FAILED: patch "[PATCH] regulator: stm32-vrefbuf: fix a possible overshoot when" failed to apply to 4.14-stable tree

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 02fbabd5f4ed182d2c616e49309f5a3efd9ec671 Mon Sep 17 00:00:00 2001
From: Fabrice Gasnier <[email protected]>
Date: Wed, 4 Mar 2020 09:55:32 +0100
Subject: [PATCH] regulator: stm32-vrefbuf: fix a possible overshoot when
re-enabling

There maybe an overshoot, when disabling, then re-enabling vrefbuf too quickly. VREFBUF is used by ADC/DAC on some boards. When re-enabling too quickly, an overshoot on the reference voltage make the conversions inaccurate for a short period of time.
- Don't put the VREFBUF in HiZ when disabling, to force an active discharge.
- Enforce a 1ms OFF/ON delay

Message-Id: <[email protected]>

index bdfaf7edb75a..992bc18101ef 100644
@@ -88,7 +88,7 @@ static int stm32_vrefbuf_disable(struct regulator_dev *rdev)
 	}
 
 	val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
-	val = (val & ~STM32_ENVR) | STM32_HIZ;
+	val &= ~STM32_ENVR;
 	writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
 
 	pm_runtime_mark_last_busy(priv->dev);

@@ -175,6 +175,7 @@ static const struct regulator_desc stm32_vrefbuf_regu = {
 	.volt_table = stm32_vrefbuf_voltages,
 	.n_voltages = ARRAY_SIZE(stm32_vrefbuf_voltages),
 	.ops = &stm32_vrefbuf_volt_ops,
+	.off_on_delay = 1000,
 	.type = REGULATOR_VOLTAGE,
 	.owner = THIS_MODULE,
 };