[PATCH v4 3/3] mmc: mediatek: add support for SDIO eint 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 named state_dat1 and state_eint
are mandatory. And cap-sdio-async-irq flag is necessary since this
feature depends on asynchronous interrupt:
        &mmcX {
                ...
                pinctrl-names = "default", "state_uhs", "state_eint",
                                "state_dat1";
                ...
                pinctrl-2 = <&mmc2_pins_eint>;
                pinctrl-3 = <&mmc2_pins_dat1>;
                ...
                cap-sdio-async-irq;
                ...
        };

Signed-off-by: Axe Yang <axe.yang@xxxxxxxxxxxx>
Signed-off-by: Yong Mao <yong.mao@xxxxxxxxxxxx>
---
 drivers/mmc/host/mtk-sd.c | 124 +++++++++++++++++++++++++++++++++++---
 1 file changed, 116 insertions(+), 8 deletions(-)

diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
index 65037e1d7723..066616ddc88f 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) 2022 MediaTek Inc.
  * Author: Chaotian.Jing <chaotian.jing@xxxxxxxxxxxx>
  */
 
@@ -9,6 +9,7 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/dma-mapping.h>
+#include <linux/gpio/consumer.h>
 #include <linux/iopoll.h>
 #include <linux/ioport.h>
 #include <linux/irq.h>
@@ -440,8 +441,12 @@ struct msdc_host {
 	struct pinctrl *pinctrl;
 	struct pinctrl_state *pins_default;
 	struct pinctrl_state *pins_uhs;
+	struct pinctrl_state *pins_eint;
+	struct pinctrl_state *pins_dat1;
 	struct delayed_work req_timeout;
 	int irq;		/* host interrupt */
+	int eint_irq;		/* device interrupt */
+	int sdio_irq_cnt;	/* irq enable cnt */
 	struct reset_control *reset;
 
 	struct clk *src_clk;	/* msdc source clock */
@@ -465,6 +470,7 @@ struct msdc_host {
 	bool hs400_tuning;	/* hs400 mode online tuning */
 	bool internal_cd;	/* Use internal card-detect logic */
 	bool cqhci;		/* support eMMC hw cmdq */
+	bool sdio_eint_ready;	/* Ready to support SDIO eint interrupt */
 	struct msdc_save_para save_para; /* used when gate HCLK */
 	struct msdc_tune_para def_tune_para; /* default tune setting */
 	struct msdc_tune_para saved_tune_para; /* tune result of CMD21/CMD19 */
@@ -1527,10 +1533,12 @@ static void msdc_enable_sdio_irq(struct mmc_host *mmc, int enb)
 	__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 && !mmc->card->cccr.enable_async_irq) {
+		if (enb)
+			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)
@@ -2461,6 +2469,49 @@ static const struct mmc_host_ops mt_msdc_ops = {
 	.hw_reset = msdc_hw_reset,
 };
 
+static irqreturn_t msdc_sdio_eint_irq(int irq, void *dev_id)
+{
+	struct msdc_host *host = dev_id;
+	struct mmc_host *mmc = mmc_from_priv(host);
+
+	spin_lock(&host->lock);
+	if (likely(host->sdio_irq_cnt > 0)) {
+		disable_irq_nosync(host->eint_irq);
+		disable_irq_wake(host->eint_irq);
+		host->sdio_irq_cnt--;
+	}
+	spin_unlock(&host->lock);
+
+	sdio_signal_irq(mmc);
+
+	return IRQ_HANDLED;
+}
+
+static int msdc_request_dat1_eint_irq(struct msdc_host *host)
+{
+	struct gpio_desc *desc;
+	int irq, ret;
+
+	desc = devm_gpiod_get(host->dev, "eint", GPIOD_IN);
+	if (IS_ERR(desc))
+		return PTR_ERR(desc);
+
+	ret = gpiod_to_irq(desc);
+	if (ret < 0)
+		return ret;
+
+	irq = ret;
+	ret = devm_request_threaded_irq(host->dev, irq, NULL, msdc_sdio_eint_irq,
+					IRQF_TRIGGER_LOW | IRQF_ONESHOT | IRQF_NO_AUTOEN,
+					"sdio-eint", host);
+	if (ret)
+		return ret;
+
+	host->eint_irq = irq;
+
+	return 0;
+}
+
 static const struct cqhci_host_ops msdc_cmdq_ops = {
 	.enable         = msdc_cqe_enable,
 	.disable        = msdc_cqe_disable,
@@ -2631,6 +2682,23 @@ static int msdc_drv_probe(struct platform_device *pdev)
 		goto host_free;
 	}
 
