Re: [PATCH v6 4/4] mmc: mediatek: Add subsys clock control for MT8192 msdc

Nicolas Boichat
2020-10-13T09:59:30Z

On Mon, Oct 12, 2020 at 8:46 PM Wenbin Mei <wenbin.mei@mediatek.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.
>

Looks ok now, but I'd still like to see 1 or 2 follow-up patches that:
1. In msdc_ungate_clock: check all clk_prepare_enable return values
before busy looping (to be consistent with how you now handle
bulk_clks)
2. In msdc_of_clock_parse: All these if(IS_ERR(clk)) clk = NULL;
should be replaced by if (IS_ERR(clk)) return PTR_ERR(clk);

Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>

> Signed-off-by: Wenbin Mei <wenbin.mei@mediatek.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..c7df7510f120 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;
> + }
> +
> 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(&pdev->dev, "source");
> + if (IS_ERR(host->src_clk))
> + return PTR_ERR(host->src_clk);
> +
> + host->h_clk = devm_clk_get(&pdev->dev, "hclk");
> + 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;
> +
> + /*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