ASoC: davinci-mcasp: add support for suspend and resume

When the system returns from suspend, it looses its configuration. Most
of it is restored by running a normal audio stream startup, but the DAI
format is left unset as that's configured on the audio device creation.

Hence, it suffices here to care for the registers which are touched by
davinci_mcasp_set_dai_fmt() and restore them when the system is resumed.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

2 files changed, 51 insertions, 0 deletions

diff --git a/sound/soc/davinci/davinci-mcasp.c b/sound/soc/davinci/davinci-mcasp.c
index 32ddb7fe5034..cdfe959d6062 100644
--- a/sound/soc/davinci/davinci-mcasp.c
+++ b/sound/soc/davinci/davinci-mcasp.c
@@ -1251,12 +1251,51 @@ static int davinci_mcasp_remove(struct platform_device *pdev)
         return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int davinci_mcasp_suspend(struct device *dev)
+{
+        struct davinci_audio_dev *a = dev_get_drvdata(dev);
+        void __iomem *base = a->base;
+
+        a->context.txfmtctl = mcasp_get_reg(base + DAVINCI_MCASP_TXFMCTL_REG);
+        a->context.rxfmtctl = mcasp_get_reg(base + DAVINCI_MCASP_RXFMCTL_REG);
+        a->context.txfmt = mcasp_get_reg(base + DAVINCI_MCASP_TXFMT_REG);
+        a->context.rxfmt = mcasp_get_reg(base + DAVINCI_MCASP_RXFMT_REG);
+        a->context.aclkxctl = mcasp_get_reg(base + DAVINCI_MCASP_ACLKXCTL_REG);
+        a->context.aclkrctl = mcasp_get_reg(base + DAVINCI_MCASP_ACLKRCTL_REG);
+        a->context.pdir = mcasp_get_reg(base + DAVINCI_MCASP_PDIR_REG);
+
+        return 0;
+}
+
+static int davinci_mcasp_resume(struct device *dev)
+{
+        struct davinci_audio_dev *a = dev_get_drvdata(dev);
+        void __iomem *base = a->base;
+
+        mcasp_set_reg(base + DAVINCI_MCASP_TXFMCTL_REG, a->context.txfmtctl);
+        mcasp_set_reg(base + DAVINCI_MCASP_RXFMCTL_REG, a->context.rxfmtctl);
+        mcasp_set_reg(base + DAVINCI_MCASP_TXFMT_REG, a->context.txfmt);
+        mcasp_set_reg(base + DAVINCI_MCASP_RXFMT_REG, a->context.rxfmt);
+        mcasp_set_reg(base + DAVINCI_MCASP_ACLKXCTL_REG, a->context.aclkxctl);
+        mcasp_set_reg(base + DAVINCI_MCASP_ACLKRCTL_REG, a->context.aclkrctl);
+        mcasp_set_reg(base + DAVINCI_MCASP_PDIR_REG, a->context.pdir);
+
+        return 0;
+}
+#endif
+
+SIMPLE_DEV_PM_OPS(davinci_mcasp_pm_ops,
+                  davinci_mcasp_suspend,
+                  davinci_mcasp_resume);
+
 static struct platform_driver davinci_mcasp_driver = {
         .probe          = davinci_mcasp_probe,
         .remove         = davinci_mcasp_remove,
         .driver         = {
                 .name   = "davinci-mcasp",
                 .owner  = THIS_MODULE,
+                .pm     = &davinci_mcasp_pm_ops,
                 .of_match_table = mcasp_dt_ids,
         },
 };
diff --git a/sound/soc/davinci/davinci-mcasp.h b/sound/soc/davinci/davinci-mcasp.h
index a9ac0c11da71..a2e27e1c32f3 100644
--- a/sound/soc/davinci/davinci-mcasp.h
+++ b/sound/soc/davinci/davinci-mcasp.h
@@ -43,6 +43,18 @@ struct davinci_audio_dev {
         /* McASP FIFO related */
         u8      txnumevt;
         u8      rxnumevt;
+
+#ifdef CONFIG_PM_SLEEP
+        struct {
+                u32     txfmtctl;
+                u32     rxfmtctl;
+                u32     txfmt;
+                u32     rxfmt;
+                u32     aclkxctl;
+                u32     aclkrctl;
+                u32     pdir;
+        } context;
+#endif
 };
 
 #endif  /* DAVINCI_MCASP_H */