Re: [PATCH v3] mmc: sdhci-xenon: Fix clock resource by adding an optional bus clock

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Hi Ulf,
 
 On mer., oct. 04 2017, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:

> On 2 October 2017 at 16:58, Gregory CLEMENT
> <gregory.clement@xxxxxxxxxxxxxxxxxx> wrote:
>> On Armada 7K/8K we need to explicitly enable the bus clock. The bus clock
>> is optional because not all the SoCs need them but at least for Armada
>> 7K/8K it is actually mandatory.
>>
>> The binding documentation is updating accordingly.
>>
>> Without this patch the kernel hand during boot if the mvpp2.2 network
>> driver was not present in the kernel. Indeed the clock needed by the
>> xenon controller was set by the network driver.
>>
>> Fixes: 3a3748dba881 ("mmc: sdhci-xenon: Add Marvell Xenon SDHC core
>> functionality)"
>> CC: Stable <stable@xxxxxxxxxxxxxxx>
>> Tested-by: Zhoujie Wu <zjwu@xxxxxxxxxxx>
>> Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
>
> Thanks, applied for fixes!
>
> Next time, please split DT changes into separate patches - as that
> simplifies the review process.

OK I will do this,

Thanks,

Gregory

>
> Kind regards
> Uffe
>
>> ---
>> Hi Ulf and Adrian,
>>
>> This patch should be merged in 4.14-rc, as it fixes real issues.
>>
>> This patch may looks like just as a nice clean-up but it is not. On
>> the earlier version of the series adding the support for the xenon
>> controller there was already this axi bus clock. But at this moment
>> the documentation for the clock on the Armada 7K/8K was missing and
>> there was no driver for it, so we just use the clock set by the
>> bootloader and never change them that's why it worked without any
>> visible problem.
>>
>> Then as explained in the commit log the network driver enabled the
>> clock for us, and it happened that it was setup before the xenon
>> driver. It is only thanks the new information we received on the
>> clocks of the SoC and with more exhaustive testes that we found this
>> issue and the fix for it.
>>
>> Thanks,
>>
>> Gregory
>>
>> Changelog:
>> v2->v3:
>>  - remove useless test on clk pointer
>>  - added tested-by from  Zhoujie Wu
>>
>> v1->v2:
>>  - manage the -EPROBE_DEFER case
>>  - remove warning message when axi clock is not present
>>  - remove useless test before clk_disable_unprepare()
>>
>>  .../bindings/mmc/marvell,xenon-sdhci.txt           | 12 ++++++-----
>>  drivers/mmc/host/sdhci-xenon.c                     | 24 ++++++++++++++++++----
>>  drivers/mmc/host/sdhci-xenon.h                     |  1 +
>>  3 files changed, 28 insertions(+), 9 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt b/Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt
>> index b878a1e305af..ed1456f5c94d 100644
>> --- a/Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt
>> +++ b/Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt
>> @@ -16,11 +16,13 @@ Required Properties:
>>
>>  - clocks:
>>    Array of clocks required for SDHC.
>> -  Require at least input clock for Xenon IP core.
>> +  Require at least input clock for Xenon IP core. For Armada AP806 and
>> +  CP110, the AXI clock is also mandatory.
>>
>>  - clock-names:
>>    Array of names corresponding to clocks property.
>>    The input clock for Xenon IP core should be named as "core".
>> +  The input clock for the AXI bus must be named as "axi".
>>
>>  - reg:
>>    * For "marvell,armada-3700-sdhci", two register areas.
>> @@ -106,8 +108,8 @@ Example:
>>                 compatible = "marvell,armada-ap806-sdhci";
>>                 reg = <0xaa0000 0x1000>;
>>                 interrupts = <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>
>> -               clocks = <&emmc_clk>;
>> -               clock-names = "core";
>> +               clocks = <&emmc_clk>,<&axi_clk>;
>> +               clock-names = "core", "axi";
>>                 bus-width = <4>;
>>                 marvell,xenon-phy-slow-mode;
>>                 marvell,xenon-tun-count = <11>;
>> @@ -126,8 +128,8 @@ Example:
