From: "Heiko Stübner" <heiko@sntech.de>
To: Julien CHAUVEAU <julien.chauveau@neo-technologies.fr>,
Max Schwarz <max.schwarz@online.de>,
Addy Ke <addy.ke@rock-chips.com>,
wsa@the-dreams.de
Cc: Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
Kumar Gala <galak@codeaurora.org>,
Russell King <linux@arm.linux.org.uk>,
"moderated list:ARM/Rockchip SoC..."
<linux-arm-kernel@lists.infradead.org>,
"open list:ARM/Rockchip SoC..."
<linux-rockchip@lists.infradead.org>,
"open list:OPEN FIRMWARE AND..." <devicetree@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] ARM: dts: rockchip: use internal pull-up resistors on I2C busses
Date: Wed, 29 Oct 2014 14:17:23 +0100 [thread overview]
Message-ID: <2234299.BSD6RSf1dG@diego> (raw)
In-Reply-To: <1414492597-13566-1-git-send-email-julien.chauveau@neo-technologies.fr>
Hi Addy, Max, Wolfram,
after Doug's explanation of disfavour [0] and Julien's subsequent response I'm
not sure which direction to go. So if possible I'd like to collect some more
opinions of people knowing a lot more about i2c internals than myself :-) .
Thanks
Heiko
[0] http://lists.infradead.org/pipermail/linux-rockchip/2014-October/000934.html
Am Dienstag, 28. Oktober 2014, 11:36:36 schrieb Julien CHAUVEAU:
> According to the I2C bus specification, it is required to use pull-up
> resistors on the clock and data lines. Probing the I2C busses with
> i2cdetect results in bad results when no devices are connected and no
> external resistors are used.
>
> This patch configures the I2C busses to use the internal pull-up resistors
> on the RK3066, RK3188 and RK3288 Rockchip processors. It should also be
> noted that these default pull settings match the original configuration on
> these SoCs.
>
> Below is the results of using i2cdetect on a I2C bus with no devices
> connected before (1) and after (2) applying this patch.
>
> (1) root@localhost:~# i2cdetect -y 3
> 0 1 2 3 4 5 6 7 8 9 a b c d e f
> 00: 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f
> 10: 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f
> 20: 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
> 30: -- -- -- -- -- rk3x-i2c 2005a000.i2c: timeout, ipd: 0x81, state: 2
> -- rk3x-i2c 2005a000.i2c: timeout, ipd: 0x80, state: 2
> -- rk3x-i2c 2005a000.i2c: timeout, ipd: 0x80, state: 2
> -- rk3x-i2c 2005a000.i2c: timeout, ipd: 0x80, state: 3
> -- rk3x-i2c 2005a000.i2c: timeout, ipd: 0x80, state: 3
> -- rk3x-i2c 2005a000.i2c: timeout, ipd: 0x80, state: 3
> ...
>
> (2) root@localhost:~# i2cdetect -y 3
> 0 1 2 3 4 5 6 7 8 9 a b c d e f
> 00: -- -- -- -- -- -- -- -- -- -- -- -- --
> 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
> 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
> 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
> 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
> 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
> 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
> 70: -- -- -- -- -- -- -- --
>
> Signed-off-by: Julien CHAUVEAU <julien.chauveau@neo-technologies.fr>
> ---
> Changes since v1:
