[PATCH 7/8] mmc: sdhci-pxav2: add optional pinctrl for SDIO IRQ workaround

[Doug Brown <doug@schmorgal.com>]

The PXA168 errata recommends that the CMD signal should be detached from
the SD bus while performing the dummy CMD0 to restart the clock.
Implement this using pinctrl states.

Signed-off-by: Doug Brown <doug@schmorgal.com>
---
 drivers/mmc/host/sdhci-pxav2.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/mmc/host/sdhci-pxav2.c b/drivers/mmc/host/sdhci-pxav2.c
index 0b9b2e4b2153..6b30f70675e2 100644
--- a/drivers/mmc/host/sdhci-pxav2.c
+++ b/drivers/mmc/host/sdhci-pxav2.c
@@ -22,6 +22,7 @@
 #include <linux/of_device.h>
 #include <linux/mmc/sdio.h>
 #include <linux/mmc/mmc.h>
+#include <linux/pinctrl/consumer.h>
 
 #include "sdhci.h"
 #include "sdhci-pltfm.h"
@@ -46,6 +47,9 @@
 struct sdhci_pxav2_host {
 	struct clk *clk_core;
 	void (*orig_post_req)(struct mmc_host *mmc, struct mmc_request *mrq, int err);
+	struct pinctrl *pinctrl;
+	struct pinctrl_state *pins_default;
+	struct pinctrl_state *pins_cmd_gpio;
 };
 
 static void pxav2_reset(struct sdhci_host *host, u8 mask)
@@ -118,11 +122,19 @@ static void pxav1_post_req(struct mmc_host *mmc, struct mmc_request *mrq, int er
 		/* Clock is now stopped, so restart it by sending a dummy CMD0. */
 		pxav2_host = sdhci_pltfm_priv(sdhci_priv(host));
 
+		/* Set CMD as high output rather than MMC function while we do CMD0 */
+		if (pxav2_host->pinctrl && pxav2_host->pins_cmd_gpio)
+			pinctrl_select_state(pxav2_host->pinctrl, pxav2_host->pins_cmd_gpio);
+
 		dummy_cmd.opcode = MMC_GO_IDLE_STATE;
 		dummy_cmd.arg = 0;
 		dummy_cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_NONE | MMC_CMD_BC;
 
 		mmc_wait_for_cmd(host->mmc, &dummy_cmd, 0);
+
+		/* Set as MMC function after dummy command is complete */
+		if (pxav2_host->pinctrl && pxav2_host->pins_default)
+			pinctrl_select_state(pxav2_host->pinctrl, pxav2_host->pins_default);
 	}
 
 	/* Pass onto SDHCI host driver now */
@@ -288,6 +300,21 @@ static int sdhci_pxav2_probe(struct platform_device *pdev)
 		host->ops = &pxav1_sdhci_ops;
 		pxav2_host->orig_post_req = host->mmc_host_ops.post_req;
 		host->mmc_host_ops.post_req = pxav1_post_req;
+
+		/* Set up optional pinctrl for PXA168 SDIO IRQ fix */
+		pxav2_host->pinctrl = devm_pinctrl_get(&pdev->dev);
+		if (!IS_ERR(pxav2_host->pinctrl)) {
+			pxav2_host->pins_cmd_gpio = pinctrl_lookup_state(pxav2_host->pinctrl,
+									 "state_cmd_gpio");
+			if (IS_ERR(pxav2_host->pins_cmd_gpio))
+				pxav2_host->pins_cmd_gpio = NULL;
+			pxav2_host->pins_default = pinctrl_lookup_state(pxav2_host->pinctrl,
+									"default");
+			if (IS_ERR(pxav2_host->pins_default))
+				pxav2_host->pins_default = NULL;
+		} else {
+			pxav2_host->pinctrl = NULL;
+		}
 	} else {
 		host->ops = &pxav2_sdhci_ops;
 	}
-- 
2.34.1