[PATCH 2/3] mmc: omap_hsmmc: Pin remux workaround to support SDIO interrupt on AM335x.

[Andreas Fenkart <afenkart@gmail.com>]

From: Andreas Fenkart <andreas.fenkart@dev.digitalstrom.org>

The am335x can't detect pending cirq in PM runtime suspend.
This patch reconfigures dat1 as a GPIO before going to suspend.
SDIO interrupts are detected with the GPIO, the GPIO will only wake
the module from suspend, SDIO irq detection will still happen through the
IP block.

Idea of remuxing the pins by Tony Lindgren as well as the implementation
of omap_hsmmc_pin_init.

Signed-off-by: Andreas Fenkart <afenkart@gmail.com>
---
 .../devicetree/bindings/mmc/ti-omap-hsmmc.txt      |   28 ++-
 drivers/mmc/host/omap_hsmmc.c                      |  195 ++++++++++++++++++--
 include/linux/platform_data/mmc-omap.h             |    4 +
 3 files changed, 213 insertions(+), 14 deletions(-)

diff --git a/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt
index 1136e6b..146f3ad 100644
--- a/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt
+++ b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt
@@ -21,8 +21,11 @@ ti,non-removable: non-removable slot (like eMMC)
 ti,needs-special-reset: Requires a special softreset sequence
 ti,needs-special-hs-handling: HSMMC IP needs special setting for handling High Speed
 ti,quirk-swakup-missing: SOC missing the swakeup line, will not detect
-SDIO irq while in suspend. Fallback to polling. Affected chips are
-am335x,
+SDIO irq while in suspend. The workaround is to reconfigure the dat1 line as a
+GPIO upon suspend. Beyond this option and the GPIO config, you also need to set
+named pinctrl states "default", "active" and "idle ", see example below.  The
+MMC driver will then then toggle between default and idle during the runtime
+Affected chips are am335x,
 
                             ------
                             | PRCM |
@@ -49,3 +52,24 @@ Example:
 		vmmc-supply = <&vmmc>; /* phandle to regulator node */
 		ti,non-removable;
 	};
+
+[am335x with with gpio for sdio irq]
+
+	mmc1_cirq_pin: pinmux_cirq_pin {
+		pinctrl-single,pins = <
+			0x0f8 0x3f	/* MMC0_DAT1 as GPIO2_28 */
+		>;
+	};
+
+	mmc1: mmc@48060000 {
+		ti,non-removable;
+		bus-width = <4>;
+		vmmc-supply = <&ldo2_reg>;
+		vmmc_aux-supply = <&vmmc>;
+	        ti,quirk-swakeup-missing;
+		pinctrl-names = "default", "active", "idle";
+		pinctrl-0 = <&mmc1_pins>;
+		pinctrl-1 = <&mmc1_pins>;
+		pinctrl-2 = <&mmc1_cirq_pin>;
+		ti,cirq-gpio = <&gpio3 28 0>;
+	};
diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index 6b0ec55..e880b44 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -36,6 +36,7 @@
 #include <linux/mmc/core.h>
 #include <linux/mmc/mmc.h>
 #include <linux/io.h>
+#include <linux/irq.h>
 #include <linux/gpio.h>
 #include <linux/regulator/consumer.h>
 #include <linux/pinctrl/consumer.h>
@@ -213,11 +214,30 @@ struct omap_hsmmc_host {
 	int			req_in_progress;
 	int                     flags;
 #define HSMMC_SDIO_IRQ_ENABLED	(1 << 0)        /* SDIO irq enabled */
+#define HSMMC_SWAKEUP_QUIRK	(1 << 1)
+#define HSMMC_CIRQ_GPIO_FIRED	(1 << 2)
 
 	struct omap_hsmmc_next	next_data;
+	struct pinctrl		*pinctrl;
+	struct pinctrl_state	*fixed, *active, *idle;
 	struct	omap_mmc_platform_data	*pdata;
 };
 
