[PATCH] mmc: sdhci-esdhc-imx: make sure ipg clock enabled during suspend/resume

[haibo.chen@xxxxxxx]

From: Haibo Chen <haibo.chen@xxxxxxx>

During suspend/resume, need to access usdhc register, so need to enable
IPG clock to avoid bus error.

Find this issue when both enable CONFIG_PM and CONFIG_PM_SLEEP, which
means both support PM and Runtime PM. If the card slot do not insert
a card, then after system boot up, will do sdhci_esdhc_runtime_suspend(),
disable all clocks, include the ipg clock. In this case, when suspend the
system, due to no card present, sdhci_esdhc_runtime_resume() will not be
called before sdhci_esdhc_suspend(), so will meet system hung or bus err
once access usdhc register.

Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx>
---
 drivers/mmc/host/sdhci-esdhc-imx.c | 30 ++++++++++++++++++++++++------
 1 file changed, 24 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index 94327988da91..a48b977ca13f 100644
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -1695,10 +1695,14 @@ static int sdhci_esdhc_suspend(struct device *dev)
 	struct pltfm_imx_data *imx_data = sdhci_pltfm_priv(pltfm_host);
 	int ret;
 
+	ret = clk_prepare_enable(imx_data->clk_ipg);
+	if (ret)
+		return ret;
+
 	if (host->mmc->caps2 & MMC_CAP2_CQE) {
 		ret = cqhci_suspend(host->mmc);
 		if (ret)
-			return ret;
+			goto disable_ipg_clk;
 	}
 
 	if ((imx_data->socdata->flags & ESDHC_FLAG_STATE_LOST_IN_LPMODE) &&
@@ -1712,38 +1716,52 @@ static int sdhci_esdhc_suspend(struct device *dev)
 
 	ret = sdhci_suspend_host(host);
 	if (ret)
-		return ret;
+		goto disable_ipg_clk;
 
 	ret = pinctrl_pm_select_sleep_state(dev);
 	if (ret)
-		return ret;
+		goto disable_ipg_clk;
 
 	ret = mmc_gpio_set_cd_wake(host->mmc, true);
 
+disable_ipg_clk:
+	clk_disable_unprepare(imx_data->clk_ipg);
+
 	return ret;
 }
 
 static int sdhci_esdhc_resume(struct device *dev)
 {
 	struct sdhci_host *host = dev_get_drvdata(dev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct pltfm_imx_data *imx_data = sdhci_pltfm_priv(pltfm_host);
 	int ret;
 
 	ret = pinctrl_pm_select_default_state(dev);
 	if (ret)
 		return ret;
 
+	ret = clk_prepare_enable(imx_data->clk_ipg);
+	if (ret)
+		return ret;
+
 	/* re-initialize hw state in case it's lost in low power mode */
 	sdhci_esdhc_imx_hwinit(host);
 
 	ret = sdhci_resume_host(host);
 	if (ret)
-		return ret;
+		goto disable_ipg_clk;
 
 	if (host->mmc->caps2 & MMC_CAP2_CQE)
 		ret = cqhci_resume(host->mmc);
 
-	if (!ret)
-		ret = mmc_gpio_set_cd_wake(host->mmc, false);
+	if (ret)
+		goto disable_ipg_clk;
+
+	ret = mmc_gpio_set_cd_wake(host->mmc, false);
+
+disable_ipg_clk:
+	clk_disable_unprepare(imx_data->clk_ipg);
 
 	return ret;
 }
-- 
2.17.1