linux-kernel - [PATCH] PM / devfreq: mtk-cci: Handle sram regulator probe deferral

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Date:   Wed, 13 Jul 2022 13:15:11 +0200
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     myungjoo.ham@...sung.com
Cc:     kyungmin.park@...sung.com, cw00.choi@...sung.com,
        matthias.bgg@...il.com, lgirdwood@...il.com, broonie@...nel.org,
        jia-wei.chang@...iatek.com, johnson.wang@...iatek.com,
        linux-pm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
Subject: [PATCH] PM / devfreq: mtk-cci: Handle sram regulator probe deferral

If the regulator_get_optional()	call for the SRAM regulator returns
a probe deferral, we must bail out and retry probing later: failing
to do this will	produce	unstabilities on platforms requiring the
handling for this regulator.

Fixes: b615b00c42da ("PM / devfreq: mediatek: Introduce MediaTek CCI devfreq driver")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
---
 drivers/devfreq/mtk-cci-devfreq.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/devfreq/mtk-cci-devfreq.c b/drivers/devfreq/mtk-cci-devfreq.c
index 71abb3fbd042..e5458ada5197 100644
--- a/drivers/devfreq/mtk-cci-devfreq.c
+++ b/drivers/devfreq/mtk-cci-devfreq.c
@@ -291,9 +291,13 @@ static int mtk_ccifreq_probe(struct platform_device *pdev)
 	}
 
 	drv->sram_reg = devm_regulator_get_optional(dev, "sram");
-	if (IS_ERR(drv->sram_reg))
+	if (IS_ERR(drv->sram_reg)) {
+		ret = PTR_ERR(drv->sram_reg);
+		if (ret == -EPROBE_DEFER)
+			goto out_free_resources;
+
 		drv->sram_reg = NULL;
-	else {
+	} else {
 		ret = regulator_enable(drv->sram_reg);
 		if (ret) {
 			dev_err(dev, "failed to enable sram regulator\n");
-- 
2.35.1