[PATCH v3 2/6] ALSA: hda/tegra: Reset hardware

[Dmitry Osipenko]

Reset hardware on RPM-resume in order to bring it into a predictable
state.

Tested-by: Peter Geis <pgwipe...@gmail.com> # Ouya T30 audio works
Tested-by: Matt Merhar <mattmer...@protonmail.com> # Ouya T30 boot-tested
Tested-by: Nicolas Chauvet <kwiz...@gmail.com> # TK1 boot-tested
Signed-off-by: Dmitry Osipenko <dig...@gmail.com>
---
 sound/pci/hda/hda_tegra.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/sound/pci/hda/hda_tegra.c b/sound/pci/hda/hda_tegra.c
index a25bf7083c28..04dcd4cdfd9e 100644
--- a/sound/pci/hda/hda_tegra.c
+++ b/sound/pci/hda/hda_tegra.c
@@ -17,6 +17,7 @@
 #include <linux/moduleparam.h>
 #include <linux/mutex.h>
 #include <linux/of_device.h>
+#include <linux/reset.h>
 #include <linux/slab.h>
 #include <linux/time.h>
 #include <linux/string.h>
@@ -70,6 +71,7 @@
 struct hda_tegra {
        struct azx chip;
        struct device *dev;
+       struct reset_control *reset;
        struct clk_bulk_data clocks[3];
        unsigned int nclocks;
        void __iomem *regs;
@@ -167,6 +169,12 @@ static int __maybe_unused hda_tegra_runtime_resume(struct 
device *dev)
        struct hda_tegra *hda = container_of(chip, struct hda_tegra, chip);
        int rc;
 
+       if (!chip->running) {
+               rc = reset_control_assert(hda->reset);
+               if (rc)
+                       return rc;
+       }
+
        rc = clk_bulk_prepare_enable(hda->nclocks, hda->clocks);
        if (rc != 0)
                return rc;
@@ -176,6 +184,12 @@ static int __maybe_unused hda_tegra_runtime_resume(struct 
device *dev)
                /* disable controller wake up event*/
                azx_writew(chip, WAKEEN, azx_readw(chip, WAKEEN) &
                           ~STATESTS_INT_MASK);
+       } else {
+               usleep_range(10, 100);
+
+               rc = reset_control_deassert(hda->reset);
+               if (rc)
+                       return rc;
        }
 
        return 0;
@@ -441,6 +455,12 @@ static int hda_tegra_probe(struct platform_device *pdev)
                return err;
        }
 
+       hda->reset = devm_reset_control_array_get_exclusive(&pdev->dev);
+       if (IS_ERR(hda->reset)) {
+               err = PTR_ERR(hda->reset);
+               goto out_free;
+       }
+
        hda->clocks[hda->nclocks++].id = "hda";
        hda->clocks[hda->nclocks++].id = "hda2hdmi";
        hda->clocks[hda->nclocks++].id = "hda2codec_2x";
-- 
2.29.2