[PATCH v11 3/3] mmc: mediatek: add support for SDIO eint wakup IRQ

[Axe Yang]

Add support for eint IRQ when MSDC is used as an SDIO host. This
feature requires SDIO device support async IRQ function. With this
feature, SDIO host can be awakened by SDIO card in suspend state,
without additional pin.

MSDC driver will time-share the SDIO DAT1 pin. During suspend, MSDC
turn off clock and switch SDIO DAT1 pin to GPIO mode. And during
resume, switch GPIO function back to DAT1 mode then turn on clock.

Some device tree property should be added or modified in MSDC node
to support SDIO eint IRQ. Pinctrls "state_eint" is mandatory. Since
this feature depends on asynchronous interrupts, "wakeup-source",
"keep-power-in-suspend" and "cap-sdio-irq" flags are necessary, and
the interrupts list should be extended(the interrupt named with
sdio_wakeup):
        &mmcX {
		...
		interrupt-names = "msdc", "sdio_wakeup";
		interrupts-extended = <...>,
                              	      <&pio xxx IRQ_TYPE_LEVEL_LOW>;
                ...
                pinctrl-names = "default", "state_uhs", "state_eint";
                ...
                pinctrl-2 = <&mmc2_pins_eint>;
                ...
                cap-sdio-irq;
		keep-power-in-suspend;
		wakeup-source;
                ...
        };

Co-developed-by: Yong Mao <yong.mao at mediatek.com>
Signed-off-by: Yong Mao <yong.mao at mediatek.com>
Signed-off-by: Axe Yang <axe.yang at mediatek.com>
---
 drivers/mmc/host/mtk-sd.c | 80 ++++++++++++++++++++++++++++++++++++---
 1 file changed, 74 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
index 195dc897188b..1233adb1bd0c 100644
--- a/drivers/mmc/host/mtk-sd.c
+++ b/drivers/mmc/host/mtk-sd.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Copyright (c) 2014-2015 MediaTek Inc.
+ * Copyright (c) 2014-2015, 2022 MediaTek Inc.
  * Author: Chaotian.Jing <chaotian.jing at mediatek.com>
  */
 
@@ -20,6 +20,7 @@
 #include <linux/platform_device.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
+#include <linux/pm_wakeirq.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
@@ -440,8 +441,10 @@ struct msdc_host {
 	struct pinctrl *pinctrl;
 	struct pinctrl_state *pins_default;
 	struct pinctrl_state *pins_uhs;
+	struct pinctrl_state *pins_eint;
 	struct delayed_work req_timeout;
 	int irq;		/* host interrupt */
+	int eint_irq;		/* interrupt from sdio device for waking up system */
 	struct reset_control *reset;
 
 	struct clk *src_clk;	/* msdc source clock */
@@ -1520,17 +1523,41 @@ static void __msdc_enable_sdio_irq(struct msdc_host *host, int enb)
 
 static void msdc_enable_sdio_irq(struct mmc_host *mmc, int enb)
 {
-	unsigned long flags;
 	struct msdc_host *host = mmc_priv(mmc);
+	unsigned long flags;
+	int ret;
 
 	spin_lock_irqsave(&host->lock, flags);
 	__msdc_enable_sdio_irq(host, enb);
 	spin_unlock_irqrestore(&host->lock, flags);
 
