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From: Adrian Hunter <adrian.hunter@intel.com>
To: "Michał Mirosław" <mirq-linux@rere.qmqm.pl>,
	"Kevin Liu" <kliu5@marvell.com>,
	"Michal Simek" <michal.simek@xilinx.com>,
	"Suneel Garapati" <suneel.garapati@xilinx.com>,
	"Ulf Hansson" <ulf.hansson@linaro.org>
Cc: linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
	Al Cooper <alcooperx@gmail.com>
Subject: Re: [PATCH v4 2/5] mmc: sdhci: always obey programmable clock config in preset value
Date: Wed, 4 Aug 2021 13:52:21 +0300	[thread overview]
Message-ID: <fe01b20d-779b-1e2c-7702-5a4702900d84@intel.com> (raw)
In-Reply-To: <e65dc96eb24caf8baa5431a51fe694b969e2d51f.1627204633.git.mirq-linux@rere.qmqm.pl>

On 25/07/21 12:20 pm, Michał Mirosław wrote:
> When host controller uses programmable clock presets but doesn't
> advertise programmable clock support, we can only guess what frequency
> it generates. Let's at least return correct SDHCI_PROG_CLOCK_MODE bit
> value in this case.

If the preset value doesn't make sense, why use it at all?

> 
> Fixes: 52983382c74f ("mmc: sdhci: enhance preset value function")
> Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
> ---
> v4: no changes
> v3: added a comment for this case
> v2: no changes
> ---
>  drivers/mmc/host/sdhci.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index c7438dd13e3e..3ab60e7f936b 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1859,11 +1859,14 @@ u16 sdhci_calc_clk(struct sdhci_host *host, unsigned int clock,
>  
>  			pre_val = sdhci_get_preset_value(host);
>  			div = FIELD_GET(SDHCI_PRESET_SDCLK_FREQ_MASK, pre_val);
> -			if (host->clk_mul &&
> -				(pre_val & SDHCI_PRESET_CLKGEN_SEL)) {
> +			if (pre_val & SDHCI_PRESET_CLKGEN_SEL) {
>  				clk = SDHCI_PROG_CLOCK_MODE;
>  				real_div = div + 1;
>  				clk_mul = host->clk_mul;
> +				if (!clk_mul) {
> +					/* The clock frequency is unknown. Assume undivided base. */
> +					clk_mul = 1;
> +				}
>  			} else {
>  				real_div = max_t(int, 1, div << 1);
>  			}
> 


  reply	other threads:[~2021-08-04 10:51 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-25  9:20 [PATCH v4 0/5] SDHCI clock handling fixes and cleanups Michał Mirosław
2021-07-25  9:20 ` [PATCH v4 1/5] mmc: sdhci: fix base clock usage in preset value Michał Mirosław
2021-08-04 10:50   ` Adrian Hunter
2021-07-25  9:20 ` [PATCH v4 2/5] mmc: sdhci: always obey programmable clock config " Michał Mirosław
2021-08-04 10:52   ` Adrian Hunter [this message]
2021-08-07 14:05     ` Michał Mirosław
2021-08-12  9:54       ` Adrian Hunter
2021-07-25  9:20 ` [PATCH v4 3/5] mmc: sdhci: fix SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN Michał Mirosław
2021-08-04 11:06   ` Adrian Hunter
2021-08-07 14:08     ` Michał Mirosław
2021-07-25  9:20 ` [PATCH v4 5/5] mmc: sdhci: simplify v2/v3+ clock calculation Michał Mirosław
2021-08-04 12:40   ` Adrian Hunter
2021-08-07 15:39     ` Michał Mirosław
2021-07-25  9:20 ` [PATCH v4 4/5] mmc: sdhci: move SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN frequency limit Michał Mirosław
2021-08-04 12:33   ` Adrian Hunter
2021-08-07 14:12     ` Michał Mirosław
2021-08-12 10:01       ` Adrian Hunter

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