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From: Lucas Stach <l.stach@pengutronix.de>
To: barebox@lists.infradead.org
Subject: [PATCH] ARM: i.MX8MP-EVK: increase VDD_ARM to OD voltage
Date: Mon,  6 Feb 2023 21:59:28 +0100	[thread overview]
Message-ID: <20230206205928.627270-1-l.stach@pengutronix.de> (raw)

The Linux kernel or whatever is started from Barebox might switch the
ARM frequency to OD level, without first reprogramming the PMIC as
required. This might lead to system instability. To avoid this,
increase VDD_ARM to OD level. When the kernel handles the PMIC properly
it will drop the voltage back to ND level when appropriate.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
---
 arch/arm/boards/nxp-imx8mp-evk/lowlevel.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm/boards/nxp-imx8mp-evk/lowlevel.c b/arch/arm/boards/nxp-imx8mp-evk/lowlevel.c
index 3cb24df1ca3f..d6fc32e65b61 100644
--- a/arch/arm/boards/nxp-imx8mp-evk/lowlevel.c
+++ b/arch/arm/boards/nxp-imx8mp-evk/lowlevel.c
@@ -61,6 +61,12 @@ static struct pmic_config pca9450_cfg[] = {
 	{ PCA9450_BUCK1OUT_DVS0, 0x1C },
 	{ PCA9450_BUCK1OUT_DVS1, 0x14 },
 	{ PCA9450_BUCK1CTRL, 0x59 },
+	/*
+	 * Increase VDD_ARM to 0.95V to avoid issues in case software after
+	 * Barebox switches to the OD ARM frequency without reprogramming the
+	 * PMIC first.
+	 */
+	{ PCA9450_BUCK2OUT_DVS0, 0x1C },
 	/* set WDOG_B_CFG to cold reset */
 	{ PCA9450_RESET_CTRL, 0xA1 },
 };
-- 
2.39.1




             reply	other threads:[~2023-02-06 21:02 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-06 20:59 Lucas Stach [this message]
2023-02-07  9:54 ` Ahmad Fatoum
2023-02-07 19:57   ` Lucas Stach
2023-02-08  7:55 ` Sascha Hauer

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