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From:   Thomas Petazzoni <thomas.petazzoni@bootlin.com>
To:     Adrian Hunter <adrian.hunter@intel.com>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>
Cc:     linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-tegra@vger.kernel.org, Faiz Abbas <faiz_abbas@ti.com>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: [PATCH v2 1/3] mmc: sdhci: use WP GPIO in sdhci_check_ro()
Date:   Mon, 11 Feb 2019 14:23:40 +0100
Message-Id: <20190211132342.31009-2-thomas.petazzoni@bootlin.com>
In-Reply-To: <20190211132342.31009-1-thomas.petazzoni@bootlin.com>
References: <20190211132342.31009-1-thomas.petazzoni@bootlin.com>
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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