From: Olliver Schinagl <oliver@schinagl.nl>
Date: Wed, 21 Nov 2018 18:05:26 +0000 (+0200)
Subject: sunxi: pmic_bus: Decrease boot time by not writing duplicate data
X-Git-Tag: v2019.01-rc2~23^2~8
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=c970e8954f084b543d241fd96c0377988d8d4971;p=oweals%2Fu-boot.git

sunxi: pmic_bus: Decrease boot time by not writing duplicate data

When we clear a pmic_bus bit, we do a read-modify-write operation.
We waste some time however, by writing back the exact samea value
that was already set in the chip. Let us thus only do the write
in case data was changed.

Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>
Signed-off-by: Priit Laes <plaes@plaes.org>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
---

diff --git a/arch/arm/mach-sunxi/pmic_bus.c b/arch/arm/mach-sunxi/pmic_bus.c
index 5d91d7e2c1..dea42de833 100644
--- a/arch/arm/mach-sunxi/pmic_bus.c
+++ b/arch/arm/mach-sunxi/pmic_bus.c
@@ -101,6 +101,9 @@ int pmic_bus_setbits(u8 reg, u8 bits)
 	if (ret)
 		return ret;
 
+	if ((val & bits) == bits)
+		return 0;
+
 	val |= bits;
 	return pmic_bus_write(reg, val);
 }
@@ -114,6 +117,9 @@ int pmic_bus_clrbits(u8 reg, u8 bits)
 	if (ret)
 		return ret;
 
+	if (!(val & bits))
+		return 0;
+
 	val &= ~bits;
 	return pmic_bus_write(reg, val);
 }