>>                 interrupts = <GIC_SPI 55 IRQ_TYPE_LEVEL_HIGH>
>>                 vqmmc-supply = <&sd_vqmmc_regulator>;
>>                 vmmc-supply = <&sd_vmmc_regulator>;
>> -               clocks = <&sdclk>;
>> -               clock-names = "core";
>> +               clocks = <&sdclk>, <&axi_clk>;
>> +               clock-names = "core", "axi";
>>                 bus-width = <4>;
>>                 marvell,xenon-tun-count = <9>;
>>         };
>> diff --git a/drivers/mmc/host/sdhci-xenon.c b/drivers/mmc/host/sdhci-xenon.c
>> index 2eec2e652c53..0842bbc2d7ad 100644
>> --- a/drivers/mmc/host/sdhci-xenon.c
>> +++ b/drivers/mmc/host/sdhci-xenon.c
>> @@ -466,6 +466,7 @@ static int xenon_probe(struct platform_device *pdev)
>>  {
>>         struct sdhci_pltfm_host *pltfm_host;
>>         struct sdhci_host *host;
>> +       struct xenon_priv *priv;
>>         int err;
>>
>>         host = sdhci_pltfm_init(pdev, &sdhci_xenon_pdata,
>> @@ -474,6 +475,7 @@ static int xenon_probe(struct platform_device *pdev)
>>                 return PTR_ERR(host);
>>
>>         pltfm_host = sdhci_priv(host);
>> +       priv = sdhci_pltfm_priv(pltfm_host);
>>
>>         /*
>>          * Link Xenon specific mmc_host_ops function,
>> @@ -491,9 +493,20 @@ static int xenon_probe(struct platform_device *pdev)
>>         if (err)
>>                 goto free_pltfm;
>>
>> +       priv->axi_clk = devm_clk_get(&pdev->dev, "axi");
>> +       if (IS_ERR(priv->axi_clk)) {
>> +               err = PTR_ERR(priv->axi_clk);
>> +               if (err == -EPROBE_DEFER)
>> +                       goto err_clk;
>> +       } else {
>> +               err = clk_prepare_enable(priv->axi_clk);
>> +               if (err)
>> +                       goto err_clk;
>> +       }
>> +
>>         err = mmc_of_parse(host->mmc);
>>         if (err)
>> -               goto err_clk;
>> +               goto err_clk_axi;
>>
>>         sdhci_get_of_property(pdev);
>>
>> @@ -502,11 +515,11 @@ static int xenon_probe(struct platform_device *pdev)
>>         /* Xenon specific dt parse */
>>         err = xenon_probe_dt(pdev);
>>         if (err)
>> -               goto err_clk;
>> +               goto err_clk_axi;
>>
>>         err = xenon_sdhc_prepare(host);
>>         if (err)
>> -               goto err_clk;
>> +               goto err_clk_axi;
>>
>>         pm_runtime_get_noresume(&pdev->dev);
>>         pm_runtime_set_active(&pdev->dev);
>> @@ -527,6 +540,8 @@ static int xenon_probe(struct platform_device *pdev)
>>         pm_runtime_disable(&pdev->dev);
>>         pm_runtime_put_noidle(&pdev->dev);
>>         xenon_sdhc_unprepare(host);
>> +err_clk_axi:
>> +       clk_disable_unprepare(priv->axi_clk);
>>  err_clk:
>>         clk_disable_unprepare(pltfm_host->clk);
>>  free_pltfm:
>> @@ -538,6 +553,7 @@ static int xenon_remove(struct platform_device *pdev)
>>  {
>>         struct sdhci_host *host = platform_get_drvdata(pdev);
>>         struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>> +       struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
>>
>>         pm_runtime_get_sync(&pdev->dev);
>>         pm_runtime_disable(&pdev->dev);
>> @@ -546,7 +562,7 @@ static int xenon_remove(struct platform_device *pdev)
>>         sdhci_remove_host(host, 0);
>>
>>         xenon_sdhc_unprepare(host);
>> -
>> +       clk_disable_unprepare(priv->axi_clk);
>>         clk_disable_unprepare(pltfm_host->clk);
>>
>>         sdhci_pltfm_free(pdev);
>> diff --git a/drivers/mmc/host/sdhci-xenon.h b/drivers/mmc/host/sdhci-xenon.h
>> index 2bc0510c0769..9994995c7c56 100644
>> --- a/drivers/mmc/host/sdhci-xenon.h
>> +++ b/drivers/mmc/host/sdhci-xenon.h
>> @@ -83,6 +83,7 @@ struct xenon_priv {
>>         unsigned char   bus_width;
>>         unsigned char   timing;
>>         unsigned int    clock;
>> +       struct clk      *axi_clk;
>>
>>         int             phy_type;
>>         /*
>> --
>> 2.14.1
>>

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
--
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