[PATCH linux 2/2] arm: aspeed: zaius: Disable pulldown resistors on 1-wire IOs

[Xo Wang]

Disable internal pulldown resistors on pins used by the 1-wire interface
to thermal sensors.

Signed-off-by: Xo Wang <xow at google.com>
---
 arch/arm/mach-aspeed/aspeed.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/mach-aspeed/aspeed.c b/arch/arm/mach-aspeed/aspeed.c
index e4150c8a5d8d..4bd3680d742d 100644
--- a/arch/arm/mach-aspeed/aspeed.c
+++ b/arch/arm/mach-aspeed/aspeed.c
@@ -152,6 +152,10 @@ static void __init do_zaius_setup(void)
 		writel(reg | BIT(24) | BIT(22), AST_IO(AST_BASE_SCU | 0x8C));
 	}
 
+	/* Disable GPIO H/AC pulldowns to float 1-wire interface pins */
+	reg = readl(AST_IO(AST_BASE_SCU | 0x8C));
+	writel(reg | BIT(23), AST_IO(AST_BASE_SCU | 0x8C));
+
 	/* Assert MAC2 PHY hardware reset */
 	/* Set pin low */
 	reg = readl(AST_IO(AST_BASE_GPIO | 0x00));
-- 
2.11.0.390.gc69c2f50cf-goog