RE: [PATCH 2/2] mmc: dw_mmc: Handle wp-gpios from device tree

Seungwon Jeon
2012-11-22T19:53:21Z

Hi,

wp-gpios has been implemented in dw_mmc-exynos.c
It can be reused for EXYNOS platform? We need to modify some though.

Thanks,
Seungwon Jeon

On Thursday, November 22, 2012, Doug Anderson <dianders@chromium.org> wrote:
> On some SoCs (like exynos5250) you need to use an external GPIO for
> write protect. Add support for wp-gpios to the core dw_mmc driver
> since it could be useful across multiple SoCs.
>
> With this change I am able to make use of the write protect for the
> external SD slot on exynos5250-snow.
>
> Signed-off-by: Doug Anderson <dianders@chromium.org>
> ---
> drivers/mmc/host/dw_mmc.c | 35 +++++++++++++++++++++++++++++++++++
> 1 files changed, 35 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 5b41348..9c79870 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -34,6 +34,7 @@
> #include <linux/regulator/consumer.h>
> #include <linux/workqueue.h>
> #include <linux/of.h>
> +#include <linux/of_gpio.h>
>
> #include "dw_mmc.h"
>
> @@ -74,6 +75,7 @@ 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.
> + * @wp_gpio: If gpio_is_valid() we'll use this to read write protect.
> * @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 +90,8 @@ struct dw_mci_slot {
> struct mmc_host *mmc;
> struct dw_mci *host;
>
> + int wp_gpio;
> +
> u32 ctype;
>
> struct mmc_request *mrq;
> @@ -832,6 +836,8 @@ static int dw_mci_get_ro(struct mmc_host *mmc)
> read_only = 0;
> else if (brd->get_ro)
> read_only = brd->get_ro(slot->id);
> + else if (gpio_is_valid(slot->wp_gpio))
> + read_only = gpio_get_value(slot->wp_gpio);
> else
> read_only =
> mci_readl(slot->host, WRTPRT) & (1 << slot->id) ? 1 : 0;
> @@ -1802,6 +1808,29 @@ static u32 dw_mci_of_get_bus_wd(struct device *dev, u8 slot)
> " as 1\n");
> return bus_wd;
> }
> +
> +/* find the write protect gpio for a given slot; or -1 if none specified */
> +static u32 dw_mci_of_get_wp_gpio(struct device *dev, u8 slot)
> +{
> + struct device_node *np = dw_mci_of_find_slot_node(dev, slot);
> + int gpio;
> +
> + if (!np)
> + return -1;
> +
> + gpio = of_get_named_gpio(np, "wp-gpios", 0);
> +
> + /* Having a missing entry is valid; return silently */
> + if (!gpio_is_valid(gpio))
> + return -1;
> +
> + if (devm_gpio_request(dev, gpio, "dw-mci-wp")) {
> + dev_warn(dev, "gpio [%d] request failed\n", gpio);
> + return -1;
> + }
> +
> + return gpio;
> +}
> #else /* CONFIG_OF */
> static u32 dw_mci_of_get_bus_wd(struct device *dev, u8 slot)
> {
> @@ -1811,6 +1840,10 @@ static struct device_node *dw_mci_of_find_slot_node(struct device *dev, u8 slot)
> {
> return NULL;
> }
> +static u32 dw_mci_of_get_wp_gpio(struct device *dev, u8 slot)
> +{
> + return -1;
> +}
> #endif /* CONFIG_OF */
>
> static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
> @@ -1923,6 +1956,8 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
> else
> clear_bit(DW_MMC_CARD_PRESENT, &slot->flags);
>
> + slot->wp_gpio = dw_mci_of_get_wp_gpio(host->dev, slot->id);
> +
> mmc_add_host(mmc);
>
> #if defined(CONFIG_DEBUG_FS)
> --
> 1.7.7.3