+static irqreturn_t omap_hsmmc_cirq(int irq, void *dev_id)
+{
+	struct omap_hsmmc_host *host = dev_id;
+	unsigned long flags;
+
+	spin_lock_irqsave(&host->irq_lock, flags);
+	host->flags |= HSMMC_CIRQ_GPIO_FIRED;
+	disable_irq_nosync(mmc_slot(host).sdio_irq);
+	spin_unlock_irqrestore(&host->irq_lock, flags);
+
+	pm_request_resume(host->dev); /* no use counter */
+
+	return IRQ_HANDLED;
+}
+
 static int omap_hsmmc_card_detect(struct device *dev, int slot)
 {
 	struct omap_hsmmc_host *host = dev_get_drvdata(dev);
@@ -452,10 +472,31 @@ static int omap_hsmmc_gpio_init(struct omap_mmc_platform_data *pdata)
 	} else
 		pdata->slots[0].gpio_wp = -EINVAL;
 
+	if (pdata->slots[0].gpio_cirq > 0 &&
+	    gpio_is_valid(pdata->slots[0].gpio_cirq)) {
+		pdata->slots[0].sdio_irq =
+				gpio_to_irq(pdata->slots[0].gpio_cirq);
+
+		ret = gpio_request(pdata->slots[0].gpio_cirq, "sdio_cirq");
+		if (ret)
+			goto err_free_ro;
+		ret = gpio_direction_input(pdata->slots[0].gpio_cirq);
+		if (ret)
+			goto err_free_cirq;
+
+	} else {
+		pdata->slots[0].gpio_cirq = -EINVAL;
+	}
+
+
 	return 0;
 
+err_free_cirq:
+	gpio_free(pdata->slots[0].gpio_cirq);
+err_free_ro:
+	if (gpio_is_valid(pdata->slots[0].gpio_wp))
 err_free_wp:
-	gpio_free(pdata->slots[0].gpio_wp);
+		gpio_free(pdata->slots[0].gpio_wp);
 err_free_cd:
 	if (gpio_is_valid(pdata->slots[0].switch_pin))
 err_free_sp:
@@ -469,6 +510,69 @@ static void omap_hsmmc_gpio_free(struct omap_mmc_platform_data *pdata)
 		gpio_free(pdata->slots[0].gpio_wp);
 	if (gpio_is_valid(pdata->slots[0].switch_pin))
 		gpio_free(pdata->slots[0].switch_pin);
+	if (gpio_is_valid(pdata->slots[0].gpio_cirq))
+		gpio_free(pdata->slots[0].gpio_cirq);
+}
+
+static int omap_hsmmc_pin_init(struct omap_hsmmc_host *host)
+{
+	int ret;
+
+	host->pinctrl = devm_pinctrl_get(host->dev);
+	if (IS_ERR(host->pinctrl)) {
+		dev_dbg(host->dev, "no pinctrl handle\n");
+		ret = 0;
+		goto out;
+	}
+
+	host->fixed = pinctrl_lookup_state(host->pinctrl,
+					   PINCTRL_STATE_DEFAULT);
+	if (IS_ERR(host->fixed)) {
+		dev_dbg(host->dev,
+			 "pins are not configured from the driver\n");
+		host->fixed = NULL;
+		ret = 0;
+		goto out;
+	}
+
+	ret = pinctrl_select_state(host->pinctrl, host->fixed);
+	if (ret < 0)
+		goto err;
+
+	/* For most cases we don't have wake-ups, and exit after this */
+	host->active = pinctrl_lookup_state(host->pinctrl, "active");
+	if (IS_ERR(host->active)) {
+		ret = PTR_ERR(host->active);
+		host->active = NULL;
+		return 0;
+	}
+
+	host->idle = pinctrl_lookup_state(host->pinctrl,
+					  PINCTRL_STATE_IDLE);
+	if (IS_ERR(host->idle)) {
+		ret = PTR_ERR(host->idle);
+		host->idle = NULL;
+		goto err;
+	}
+
+	/* Let's make sure the active and idle states work */
+	ret = pinctrl_select_state(host->pinctrl, host->idle);
+	if (ret < 0)
+		goto err;
+
+	ret = pinctrl_select_state(host->pinctrl, host->active);
+	if (ret < 0)
+		goto err;
+
+	dev_info(mmc_dev(host->mmc), "pins configured for wake-up events\n");
+
+	return 0;
+
+err:
+	dev_err(mmc_dev(host->mmc), "pins configuration error: %i\n", ret);
+
+out:
+	return ret;
 }
 