> - fix the rk3066a pull settings (only available is pull_none/pull_default)
> - remove the warnings in the results of i2cdetect
>
> arch/arm/boot/dts/rk3066a.dtsi | 20 ++++++++++----------
> arch/arm/boot/dts/rk3188.dtsi | 20 ++++++++++----------
> arch/arm/boot/dts/rk3288.dtsi | 24 ++++++++++++------------
> 3 files changed, 32 insertions(+), 32 deletions(-)
>
> diff --git a/arch/arm/boot/dts/rk3066a.dtsi b/arch/arm/boot/dts/rk3066a.dtsi
> index ad9c2db..dbc1a0b 100644
> --- a/arch/arm/boot/dts/rk3066a.dtsi
> +++ b/arch/arm/boot/dts/rk3066a.dtsi
> @@ -202,36 +202,36 @@
>
> i2c0 {
> i2c0_xfer: i2c0-xfer {
> - rockchip,pins = <RK_GPIO2 28 RK_FUNC_1 &pcfg_pull_none>,
> - <RK_GPIO2 29 RK_FUNC_1 &pcfg_pull_none>;
> + rockchip,pins = <RK_GPIO2 28 RK_FUNC_1 &pcfg_pull_default>,
> + <RK_GPIO2 29 RK_FUNC_1 &pcfg_pull_default>;
> };
> };
>
> i2c1 {
> i2c1_xfer: i2c1-xfer {
> - rockchip,pins = <RK_GPIO2 30 RK_FUNC_1 &pcfg_pull_none>,
> - <RK_GPIO2 31 RK_FUNC_1 &pcfg_pull_none>;
> + rockchip,pins = <RK_GPIO2 30 RK_FUNC_1 &pcfg_pull_default>,
> + <RK_GPIO2 31 RK_FUNC_1 &pcfg_pull_default>;
> };
> };
>
> i2c2 {
> i2c2_xfer: i2c2-xfer {
> - rockchip,pins = <RK_GPIO3 0 RK_FUNC_1 &pcfg_pull_none>,
> - <RK_GPIO3 1 RK_FUNC_1 &pcfg_pull_none>;
> + rockchip,pins = <RK_GPIO3 0 RK_FUNC_1 &pcfg_pull_default>,
> + <RK_GPIO3 1 RK_FUNC_1 &pcfg_pull_default>;
> };
> };
>
> i2c3 {
> i2c3_xfer: i2c3-xfer {
> - rockchip,pins = <RK_GPIO3 2 RK_FUNC_2 &pcfg_pull_none>,
> - <RK_GPIO3 3 RK_FUNC_2 &pcfg_pull_none>;
> + rockchip,pins = <RK_GPIO3 2 RK_FUNC_2 &pcfg_pull_default>,
> + <RK_GPIO3 3 RK_FUNC_2 &pcfg_pull_default>;
> };
> };
>
> i2c4 {
> i2c4_xfer: i2c4-xfer {
> - rockchip,pins = <RK_GPIO3 4 RK_FUNC_1 &pcfg_pull_none>,
> - <RK_GPIO3 5 RK_FUNC_1 &pcfg_pull_none>;
> + rockchip,pins = <RK_GPIO3 4 RK_FUNC_1 &pcfg_pull_default>,
> + <RK_GPIO3 5 RK_FUNC_1 &pcfg_pull_default>;
> };
> };
>
> diff --git a/arch/arm/boot/dts/rk3188.dtsi b/arch/arm/boot/dts/rk3188.dtsi
> index ddaada7..ee2865f 100644
> --- a/arch/arm/boot/dts/rk3188.dtsi
> +++ b/arch/arm/boot/dts/rk3188.dtsi
> @@ -188,36 +188,36 @@
>
> i2c0 {
> i2c0_xfer: i2c0-xfer {
> - rockchip,pins = <RK_GPIO1 24 RK_FUNC_1 &pcfg_pull_none>,
> - <RK_GPIO1 25 RK_FUNC_1 &pcfg_pull_none>;
> + rockchip,pins = <RK_GPIO1 24 RK_FUNC_1 &pcfg_pull_up>,
> + <RK_GPIO1 25 RK_FUNC_1 &pcfg_pull_up>;
> };
> };
>
> i2c1 {
> i2c1_xfer: i2c1-xfer {
> - rockchip,pins = <RK_GPIO1 26 RK_FUNC_1 &pcfg_pull_none>,
> - <RK_GPIO1 27 RK_FUNC_1 &pcfg_pull_none>;
> + rockchip,pins = <RK_GPIO1 26 RK_FUNC_1 &pcfg_pull_up>,
> + <RK_GPIO1 27 RK_FUNC_1 &pcfg_pull_up>;
> };
> };
>
> i2c2 {
> i2c2_xfer: i2c2-xfer {
> - rockchip,pins = <RK_GPIO1 28 RK_FUNC_1 &pcfg_pull_none>,
> - <RK_GPIO1 29 RK_FUNC_1 &pcfg_pull_none>;
> + rockchip,pins = <RK_GPIO1 28 RK_FUNC_1 &pcfg_pull_up>,
> + <RK_GPIO1 29 RK_FUNC_1 &pcfg_pull_up>;
> };
> };
>
> i2c3 {
> i2c3_xfer: i2c3-xfer {
> - rockchip,pins = <RK_GPIO3 14 RK_FUNC_2 &pcfg_pull_none>,
> - <RK_GPIO3 15 RK_FUNC_2 &pcfg_pull_none>;
> + rockchip,pins = <RK_GPIO3 14 RK_FUNC_2 &pcfg_pull_up>,
