ASoC: stm32: sai: Add synchronization support

Add Synchronization support for STM32 SAI.

Signed-off-by: olivier moysan <olivier.moysan@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 155 insertions, 5 deletions

diff --git a/sound/soc/stm/stm32_sai.c b/sound/soc/stm/stm32_sai.c
index 5fe878ace605..d6f71a3406e9 100644
--- a/sound/soc/stm/stm32_sai.c
+++ b/sound/soc/stm/stm32_sai.c
@@ -16,6 +16,7 @@
  * details.
  */
 
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/module.h>
@@ -27,6 +28,16 @@
 
 #include "stm32_sai.h"
 
+static LIST_HEAD(sync_providers);
+static DEFINE_MUTEX(sync_mutex);
+
+struct sync_provider {
+	struct list_head link;
+	struct device_node *node;
+	int  (*sync_conf)(void *data, int synco);
+	void *data;
+};
+
 static const struct stm32_sai_conf stm32_sai_conf_f4 = {
 	.version = SAI_STM32F4,
 };
@@ -41,23 +52,143 @@ static const struct of_device_id stm32_sai_ids[] = {
 	{}
 };
 
+static int stm32_sai_sync_conf_client(struct stm32_sai_data *sai, int synci)
+{
+	int ret;
+
+	/* Enable peripheral clock to allow GCR register access */
+	ret = clk_prepare_enable(sai->pclk);
+	if (ret) {
+		dev_err(&sai->pdev->dev, "failed to enable clock: %d\n", ret);
+		return ret;
+	}
+
+	writel_relaxed(FIELD_PREP(SAI_GCR_SYNCIN_MASK, (synci - 1)), sai->base);
+
+	clk_disable_unprepare(sai->pclk);
+
+	return 0;
+}
+
+static int stm32_sai_sync_conf_provider(void *data, int synco)
+{
+	struct stm32_sai_data *sai = (struct stm32_sai_data *)data;
+	u32 prev_synco;
+	int ret;
+
+	/* Enable peripheral clock to allow GCR register access */
+	ret = clk_prepare_enable(sai->pclk);
+	if (ret) {
+		dev_err(&sai->pdev->dev, "failed to enable clock: %d\n", ret);
+		return ret;
+	}
+
+	dev_dbg(&sai->pdev->dev, "Set %s%s as synchro provider\n",
+		sai->pdev->dev.of_node->name,
+		synco == STM_SAI_SYNC_OUT_A ? "A" : "B");
+
+	prev_synco = FIELD_GET(SAI_GCR_SYNCOUT_MASK, readl_relaxed(sai->base));
+	if (prev_synco != STM_SAI_SYNC_OUT_NONE && synco != prev_synco) {
+		dev_err(&sai->pdev->dev, "%s%s already set as sync provider\n",
+			sai->pdev->dev.of_node->name,
+			prev_synco == STM_SAI_SYNC_OUT_A ? "A" : "B");
+		clk_disable_unprepare(sai->pclk);
+		return -EINVAL;
+	}
+
+	writel_relaxed(FIELD_PREP(SAI_GCR_SYNCOUT_MASK, synco), sai->base);
+
+	clk_disable_unprepare(sai->pclk);
+
+	return 0;
+}
+
+static int stm32_sai_set_sync_provider(struct device_node *np, int synco)
+{
+	struct sync_provider *provider;
+	int ret;
+
+	mutex_lock(&sync_mutex);
+	list_for_each_entry(provider, &sync_providers, link) {
+		if (provider->node == np) {
+			ret = provider->sync_conf(provider->data, synco);
+			mutex_unlock(&sync_mutex);
+			return ret;
+		}
+	}
+	mutex_unlock(&sync_mutex);
+
+	/* SAI sync provider not found */
+	return -ENODEV;
+}
+
+static int stm32_sai_set_sync(struct stm32_sai_data *sai,
+			      struct device_node *np_provider,
+			      int synco, int synci)
+{
+	int ret;
+
+	/* Configure sync client */
+	stm32_sai_sync_conf_client(sai, synci);
+
+	/* Configure sync provider */
+	ret = stm32_sai_set_sync_provider(np_provider, synco);
+
+	return ret;
+}
+
+static int stm32_sai_sync_add_provider(struct platform_device *pdev,
+				       void *data)
+{
+	struct sync_provider *sp;
+
+	sp = devm_kzalloc(&pdev->dev, sizeof(*sp), GFP_KERNEL);
+	if (!sp)
+		return -ENOMEM;
+
+	sp->node = of_node_get(pdev->dev.of_node);
+	sp->data = data;
+	sp->sync_conf = &stm32_sai_sync_conf_provider;
+
+	mutex_lock(&sync_mutex);
+	list_add(&sp->link, &sync_providers);
+	mutex_unlock(&sync_mutex);
+
+	return 0;
+}
+
+static void stm32_sai_sync_del_provider(struct device_node *np)
+{
+	struct sync_provider *sp;
+
+	mutex_lock(&sync_mutex);
+	list_for_each_entry(sp, &sync_providers, link) {
+		if (sp->node == np) {
+			list_del(&sp->link);
+			of_node_put(sp->node);
+			break;
+		}
+	}
+	mutex_unlock(&sync_mutex);
+}
+
 static int stm32_sai_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
 	struct stm32_sai_data *sai;
 	struct reset_control *rst;
 	struct resource *res;
-	void __iomem *base;
 	const struct of_device_id *of_id;
+	int ret;
 
 	sai = devm_kzalloc(&pdev->dev, sizeof(*sai), GFP_KERNEL);
 	if (!sai)
 		return -ENOMEM;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	base = devm_ioremap_resource(&pdev->dev, res);
-	if (IS_ERR(base))
-		return PTR_ERR(base);
+	sai->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(sai->base))
+		return PTR_ERR(sai->base);
 
 	of_id = of_match_device(stm32_sai_ids, &pdev->dev);
 	if (of_id)
@@ -65,6 +196,14 @@ static int stm32_sai_probe(struct platform_device *pdev)
 	else
 		return -EINVAL;
 
+	if (!STM_SAI_IS_F4(sai)) {
+		sai->pclk = devm_clk_get(&pdev->dev, "pclk");
+		if (IS_ERR(sai->pclk)) {
+			dev_err(&pdev->dev, "missing bus clock pclk\n");
+			return PTR_ERR(sai->pclk);
+		}
+	}
+
 	sai->clk_x8k = devm_clk_get(&pdev->dev, "x8k");
 	if (IS_ERR(sai->clk_x8k)) {
 		dev_err(&pdev->dev, "missing x8k parent clock\n");
@@ -92,16 +231,27 @@ static int stm32_sai_probe(struct platform_device *pdev)
 		reset_control_deassert(rst);
 	}
 
+	ret = stm32_sai_sync_add_provider(pdev, sai);
+	if (ret < 0)
+		return ret;
+	sai->set_sync = &stm32_sai_set_sync;
+
 	sai->pdev = pdev;
 	platform_set_drvdata(pdev, sai);
 
-	return of_platform_populate(np, NULL, NULL, &pdev->dev);
+	ret = of_platform_populate(np, NULL, NULL, &pdev->dev);
+	if (ret < 0)
+		stm32_sai_sync_del_provider(np);
+
+	return ret;
 }
 
 static int stm32_sai_remove(struct platform_device *pdev)
 {
 	of_platform_depopulate(&pdev->dev);
 
+	stm32_sai_sync_del_provider(pdev->dev.of_node);
+
 	return 0;
 }