linux-kernel - [PATCH] cpufreq: mediatek: Handle sram regulator probe deferral

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Message-Id: <20220713111536.115097-1-angelogioacchino.delregno@collabora.com>
Date:   Wed, 13 Jul 2022 13:15:36 +0200
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     rafael@...nel.org
Cc:     viresh.kumar@...aro.org, lgirdwood@...il.com, broonie@...nel.org,
        matthias.bgg@...il.com, angelogioacchino.delregno@...labora.com,
        rex-bc.chen@...iatek.com, jia-wei.chang@...iatek.com,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org
Subject: [PATCH] cpufreq: mediatek: 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: ffa7bdf7f344 ("cpufreq: mediatek: Make sram regulator optional")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
---
 drivers/cpufreq/mediatek-cpufreq.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
index 3a2be4552020..7f2680bc9a0f 100644
--- a/drivers/cpufreq/mediatek-cpufreq.c
+++ b/drivers/cpufreq/mediatek-cpufreq.c
@@ -439,9 +439,13 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
 
 	/* Both presence and absence of sram regulator are valid cases. */
 	info->sram_reg = regulator_get_optional(cpu_dev, "sram");
-	if (IS_ERR(info->sram_reg))
+	if (IS_ERR(info->sram_reg)) {
+		ret = PTR_ERR(info->sram_reg);
+		if (ret == -EPROBE_DEFER)
+			goto out_free_resources;
+
 		info->sram_reg = NULL;
-	else {
+	} else {
 		ret = regulator_enable(info->sram_reg);
 		if (ret) {
 			dev_warn(cpu_dev, "cpu%d: failed to enable vsram\n", cpu);
-- 
2.35.1