On 18 October 2016 at 23:05, Zach Brown <zach.brown@xxxxxx> wrote:
> When the sdhci-cap-speed-modes-broken DT property is set, the driver
> will ignore the bits of the capability registers that correspond to
> speed modes and will read the of properties of the device to determine
> which speeds are supported.
To me this seems like a great idea. Yeah, I proposed it so I guess
that's why. :-)
Anyway, it's Adrian call to decide how he want to go with this. He
might consider the other option [1] to be better.
Some more comments below.
>
> Signed-off-by: Zach Brown <zach.brown@xxxxxx>
> ---
> drivers/mmc/host/sdhci.c | 31 +++++++++++++++++++++++++++++++
> 1 file changed, 31 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 1e25b01..100649a 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -22,6 +22,7 @@
> #include <linux/scatterlist.h>
> #include <linux/regulator/consumer.h>
> #include <linux/pm_runtime.h>
> +#include <linux/of.h>
>
> #include <linux/leds.h>
>
> @@ -3020,6 +3021,32 @@ void __sdhci_read_caps(struct sdhci_host *host, u16 *ver, u32 *caps, u32 *caps1)
> }
> EXPORT_SYMBOL_GPL(__sdhci_read_caps);
>
> +void sdhci_get_speed_caps_from_of(struct sdhci_host *host)
> +{
> + struct mmc_host *mmc = host->mmc;
> +
> + host->caps &= ~SDHCI_CAN_DO_HISPD;
> +
> + if (of_property_read_bool(mmc_dev(mmc)->of_node, "cap-sd-highspeed"))
> + host->caps |= SDHCI_CAN_DO_HISPD;
> +
> + if (host->version < SDHCI_SPEC_300)
> + return;
> +
> + host->caps1 &= ~(SDHCI_SUPPORT_SDR50 | SDHCI_SUPPORT_SDR104 |
> + SDHCI_SUPPORT_DDR50);
> +
> + if (of_property_read_bool(mmc_dev(mmc)->of_node, "sd-uhs-sdr50"))
> + host->caps1 |= SDHCI_SUPPORT_SDR50;
> +
> + if (of_property_read_bool(mmc_dev(mmc)->of_node, "sd-uhs-sdr104"))
> + host->caps1 |= SDHCI_SUPPORT_SDR104;
> +
> + if (of_property_read_bool(mmc_dev(mmc)->of_node, "sd-uhs-ddr50"))
> + host->caps1 |= SDHCI_SUPPORT_DDR50;
> +
I don't think you need a separate OF parsing function. Instead the
SDHCI variant drivers may call mmc_of_parse() to parse the generic mmc
OF properties and then read the SDHCI caps registers (in some way or
the other).
As reading the SDHCI caps registers is done in __sdhci_read_caps(),
you could instead check for the OF property
"sdhci-cap-speed-modes-broken" in there, and if it's set, clear the
related bits. I think that's all you need.
Note, the above code considers only SD speed modes, I assume we should
include eMMC speed modes to be broken as well!?
> +}
> +
> int sdhci_setup_host(struct sdhci_host *host)
> {
> struct mmc_host *mmc;
> @@ -3046,6 +3073,10 @@ int sdhci_setup_host(struct sdhci_host *host)
> return ret;
>
> sdhci_read_caps(host);
> + if (of_property_read_bool(mmc_dev(mmc)->of_node,
> + "sdhci-cap-speed-modes-broken"))
> + sdhci_get_speed_caps_from_of(host);
> +
>
> override_timeout_clk = host->timeout_clk;
>
> --
> 2.7.4
>
Kind regards
Uffe
[1]
http://www.spinics.net/lists/devicetree/msg146401.html
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