diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0138-BCM270X_DT-Add-sdio_overclock-parameter-to-sdio-over.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.4/0138-BCM270X_DT-Add-sdio_overclock-parameter-to-sdio-over.patch | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0138-BCM270X_DT-Add-sdio_overclock-parameter-to-sdio-over.patch b/target/linux/brcm2708/patches-4.4/0138-BCM270X_DT-Add-sdio_overclock-parameter-to-sdio-over.patch new file mode 100644 index 0000000000..9d0e83a31c --- /dev/null +++ b/target/linux/brcm2708/patches-4.4/0138-BCM270X_DT-Add-sdio_overclock-parameter-to-sdio-over.patch @@ -0,0 +1,69 @@ +From 94dab6838e9ba91d6da49d864b0f408a89f08ce5 Mon Sep 17 00:00:00 2001 +From: Phil Elwell <phil@raspberrypi.org> +Date: Mon, 25 Jan 2016 09:12:06 +0000 +Subject: [PATCH 138/156] BCM270X_DT: Add sdio_overclock parameter to sdio + overlay + +The sdio_overclock parameter is like the overclock_50 parameter, i.e. +it sets an alternate frequency (in MHz) to use when the MMC framework +requests 50MHz, except that it applies to the SDIO bus. + +Be aware that the actual frequencies achievable are limited to even integer +divisions of 250MHz, and that the driver will round up to include fractions +(e.g. 62 will include 62.5) but then round down to the nearest frequency. +In other words, the chosen frequency is the highest possible that is less than +the parameter value + 1. In practise this means that 62 is the only sensible +value. + +Examples: + 250MHz/4 = 62.5MHz (sdio_overclock=62) + 250MHz/2 = 125MHz (sdio_overclock=125) # Too fast +--- + arch/arm/boot/dts/overlays/README | 9 ++++++--- + arch/arm/boot/dts/overlays/sdio-overlay.dts | 2 ++ + 2 files changed, 8 insertions(+), 3 deletions(-) + +--- a/arch/arm/boot/dts/overlays/README ++++ b/arch/arm/boot/dts/overlays/README +@@ -53,8 +53,8 @@ have its contents deleted (or commented + Using Overlays + ============== + +-Overlays are loaded using the "dtoverlay" directive. As an example, consider the +-popular lirc-rpi module, the Linux Infrared Remote Control driver. In the ++Overlays are loaded using the "dtoverlay" directive. As an example, consider ++the popular lirc-rpi module, the Linux Infrared Remote Control driver. In the + pre-DT world this would be loaded from /etc/modules, with an explicit + "modprobe lirc-rpi" command, or programmatically by lircd. With DT enabled, + this becomes a line in config.txt: +@@ -621,9 +621,12 @@ Name: sdio + Info: Selects the bcm2835-sdhost SD/MMC driver, optionally with overclock, + and enables SDIO via GPIOs 22-27. + Load: dtoverlay=sdio,<param>=<val> +-Params: overclock_50 Clock (in MHz) to use when the MMC framework ++Params: overclock_50 SD Clock (in MHz) to use when the MMC framework + requests 50MHz + ++ sdio_overclock SDIO Clock (in MHz) to use when the MMC ++ framework requests 50MHz ++ + force_pio Disable DMA support (default off) + + pio_limit Number of blocks above which to use DMA +--- a/arch/arm/boot/dts/overlays/sdio-overlay.dts ++++ b/arch/arm/boot/dts/overlays/sdio-overlay.dts +@@ -12,6 +12,7 @@ + pinctrl-0 = <&sdio_pins>; + non-removable; + bus-width = <4>; ++ brcm,overclock-50 = <0>; + status = "okay"; + }; + }; +@@ -30,5 +31,6 @@ + __overrides__ { + poll_once = <&sdio_mmc>,"non-removable?"; + bus_width = <&sdio_mmc>,"bus-width:0"; ++ sdio_overclock = <&sdio_mmc>,"brcm,overclock-50:0"; + }; + }; |