Hi Morimoto-san,
On Wed, May 13, 2015 at 4:18 AM, Kuninori Morimoto
<kuninori.morimoto.gx@xxxxxxxxxxx> wrote:
> MMCIF IP on R-Car series has parent clock which can be set
> several rate, and it was not implemented on old SH-Mobile series
> (= SH-Mobile series parent clock was fixed rate)
> R-Car series MMCIF can use more high speed access if it setup
> parent clock. This patch adds parent clock setup method,
> and r8a7790/r8a7791 can use it.
Thanks for this update.
I'm still wondering if we can do this without hardcoding frequencies in the
driver...
>From the discussion before:
"So the upper limit is a limitation of the MMCIF hardware, while the lower
limit is a limitation of the CPG."
> index e13c5f41..7ade263 100644
> --- a/drivers/mmc/host/sh_mmcif.c
> +++ b/drivers/mmc/host/sh_mmcif.c
> @@ -224,6 +225,15 @@ enum sh_mmcif_wait_for {
> MMCIF_WAIT_FOR_STOP,
> };
>
> +/*
> + * difference for each SoC
> + */
> +struct sh_mmcif_ver {
> + u32 clkdiv_map; /* see CE_CLK_CTRL::CLKDIV */
> + unsigned int pf_min; /* parent frequency min */
I don't think you need an explicit lower limit: clk_round_rate() will
never return a frequency that's lower than the parent clock's lower limit.
> + unsigned int pf_max; /* parent frequency max */
> +};
> +
> struct sh_mmcif_host {
> struct mmc_host *mmc;
> struct mmc_request *mrq;
> @@ -248,6 +258,7 @@ struct sh_mmcif_host {
> bool ccs_enable; /* Command Completion Signal support */
> bool clk_ctrl2_enable;
> struct mutex thread_lock;
> + const struct sh_mmcif_ver *ver;
>
> /* DMA support */
> struct dma_chan *chan_rx;
> @@ -256,8 +267,16 @@ struct sh_mmcif_host {
> bool dma_active;
> };
>
> +static const struct sh_mmcif_ver sh_mmcif_gen2 = {
> + .clkdiv_map = 0x3ff,
> + .pf_min = 12187500,
> + .pf_max = 97500000,
By any chance, does setting "max-frequency = <97500000>" from the standard
MMC DT bindings have the same effect?
> +};
> +
> static const struct of_device_id sh_mmcif_of_match[] = {
> { .compatible = "renesas,sh-mmcif" },
> + { .compatible = "renesas,mmcif-r8a7790", .data = &sh_mmcif_gen2 },
> + { .compatible = "renesas,mmcif-r8a7791", .data = &sh_mmcif_gen2 },
> { }
> };
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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