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

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Message-ID: <20190814092140.30995-2-ckeepax@opensource.cirrus.com>
Date:   Wed, 14 Aug 2019 10:21:40 +0100
From:   Charles Keepax <ckeepax@...nsource.cirrus.com>
To:     <lee.jones@...aro.org>
CC:     <robh+dt@...nel.org>, <mark.rutland@....com>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <patches@...nsource.cirrus.com>
Subject: [PATCH v2 2/2] mfd: madera: Add support for requesting the supply clocks

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@...nsource.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