[PATCH v2 2/6] mmc: sdhci-of-at91: add option to keep clocks enabled

[Robert Marko]

sdhci_at91_set_clks_presets() both enables the controller clocks and
programs its capabilities and preset registers. This prevents callers from
restoring the registers without changing the clock enable counts.

Move clock enablement to callers and add a SoC data flag for controllers
that must keep their clocks enabled. Use it in the runtime PM paths while
keeping register restoration separate from clock enablement.

Signed-off-by: Robert Marko <robert.marko at sartura.hr>

 drivers/mmc/host/sdhci-of-at91.c | 39 +++++++++++++++++++-------------
 1 file changed, 23 insertions(+), 16 deletions(-)

diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
index 7c4ac65f247d..b7e2a89da348 100644
--- a/drivers/mmc/host/sdhci-of-at91.c
+++ b/drivers/mmc/host/sdhci-of-at91.c
@@ -38,6 +38,7 @@
 struct sdhci_at91_soc_data {
 	const struct sdhci_pltfm_data *pdata;
 	bool baseclk_is_generated_internally;
+	bool keep_clks_on;
 	unsigned int divider_for_baseclk;
 };
 
@@ -164,7 +165,7 @@ static const struct of_device_id sdhci_at91_dt_match[] = {
 };
 MODULE_DEVICE_TABLE(of, sdhci_at91_dt_match);
 
-static int sdhci_at91_set_clks_presets(struct device *dev)
+static void sdhci_at91_set_clks_presets(struct device *dev)
 {
 	struct sdhci_host *host = dev_get_drvdata(dev);
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
@@ -174,7 +175,6 @@ static int sdhci_at91_set_clks_presets(struct device *dev)
 	unsigned int			gck_rate, clk_base_rate;
 	unsigned int			preset_div;
 
-	clk_prepare_enable(priv->hclock);
 	caps0 = readl(host->ioaddr + SDHCI_CAPABILITIES);
 	caps1 = readl(host->ioaddr + SDHCI_CAPABILITIES_1);
 
@@ -222,11 +222,6 @@ static int sdhci_at91_set_clks_presets(struct device *dev)
 	preset_div = DIV_ROUND_UP(gck_rate, 50000000) - 1;
 	writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
 	       host->ioaddr + SDHCI_PRESET_FOR_DDR50);
-
-	clk_prepare_enable(priv->mainck);
-	clk_prepare_enable(priv->gck);
-
-	return 0;
 }
 
 static int sdhci_at91_suspend(struct device *dev)
@@ -254,9 +249,11 @@ static int sdhci_at91_runtime_suspend(struct device *dev)
 	if (host->tuning_mode != SDHCI_TUNING_MODE_3)
 		mmc_retune_needed(host->mmc);
 
-	clk_disable_unprepare(priv->gck);
-	clk_disable_unprepare(priv->hclock);
-	clk_disable_unprepare(priv->mainck);
+	if (!priv->soc_data->keep_clks_on) {
+		clk_disable_unprepare(priv->gck);
+		clk_disable_unprepare(priv->hclock);
+		clk_disable_unprepare(priv->mainck);
+	}
 
 	return 0;
 }
@@ -269,14 +266,23 @@ static int sdhci_at91_runtime_resume(struct device *dev)
 	int ret;
 
 	if (priv->restore_needed) {
-		ret = sdhci_at91_set_clks_presets(dev);
-		if (ret)
-			return ret;
+		if (!priv->soc_data->keep_clks_on)
+			clk_prepare_enable(priv->hclock);
+
+		sdhci_at91_set_clks_presets(dev);
+
+		if (!priv->soc_data->keep_clks_on) {
+			clk_prepare_enable(priv->mainck);
+			clk_prepare_enable(priv->gck);
+		}
 
 		priv->restore_needed = false;
 		goto out;
 	}
 
+	if (priv->soc_data->keep_clks_on)
+		goto out;
+
 	ret = clk_prepare_enable(priv->mainck);
 	if (ret) {
 		dev_err(dev, "can't enable mainck\n");
@@ -344,9 +350,10 @@ static int sdhci_at91_probe(struct platform_device *pdev)
 		return dev_err_probe(&pdev->dev, PTR_ERR(priv->gck),
 				     "failed to get multclk\n");
 
-	ret = sdhci_at91_set_clks_presets(&pdev->dev);
-	if (ret)
-		return ret;
+	clk_prepare_enable(priv->hclock);
+	sdhci_at91_set_clks_presets(&pdev->dev);
+	clk_prepare_enable(priv->mainck);
+	clk_prepare_enable(priv->gck);
 
 	priv->restore_needed = false;
 
-- 
2.55.0