+	if (!(mmc->caps2 & MMC_CAP2_NO_SDIO) && (mmc->caps2 & MMC_CAP2_SDIO_ASYNC_IRQ)) {
+		/* Support for SDIO eint irq */
+		host->pins_eint = pinctrl_lookup_state(host->pinctrl, "state_eint");
+		if (IS_ERR(host->pins_eint)) {
+			dev_dbg(&pdev->dev, "Cannot find pinctrl eint!\n");
+		} else {
+			host->pins_dat1 = pinctrl_lookup_state(host->pinctrl, "state_dat1");
+			if (IS_ERR(host->pins_dat1)) {
+				ret = dev_err_probe(&pdev->dev, PTR_ERR(host->pins_dat1),
+						    "Cannot find pinctrl dat1!\n");
+				goto host_free;
+			}
+
+			host->sdio_eint_ready = true;
+		}
+	}
+
 	msdc_of_property_parse(pdev, host);
 
 	host->dev = &pdev->dev;
@@ -2722,6 +2790,16 @@ static int msdc_drv_probe(struct platform_device *pdev)
 	if (ret)
 		goto release;
 
+	if (host->sdio_eint_ready) {
+		ret = msdc_request_dat1_eint_irq(host);
+		if (ret) {
+			dev_err(host->dev, "Failed to register data1 eint irq!\n");
+			goto release;
+		}
+
+		pinctrl_select_state(host->pinctrl, host->pins_dat1);
+	}
+
 	pm_runtime_set_active(host->dev);
 	pm_runtime_set_autosuspend_delay(host->dev, MTK_MMC_AUTOSUSPEND_DELAY);
 	pm_runtime_use_autosuspend(host->dev);
@@ -2841,16 +2919,31 @@ static void msdc_restore_reg(struct msdc_host *host)
 
 static int __maybe_unused msdc_runtime_suspend(struct device *dev)
 {
+	unsigned long flags;
 	struct mmc_host *mmc = dev_get_drvdata(dev);
 	struct msdc_host *host = mmc_priv(mmc);
 
 	msdc_save_reg(host);
+
+	if (host->sdio_eint_ready) {
+		disable_irq(host->irq);
+		pinctrl_select_state(host->pinctrl, host->pins_eint);
+		spin_lock_irqsave(&host->lock, flags);
+		if (host->sdio_irq_cnt == 0) {
+			enable_irq(host->eint_irq);
+			enable_irq_wake(host->eint_irq);
+			host->sdio_irq_cnt++;
+		}
+		sdr_clr_bits(host->base + SDC_CFG, SDC_CFG_SDIOIDE);
+		spin_unlock_irqrestore(&host->lock, flags);
+	}
 	msdc_gate_clock(host);
 	return 0;
 }
 
 static int __maybe_unused msdc_runtime_resume(struct device *dev)
 {
+	unsigned long flags;
 	struct mmc_host *mmc = dev_get_drvdata(dev);
 	struct msdc_host *host = mmc_priv(mmc);
 	int ret;
@@ -2860,10 +2953,25 @@ static int __maybe_unused msdc_runtime_resume(struct device *dev)
 		return ret;
 
 	msdc_restore_reg(host);
+
+	if (host->sdio_eint_ready) {
+		spin_lock_irqsave(&host->lock, flags);
+		if (host->sdio_irq_cnt > 0) {
+			disable_irq_nosync(host->eint_irq);
+			disable_irq_wake(host->eint_irq);
+			host->sdio_irq_cnt--;
+			sdr_set_bits(host->base + SDC_CFG, SDC_CFG_SDIOIDE);
+		} else {
+			sdr_clr_bits(host->base + MSDC_INTEN, MSDC_INTEN_SDIOIRQ);
+		}
+		spin_unlock_irqrestore(&host->lock, flags);
+		pinctrl_select_state(host->pinctrl, host->pins_uhs);
+		enable_irq(host->irq);
+	}
 	return 0;
 }
 
-static int __maybe_unused msdc_suspend(struct device *dev)
+static int __maybe_unused msdc_suspend_noirq(struct device *dev)
 {
 	struct mmc_host *mmc = dev_get_drvdata(dev);
 	int ret;
@@ -2877,13 +2985,13 @@ static int __maybe_unused msdc_suspend(struct device *dev)
 	return pm_runtime_force_suspend(dev);
 }
 
-static int __maybe_unused msdc_resume(struct device *dev)
+static int __maybe_unused msdc_resume_noirq(struct device *dev)
 {
 	return pm_runtime_force_resume(dev);
 }
 
 static const struct dev_pm_ops msdc_dev_pm_ops = {
-	SET_SYSTEM_SLEEP_PM_OPS(msdc_suspend, msdc_resume)
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(msdc_suspend_noirq, msdc_resume_noirq)
 	SET_RUNTIME_PM_OPS(msdc_runtime_suspend, msdc_runtime_resume, NULL)
 };
 
-- 
2.25.1