 /*
@@ -1791,6 +1895,7 @@ static struct omap_mmc_platform_data *of_get_hsmmc_pdata(struct device *dev)
 	pdata->nr_slots = 1;
 	pdata->slots[0].switch_pin = cd_gpio;
 	pdata->slots[0].gpio_wp = wp_gpio;
+	pdata->slots[0].gpio_cirq = of_get_named_gpio(np, "ti,cirq-gpio", 0);
 
 	if (of_find_property(np, "ti,non-removable", NULL)) {
 		pdata->slots[0].nonremovable = true;
@@ -1837,7 +1942,6 @@ static int omap_hsmmc_probe(struct platform_device *pdev)
 	const struct of_device_id *match;
 	dma_cap_mask_t mask;
 	unsigned tx_req, rx_req;
-	struct pinctrl *pinctrl;
 
 	match = of_match_device(of_match_ptr(omap_mmc_of_match), &pdev->dev);
 	if (match) {
@@ -2068,10 +2172,22 @@ static int omap_hsmmc_probe(struct platform_device *pdev)
 
 	omap_hsmmc_disable_irq(host);
 
-	pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
-	if (IS_ERR(pinctrl))
-		dev_warn(&pdev->dev,
-			"pins are not configured from the driver\n");
+	ret = omap_hsmmc_pin_init(host);
+	if (ret)
+		goto err_pinctrl_state;
+
+	if ((mmc_slot(host).sdio_irq)) {
+		/* prevent auto-enabling of IRQ */
+		irq_set_status_flags(mmc_slot(host).sdio_irq, IRQ_NOAUTOEN);
+		ret = request_irq(mmc_slot(host).sdio_irq, omap_hsmmc_cirq,
+				  IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+				  mmc_hostname(mmc), host);
+		if (ret) {
+			dev_dbg(mmc_dev(host->mmc),
+				"Unable to grab MMC SDIO IRQ\n");
+			goto err_irq_sdio;
+		}
+	}
 
 	/*
 	 * For now, only support SDIO interrupt if we are booted with
@@ -2084,8 +2200,14 @@ static int omap_hsmmc_probe(struct platform_device *pdev)
 		mmc->caps |= MMC_CAP_SDIO_IRQ;
 		if (of_find_property(host->dev->of_node,
 				     "ti,quirk-swakeup-missing", NULL)) {
-			/* no wakeup from deeper power states, use polling */
-			mmc->caps &= ~MMC_CAP_SDIO_IRQ;
+			/* use GPIO to wakeup from deeper power states */
+			if (!host->idle || !mmc_slot(host).sdio_irq) {
+				dev_err(mmc_dev(host->mmc),
+					"Missing GPIO config or pinctrl idle state\n");
+				goto err_irq_sdio;
+			}
+
+			host->flags |= HSMMC_SWAKEUP_QUIRK;
 		}
 	}
 
@@ -2113,7 +2235,13 @@ static int omap_hsmmc_probe(struct platform_device *pdev)
 
 err_slot_name:
 	mmc_remove_host(mmc);
-	free_irq(mmc_slot(host).card_detect_irq, host);
+err_irq_sdio:
+	if ((mmc_slot(host).sdio_irq))
+		free_irq(mmc_slot(host).sdio_irq, host);
+err_pinctrl_state:
+	devm_pinctrl_put(host->pinctrl);
+	if ((mmc_slot(host).card_detect_irq))
+		free_irq(mmc_slot(host).card_detect_irq, host);
 err_irq_cd:
 	if (host->use_reg)
 		omap_hsmmc_reg_put(host);
@@ -2158,13 +2286,15 @@ static int omap_hsmmc_remove(struct platform_device *pdev)
 	if (host->pdata->cleanup)
 		host->pdata->cleanup(&pdev->dev);
 	free_irq(host->irq, host);
+	if ((mmc_slot(host).sdio_irq))
+		free_irq(mmc_slot(host).sdio_irq, host);
 	if (mmc_slot(host).card_detect_irq)
 		free_irq(mmc_slot(host).card_detect_irq, host);
-
 	if (host->tx_chan)
 		dma_release_channel(host->tx_chan);
 	if (host->rx_chan)
 		dma_release_channel(host->rx_chan);
+	devm_pinctrl_put(host->pinctrl);
 
 	pm_runtime_put_sync(host->dev);
 	pm_runtime_disable(host->dev);
@@ -2231,6 +2361,9 @@ static int omap_hsmmc_suspend(struct device *dev)
 				OMAP_HSMMC_READ(host->base, HCTL) & ~SDBP);
 	}
 
