[PATCH] mmc: sdhci-xenon: Fix clock resource by adding an optional bus clock
Gregory CLEMENT
gregory.clement at free-electrons.com
Fri Sep 29 02:13:00 PDT 2017
Hi Jisheng,
On ven., sept. 29 2017, Jisheng Zhang <Jisheng.Zhang at synaptics.com> wrote:
> + DT maintainers
>
> On Thu, 28 Sep 2017 17:05:20 +0200 Gregory CLEMENT 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 at vger.kernel.org>
>> Signed-off-by: Gregory CLEMENT <gregory.clement at free-electrons.com>
>> ---
>> Hi Ulf and Adrian,
>>
>> This patch should be merged in 4.14-rc, as it fixes real issues.
>>
>> This patch maye 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 Sov and with more exhaustive testes that we found this
>> issue and the fix for it.
>>
>> Thanks,
>>
>> Gregory
>>
>>
>> .../bindings/mmc/marvell,xenon-sdhci.txt | 12 ++++++-----
>> drivers/mmc/host/sdhci-xenon.c | 25 +++++++++++++++++++---
>> drivers/mmc/host/sdhci-xenon.h | 1 +
>> 3 files changed, 30 insertions(+), 8 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt b/Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt
>> index b878a1e305af..6f3db1f809ab 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".
>
> Is "bus" more suitable?
I find bus too vague.
>
>>
>> - 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..845575593b59 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);
>> + dev_err(&pdev->dev, "Failed to setup axi clk: %d\n", err);
>
> Since the bus clock is optional, can we remove this err msg?
I will change it in dev_info.
>
>> + priv->axi_clk = NULL;
>> + } 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 +540,9 @@ 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:
>> + if (priv->axi_clk)
>
> clk_disable_unprepare() will do the check. So this check could be removed
> to simplify the err path
Right I removed it
>
>> + clk_disable_unprepare(priv->axi_clk);
>> err_clk:
>> clk_disable_unprepare(pltfm_host->clk);
>> free_pltfm:
>> @@ -538,6 +554,7 @@ 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);
>> @@ -546,6 +563,8 @@ static int xenon_remove(struct platform_device *pdev)
>> sdhci_remove_host(host, 0);
>>
>> xenon_sdhc_unprepare(host);
>> + if (priv->axi_clk)
>> + clk_disable_unprepare(priv->axi_clk);
>
> ditto
OK
Thanks,
Gregory
--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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