This reverts commit 9de2b9286a6d ("ASoC: mediatek: Check for error clk
pointer").

With this patch in the tree, Chromebooks running the affected hardware
no longer boot. Bisect points to this patch, and reverting it fixes
the problem.

An analysis of the code with this patch applied shows:

        ret = init_clks(pdev, clk);
        if (ret)
                return ERR_PTR(ret);
...
                for (j = 0; j < MAX_CLKS && data->clk_id[j]; j++) {
                        struct clk *c = clk[data->clk_id[j]];

                        if (IS_ERR(c)) {
                                dev_err(&pdev->dev, "%s: clk unavailable\n",
                                        data->name);
                                return ERR_CAST(c);
                        }

                        scpd->clk[j] = c;
                }

Not all clocks in the clk_names array have to be present. Only the clocks
in the data->clk_id array are actually needed. The code already checks if
the required clocks are available and bails out if not. The assumption that
all clocks have to be present is wrong, and commit 9de2b9286a6d ("ASoC:
mediatek: Check for error clk pointer") needs to be reverted.

Cc: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Cc: Mark Brown <broonie@kernel.org>
Cc: James Liao <jamesjj.liao@mediatek.com>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Reported-by: Frank Wunderlich <frank-w@public-files.de>
Reported-by: Daniel Golle <daniel@makrotopia.org>
Fixes: 9de2b9286a6d ("ASoC: mediatek: Check for error clk pointer")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v2: Updated subject and description, trying to match expected subsystem
    style.
    Replaced two Cc: tags with Reported-by: to give proper credit.

 drivers/soc/mediatek/mtk-scpsys.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/drivers/soc/mediatek/mtk-scpsys.c b/drivers/soc/mediatek/mtk-scpsys.c
index 670cc82d17dc..ca75b14931ec 100644
--- a/drivers/soc/mediatek/mtk-scpsys.c
+++ b/drivers/soc/mediatek/mtk-scpsys.c
@@ -411,17 +411,12 @@ static int scpsys_power_off(struct generic_pm_domain *genpd)
 	return ret;
 }
 
-static int init_clks(struct platform_device *pdev, struct clk **clk)
+static void init_clks(struct platform_device *pdev, struct clk **clk)
 {
 	int i;
 
-	for (i = CLK_NONE + 1; i < CLK_MAX; i++) {
+	for (i = CLK_NONE + 1; i < CLK_MAX; i++)
 		clk[i] = devm_clk_get(&pdev->dev, clk_names[i]);
-		if (IS_ERR(clk[i]))
-			return PTR_ERR(clk[i]);
-	}
-
-	return 0;
 }
 
 static struct scp *init_scp(struct platform_device *pdev,
@@ -431,7 +426,7 @@ static struct scp *init_scp(struct platform_device *pdev,
 {
 	struct genpd_onecell_data *pd_data;
 	struct resource *res;
-	int i, j, ret;
+	int i, j;
 	struct scp *scp;
 	struct clk *clk[CLK_MAX];
 
@@ -486,9 +481,7 @@ static struct scp *init_scp(struct platform_device *pdev,
 
 	pd_data->num_domains = num;
 
-	ret = init_clks(pdev, clk);
-	if (ret)
-		return ERR_PTR(ret);
+	init_clks(pdev, clk);
 
 	for (i = 0; i < num; i++) {
 		struct scp_domain *scpd = &scp->domains[i];
-- 
2.35.1

On Mon, 7 Feb 2022 08:09:23 -0800, Guenter Roeck wrote:
> This reverts commit 9de2b9286a6d ("ASoC: mediatek: Check for error clk
> pointer").
> 
> With this patch in the tree, Chromebooks running the affected hardware
> no longer boot. Bisect points to this patch, and reverting it fixes
> the problem.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-linus

Thanks!

[1/1] ASoC: Revert "ASoC: mediatek: Check for error clk pointer"
      commit: 946eb87114af37c9c13c618a7c1cdaca936905fa

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark