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Message-ID: <CANMq1KD5MRvAiwk+EPfOTqaEqjcXz5FUAvmkX+OjQ=kpEP_=8A@mail.gmail.com>
Date: Mon, 12 Oct 2020 11:38:53 +0800
From: Nicolas Boichat <drinkcat@...omium.org>
To: Wenbin Mei <wenbin.mei@...iatek.com>
Cc: Ulf Hansson <ulf.hansson@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
Chaotian Jing <chaotian.jing@...iatek.com>,
Matthias Brugger <matthias.bgg@...il.com>,
linux-mmc@...r.kernel.org,
Devicetree List <devicetree@...r.kernel.org>,
linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
"moderated list:ARM/Mediatek SoC support"
<linux-mediatek@...ts.infradead.org>,
lkml <linux-kernel@...r.kernel.org>,
srv_heupstream <srv_heupstream@...iatek.com>
Subject: Re: [PATCH v5 4/4] mmc: mediatek: Add subsys clock control for MT8192 msdc
Thanks for the quick turnaround.
And sorry, I should have noticed these issues in my previous pass.
On Mon, Oct 12, 2020 at 10:44 AM Wenbin Mei <wenbin.mei@...iatek.com> wrote:
>
> MT8192 msdc is an independent sub system, we need control more bus
> clocks for it.
> Add support for the additional subsys clocks to allow it to be
> configured appropriately.
>
> Signed-off-by: Wenbin Mei <wenbin.mei@...iatek.com>
> ---
> drivers/mmc/host/mtk-sd.c | 74 +++++++++++++++++++++++++++++----------
> 1 file changed, 56 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> index a704745e5882..41703e6d6b17 100644
> --- a/drivers/mmc/host/mtk-sd.c
> +++ b/drivers/mmc/host/mtk-sd.c
> @@ -35,6 +35,7 @@
> #include "cqhci.h"
>
> #define MAX_BD_NUM 1024
> +#define MSDC_NR_CLOCKS 3
>
> /*--------------------------------------------------------------------------*/
> /* Common Definition */
> @@ -425,6 +426,8 @@ struct msdc_host {
> struct clk *h_clk; /* msdc h_clk */
> struct clk *bus_clk; /* bus clock which used to access register */
> struct clk *src_clk_cg; /* msdc source clock control gate */
> + struct clk *sys_clk_cg; /* msdc subsys clock control gate */
> + struct clk_bulk_data bulk_clks[MSDC_NR_CLOCKS];
> u32 mclk; /* mmc subsystem clock frequency */
> u32 src_clk_freq; /* source clock frequency */
> unsigned char timing;
> @@ -784,6 +787,7 @@ static void msdc_set_busy_timeout(struct msdc_host *host, u64 ns, u64 clks)
>
> static void msdc_gate_clock(struct msdc_host *host)
> {
> + clk_bulk_disable_unprepare(MSDC_NR_CLOCKS, host->bulk_clks);
> clk_disable_unprepare(host->src_clk_cg);
> clk_disable_unprepare(host->src_clk);
> clk_disable_unprepare(host->bus_clk);
> @@ -792,10 +796,18 @@ static void msdc_gate_clock(struct msdc_host *host)
>
> static void msdc_ungate_clock(struct msdc_host *host)
> {
> + int ret;
> +
> clk_prepare_enable(host->h_clk);
> clk_prepare_enable(host->bus_clk);
> clk_prepare_enable(host->src_clk);
> clk_prepare_enable(host->src_clk_cg);
> + ret = clk_bulk_prepare_enable(MSDC_NR_CLOCKS, host->bulk_clks);
> + if (ret) {
> + dev_err(host->dev, "Cannot enable pclk/axi/ahb clock gates\n");
> + return;
> + }
It's a bit odd that we only care about the last 3 clocks... Should we
return early if any of the clocks can't be enabled? Changing the
behaviour for the other clocks should be in another patch though.
> +
> while (!(readl(host->base + MSDC_CFG) & MSDC_CFG_CKSTB))
> cpu_relax();
> }
> @@ -2366,6 +2378,48 @@ static void msdc_of_property_parse(struct platform_device *pdev,
> host->cqhci = false;
> }
>
> +static int msdc_of_clock_parse(struct platform_device *pdev,
> + struct msdc_host *host)
> +{
> + int ret;
> +
> + host->src_clk = devm_clk_get_optional(&pdev->dev, "source");
I think you want devm_clk_get, as the previous version of the code
does not make this clock optional.
> + if (IS_ERR(host->src_clk))
> + return PTR_ERR(host->src_clk);
> +
> + host->h_clk = devm_clk_get_optional(&pdev->dev, "hclk");
ditto, devm_clk_get
> + if (IS_ERR(host->h_clk))
> + return PTR_ERR(host->h_clk);
> +
> + host->bus_clk = devm_clk_get_optional(&pdev->dev, "bus_clk");
> + if (IS_ERR(host->bus_clk))
> + host->bus_clk = NULL;
This is consistent with previous behaviour, but this looks wrong. If
the clock exists (!= NULL return value), but you get an error, you
should return that error. This belongs in another patch though.
> +
> + /*source clock control gate is optional clock*/
> + host->src_clk_cg = devm_clk_get_optional(&pdev->dev, "source_cg");
> + if (IS_ERR(host->src_clk_cg))
> + host->src_clk_cg = NULL;
> +
> + host->sys_clk_cg = devm_clk_get_optional(&pdev->dev, "sys_cg");
> + if (IS_ERR(host->sys_clk_cg))
> + host->sys_clk_cg = NULL;
> +
> + /* If present, always enable for this clock gate */
> + clk_prepare_enable(host->sys_clk_cg);
> +
> + host->bulk_clks[0].id = "pclk_cg";
> + host->bulk_clks[1].id = "axi_cg";
> + host->bulk_clks[2].id = "ahb_cg";
> + ret = devm_clk_bulk_get_optional(&pdev->dev, MSDC_NR_CLOCKS,
> + host->bulk_clks);
> + if (ret) {
> + dev_err(&pdev->dev, "Cannot get pclk/axi/ahb clock gates\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> static int msdc_drv_probe(struct platform_device *pdev)
> {
> struct mmc_host *mmc;
> @@ -2405,25 +2459,9 @@ static int msdc_drv_probe(struct platform_device *pdev)
> if (ret)
> goto host_free;
>
> - host->src_clk = devm_clk_get(&pdev->dev, "source");
> - if (IS_ERR(host->src_clk)) {
> - ret = PTR_ERR(host->src_clk);
> - goto host_free;
> - }
> -
> - host->h_clk = devm_clk_get(&pdev->dev, "hclk");
> - if (IS_ERR(host->h_clk)) {
> - ret = PTR_ERR(host->h_clk);
> + ret = msdc_of_clock_parse(pdev, host);
> + if (ret)
> goto host_free;
> - }
> -
> - host->bus_clk = devm_clk_get(&pdev->dev, "bus_clk");
> - if (IS_ERR(host->bus_clk))
> - host->bus_clk = NULL;
> - /*source clock control gate is optional clock*/
> - host->src_clk_cg = devm_clk_get(&pdev->dev, "source_cg");
> - if (IS_ERR(host->src_clk_cg))
> - host->src_clk_cg = NULL;
>
> host->reset = devm_reset_control_get_optional_exclusive(&pdev->dev,
> "hrst");
> --
> 2.18.0
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