+	if (host->flags & HSMMC_SWAKEUP_QUIRK)
+		disable_irq(mmc_slot(host).sdio_irq);
+
 	if (host->dbclk)
 		clk_disable_unprepare(host->dbclk);
 
@@ -2268,6 +2401,9 @@ static int omap_hsmmc_resume(struct device *dev)
 	if (ret == 0)
 		host->suspended = 0;
 
+	if (host->flags & HSMMC_SWAKEUP_QUIRK)
+		enable_irq(mmc_slot(host).sdio_irq);
+
 	pm_runtime_mark_last_busy(host->dev);
 	pm_runtime_put_autosuspend(host->dev);
 
@@ -2285,23 +2421,58 @@ static int omap_hsmmc_resume(struct device *dev)
 static int omap_hsmmc_runtime_suspend(struct device *dev)
 {
 	struct omap_hsmmc_host *host;
+	unsigned long flags;
+	int ret = 0;
 
 	host = platform_get_drvdata(to_platform_device(dev));
 	omap_hsmmc_context_save(host);
 	dev_dbg(dev, "disabled\n");
 
-	return 0;
+	if (host->flags & HSMMC_SWAKEUP_QUIRK) {
+		OMAP_HSMMC_WRITE(host->base, ISE, 0);
+		OMAP_HSMMC_WRITE(host->base, IE, 0);
+		OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR);
+
+		ret = pinctrl_select_state(host->pinctrl, host->idle);
+		if (ret < 0)
+			dev_warn(mmc_dev(host->mmc), "Unable to select idle pinmux\n");
+
+		spin_lock_irqsave(&host->irq_lock, flags);
+		if (host->flags & HSMMC_SDIO_IRQ_ENABLED)
+			enable_irq(mmc_slot(host).sdio_irq);
+		spin_unlock_irqrestore(&host->irq_lock, flags);
+	}
+
+	return ret;
 }
 
 static int omap_hsmmc_runtime_resume(struct device *dev)
 {
 	struct omap_hsmmc_host *host;
+	unsigned long flags;
+	int ret = 0;
 
 	host = platform_get_drvdata(to_platform_device(dev));
 	omap_hsmmc_context_restore(host);
 	dev_dbg(dev, "enabled\n");
 
-	return 0;
+	if (host->flags & HSMMC_SWAKEUP_QUIRK) {
+		ret = pinctrl_select_state(host->pinctrl, host->active);
+		if (ret < 0)
+			dev_warn(mmc_dev(host->mmc), "Unable to select active pinmux\n");
+
+		spin_lock_irqsave(&host->irq_lock, flags);
+		if (host->flags & HSMMC_SDIO_IRQ_ENABLED) {
+			if (!(host->flags & HSMMC_CIRQ_GPIO_FIRED))
+				disable_irq(mmc_slot(host).sdio_irq);
+			host->flags &= ~HSMMC_CIRQ_GPIO_FIRED;
+			OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR);
+			OMAP_HSMMC_WRITE(host->base, ISE, CIRQ_EN);
+			OMAP_HSMMC_WRITE(host->base, IE, CIRQ_EN);
+		}
+		spin_unlock_irqrestore(&host->irq_lock, flags);
+	}
+	return ret;
 }
 
 static struct dev_pm_ops omap_hsmmc_dev_pm_ops = {
diff --git a/include/linux/platform_data/mmc-omap.h b/include/linux/platform_data/mmc-omap.h
index 2bf1b30..fd5fff5 100644
--- a/include/linux/platform_data/mmc-omap.h
+++ b/include/linux/platform_data/mmc-omap.h
@@ -115,6 +115,7 @@ struct omap_mmc_platform_data {
 
 		int switch_pin;			/* gpio (card detect) */
 		int gpio_wp;			/* gpio (write protect) */
+		int gpio_cirq;			/* gpio (card irq) */
 
 		int (*set_bus_mode)(struct device *dev, int slot, int bus_mode);
 		int (*set_power)(struct device *dev, int slot,
@@ -145,6 +146,9 @@ struct omap_mmc_platform_data {
 		int card_detect_irq;
 		int (*card_detect)(struct device *dev, int slot);
 
+		/* SDIO IRQs */
+		int sdio_irq;
+
 		unsigned int ban_openended:1;
 
 	} slots[OMAP_MMC_MAX_SLOTS];
-- 
1.7.10.4