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Subject[PATCH] ASoC: stm32: sai: add power management
Date
Add support of low power modes to STM32 SAI driver.

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
---
sound/soc/stm/stm32_sai.c | 80 ++++++++++++++++++++++++++++++++++++++-----
sound/soc/stm/stm32_sai.h | 2 ++
sound/soc/stm/stm32_sai_sub.c | 45 ++++++++++++++++++------
3 files changed, 108 insertions(+), 19 deletions(-)

diff --git a/sound/soc/stm/stm32_sai.c b/sound/soc/stm/stm32_sai.c
index d68d62f12df5..7550d5f08be3 100644
--- a/sound/soc/stm/stm32_sai.c
+++ b/sound/soc/stm/stm32_sai.c
@@ -21,6 +21,7 @@
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/of_platform.h>
+#include <linux/pinctrl/consumer.h>
#include <linux/reset.h>

#include <sound/dmaengine_pcm.h>
@@ -44,20 +45,41 @@ static const struct of_device_id stm32_sai_ids[] = {
{}
};

-static int stm32_sai_sync_conf_client(struct stm32_sai_data *sai, int synci)
+static int stm32_sai_pclk_disable(struct device *dev)
+{
+ struct stm32_sai_data *sai = dev_get_drvdata(dev);
+
+ clk_disable_unprepare(sai->pclk);
+
+ return 0;
+}
+
+static int stm32_sai_pclk_enable(struct device *dev)
{
+ struct stm32_sai_data *sai = dev_get_drvdata(dev);
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;
}

+ return 0;
+}
+
+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 = stm32_sai_pclk_enable(&sai->pdev->dev);
+ if (ret)
+ return ret;
+
writel_relaxed(FIELD_PREP(SAI_GCR_SYNCIN_MASK, (synci - 1)), sai->base);

- clk_disable_unprepare(sai->pclk);
+ stm32_sai_pclk_disable(&sai->pdev->dev);

return 0;
}
@@ -68,11 +90,9 @@ static int stm32_sai_sync_conf_provider(struct stm32_sai_data *sai, int 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);
+ ret = stm32_sai_pclk_enable(&sai->pdev->dev);
+ if (ret)
return ret;
- }

dev_dbg(&sai->pdev->dev, "Set %pOFn%s as synchro provider\n",
sai->pdev->dev.of_node,
@@ -83,13 +103,13 @@ static int stm32_sai_sync_conf_provider(struct stm32_sai_data *sai, int synco)
dev_err(&sai->pdev->dev, "%pOFn%s already set as sync provider\n",
sai->pdev->dev.of_node,
prev_synco == STM_SAI_SYNC_OUT_A ? "A" : "B");
- clk_disable_unprepare(sai->pclk);
+ stm32_sai_pclk_disable(&sai->pdev->dev);
return -EINVAL;
}

writel_relaxed(FIELD_PREP(SAI_GCR_SYNCOUT_MASK, synco), sai->base);

- clk_disable_unprepare(sai->pclk);
+ stm32_sai_pclk_disable(&sai->pdev->dev);

return 0;
}
@@ -195,12 +215,54 @@ static int stm32_sai_probe(struct platform_device *pdev)
return devm_of_platform_populate(&pdev->dev);
}

+#ifdef CONFIG_PM_SLEEP
+/*
+ * When pins are shared by two sai sub instances, pins have to be defined
+ * in sai parent node. In this case, pins state is not managed by alsa fw.
+ * These pins are managed in suspend/resume callbacks.
+ */
+static int stm32_sai_suspend(struct device *dev)
+{
+ struct stm32_sai_data *sai = dev_get_drvdata(dev);
+ int ret;
+
+ ret = stm32_sai_pclk_enable(dev);
+ if (ret)
+ return ret;
+
+ sai->gcr = readl_relaxed(sai->base);
+ stm32_sai_pclk_disable(dev);
+
+ return pinctrl_pm_select_sleep_state(dev);
+}
+
+static int stm32_sai_resume(struct device *dev)
+{
+ struct stm32_sai_data *sai = dev_get_drvdata(dev);
+ int ret;
+
+ ret = stm32_sai_pclk_enable(dev);
+ if (ret)
+ return ret;
+
+ writel_relaxed(sai->gcr, sai->base);
+ stm32_sai_pclk_disable(dev);
+
+ return pinctrl_pm_select_default_state(dev);
+}
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct dev_pm_ops stm32_sai_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(stm32_sai_suspend, stm32_sai_resume)
+};
+
MODULE_DEVICE_TABLE(of, stm32_sai_ids);

