target/linux/brcm2708/patches-4.1/0178-BCM270X_DT-Use-fixed-factor-clock-for-uart1.patch

   1 From 72ab78d0e2048e9563179e530b315f0074b923c4 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Fri, 11 Sep 2015 09:14:01 +0100
   4 Subject: [PATCH 178/222] BCM270X_DT: Use fixed-factor-clock for uart1
   5
   6 The BCM2835 mini-UART is almost 8250-compatible, but there is
   7 a factor-of-two difference in the clock divider for the baud rate.
   8 The standard 8250 driver can be used unmodified provided we lie to it
   9 about the clock frequency, pretending it is double the actual value.
  10 The mini-UART block shares the core clock, and the current firmware
  11 uses a DT-parameter to update the clock-frequency property. Although it
  12 works, this isn't ideal because it exposes the firmware to a driver
  13 problem.
  14
  15 This patch uses the fixed-factor-clock module to create a clock that is
  16 always twice the frequency of the core clock. (N.B. These "fixed" clocks
  17 just describe an existing clock, rather than changing any hardware
  18 settings.)
  19 ---
  20  arch/arm/boot/dts/bcm2708-rpi-b-plus.dts |  1 -
  21  arch/arm/boot/dts/bcm2708-rpi-b.dts      |  1 -
  22  arch/arm/boot/dts/bcm2708-rpi-cm.dts     |  1 -
  23  arch/arm/boot/dts/bcm2708_common.dtsi    | 10 +++++++++-
  24  arch/arm/boot/dts/bcm2709-rpi-2-b.dts    |  1 -
  25  5 files changed, 9 insertions(+), 5 deletions(-)
  26
  27 --- a/arch/arm/boot/dts/bcm2708-rpi-b-plus.dts
  28 +++ b/arch/arm/boot/dts/bcm2708-rpi-b-plus.dts
  29 @@ -103,7 +103,6 @@
  30         __overrides__ {
  31                 uart0 = <&uart0>,"status";
  32                 uart0_clkrate = <&clk_uart0>,"clock-frequency:0";
  33 -               uart1_clkrate = <&uart1>,"clock-frequency:0";
  34                 i2s = <&i2s>,"status";
  35                 spi = <&spi0>,"status";
  36                 i2c0 = <&i2c0>,"status";
  37 --- a/arch/arm/boot/dts/bcm2708-rpi-b.dts
  38 +++ b/arch/arm/boot/dts/bcm2708-rpi-b.dts
  39 @@ -97,7 +97,6 @@
  40         __overrides__ {
  41                 uart0 = <&uart0>,"status";
  42                 uart0_clkrate = <&clk_uart0>,"clock-frequency:0";
  43 -               uart1_clkrate = <&uart1>,"clock-frequency:0";
  44                 i2s = <&i2s>,"status";
  45                 spi = <&spi0>,"status";
  46                 i2c0 = <&i2c0>,"status";
  47 --- a/arch/arm/boot/dts/bcm2708-rpi-cm.dts
  48 +++ b/arch/arm/boot/dts/bcm2708-rpi-cm.dts
  49 @@ -79,7 +79,6 @@
  50         __overrides__ {
  51                 uart0 = <&uart0>,"status";
  52                 uart0_clkrate = <&clk_uart0>,"clock-frequency:0";
  53 -               uart1_clkrate = <&uart1>,"clock-frequency:0";
  54                 i2s = <&i2s>,"status";
  55                 spi = <&spi0>,"status";
  56                 i2c0 = <&i2c0>,"status";
  57 --- a/arch/arm/boot/dts/bcm2708_common.dtsi
  58 +++ b/arch/arm/boot/dts/bcm2708_common.dtsi
  59 @@ -165,7 +165,7 @@
  60                         compatible = "brcm,bcm2835-aux-uart", "ns16550";
  61                         reg = <0x7e215040 0x40>;
  62                         interrupts = <1 29>;
  63 -                       clock-frequency = <500000000>;
  64 +                       clocks = <&clk_uart1>;
  65                         reg-shift = <2>;
  66                         no-loopback-test;
  67                         status = "disabled";
  68 @@ -294,6 +294,14 @@
  69                          clock-output-names = "pwm";
  70                          clock-frequency = <100000000>;
  71                 };
  72 +
  73 +               clk_uart1: clock@6 {
  74 +                       compatible = "fixed-factor-clock";
  75 +                       clocks = <&clk_core>;
  76 +                       #clock-cells = <0>;
  77 +                       clock-div = <1>;
  78 +                       clock-mult = <2>;
  79 +               };
  80         };
  81
  82         __overrides__ {
  83 --- a/arch/arm/boot/dts/bcm2709-rpi-2-b.dts
  84 +++ b/arch/arm/boot/dts/bcm2709-rpi-2-b.dts
  85 @@ -103,7 +103,6 @@
  86         __overrides__ {
  87                 uart0 = <&uart0>,"status";
  88                 uart0_clkrate = <&clk_uart0>,"clock-frequency:0";
  89 -               uart1_clkrate = <&uart1>,"clock-frequency:0";
  90                 i2s = <&i2s>,"status";
  91                 spi = <&spi0>,"status";
  92                 i2c0 = <&i2c0>,"status";