[PATCH v2 1/3] mmc: sdhci: use WP GPIO in sdhci_check_ro()

Thomas Petazzoni
2019-02-11T13:23:40Z

Even though SDHCI controllers may have a dedicated WP pin that can be
queried using the SDHCI_PRESENT_STATE register, some platforms may
chose to use a separate regular GPIO to route the WP signal. Such a
GPIO is typically represented using the wp-gpios property in the
Device Tree.

Unfortunately, the current sdhci_check_ro() function does not make use
of such GPIO when available: it either uses a host controller specific
->get_ro() operation, or uses the SDHCI_PRESENT_STATE. Several host
controller specific ->get_ro() functions are implemented just to check
a WP GPIO state.

Instead of pushing this to more controller-specific implementations,
let's handle this in the core SDHCI code, just like it is already done
for the CD GPIO in sdhci_get_cd().

The below patch simply changes sdhci_check_ro() to use the value of
the WP GPIO if available. We need to adjust the prototype of the
function to use a mmc_host* as argument instead of sdhci_host*, since
the mmc_can_gpio_ro() and mmc_gpio_get_ro() helpers take a mmc_host*.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
---
Changes since v1:

- As suggested by Adrian Hunter, call the ->get_ro() if it exists
before falling back to using mmc_gpio_get_ro(). Indeed, if the
controller-specific code has implemented a ->get_ro() callback, it
should take precedence over what the SDHCI core does.

Due to this change, I have not added Thierry Redding Reviewed-by.

- Fix typo in the commit log noticed by Thierry Redding.
---
drivers/mmc/host/sdhci.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index df05352b6a4a..e6682ea5f7c0 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2022,8 +2022,9 @@ static int sdhci_get_cd(struct mmc_host *mmc)
return !!(sdhci_readl(host, SDHCI_PRESENT_STATE) & SDHCI_CARD_PRESENT);
}

-static int sdhci_check_ro(struct sdhci_host *host)
+static int sdhci_check_ro(struct mmc_host *mmc)
{
+ struct sdhci_host *host = mmc_priv(mmc);
unsigned long flags;
int is_readonly;

@@ -2033,6 +2034,8 @@ static int sdhci_check_ro(struct sdhci_host *host)
is_readonly = 0;
else if (host->ops->get_ro)
is_readonly = host->ops->get_ro(host);
+ else if (mmc_can_gpio_ro(mmc))
+ is_readonly = mmc_gpio_get_ro(mmc);
else
is_readonly = !(sdhci_readl(host, SDHCI_PRESENT_STATE)
& SDHCI_WRITE_PROTECT);
@@ -2052,11 +2055,11 @@ static int sdhci_get_ro(struct mmc_host *mmc)
int i, ro_count;

if (!(host->quirks & SDHCI_QUIRK_UNSTABLE_RO_DETECT))
- return sdhci_check_ro(host);
+ return sdhci_check_ro(mmc);

ro_count = 0;
for (i = 0; i < SAMPLE_COUNT; i++) {
- if (sdhci_check_ro(host)) {
+ if (sdhci_check_ro(mmc)) {
if (++ro_count > SAMPLE_COUNT / 2)
return 1;
}
--
2.20.1