mmc: sdhci-xenon: Fix clock resource by adding an optional bus clock

On Armada 7K/8K we need to explicitly enable the bus clock. The bus clock
is optional because not all the SoCs need them but at least for Armada
7K/8K it is actually mandatory.

The binding documentation is updating accordingly.

Without this patch the kernel hand during boot if the mvpp2.2 network
driver was not present in the kernel. Indeed the clock needed by the
xenon controller was set by the network driver.

Fixes: 3a3748dba881 ("mmc: sdhci-xenon: Add Marvell Xenon SDHC core
functionality)"
CC: Stable <stable@vger.kernel.org>
Tested-by: Zhoujie Wu <zjwu@marvell.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 20 insertions, 4 deletions

diff --git a/drivers/mmc/host/sdhci-xenon.c b/drivers/mmc/host/sdhci-xenon.c
index 2eec2e652c53..0842bbc2d7ad 100644
--- a/drivers/mmc/host/sdhci-xenon.c
+++ b/drivers/mmc/host/sdhci-xenon.c
@@ -466,6 +466,7 @@ static int xenon_probe(struct platform_device *pdev)
 {
 	struct sdhci_pltfm_host *pltfm_host;
 	struct sdhci_host *host;
+	struct xenon_priv *priv;
 	int err;
 
 	host = sdhci_pltfm_init(pdev, &sdhci_xenon_pdata,
@@ -474,6 +475,7 @@ static int xenon_probe(struct platform_device *pdev)
 		return PTR_ERR(host);
 
 	pltfm_host = sdhci_priv(host);
+	priv = sdhci_pltfm_priv(pltfm_host);
 
 	/*
 	 * Link Xenon specific mmc_host_ops function,
@@ -491,9 +493,20 @@ static int xenon_probe(struct platform_device *pdev)
 	if (err)
 		goto free_pltfm;
 
+	priv->axi_clk = devm_clk_get(&pdev->dev, "axi");
+	if (IS_ERR(priv->axi_clk)) {
+		err = PTR_ERR(priv->axi_clk);
+		if (err == -EPROBE_DEFER)
+			goto err_clk;
+	} else {
+		err = clk_prepare_enable(priv->axi_clk);
+		if (err)
+			goto err_clk;
+	}
+
 	err = mmc_of_parse(host->mmc);
 	if (err)
-		goto err_clk;
+		goto err_clk_axi;
 
 	sdhci_get_of_property(pdev);
 
@@ -502,11 +515,11 @@ static int xenon_probe(struct platform_device *pdev)
 	/* Xenon specific dt parse */
 	err = xenon_probe_dt(pdev);
 	if (err)
-		goto err_clk;
+		goto err_clk_axi;
 
 	err = xenon_sdhc_prepare(host);
 	if (err)
-		goto err_clk;
+		goto err_clk_axi;
 
 	pm_runtime_get_noresume(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);
@@ -527,6 +540,8 @@ remove_sdhc:
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_put_noidle(&pdev->dev);
 	xenon_sdhc_unprepare(host);
+err_clk_axi:
+	clk_disable_unprepare(priv->axi_clk);
 err_clk:
 	clk_disable_unprepare(pltfm_host->clk);
 free_pltfm:
@@ -538,6 +553,7 @@ static int xenon_remove(struct platform_device *pdev)
 {
 	struct sdhci_host *host = platform_get_drvdata(pdev);
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
 
 	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
@@ -546,7 +562,7 @@ static int xenon_remove(struct platform_device *pdev)
 	sdhci_remove_host(host, 0);
 
 	xenon_sdhc_unprepare(host);
-
+	clk_disable_unprepare(priv->axi_clk);
 	clk_disable_unprepare(pltfm_host->clk);
 
 	sdhci_pltfm_free(pdev);