static struct platform_driver stm32_sai_driver = {
.driver = {
.name = "st,stm32-sai",
.of_match_table = stm32_sai_ids,
+ .pm = &stm32_sai_pm_ops,
},
.probe = stm32_sai_probe,
};
diff --git a/sound/soc/stm/stm32_sai.h b/sound/soc/stm/stm32_sai.h
index 08de899c766b..9c36a393ab7b 100644
--- a/sound/soc/stm/stm32_sai.h
+++ b/sound/soc/stm/stm32_sai.h
@@ -268,6 +268,7 @@ struct stm32_sai_conf {
* @version: SOC version
* @irq: SAI interrupt line
* @set_sync: pointer to synchro mode configuration callback
+ * @gcr: SAI Global Configuration Register
*/
struct stm32_sai_data {
struct platform_device *pdev;
@@ -279,4 +280,5 @@ struct stm32_sai_data {
int irq;
int (*set_sync)(struct stm32_sai_data *sai,
struct device_node *np_provider, int synco, int synci);
+ u32 gcr;
};
diff --git a/sound/soc/stm/stm32_sai_sub.c b/sound/soc/stm/stm32_sai_sub.c
index 55d802f51c15..2a90641cf164 100644
--- a/sound/soc/stm/stm32_sai_sub.c
+++ b/sound/soc/stm/stm32_sai_sub.c
@@ -168,6 +168,7 @@ static bool stm32_sai_sub_volatile_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case STM_SAI_DR_REGX:
+ case STM_SAI_SR_REGX:
return true;
default:
return false;
@@ -182,7 +183,6 @@ static bool stm32_sai_sub_writeable_reg(struct device *dev, unsigned int reg)
case STM_SAI_FRCR_REGX:
case STM_SAI_SLOTR_REGX:
case STM_SAI_IMR_REGX:
- case STM_SAI_SR_REGX:
case STM_SAI_CLRFR_REGX:
case STM_SAI_DR_REGX:
case STM_SAI_PDMCR_REGX:
@@ -202,6 +202,7 @@ static const struct regmap_config stm32_sai_sub_regmap_config_f4 = {
.volatile_reg = stm32_sai_sub_volatile_reg,
.writeable_reg = stm32_sai_sub_writeable_reg,
.fast_io = true,
+ .cache_type = REGCACHE_FLAT,
};

static const struct regmap_config stm32_sai_sub_regmap_config_h7 = {
@@ -213,6 +214,7 @@ static const struct regmap_config stm32_sai_sub_regmap_config_h7 = {
.volatile_reg = stm32_sai_sub_volatile_reg,
.writeable_reg = stm32_sai_sub_writeable_reg,
.fast_io = true,
+ .cache_type = REGCACHE_FLAT,
};

static int snd_pcm_iec958_info(struct snd_kcontrol *kcontrol,
@@ -441,8 +443,8 @@ static irqreturn_t stm32_sai_isr(int irq, void *devid)
if (!flags)
return IRQ_NONE;

- regmap_update_bits(sai->regmap, STM_SAI_CLRFR_REGX, SAI_XCLRFR_MASK,
- SAI_XCLRFR_MASK);
+ regmap_write_bits(sai->regmap, STM_SAI_CLRFR_REGX, SAI_XCLRFR_MASK,
+ SAI_XCLRFR_MASK);

if (!sai->substream) {
dev_err(&pdev->dev, "Device stopped. Spurious IRQ 0x%x\n", sr);
@@ -704,9 +706,8 @@ static int stm32_sai_startup(struct snd_pcm_substream *substream,
}

/* Enable ITs */
-
- regmap_update_bits(sai->regmap, STM_SAI_CLRFR_REGX,
- SAI_XCLRFR_MASK, SAI_XCLRFR_MASK);
+ regmap_write_bits(sai->regmap, STM_SAI_CLRFR_REGX,
+ SAI_XCLRFR_MASK, SAI_XCLRFR_MASK);

imr = SAI_XIMR_OVRUDRIE;
if (STM_SAI_IS_CAPTURE(sai)) {
@@ -738,10 +739,10 @@ static int stm32_sai_set_config(struct snd_soc_dai *cpu_dai,
* SAI fifo threshold is set to half fifo, to keep enough space
* for DMA incoming bursts.
*/
- regmap_update_bits(sai->regmap, STM_SAI_CR2_REGX,
- SAI_XCR2_FFLUSH | SAI_XCR2_FTH_MASK,
- SAI_XCR2_FFLUSH |
- SAI_XCR2_FTH_SET(STM_SAI_FIFO_TH_HALF));
+ regmap_write_bits(sai->regmap, STM_SAI_CR2_REGX,
+ SAI_XCR2_FFLUSH | SAI_XCR2_FTH_MASK,
+ SAI_XCR2_FFLUSH |
+ SAI_XCR2_FTH_SET(STM_SAI_FIFO_TH_HALF));

/* DS bits in CR1 not set for SPDIF (size forced to 24 bits).*/
if (STM_SAI_PROTOCOL_IS_SPDIF(sai)) {
@@ -1492,10 +1493,34 @@ static int stm32_sai_sub_probe(struct platform_device *pdev)
return 0;
}

+#ifdef CONFIG_PM_SLEEP
+static int stm32_sai_sub_suspend(struct device *dev)
+{
+ struct stm32_sai_sub_data *sai = dev_get_drvdata(dev);
+
+ regcache_cache_only(sai->regmap, true);
+ regcache_mark_dirty(sai->regmap);
+ return 0;
+}
+
+static int stm32_sai_sub_resume(struct device *dev)
+{
+ struct stm32_sai_sub_data *sai = dev_get_drvdata(dev);
+
+ regcache_cache_only(sai->regmap, false);
+ return regcache_sync(sai->regmap);
+}
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct dev_pm_ops stm32_sai_sub_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(stm32_sai_sub_suspend, stm32_sai_sub_resume)
+};
+
static struct platform_driver stm32_sai_sub_driver = {
.driver = {
.name = "st,stm32-sai-sub",
.of_match_table = stm32_sai_sub_ids,
+ .pm = &stm32_sai_sub_pm_ops,
},
.probe = stm32_sai_sub_probe,
};
--
2.7.4
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