diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.1/0178-BCM270X_DT-Use-fixed-factor-clock-for-uart1.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.1/0178-BCM270X_DT-Use-fixed-factor-clock-for-uart1.patch | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.1/0178-BCM270X_DT-Use-fixed-factor-clock-for-uart1.patch b/target/linux/brcm2708/patches-4.1/0178-BCM270X_DT-Use-fixed-factor-clock-for-uart1.patch new file mode 100644 index 0000000..54afb54 --- /dev/null +++ b/target/linux/brcm2708/patches-4.1/0178-BCM270X_DT-Use-fixed-factor-clock-for-uart1.patch @@ -0,0 +1,92 @@ +From 502a751c5b49d0730f25280345d145e26f0b671d Mon Sep 17 00:00:00 2001 +From: Phil Elwell <phil@raspberrypi.org> +Date: Fri, 11 Sep 2015 09:14:01 +0100 +Subject: [PATCH 178/203] BCM270X_DT: Use fixed-factor-clock for uart1 + +The BCM2835 mini-UART is almost 8250-compatible, but there is +a factor-of-two difference in the clock divider for the baud rate. +The standard 8250 driver can be used unmodified provided we lie to it +about the clock frequency, pretending it is double the actual value. +The mini-UART block shares the core clock, and the current firmware +uses a DT-parameter to update the clock-frequency property. Although it +works, this isn't ideal because it exposes the firmware to a driver +problem. + +This patch uses the fixed-factor-clock module to create a clock that is +always twice the frequency of the core clock. (N.B. These "fixed" clocks +just describe an existing clock, rather than changing any hardware +settings.) +--- + arch/arm/boot/dts/bcm2708-rpi-b-plus.dts | 1 - + arch/arm/boot/dts/bcm2708-rpi-b.dts | 1 - + arch/arm/boot/dts/bcm2708-rpi-cm.dts | 1 - + arch/arm/boot/dts/bcm2708_common.dtsi | 10 +++++++++- + arch/arm/boot/dts/bcm2709-rpi-2-b.dts | 1 - + 5 files changed, 9 insertions(+), 5 deletions(-) + +--- a/arch/arm/boot/dts/bcm2708-rpi-b-plus.dts ++++ b/arch/arm/boot/dts/bcm2708-rpi-b-plus.dts +@@ -103,7 +103,6 @@ + __overrides__ { + uart0 = <&uart0>,"status"; + uart0_clkrate = <&clk_uart0>,"clock-frequency:0"; +- uart1_clkrate = <&uart1>,"clock-frequency:0"; + i2s = <&i2s>,"status"; + spi = <&spi0>,"status"; + i2c0 = <&i2c0>,"status"; +--- a/arch/arm/boot/dts/bcm2708-rpi-b.dts ++++ b/arch/arm/boot/dts/bcm2708-rpi-b.dts +@@ -97,7 +97,6 @@ + __overrides__ { + uart0 = <&uart0>,"status"; + uart0_clkrate = <&clk_uart0>,"clock-frequency:0"; +- uart1_clkrate = <&uart1>,"clock-frequency:0"; + i2s = <&i2s>,"status"; + spi = <&spi0>,"status"; + i2c0 = <&i2c0>,"status"; +--- a/arch/arm/boot/dts/bcm2708-rpi-cm.dts ++++ b/arch/arm/boot/dts/bcm2708-rpi-cm.dts +@@ -79,7 +79,6 @@ + __overrides__ { + uart0 = <&uart0>,"status"; + uart0_clkrate = <&clk_uart0>,"clock-frequency:0"; +- uart1_clkrate = <&uart1>,"clock-frequency:0"; + i2s = <&i2s>,"status"; + spi = <&spi0>,"status"; + i2c0 = <&i2c0>,"status"; +--- a/arch/arm/boot/dts/bcm2708_common.dtsi ++++ b/arch/arm/boot/dts/bcm2708_common.dtsi +@@ -165,7 +165,7 @@ + compatible = "brcm,bcm2835-aux-uart", "ns16550"; + reg = <0x7e215040 0x40>; + interrupts = <1 29>; +- clock-frequency = <500000000>; ++ clocks = <&clk_uart1>; + reg-shift = <2>; + no-loopback-test; + status = "disabled"; +@@ -294,6 +294,14 @@ + clock-output-names = "pwm"; + clock-frequency = <100000000>; + }; ++ ++ clk_uart1: clock@6 { ++ compatible = "fixed-factor-clock"; ++ clocks = <&clk_core>; ++ #clock-cells = <0>; ++ clock-div = <1>; ++ clock-mult = <2>; ++ }; + }; + + __overrides__ { +--- a/arch/arm/boot/dts/bcm2709-rpi-2-b.dts ++++ b/arch/arm/boot/dts/bcm2709-rpi-2-b.dts +@@ -103,7 +103,6 @@ + __overrides__ { + uart0 = <&uart0>,"status"; + uart0_clkrate = <&clk_uart0>,"clock-frequency:0"; +- uart1_clkrate = <&uart1>,"clock-frequency:0"; + i2s = <&i2s>,"status"; + spi = <&spi0>,"status"; + i2c0 = <&i2c0>,"status"; |