[PATCH v2 2/2] mfd: madera: Add support for requesting the supply clocks

[Charles Keepax <ckeepax@opensource.cirrus.com>]

Add the ability to get the clock for each clock input pin of the chip
and enable MCLK2 since that is expected to be a permanently enabled
32kHz clock.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---

Changes since v1:
 - Fail probe if we encounter a clock error
 - Print a warning if MCLK2 is not specified

Thanks,
Charles

 drivers/mfd/madera-core.c       | 29 ++++++++++++++++++++++++++++-
 include/linux/mfd/madera/core.h | 11 +++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/drivers/mfd/madera-core.c b/drivers/mfd/madera-core.c
index 29540cbf75934..9a0dee9400dd8 100644
--- a/drivers/mfd/madera-core.c
+++ b/drivers/mfd/madera-core.c
@@ -428,6 +428,7 @@ static void madera_set_micbias_info(struct madera *madera)
 
 int madera_dev_init(struct madera *madera)
 {
+	static const char * const mclk_name[] = { "mclk1", "mclk2", "mclk3" };
 	struct device *dev = madera->dev;
 	unsigned int hwid;
 	int (*patch_fn)(struct madera *) = NULL;
@@ -450,6 +451,22 @@ int madera_dev_init(struct madera *madera)
 		       sizeof(madera->pdata));
 	}
 
+	BUILD_BUG_ON(ARRAY_SIZE(madera->mclk) != ARRAY_SIZE(mclk_name));
+	for (i = 0; i < ARRAY_SIZE(madera->mclk); i++) {
+		madera->mclk[i] = devm_clk_get_optional(madera->dev,
+							mclk_name[i]);
+		if (IS_ERR(madera->mclk[i])) {
+			ret = PTR_ERR(madera->mclk[i]);
+			dev_err(madera->dev, "Failed to get %s: %d\n",
+				mclk_name[i], ret);
+			return ret;
+		}
+	}
+
+	/* Not using devm_clk_get to prevent breakage of existing DTs */
+	if (!madera->mclk[MADERA_MCLK2])
+		dev_warn(madera->dev, "Missing MCLK2, requires 32kHz clock\n");
+
 	ret = madera_get_reset_gpio(madera);
 	if (ret)
 		return ret;
@@ -660,13 +677,19 @@ int madera_dev_init(struct madera *madera)
 	}
 
 	/* Init 32k clock sourced from MCLK2 */
+	ret = clk_prepare_enable(madera->mclk[MADERA_MCLK2]);
+	if (ret != 0) {
+		dev_err(madera->dev, "Failed to enable 32k clock: %d\n", ret);
+		goto err_reset;
+	}
+
 	ret = regmap_update_bits(madera->regmap,
 			MADERA_CLOCK_32K_1,
 			MADERA_CLK_32K_ENA_MASK | MADERA_CLK_32K_SRC_MASK,
 			MADERA_CLK_32K_ENA | MADERA_32KZ_MCLK2);
 	if (ret) {
 		dev_err(madera->dev, "Failed to init 32k clock: %d\n", ret);
-		goto err_reset;
+		goto err_clock;
 	}
 
 	pm_runtime_set_active(madera->dev);
@@ -687,6 +710,8 @@ int madera_dev_init(struct madera *madera)
 
 err_pm_runtime:
 	pm_runtime_disable(madera->dev);
+err_clock:
+	clk_disable_unprepare(madera->mclk[MADERA_MCLK2]);
 err_reset:
 	madera_enable_hard_reset(madera);
 	regulator_disable(madera->dcvdd);
@@ -713,6 +738,8 @@ int madera_dev_exit(struct madera *madera)
 	 */
 	pm_runtime_disable(madera->dev);
 
+	clk_disable_unprepare(madera->mclk[MADERA_MCLK2]);
+
 	regulator_disable(madera->dcvdd);
 	regulator_put(madera->dcvdd);
 
diff --git a/include/linux/mfd/madera/core.h b/include/linux/mfd/madera/core.h
index 7ffa696cce7ca..2b6c83fe221dc 100644
--- a/include/linux/mfd/madera/core.h
+++ b/include/linux/mfd/madera/core.h
@@ -8,6 +8,7 @@
 #ifndef MADERA_CORE_H
 #define MADERA_CORE_H
 
+#include <linux/clk.h>
 #include <linux/gpio/consumer.h>
 #include <linux/interrupt.h>
 #include <linux/mfd/madera/pdata.h>
@@ -29,6 +30,13 @@ enum madera_type {
 	CS42L92 = 9,
 };
 
+enum {
+	MADERA_MCLK1,
+	MADERA_MCLK2,
+	MADERA_MCLK3,
+	MADERA_NUM_MCLK
+};
+
 #define MADERA_MAX_CORE_SUPPLIES	2
 #define MADERA_MAX_GPIOS		40
 
@@ -155,6 +163,7 @@ struct snd_soc_dapm_context;
  * @irq_dev:		the irqchip child driver device
  * @irq_data:		pointer to irqchip data for the child irqchip driver
  * @irq:		host irq number from SPI or I2C configuration
+ * @mclk:		pointers to clock supplies
  * @out_clamp:		indicates output clamp state for each analogue output
  * @out_shorted:	indicates short circuit state for each analogue output
  * @hp_ena:		bitflags of enable state for the headphone outputs
@@ -184,6 +193,8 @@ struct madera {
 	struct regmap_irq_chip_data *irq_data;
 	int irq;
 
+	struct clk *mclk[MADERA_NUM_MCLK];
+
 	unsigned int num_micbias;
 	unsigned int num_childbias[MADERA_MAX_MICBIAS];
 
-- 
2.11.0