mmc: sdhci: allow sdio interrupts while sdhci runtime suspended

Allow SDIO interrupts to be received while the SDHCI host is runtime
suspended.  We do this by leaving the AHB clock enabled while the
host is runtime suspended so we can access the SDHCI registers, and
so read and raise the SDIO card interrupt.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Markus Pargmann <mpa@pengutronix.de>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>
diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index b841bb7..b0b4eea 100644
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -1170,8 +1170,10 @@
 
 	ret = sdhci_runtime_suspend_host(host);
 
-	clk_disable_unprepare(imx_data->clk_per);
-	clk_disable_unprepare(imx_data->clk_ipg);
+	if (!sdhci_sdio_irq_enabled(host)) {
+		clk_disable_unprepare(imx_data->clk_per);
+		clk_disable_unprepare(imx_data->clk_ipg);
+	}
 	clk_disable_unprepare(imx_data->clk_ahb);
 
 	return ret;
@@ -1183,8 +1185,10 @@
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct pltfm_imx_data *imx_data = pltfm_host->priv;
 
-	clk_prepare_enable(imx_data->clk_per);
-	clk_prepare_enable(imx_data->clk_ipg);
+	if (!sdhci_sdio_irq_enabled(host)) {
+		clk_prepare_enable(imx_data->clk_per);
+		clk_prepare_enable(imx_data->clk_ipg);
+	}
 	clk_prepare_enable(imx_data->clk_ahb);
 
 	return sdhci_runtime_resume_host(host);