On 14/10/2020 05:06, Nicolas Boichat wrote:
On Wed, Oct 14, 2020 at 10:29 AM Wenbin Mei <wenbin.mei@xxxxxxxxxxxx> wrote:
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@xxxxxxxxxxxx>
---
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.
Yes I guess the constants end up in .rodata (or similar section), but
I'm not sure if this is absolutely guaranteed.
In any case, this is a commonly used pattern, so I'd hope it's fine
(just a sample, there are more):
https://elixir.bootlin.com/linux/latest/source/drivers/pci/controller/dwc/pcie-qcom.c#L266
https://elixir.bootlin.com/linux/latest/source/sound/soc/codecs/wm8994.c#L4638
https://elixir.bootlin.com/linux/latest/source/drivers/mfd/madera-core.c#L467
https://elixir.bootlin.com/linux/latest/source/drivers/gpio/gpio-dwapb.c#L675
Alright, then this looks good, sorry for the noise!
Matthias
