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 at 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 at 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 at 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>; > }; > };
