > Embedded Linux and Kernel engineering > https://bootlin.com > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-07-01 9:47 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-06-25 10:09 [PATCH 1/2] clk: at91: remove the checking of parent_name Claudiu Beznea 2020-06-25 10:09 ` Claudiu Beznea 2020-06-25 10:09 ` [PATCH 2/2] clk: at91: main: do not continue if oscillators already prepared Claudiu Beznea 2020-06-25 10:09 ` Claudiu Beznea 2020-06-26 21:03 ` Alexandre Belloni 2020-06-26 21:03 ` Alexandre Belloni 2020-07-01 9:47 ` Claudiu.Beznea [this message] 2020-07-01 9:47 ` Claudiu.Beznea 2020-06-26 20:58 ` [PATCH 1/2] clk: at91: remove the checking of parent_name Alexandre Belloni 2020-06-26 20:58 ` Alexandre Belloni
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