linux-kernel - [PATCH 2/2] drivers: mmc: sdhci_am654: Add the quirk to set TESTCD bit

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Date:   Mon, 18 Apr 2022 15:50:40 +0530
From:   Aswath Govindraju <a-govindraju@...com>
To:     unlisted-recipients:; (no To-header on input)
CC:     Vignesh Raghavendra <vigneshr@...com>,
        Kishon Vijay Abraham I <kishon@...com>,
        Aswath Govindraju <a-govindraju@...com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        <linux-mmc@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] drivers: mmc: sdhci_am654: Add the quirk to set TESTCD bit

From: Vignesh Raghavendra <vigneshr@...com>

The ARASAN MMC controller on Keystone 3 class of devices need the SDCD
line to be connected for proper functioning. Similar to the issue pointed
out in sdhci-of-arasan.c driver, commit 3794c542641f ("mmc:
sdhci-of-arasan: Set controller to test mode when no CD bit").

In cases where this can't be connected, add a quirk to force the
controller into test mode and set the TESTCD bit. Use the flag
"ti,fails-without-test-cd", to implement this above quirk when required.

Signed-off-by: Vignesh Raghavendra <vigneshr@...com>
Signed-off-by: Aswath Govindraju <a-govindraju@...com>
---
 drivers/mmc/host/sdhci_am654.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci_am654.c b/drivers/mmc/host/sdhci_am654.c
index e54fe24d47e7..c36b969ed1b6 100644
--- a/drivers/mmc/host/sdhci_am654.c
+++ b/drivers/mmc/host/sdhci_am654.c
@@ -147,6 +147,9 @@ struct sdhci_am654_data {
 	int drv_strength;
 	int strb_sel;
 	u32 flags;
+	u32 quirks;
+
+#define SDHCI_AM654_QUIRK_FORCE_CDTEST BIT(0)
 };
 
 struct sdhci_am654_driver_data {
@@ -369,6 +372,21 @@ static void sdhci_am654_write_b(struct sdhci_host *host, u8 val, int reg)
 	}
 }
 
+void sdhci_am654_reset(struct sdhci_host *host, u8 mask)
+{
+	u8 ctrl;
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_am654_data *sdhci_am654 = sdhci_pltfm_priv(pltfm_host);
+
+	sdhci_reset(host, mask);
+
+	if (sdhci_am654->quirks & SDHCI_AM654_QUIRK_FORCE_CDTEST) {
+		ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
+		ctrl |= SDHCI_CTRL_CDTEST_INS | SDHCI_CTRL_CDTEST_EN;
+		sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
+	}
+}
+
 static int sdhci_am654_execute_tuning(struct mmc_host *mmc, u32 opcode)
 {
 	struct sdhci_host *host = mmc_priv(mmc);
@@ -500,7 +518,7 @@ static struct sdhci_ops sdhci_j721e_4bit_ops = {
 	.set_clock = sdhci_j721e_4bit_set_clock,
 	.write_b = sdhci_am654_write_b,
 	.irq = sdhci_am654_cqhci_irq,
-	.reset = sdhci_reset,
+	.reset = sdhci_am654_reset,
 };
 
 static const struct sdhci_pltfm_data sdhci_j721e_4bit_pdata = {
@@ -719,6 +737,9 @@ static int sdhci_am654_get_of_property(struct platform_device *pdev,
 	device_property_read_u32(dev, "ti,clkbuf-sel",
 				 &sdhci_am654->clkbuf_sel);
 
+	if (device_property_read_bool(dev, "ti,fails-without-test-cd"))
+		sdhci_am654->quirks |= SDHCI_AM654_QUIRK_FORCE_CDTEST;
+
 	sdhci_get_of_property(pdev);
 
 	return 0;
-- 
2.17.1