2015-12-17 09:29:22 +00:00
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From 72ab78d0e2048e9563179e530b315f0074b923c4 Mon Sep 17 00:00:00 2001
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2015-10-26 09:01:05 +00:00
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From: Phil Elwell <phil@raspberrypi.org>
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Date: Fri, 11 Sep 2015 09:14:01 +0100
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2015-12-17 09:29:22 +00:00
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Subject: [PATCH 178/222] BCM270X_DT: Use fixed-factor-clock for uart1
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2015-10-26 09:01:05 +00:00
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The BCM2835 mini-UART is almost 8250-compatible, but there is
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a factor-of-two difference in the clock divider for the baud rate.
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The standard 8250 driver can be used unmodified provided we lie to it
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about the clock frequency, pretending it is double the actual value.
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The mini-UART block shares the core clock, and the current firmware
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uses a DT-parameter to update the clock-frequency property. Although it
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works, this isn't ideal because it exposes the firmware to a driver
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problem.
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This patch uses the fixed-factor-clock module to create a clock that is
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always twice the frequency of the core clock. (N.B. These "fixed" clocks
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just describe an existing clock, rather than changing any hardware
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settings.)
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---
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arch/arm/boot/dts/bcm2708-rpi-b-plus.dts | 1 -
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arch/arm/boot/dts/bcm2708-rpi-b.dts | 1 -
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arch/arm/boot/dts/bcm2708-rpi-cm.dts | 1 -
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arch/arm/boot/dts/bcm2708_common.dtsi | 10 +++++++++-
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arch/arm/boot/dts/bcm2709-rpi-2-b.dts | 1 -
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5 files changed, 9 insertions(+), 5 deletions(-)
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--- a/arch/arm/boot/dts/bcm2708-rpi-b-plus.dts
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+++ b/arch/arm/boot/dts/bcm2708-rpi-b-plus.dts
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@@ -103,7 +103,6 @@
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__overrides__ {
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uart0 = <&uart0>,"status";
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uart0_clkrate = <&clk_uart0>,"clock-frequency:0";
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- uart1_clkrate = <&uart1>,"clock-frequency:0";
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i2s = <&i2s>,"status";
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spi = <&spi0>,"status";
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i2c0 = <&i2c0>,"status";
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--- a/arch/arm/boot/dts/bcm2708-rpi-b.dts
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+++ b/arch/arm/boot/dts/bcm2708-rpi-b.dts
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@@ -97,7 +97,6 @@
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__overrides__ {
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uart0 = <&uart0>,"status";
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uart0_clkrate = <&clk_uart0>,"clock-frequency:0";
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- uart1_clkrate = <&uart1>,"clock-frequency:0";
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i2s = <&i2s>,"status";
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spi = <&spi0>,"status";
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i2c0 = <&i2c0>,"status";
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--- a/arch/arm/boot/dts/bcm2708-rpi-cm.dts
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+++ b/arch/arm/boot/dts/bcm2708-rpi-cm.dts
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@@ -79,7 +79,6 @@
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__overrides__ {
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uart0 = <&uart0>,"status";
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uart0_clkrate = <&clk_uart0>,"clock-frequency:0";
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- uart1_clkrate = <&uart1>,"clock-frequency:0";
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i2s = <&i2s>,"status";
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spi = <&spi0>,"status";
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i2c0 = <&i2c0>,"status";
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--- a/arch/arm/boot/dts/bcm2708_common.dtsi
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+++ b/arch/arm/boot/dts/bcm2708_common.dtsi
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@@ -165,7 +165,7 @@
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compatible = "brcm,bcm2835-aux-uart", "ns16550";
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reg = <0x7e215040 0x40>;
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interrupts = <1 29>;
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- clock-frequency = <500000000>;
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+ clocks = <&clk_uart1>;
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reg-shift = <2>;
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no-loopback-test;
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status = "disabled";
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@@ -294,6 +294,14 @@
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clock-output-names = "pwm";
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clock-frequency = <100000000>;
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};
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+
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+ clk_uart1: clock@6 {
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+ compatible = "fixed-factor-clock";
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+ clocks = <&clk_core>;
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+ #clock-cells = <0>;
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+ clock-div = <1>;
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+ clock-mult = <2>;
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+ };
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};
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__overrides__ {
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--- a/arch/arm/boot/dts/bcm2709-rpi-2-b.dts
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+++ b/arch/arm/boot/dts/bcm2709-rpi-2-b.dts
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@@ -103,7 +103,6 @@
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__overrides__ {
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uart0 = <&uart0>,"status";
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uart0_clkrate = <&clk_uart0>,"clock-frequency:0";
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- uart1_clkrate = <&uart1>,"clock-frequency:0";
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i2s = <&i2s>,"status";
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spi = <&spi0>,"status";
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i2c0 = <&i2c0>,"status";
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