| Message ID | 1413556830-27854-1-git-send-email-julien.chauveau@neo-technologies.fr (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 2014/10/17 22:40, Julien CHAUVEAU wrote: > 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. > I think external resistors is necessary. on the RK3066, RK3188 and RK3288, Internal pull-up is weak. So we usually use external pull-up in hardware design, and pull-up/pull-down is disabled by software. We have found the bug that hdmi got error edid on rk3288 if internal pull-up was enabled. > 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 3 > > WARNING! This program can confuse your I2C bus, cause data loss and worse! > I will probe file /dev/i2c-3. > I will probe address range 0x03-0x77. > Continue? [Y/n] > 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 > -- rk3x-i2c 2005a000.i2c: timeout, ipd: 0x80, state: 3 > ... > > (2) root@localhost:~# i2cdetect 3 > > WARNING! This program can confuse your I2C bus, cause data loss and worse! > I will probe file /dev/i2c-3. > I will probe address range 0x03-0x77. > Continue? [Y/n] > 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> > --- > 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..c5cdf55 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_up>, > + <RK_GPIO2 29 RK_FUNC_1 &pcfg_pull_up>; > }; > }; > > 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_up>, > + <RK_GPIO2 31 RK_FUNC_1 &pcfg_pull_up>; > }; > }; > > 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_up>, > + <RK_GPIO3 1 RK_FUNC_1 &pcfg_pull_up>; > }; > }; > > 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_up>, > + <RK_GPIO3 3 RK_FUNC_2 &pcfg_pull_up>; > }; > }; > > 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_up>, > + <RK_GPIO3 5 RK_FUNC_1 &pcfg_pull_up>; > }; > }; > > 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>; > }; > }; > >
On 2014/10/19 23:06, Addy Ke wrote: > On 2014/10/17 22:40, Julien CHAUVEAU wrote: > >/ 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. > />/ > /I think external resistors is necessary. > > on the RK3066, RK3188 and RK3288, Internal pull-up is weak. > So we usually use external pull-up in hardware design, and pull-up/pull-down is > disabled by software. > > We have found the bug that hdmi got error edid on rk3288 if internal pull-up was enabled. Hi Addy, Thanks for reporting, but can you be more precise on what you did. Have you found a bug by applying my patch or by using a different hardware configuration? I haven't said that we should remove the external resistors on the I2C lines. In fact, it is normal to have communication issues at fast speed when using only internal pull-up resistors. I just say that it should be harmless to activate the internal pull-up resistors, and furthermore, it can help to fix some bugs when using i2cdetect. In the TRM, the DC characteristics give these typical values for the pull-up resistors @3.3V: - 60 Kilo-ohms for the RK3066 - 58 Kilo-ohms for the RK3188 and RK3288. The reference hardware designs use 2K or 1.5K pull-up resistors on the I2C lines and HDMI DDC lines. Using both internal and external pull-up resistors (being in parallel) would result in equivalent resistors of: - 1 / (1 / 60 + 1 / 2) = 1.93K, instead of 2K - 1 / (1 / 60 + 1 / 1.5) = 1.46K, instead of 1.5K The difference of resistance is so small actually that I guess it should be harmless on every boards... Please also have a look on the following page [0] for good explanations on the effects of varying I2C pull-up resistors. What's the others' opinion about that? Julien [0] http://www.dsscircuits.com/index.php/articles/47-effects-of-varying-i2c-pull-up-resistors
Hi Julien, Am Freitag, 17. Oktober 2014, 16:40:30 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 3 > > WARNING! This program can confuse your I2C bus, cause data loss and worse! > I will probe file /dev/i2c-3. > I will probe address range 0x03-0x77. > Continue? [Y/n] > 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 > -- rk3x-i2c 2005a000.i2c: timeout, ipd: 0x80, state: 3 > ... > > (2) root@localhost:~# i2cdetect 3 > > WARNING! This program can confuse your I2C bus, cause data loss and worse! > I will probe file /dev/i2c-3. > I will probe address range 0x03-0x77. > Continue? [Y/n] > 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> > --- > 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..c5cdf55 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_up>, > + <RK_GPIO2 29 RK_FUNC_1 &pcfg_pull_up>; The rk3066a does not support distinguishing between up and down pulls. On it only &pcfg_pull_default is possible that configures the pull to a pin-specific pull direction. For the i2c pins the direction is (of course) "up". Heiko
Hi Heiko, Le 27/10/2014 01:27, Heiko Stübner a écrit : > The rk3066a does not support distinguishing between up and down pulls. On it > only &pcfg_pull_default is possible that configures the pull to a pin-specific > pull direction. For the i2c pins the direction is (of course) "up". Thank you for the information. I will send a new patch to fix the pull configuration for the rk3066a. Julien
diff --git a/arch/arm/boot/dts/rk3066a.dtsi b/arch/arm/boot/dts/rk3066a.dtsi index ad9c2db..c5cdf55 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_up>, + <RK_GPIO2 29 RK_FUNC_1 &pcfg_pull_up>; }; }; 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_up>, + <RK_GPIO2 31 RK_FUNC_1 &pcfg_pull_up>; }; }; 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_up>, + <RK_GPIO3 1 RK_FUNC_1 &pcfg_pull_up>; }; }; 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_up>, + <RK_GPIO3 3 RK_FUNC_2 &pcfg_pull_up>; }; }; 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_up>, + <RK_GPIO3 5 RK_FUNC_1 &pcfg_pull_up>; }; }; 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>; }; };
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 3 WARNING! This program can confuse your I2C bus, cause data loss and worse! I will probe file /dev/i2c-3. I will probe address range 0x03-0x77. Continue? [Y/n] 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 -- rk3x-i2c 2005a000.i2c: timeout, ipd: 0x80, state: 3 ... (2) root@localhost:~# i2cdetect 3 WARNING! This program can confuse your I2C bus, cause data loss and worse! I will probe file /dev/i2c-3. I will probe address range 0x03-0x77. Continue? [Y/n] 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> --- 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(-)