[PATCH 5.0 62/95] ASoC: stm32: sai: fix master clock management

Greg Kroah-Hartman
2019-05-09T18:52:31Z

[ Upstream commit e37c2deafe7058cf7989c4c47bbf1140cc867d89 ]

When master clock is used, master clock rate is set exclusively.
Parent clocks of master clock cannot be changed after a call to
clk_set_rate_exclusive(). So the parent clock of SAI kernel clock
must be set before.
Ensure also that exclusive rate operations are balanced
in STM32 SAI driver.

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
sound/soc/stm/stm32_sai_sub.c | 64 +++++++++++++++++++++++++----------
1 file changed, 47 insertions(+), 17 deletions(-)

diff --git a/sound/soc/stm/stm32_sai_sub.c b/sound/soc/stm/stm32_sai_sub.c
index bc69e68191ad1..1cf9df4b6f11c 100644
--- a/sound/soc/stm/stm32_sai_sub.c
+++ b/sound/soc/stm/stm32_sai_sub.c
@@ -70,6 +70,7 @@
#define SAI_IEC60958_STATUS_BYTES 24

#define SAI_MCLK_NAME_LEN 32
+#define SAI_RATE_11K 11025

/**
* struct stm32_sai_sub_data - private data of SAI sub block (block A or B)
@@ -309,6 +310,25 @@ static int stm32_sai_set_clk_div(struct stm32_sai_sub_data *sai,
return ret;
}

+static int stm32_sai_set_parent_clock(struct stm32_sai_sub_data *sai,
+ unsigned int rate)
+{
+ struct platform_device *pdev = sai->pdev;
+ struct clk *parent_clk = sai->pdata->clk_x8k;
+ int ret;
+
+ if (!(rate % SAI_RATE_11K))
+ parent_clk = sai->pdata->clk_x11k;
+
+ ret = clk_set_parent(sai->sai_ck, parent_clk);
+ if (ret)
+ dev_err(&pdev->dev, " Error %d setting sai_ck parent clock. %s",
+ ret, ret == -EBUSY ?
+ "Active stream rates conflict\n" : "\n");
+
+ return ret;
+}
+
static long stm32_sai_mclk_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
@@ -490,25 +510,29 @@ static int stm32_sai_set_sysclk(struct snd_soc_dai *cpu_dai,
struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
int ret;

- if (dir == SND_SOC_CLOCK_OUT) {
+ if (dir == SND_SOC_CLOCK_OUT && sai->sai_mclk) {
ret = regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX,
SAI_XCR1_NODIV,
(unsigned int)~SAI_XCR1_NODIV);
if (ret < 0)
return ret;

- dev_dbg(cpu_dai->dev, "SAI MCLK frequency is %uHz\n", freq);
- sai->mclk_rate = freq;
+ /* If master clock is used, set parent clock now */
+ ret = stm32_sai_set_parent_clock(sai, freq);
+ if (ret)
+ return ret;

- if (sai->sai_mclk) {
- ret = clk_set_rate_exclusive(sai->sai_mclk,
- sai->mclk_rate);
- if (ret) {
- dev_err(cpu_dai->dev,
- "Could not set mclk rate\n");
- return ret;
- }
+ ret = clk_set_rate_exclusive(sai->sai_mclk, freq);
+ if (ret) {
+ dev_err(cpu_dai->dev,
+ ret == -EBUSY ?
+ "Active streams have incompatible rates" :
+ "Could not set mclk rate\n");
+ return ret;
}
+
+ dev_dbg(cpu_dai->dev, "SAI MCLK frequency is %uHz\n", freq);
+ sai->mclk_rate = freq;
}

return 0;
@@ -916,11 +940,13 @@ static int stm32_sai_configure_clock(struct snd_soc_dai *cpu_dai,
int cr1, mask, div = 0;
int sai_clk_rate, mclk_ratio, den;
unsigned int rate = params_rate(params);
+ int ret;

- if (!(rate % 11025))
- clk_set_parent(sai->sai_ck, sai->pdata->clk_x11k);
- else
- clk_set_parent(sai->sai_ck, sai->pdata->clk_x8k);
+ if (!sai->sai_mclk) {
+ ret = stm32_sai_set_parent_clock(sai, rate);
+ if (ret)
+ return ret;
+ }
sai_clk_rate = clk_get_rate(sai->sai_ck);

if (STM_SAI_IS_F4(sai->pdata)) {
@@ -1075,9 +1101,13 @@ static void stm32_sai_shutdown(struct snd_pcm_substream *substream,
regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX, SAI_XCR1_NODIV,
SAI_XCR1_NODIV);

- clk_disable_unprepare(sai->sai_ck);
+ /* Release mclk rate only if rate was actually set */
+ if (sai->mclk_rate) {
+ clk_rate_exclusive_put(sai->sai_mclk);
+ sai->mclk_rate = 0;
+ }

- clk_rate_exclusive_put(sai->sai_mclk);
+ clk_disable_unprepare(sai->sai_ck);

spin_lock_irqsave(&sai->irq_lock, flags);
sai->substream = NULL;
--
2.20.1