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

Wenbin Mei
2020-10-14T02:29:07Z

On Tue, 2020-10-13 at 17:10 +0200, Matthias Brugger wrote:
>
> On 12/10/2020 14:45, Wenbin Mei 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@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
> [...]
> > +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";
>
> That looks at least suspicious. The pointers of id point to some strings defined
> in the function. Aren't they out of scope once msdc_of_clock_parse() has returned?
>
These constants are not in stack range, so they will not be lost.
And I have confirmed it after msdc_of_clock_parse() has returned, these
ids still exist.

> Regards,
> Matthias