> + <RK_GPIO3 15 RK_FUNC_2 &pcfg_pull_up>;
> };
> };
>
> i2c4 {
> i2c4_xfer: i2c4-xfer {
> - rockchip,pins = <RK_GPIO1 30 RK_FUNC_1 &pcfg_pull_none>,
> - <RK_GPIO1 31 RK_FUNC_1 &pcfg_pull_none>;
> + rockchip,pins = <RK_GPIO1 30 RK_FUNC_1 &pcfg_pull_up>,
> + <RK_GPIO1 31 RK_FUNC_1 &pcfg_pull_up>;
> };
> };
>
> diff --git a/arch/arm/boot/dts/rk3288.dtsi b/arch/arm/boot/dts/rk3288.dtsi
> index 874e66d..9a4b1f7 100644
> --- a/arch/arm/boot/dts/rk3288.dtsi
> +++ b/arch/arm/boot/dts/rk3288.dtsi
> @@ -636,43 +636,43 @@
>
> i2c0 {
> i2c0_xfer: i2c0-xfer {
> - rockchip,pins = <0 15 RK_FUNC_1 &pcfg_pull_none>,
> - <0 16 RK_FUNC_1 &pcfg_pull_none>;
> + rockchip,pins = <0 15 RK_FUNC_1 &pcfg_pull_up>,
> + <0 16 RK_FUNC_1 &pcfg_pull_up>;
> };
> };
>
> i2c1 {
> i2c1_xfer: i2c1-xfer {
> - rockchip,pins = <8 4 RK_FUNC_1 &pcfg_pull_none>,
> - <8 5 RK_FUNC_1 &pcfg_pull_none>;
> + rockchip,pins = <8 4 RK_FUNC_1 &pcfg_pull_up>,
> + <8 5 RK_FUNC_1 &pcfg_pull_up>;
> };
> };
>
> i2c2 {
> i2c2_xfer: i2c2-xfer {
> - rockchip,pins = <6 9 RK_FUNC_1 &pcfg_pull_none>,
> - <6 10 RK_FUNC_1 &pcfg_pull_none>;
> + rockchip,pins = <6 9 RK_FUNC_1 &pcfg_pull_up>,
> + <6 10 RK_FUNC_1 &pcfg_pull_up>;
> };
> };
>
> i2c3 {
> i2c3_xfer: i2c3-xfer {
> - rockchip,pins = <2 16 RK_FUNC_1 &pcfg_pull_none>,
> - <2 17 RK_FUNC_1 &pcfg_pull_none>;
> + rockchip,pins = <2 16 RK_FUNC_1 &pcfg_pull_up>,
> + <2 17 RK_FUNC_1 &pcfg_pull_up>;
> };
> };
>
> i2c4 {
> i2c4_xfer: i2c4-xfer {
> - rockchip,pins = <7 17 RK_FUNC_1 &pcfg_pull_none>,
> - <7 18 RK_FUNC_1 &pcfg_pull_none>;
> + rockchip,pins = <7 17 RK_FUNC_1 &pcfg_pull_up>,
> + <7 18 RK_FUNC_1 &pcfg_pull_up>;
> };
> };
>
> i2c5 {
> i2c5_xfer: i2c5-xfer {
> - rockchip,pins = <7 19 RK_FUNC_1 &pcfg_pull_none>,
> - <7 20 RK_FUNC_1 &pcfg_pull_none>;
> + rockchip,pins = <7 19 RK_FUNC_1 &pcfg_pull_up>,
> + <7 20 RK_FUNC_1 &pcfg_pull_up>;
> };
> };
next prev parent reply other threads:[~2014-10-29 13:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-28 10:36 [PATCH v2] ARM: dts: rockchip: use internal pull-up resistors on I2C busses Julien CHAUVEAU
[not found] ` <1414492597-13566-1-git-send-email-julien.chauveau-MwaZihP3oV2HdZQakrT3ElaPQRlvutdw@public.gmane.org>
2014-10-29 4:45 ` Doug Anderson
2014-10-29 9:50 ` NEO-Technologies / Julien CHAUVEAU
2014-10-29 13:17 ` Heiko Stübner [this message]
2014-10-29 13:44 ` Karl Palsson
2014-10-29 14:02 ` Max Schwarz
2014-10-29 14:34 ` NEO-Technologies / Julien CHAUVEAU
2014-10-29 15:05 ` Karl Palsson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=2234299.BSD6RSf1dG@diego \
--to=heiko@sntech.de \
--cc=addy.ke@rock-chips.com \
--cc=devicetree@vger.kernel.org \
--cc=galak@codeaurora.org \
--cc=ijc+devicetree@hellion.org.uk \
--cc=julien.chauveau@neo-technologies.fr \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rockchip@lists.infradead.org \
--cc=linux@arm.linux.org.uk \
--cc=mark.rutland@arm.com \
--cc=max.schwarz@online.de \
--cc=pawel.moll@arm.com \
--cc=robh+dt@kernel.org \
--cc=wsa@the-dreams.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).