-	if (enb)
-		pm_runtime_get_noresume(host->dev);
-	else
-		pm_runtime_put_noidle(host->dev);
+	if (mmc_card_enable_async_irq(mmc->card) && host->pins_eint) {
+		if (enb) {
+			pinctrl_select_state(host->pinctrl, host->pins_eint);
+			ret = dev_pm_set_dedicated_wake_irq_reverse(host->dev, host->eint_irq);
+
+			if (ret) {
+				dev_err(host->dev, "Failed to register SDIO wakeup irq!\n");
+				host->pins_eint = NULL;
+				pm_runtime_get_noresume(host->dev);
+			} else {
+				dev_info(host->dev, "SDIO eint irq: %d!\n", host->eint_irq);
+				device_init_wakeup(host->dev, true);
+			}
+
+			pinctrl_select_state(host->pinctrl, host->pins_uhs);
+		} else {
+			dev_pm_clear_wake_irq(host->dev);
+		}
+	} else {
+		if (enb) {
+			/* Ensure host->pins_eint is NULL */
+			kfree(host->pins_eint);
+			pm_runtime_get_noresume(host->dev);
+		} else {
+			pm_runtime_put_noidle(host->dev);
+		}
+	}
 }
 
 static irqreturn_t msdc_cmdq_irq(struct msdc_host *host, u32 intsts)
@@ -2631,6 +2658,19 @@ static int msdc_drv_probe(struct platform_device *pdev)
 		goto host_free;
 	}
 
+	/* Support for SDIO eint irq ? */
+	if ((mmc->pm_caps & MMC_PM_WAKE_SDIO_IRQ) && (mmc->pm_caps & MMC_PM_KEEP_POWER)) {
+		host->eint_irq = platform_get_irq_byname(pdev, "sdio_wakeup");
+		if (host->eint_irq > 0) {
+			host->pins_eint = pinctrl_lookup_state(host->pinctrl, "state_eint");
+			if (IS_ERR(host->pins_eint)) {
+				dev_err_probe(&pdev->dev, PTR_ERR(host->pins_eint),
+					      "Cannot find pinctrl eint!\n");
+				host->pins_eint = NULL;
+			}
+		}
+	}
+
 	msdc_of_property_parse(pdev, host);
 
 	host->dev = &pdev->dev;
@@ -2845,6 +2885,12 @@ static int __maybe_unused msdc_runtime_suspend(struct device *dev)
 	struct msdc_host *host = mmc_priv(mmc);
 
 	msdc_save_reg(host);
+
+	if (sdio_irq_claimed(mmc) && host->pins_eint) {
+		disable_irq(host->irq);
+		pinctrl_select_state(host->pinctrl, host->pins_eint);
+		sdr_clr_bits(host->base + SDC_CFG, SDC_CFG_SDIOIDE);
+	}
 	msdc_gate_clock(host);
 	return 0;
 }
@@ -2860,12 +2906,19 @@ static int __maybe_unused msdc_runtime_resume(struct device *dev)
 		return ret;
 
 	msdc_restore_reg(host);
+
+	if (sdio_irq_claimed(mmc) && host->pins_eint) {
+		sdr_set_bits(host->base + SDC_CFG, SDC_CFG_SDIOIDE);
+		pinctrl_select_state(host->pinctrl, host->pins_uhs);
+		enable_irq(host->irq);
+	}
 	return 0;
 }
 
 static int __maybe_unused msdc_suspend(struct device *dev)
 {
 	struct mmc_host *mmc = dev_get_drvdata(dev);
+	struct msdc_host *host = mmc_priv(mmc);
 	int ret;
 
 	if (mmc->caps2 & MMC_CAP2_CQE) {
@@ -2874,11 +2927,26 @@ static int __maybe_unused msdc_suspend(struct device *dev)
 			return ret;
 	}
 
+	if (sdio_irq_claimed(mmc) && host->pins_eint) {
+		pm_runtime_put_sync_suspend(dev);
+
+		return 0;
+	}
+
 	return pm_runtime_force_suspend(dev);
 }
 
 static int __maybe_unused msdc_resume(struct device *dev)
 {
+	struct mmc_host *mmc = dev_get_drvdata(dev);
+	struct msdc_host *host = mmc_priv(mmc);
+
+	if (sdio_irq_claimed(mmc) && host->pins_eint) {
+		pm_runtime_get_sync(dev);
+
+		return 0;
+	}
+
 	return pm_runtime_force_resume(dev);
 }
 
-- 
2.25.1