RE: [PATCH v3 1/4] mmc: dw_mmc: Add "disable-wp" device tree property

Seungwon Jeon
2012-11-30T11:57:10Z

Doug, Thanks to work.
Looks good to me with other patches.

Acked-by: Seungwon Jeon <tgih.jun@samsung.com>

On Friday, November 30, 2012, Doug Anderson wrote:
> The "disable-wp" property is used to specify that a given SD card slot
> doesn't have a concept of write protect. This eliminates the need for
> special case code for SD slots that should never be write protected
> (like a micro SD slot or a dev board).
>
> The dw_mmc driver is special in needing to specify "disable-wp"
> because the lack of a "wp-gpios" property means to use the special
> purpose write protect line. On some other mmc devices the lack of
> "wp-gpios" means that write protect should be disabled.
>
> Signed-off-by: Doug Anderson <dianders@chromium.org>
> ---
> Changes in v3:
> - New for this version of the patch series. Chose "disable-wp" rather
> than the discussed "broken-internal-wp" since it mapped more cleanly
> to an existing quirk (and the only reason to specify that the
> internal wp is broken is if you're disabling the write protect
> anyway).
>
> .../devicetree/bindings/mmc/synopsis-dw-mshc.txt | 12 +++++-
> drivers/mmc/host/dw_mmc.c | 36 +++++++++++++++++++-
> include/linux/mmc/dw_mmc.h | 4 ++
> 3 files changed, 49 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
> b/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
> index 06cd32d08..726fd21 100644
> --- a/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
> +++ b/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
> @@ -26,8 +26,16 @@ Required Properties:
> * bus-width: as documented in mmc core bindings.
>
> * wp-gpios: specifies the write protect gpio line. The format of the
> - gpio specifier depends on the gpio controller. If the write-protect
> - line is not available, this property is optional.
> + gpio specifier depends on the gpio controller. If a GPIO is not used
> + for write-protect, this property is optional.
> +
> + * disable-wp: If the wp-gpios property isn't present then (by default)
> + we'd assume that the write protect is hooked up directly to the
> + controller's special purpose write protect line (accessible via
> + the WRTPRT register). However, it's possible that we simply don't
> + want write protect. In that case specify 'disable-wp'.
> + NOTE: This property is not required for slots known to always
> + connect to eMMC or SDIO cards.
>
> Optional properties:
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 7342029..b47b1e9 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -74,6 +74,7 @@ struct idmac_desc {
> * struct dw_mci_slot - MMC slot state
> * @mmc: The mmc_host representing this slot.
> * @host: The MMC controller this slot is using.
> + * @quirks: Slot-level quirks (DW_MCI_SLOT_QUIRK_XXX)
> * @ctype: Card type for this slot.
> * @mrq: mmc_request currently being processed or waiting to be
> * processed, or NULL when the slot is idle.
> @@ -88,6 +89,8 @@ struct dw_mci_slot {
> struct mmc_host *mmc;
> struct dw_mci *host;
>
> + int quirks;
> +
> u32 ctype;
>
> struct mmc_request *mrq;
> @@ -828,7 +831,8 @@ static int dw_mci_get_ro(struct mmc_host *mmc)
> struct dw_mci_board *brd = slot->host->pdata;
>
> /* Use platform get_ro function, else try on board write protect */
> - if (brd->quirks & DW_MCI_QUIRK_NO_WRITE_PROTECT)
> + if ((brd->quirks & DW_MCI_QUIRK_NO_WRITE_PROTECT) ||
> + (slot->quirks & DW_MCI_SLOT_QUIRK_NO_WRITE_PROTECT))
> read_only = 0;
> else if (brd->get_ro)
> read_only = brd->get_ro(slot->id);
> @@ -1788,6 +1792,30 @@ static struct device_node *dw_mci_of_find_slot_node(struct device *dev, u8 slot)
> return NULL;
> }
>
> +static struct dw_mci_of_slot_quirks {
> + char *quirk;
> + int id;
> +} of_slot_quirks[] = {
> + {
> + .quirk = "disable-wp",
> + .id = DW_MCI_SLOT_QUIRK_NO_WRITE_PROTECT,
> + },
> +};
> +
> +static int dw_mci_of_get_slot_quirks(struct device *dev, u8 slot)
> +{
> + struct device_node *np = dw_mci_of_find_slot_node(dev, slot);
> + int quirks = 0;
> + int idx;
> +
> + /* get quirks */
> + for (idx = 0; idx < ARRAY_SIZE(of_slot_quirks); idx++)
> + if (of_get_property(np, of_slot_quirks[idx].quirk, NULL))
> + quirks |= of_slot_quirks[idx].id;
> +
> + return quirks;
> +}
> +
> /* find out bus-width for a given slot */
> static u32 dw_mci_of_get_bus_wd(struct device *dev, u8 slot)
> {
> @@ -1803,6 +1831,10 @@ static u32 dw_mci_of_get_bus_wd(struct device *dev, u8 slot)
> return bus_wd;
> }
> #else /* CONFIG_OF */
> +static int dw_mci_of_get_slot_quirks(struct device *dev, u8 slot)
> +{
> + return 0;
> +}
> static u32 dw_mci_of_get_bus_wd(struct device *dev, u8 slot)
> {
> return 1;
> @@ -1831,6 +1863,8 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
> slot->host = host;
> host->slot[id] = slot;
>
> + slot->quirks = dw_mci_of_get_slot_quirks(host->dev, slot->id);
> +
> mmc->ops = &dw_mci_ops;
> mmc->f_min = DIV_ROUND_UP(host->bus_hz, 510);
> mmc->f_max = host->bus_hz;
> diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
> index 34be4f4..24dc3a8 100644
> --- a/include/linux/mmc/dw_mmc.h
> +++ b/include/linux/mmc/dw_mmc.h
> @@ -212,6 +212,10 @@ struct dw_mci_dma_ops {
> /* Write Protect detection not available */
> #define DW_MCI_QUIRK_NO_WRITE_PROTECT BIT(4)
>
> +/* Slot level quirks */
> +/* This slot has no write protect */
> +#define DW_MCI_SLOT_QUIRK_NO_WRITE_PROTECT BIT(0)
> +
> struct dma_pdata;
>
> struct block_settings {
> --
> 1.7.7.3
>
> --
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