MLK-15960-2: ASoC: fsl_sai: refine the pm runtime function

In imx8qm/imx8qxp, the power domain of IP is enabled when
pm_runtime_get_sync() is called, and disabled when pm_runtime
_put_sync() is called. when power domain is disabled, the value
of registers will lost, so we need to use the regcache_sync()
to restore the registers in fsl_sai_runtime_resume.

Signed-off-by: Shengjiu Wang <shengjiu.wang@freescale.com>

diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
index e2d1f2d..cbc94ce 100644 (file)
--- a/sound/soc/fsl/fsl_sai.c
+++ b/sound/soc/fsl/fsl_sai.c
@@ -708,8 +708,6 @@ static int fsl_sai_startup(struct snd_pcm_substream *substream,
        else
                sai->is_stream_opened[tx] = true;
 
-       pm_runtime_get_sync(cpu_dai->dev);
-
        ret = clk_prepare_enable(sai->bus_clk);
        if (ret) {
                dev_err(dev, "failed to enable bus clock: %d\n", ret);
@@ -745,7 +743,6 @@ static void fsl_sai_shutdown(struct snd_pcm_substream *substream,
                                   FSL_SAI_CR3_TRCE_MASK, 0);
                clk_disable_unprepare(sai->bus_clk);
                sai->is_stream_opened[tx] = false;
-               pm_runtime_put_sync(cpu_dai->dev);
        }
 }
 
@@ -1110,6 +1107,8 @@ static int fsl_sai_probe(struct platform_device *pdev)
 
        pm_runtime_enable(&pdev->dev);
 
+       regcache_cache_only(sai->regmap, true);
+
        ret = devm_snd_soc_register_component(&pdev->dev, &fsl_component,
                        &fsl_sai_dai, 1);
        if (ret)
@@ -1128,19 +1127,31 @@ static int fsl_sai_probe(struct platform_device *pdev)
 static int fsl_sai_runtime_resume(struct device *dev)
 {
        struct fsl_sai *sai = dev_get_drvdata(dev);
+       unsigned char offset = sai->soc->reg_offset;
 
        request_bus_freq(BUS_FREQ_AUDIO);
 
        if (sai->soc->flags & SAI_FLAG_PMQOS)
                pm_qos_add_request(&sai->pm_qos_req,
                                PM_QOS_CPU_DMA_LATENCY, 0);
-       return 0;
+
+       regcache_cache_only(sai->regmap, false);
+       regcache_mark_dirty(sai->regmap);
+
+       regmap_write(sai->regmap, FSL_SAI_TCSR(offset), FSL_SAI_CSR_SR);
+       regmap_write(sai->regmap, FSL_SAI_RCSR(offset), FSL_SAI_CSR_SR);
+       usleep_range(1000, 2000);
+       regmap_write(sai->regmap, FSL_SAI_TCSR(offset), 0);
+       regmap_write(sai->regmap, FSL_SAI_RCSR(offset), 0);
+       return regcache_sync(sai->regmap);
 }
 
 static int fsl_sai_runtime_suspend(struct device *dev)
 {
        struct fsl_sai *sai = dev_get_drvdata(dev);
 
+       regcache_cache_only(sai->regmap, true);
+
        release_bus_freq(BUS_FREQ_AUDIO);
 
        if (sai->soc->flags & SAI_FLAG_PMQOS)