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by swahren
Sat Sep 15, 2018 1:57 pm
Forum: Linux Kernel
Topic: Vanilla 4.14.67 and Raspberry Pi Kernel 4.14.67
Replies: 2
Views: 193

Re: Vanilla 4.14.67 and Raspberry Pi Kernel 4.14.67

What are the differences between Vanilla Kernel 4.14.67 and current Raspberry Pi Kernel 4.14.67 ? Is there a list ? There is no complete list, because developers are lazy and don't waste their time with such documentation :D But can look at this to get an idea of the differences. Btw it doesn't mak...
by swahren
Thu May 17, 2018 4:16 pm
Forum: Device Tree
Topic: Review: eMMC part on CM1
Replies: 11
Views: 807

Re: Review: eMMC part on CM1

This statement has nothing to do with changeable voltages.

Regarding to my understanding:
Raspberry Pi 3 B SD IO voltage: fixed 3.3V
Raspberry Pi CM1 MMC IO voltage: fixed 1.8V

Per default MMC core assumes a IO voltage of 3.3V. My devicetree source provides the correct, fixed IO voltage.
by swahren
Thu May 17, 2018 2:10 pm
Forum: Device Tree
Topic: Review: eMMC part on CM1
Replies: 11
Views: 807

Re: Review: eMMC part on CM1

I never said it's changeable. There are example boards like sun7i-a20-olinuxino-lime2-emmc.dts which uses a fixed regulator as vqmmc-supply.
by swahren
Thu May 17, 2018 1:47 pm
Forum: Device Tree
Topic: Review: eMMC part on CM1
Replies: 11
Views: 807

Re: Review: eMMC part on CM1

Without providing a fixed regulator the MMC core doesn't have any chance to know the IO line power and assume 3.3 V. This is correct for most of the Raspberry Pis except the Compute Modules.
by swahren
Thu May 17, 2018 1:31 pm
Forum: Device Tree
Topic: Review: eMMC part on CM1
Replies: 11
Views: 807

Re: Review: eMMC part on CM1

As a software guy i'm not really familiar with reading schematics. But the regulators do match?
by swahren
Thu May 17, 2018 1:09 pm
Forum: Device Tree
Topic: Review: eMMC part on CM1
Replies: 11
Views: 807

Re: Review: eMMC part on CM1

What is your intention with the EMMC pwrseq support? * The simple eMMC hardware reset provider The purpose of this driver is to perform standard eMMC hw reset procedure, as described by Jedec 4.4 specification. This procedure is performed just after MMC core enabled power to the given mmc host (to ...
by swahren
Thu May 17, 2018 12:41 pm
Forum: Device Tree
Topic: Review: eMMC part on CM1
Replies: 11
Views: 807

Review: eMMC part on CM1

Hi, i'm working on the DTS for Compute Module 1 + IO board for Linux Mainline. Based on the datasheet and the schematics i created the following source and i would appreciate a review: // SPDX-License-Identifier: GPL-2.0 /dts-v1/; #include "bcm2835.dtsi" #include "bcm2835-rpi.dtsi" / { emmc_pwrseq: ...
by swahren
Sun Apr 29, 2018 9:38 am
Forum: Linux Kernel
Topic: Interrupt differences between 32-bit and 64-bit kernels
Replies: 2
Views: 637

Re: Interrupt differences between 32-bit and 64-bit kernels

As you noticed the smp_affinity isn't implemented yet. The difference in the behaviour comes from this patch:

https://github.com/raspberrypi/linux/co ... a99570d782
by swahren
Sun Apr 29, 2018 9:22 am
Forum: Device Tree
Topic: Device Tree Overlays Using New libgpiod API?
Replies: 3
Views: 1191

Re: Device Tree Overlays Using New libgpiod API?

The new GPIO device is intended for userspace not devicetree. I'm not sure what you are trying to achieve, but this could be helpful links: gpio-line-name definition in upstream RPI 1 B: https://github.com/raspberrypi/linux/blob/rpi-4.14.y/arch/arm/boot/dts/bcm2835-rpi-b.dts#L29 GPIO binding documen...
by swahren
Sat Feb 03, 2018 9:40 am
Forum: Linux Kernel
Topic: kernel from kernel.org for raspberry pi 3
Replies: 3
Views: 1558

Re: kernel from kernel.org for raspberry pi 3

I dislike the elinux upstream guide because it's more confusing and complicated (U-Boot is not necessary). I suggest to use a default raspbian stretch lite, add the upstream DT blob and replace the kernel7.img with your build zImage. In order to use the upstream DT blob you will need to modify the c...
by swahren
Wed Dec 27, 2017 1:41 pm
Forum: Linux Kernel
Topic: Optimize Arasan SDHCI driver
Replies: 0
Views: 620

Optimize Arasan SDHCI driver

Hi,
i currently try to optimize the Arasan SDHCI driver in Linux Mainline especially for the CM1/CM3.

According the BCM2835 datasheet the SDHCI controller should support eMMC double data rate (DDR). Is this correct?

