target/linux/brcm2708/patches-4.14/950-0277-overlays-Add-combine-option-to-i2c-overlays.patch

   1 From 1b02fe3ab446613cadcfac08d611b90becb02189 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Wed, 18 Apr 2018 17:04:23 +0100
   4 Subject: [PATCH 277/454] overlays: Add 'combine' option to i2c overlays
   5
   6 The i2c0-bcm2708 and i2c1-bcm2708 overlays allow the I2C pin usage to
   7 be changed. The names also suggest they revert to the old i2c_bcm2708
   8 driver, but they don't. The newer i2c_bcm2835 driver forces
   9 transactions to be combined where possible, but this breaks some
  10 devices.
  11
  12 Add an option to disable transaction combining, which is currently
  13 implemented by reverting to the old driver.
  14
  15 See: https://github.com/raspberrypi/firmware/issues/828
  16
  17 Signed-off-by: Phil Elwell <phil@raspberrypi.org>
  18 ---
  19  arch/arm/boot/dts/overlays/README                   | 12 ++++++++++--
  20  arch/arm/boot/dts/overlays/i2c0-bcm2708-overlay.dts |  8 ++++++++
  21  arch/arm/boot/dts/overlays/i2c1-bcm2708-overlay.dts |  9 +++++++++
  22  3 files changed, 27 insertions(+), 2 deletions(-)
  23
  24 --- a/arch/arm/boot/dts/overlays/README
  25 +++ b/arch/arm/boot/dts/overlays/README
  26 @@ -865,8 +865,9 @@ Params: addr                    Set the
  27
  28
  29  Name:   i2c0-bcm2708
  30 -Info:   Enable the i2c_bcm2708 driver for the i2c0 bus. Not all pin combinations
  31 -        are usable on all platforms.
  32 +Info:   Change i2c0 pin usage. Not all pin combinations are usable on all
  33 +        platforms - platforms other then Compute Modules can only use this
  34 +        to disable transaction combining.
  35  Load:   dtoverlay=i2c0-bcm2708,<param>=<val>
  36  Params: sda0_pin                GPIO pin for SDA0 (deprecated - use pins_*)
  37          scl0_pin                GPIO pin for SCL0 (deprecated - use pins_*)
  38 @@ -874,15 +875,22 @@ Params: sda0_pin                GPIO pin
  39          pins_28_29              Use pins 28 and 29
  40          pins_44_45              Use pins 44 and 45
  41          pins_46_47              Use pins 46 and 47
  42 +        combine                 Allow transactions to be combined (default
  43 +                                "yes")
  44
  45
  46  Name:   i2c1-bcm2708
  47 +Info:   Change i2c1 pin usage. Not all pin combinations are usable on all
  48 +        platforms - platforms other then Compute Modules can only use this
  49 +        to disable transaction combining.
  50  Info:   Enable the i2c_bcm2708 driver for the i2c1 bus
  51  Load:   dtoverlay=i2c1-bcm2708,<param>=<val>
  52  Params: sda1_pin                GPIO pin for SDA1 (2 or 44 - default 2)
  53          scl1_pin                GPIO pin for SCL1 (3 or 45 - default 3)
  54          pin_func                Alternative pin function (4 (alt0), 6 (alt2) -
  55                                  default 4)
  56 +        combine                 Allow transactions to be combined (default
  57 +                                "yes")
  58
  59
  60  Name:   i2s-gpio28-31
  61 --- a/arch/arm/boot/dts/overlays/i2c0-bcm2708-overlay.dts
  62 +++ b/arch/arm/boot/dts/overlays/i2c0-bcm2708-overlay.dts
  63 @@ -50,6 +50,13 @@
  64        };
  65     };
  66
  67 +   fragment@5 {
  68 +      target = <&i2c0>;
  69 +      __dormant__ {
  70 +         compatible = "brcm,bcm2708-i2c";
  71 +      };
  72 +   };
  73 +
  74     __overrides__ {
  75        sda0_pin = <&frag1>,"brcm,pins:0";
  76        scl0_pin = <&frag1>,"brcm,pins:4";
  77 @@ -57,5 +64,6 @@
  78        pins_28_29 = <0>,"-1+2-3-4";
  79        pins_44_45 = <0>,"-1-2+3-4";
  80        pins_46_47 = <0>,"-1-2-3+4";
  81 +      combine = <0>, "!5";
  82     };
  83  };
  84 --- a/arch/arm/boot/dts/overlays/i2c1-bcm2708-overlay.dts
  85 +++ b/arch/arm/boot/dts/overlays/i2c1-bcm2708-overlay.dts
  86 @@ -26,9 +26,18 @@
  87           brcm,function = <4>; /* alt 0 */
  88        };
  89     };
  90 +
  91 +   fragment@2 {
  92 +      target = <&i2c1>;
  93 +      __dormant__ {
  94 +         compatible = "brcm,bcm2708-i2c";
  95 +      };
  96 +   };
  97 +
  98     __overrides__ {
  99        sda1_pin = <&pins>,"brcm,pins:0";
 100        scl1_pin = <&pins>,"brcm,pins:4";
 101        pin_func = <&pins>,"brcm,function:0";
 102 +      combine = <0>, "!2";
 103     };
 104  };