ASoC: tegra: ahub: Reset hardware properly

Assert hardware resets before clocks are enabled and then de-assert them
after clocks are enabled. This brings hardware into a predictable state.

Tested-by: Peter Geis <pgwipeout@gmail.com> # Ouya T30 audio works
Tested-by: Matt Merhar <mattmerhar@protonmail.com> # Ouya T30 boot-tested
Tested-by: Dmitry Osipenko <digetx@gmail.com> # Nexus7 T30 audio works
Tested-by: Nicolas Chauvet <kwizart@gmail.com> # TK1 boot-tested
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20210120003154.26749-7-digetx@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/tegra/tegra30_ahub.c b/sound/soc/tegra/tegra30_ahub.c
index 12ca8e3..9ef05ca 100644 (file)
--- a/sound/soc/tegra/tegra30_ahub.c
+++ b/sound/soc/tegra/tegra30_ahub.c
@@ -65,14 +65,39 @@ static int tegra30_ahub_runtime_resume(struct device *dev)
 {
        int ret;
 
+       ret = reset_control_assert(ahub->reset);
+       if (ret)
+               return ret;
+
        ret = clk_bulk_prepare_enable(ahub->nclocks, ahub->clocks);
        if (ret)
                return ret;
 
+       usleep_range(10, 100);
+
+       ret = reset_control_deassert(ahub->reset);
+       if (ret)
+               goto disable_clocks;
+
        regcache_cache_only(ahub->regmap_apbif, false);
        regcache_cache_only(ahub->regmap_ahub, false);
+       regcache_mark_dirty(ahub->regmap_apbif);
+       regcache_mark_dirty(ahub->regmap_ahub);
+
+       ret = regcache_sync(ahub->regmap_apbif);
+       if (ret)
+               goto disable_clocks;
+
+       ret = regcache_sync(ahub->regmap_ahub);
+       if (ret)
+               goto disable_clocks;
 
        return 0;
+
+disable_clocks:
+       clk_bulk_disable_unprepare(ahub->nclocks, ahub->clocks);
+
+       return ret;
 }
 
 int tegra30_ahub_allocate_rx_fifo(enum tegra30_ahub_rxcif *rxcif,
@@ -519,7 +544,6 @@ static int tegra30_ahub_probe(struct platform_device *pdev)
        /*
         * The AHUB hosts a register bus: the "configlink". For this to
         * operate correctly, all devices on this bus must be out of reset.
-        * Ensure that here.
         */
        for (i = 0; i < ARRAY_SIZE(configlink_mods); i++) {
                if (!(configlink_mods[i].mod_list_mask &
@@ -535,10 +559,8 @@ static int tegra30_ahub_probe(struct platform_device *pdev)
                        return ret;
                }
 
-               ret = reset_control_deassert(rst);
+               /* just check presence of the reset control in DT */
                reset_control_put(rst);
-               if (ret)
-                       return ret;
        }
 
        ahub = devm_kzalloc(&pdev->dev, sizeof(struct tegra30_ahub),
@@ -557,6 +579,12 @@ static int tegra30_ahub_probe(struct platform_device *pdev)
        if (ret)
                return ret;
 
+       ahub->reset = devm_reset_control_array_get_exclusive(&pdev->dev);
+       if (IS_ERR(ahub->reset)) {
+               dev_err(&pdev->dev, "Can't get resets: %pe\n", ahub->reset);
+               return PTR_ERR(ahub->reset);
+       }
+
        res0 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        regs_apbif = devm_ioremap_resource(&pdev->dev, res0);
        if (IS_ERR(regs_apbif))

diff --git a/sound/soc/tegra/tegra30_ahub.h b/sound/soc/tegra/tegra30_ahub.h
index 01480d7..3b85244 100644 (file)
--- a/sound/soc/tegra/tegra30_ahub.h
+++ b/sound/soc/tegra/tegra30_ahub.h
@@ -511,6 +511,7 @@ struct tegra30_ahub_soc_data {
 struct tegra30_ahub {
        const struct tegra30_ahub_soc_data *soc_data;
        struct device *dev;
+       struct reset_control *reset;
        struct clk_bulk_data clocks[2];
        unsigned int nclocks;
        resource_size_t apbif_addr;