Are there any information about enabling DDR mode?
by swahren
Tue Nov 14, 2017 8:26 pm
Forum: Linux Kernel
Topic: Differences between a Generic Linux Kernel and a Raspberry Kernel
Replies: 8
Views: 2440

Re: Differences between a Generic Linux Kernel and a Raspberry Kernel

Hmm, someone tried to get the bcm2835-sdhost driver into the mainline kernel but the main issue is that the existing driver is quite out of date. There are multiple MMC drivers, which could be very confusing. Which driver is quite out of date (sdhci-bcm2835 or bcm2835 aka sdhost)? sdhci-bcm2835 has...
by swahren
Mon Nov 13, 2017 8:20 pm
Forum: Linux Kernel
Topic: Differences between a Generic Linux Kernel and a Raspberry Kernel
Replies: 8
Views: 2440

Re: Differences between a Generic Linux Kernel and a Raspberry Kernel

This should work, maybe you need to specify the upstream device tree blob in the config.txt.
by swahren
Sat Nov 11, 2017 4:42 pm
Forum: Linux Kernel
Topic: Wifi driver croaks
Replies: 1
Views: 1445

Re: Wifi driver croaks

Hi Ollittm,
does your problem persists?

I'm unable to reproduce this issue with a Raspberry Pi Zero W and mainline 4.14-rc7.

Please provide more information:
Do you use wpa_supplicant?
How do you trigger the network change?
Could you try rpi-4.14?
by swahren
Sat Nov 11, 2017 2:19 pm
Forum: Linux Kernel
Topic: Differences between a Generic Linux Kernel and a Raspberry Kernel
Replies: 8
Views: 2440

Re: Differences between a Generic Linux Kernel and a Raspberry Kernel

Hello everyone. Could you guys tell me what the differences between the generic linux kernel which can be dowloaded from kernel.org and the official raspberry kernel? In short: Raspberry Kernel = Official kernel + several improvements It's possible to use a Raspberry Pi with the generic Linux kerne...
by swahren
Sun Aug 20, 2017 8:48 pm
Forum: Troubleshooting
Topic: Wifi authentication on hostapd fails after a while (EW-7612UA)
Replies: 0
Views: 646

Wifi authentication on hostapd fails after a while (EW-7612UA)

I've setup my old RPI 1 B as a Wifi AP with an EDIMAX EW-7612UA USB dongle. Btw this uses the out of tree 8129cu kernel module from Realtek. After finding out that most of the AP setup guides are outdated and misleading. Finally i got it working. This was my hostapd.conf: interface=wlan0 ssid=.........
by swahren
Thu Jul 06, 2017 5:48 am
Forum: Linux Kernel
Topic: Looking for RPi kernel developers and testers
Replies: 0
Views: 1092

Looking for RPi kernel developers and testers

Hi folks, i'm co-maintainer for the BCM2835 ARM architecture. I take care of upstreaming as much as possible changes for the Raspberry Pi. I'm very happy that the foundation guys now sent there changes to linux-rpi-kernel , but i also want to invent other developers and testers. As an inspiration he...
by swahren
Mon Oct 24, 2016 6:06 pm
Forum: Bare metal, Assembly language
Topic: Question about GPPUDCLKn
Replies: 7
Views: 1658

Re: Question about GPPUDCLKn

Thanks for the explanation. Beside of the timing it would be good to know which of the following clocks is the parent clock of PUDCLKn: clock enable_cnt prepare_cnt rate accuracy phase ---------------------------------------------------------------------------------------- uart1_pclk 0 0 125000000 0...
by swahren
Sat Oct 22, 2016 8:06 am
Forum: Bare metal, Assembly language
Topic: Question about GPPUDCLKn
Replies: 7
Views: 1658

Re: Question about GPPUDCLKn

Hi jdb, i must confess that the question originate from the Linux pinctrl driver. The current implementation for pull up/down configuration assumes a clock of 1 MHz. This results in a delay of 300 us per pin configuration. Since i don't have a working bare metal setup, i have another idea to validat...
by swahren
Thu Oct 20, 2016 4:50 pm
Forum: Bare metal, Assembly language
Topic: Question about GPPUDCLKn
Replies: 7
Views: 1658

Question about GPPUDCLKn

According to p. 105 of the datasheet BCM2835-ARM-Peripherals.pdf there must be a wait of 150 cycles between writing to GPPUD and GPPUDCLKn in order to change pull up / down. But it doesn't explain which clock. So is it correct that the wait cycles referes to the corresponding GPIO clock (CM_GP0CTL f...
by swahren
Wed Sep 21, 2016 5:47 pm
Forum: Bare metal, Assembly language
Topic: Questions about TS_TSENSCTL [Solved]
Replies: 4
Views: 935

Re: Questions about TS_TSENSCTL

Hi jdb,
these are very helpful information. Thank you very much.

If these kind of register description would be available for the other registers then kernel driver development for the bcm2835 would be more fun. Is there any policy about providing those information?

Regards
Stefan
by swahren
Mon Sep 19, 2016 7:48 pm
Forum: Bare metal, Assembly language
Topic: Questions about TS_TSENSCTL [Solved]
Replies: 4
Views: 935

Questions about TS_TSENSCTL [Solved]

Currently i'm reviewing the mainline thermal driver for Linux. Now i've some questions about the TS_TSENSCTL (thermal sensor control) register, because we want to add some helpful comment to the driver: What's the time unit of TS_TSENSCTL_RSTDELAY? What's the meaning of the mask TS_TSENSCTL_CTRL? Wh...

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