Hi, On 09/02/2015 14:27, Li Ye-B37916 wrote: > Hi Stefano, Nikolay, > > On 1/30/2015 1:54 AM, Stefano Babic wrote: >> Hi, >> >> On 12/01/2015 11:37, Nikolay Dimitrov wrote: >>> Hi Ye.Li, >>> >>> On 01/12/2015 10:46 AM, Ye.Li wrote: >>>> The I2C SDA and SCL require the IOMUX SION bit set to get input signal. >>>> >>>> Signed-off-by: Ye.Li <[email protected]> >>>> --- >>>> arch/arm/include/asm/arch-mx6/mx6sx_pins.h | 4 ++-- >>>> 1 files changed, 2 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/arch/arm/include/asm/arch-mx6/mx6sx_pins.h >>>> b/arch/arm/include/asm/arch-mx6/mx6sx_pins.h >>>> index 7c6c1e8..da8c698 100644 >>>> --- a/arch/arm/include/asm/arch-mx6/mx6sx_pins.h >>>> +++ b/arch/arm/include/asm/arch-mx6/mx6sx_pins.h >>>> @@ -420,7 +420,7 @@ enum { >>>> >>>> MX6_PAD_KEY_COL4__KPP_COL_4 = >>>> IOMUX_PAD(0x03FC, 0x00B4, 0, 0x0000, 0, 0), >>>> MX6_PAD_KEY_COL4__ENET2_MDC = >>>> IOMUX_PAD(0x03FC, 0x00B4, 1, 0x0000, 0, 0), >>>> - MX6_PAD_KEY_COL4__I2C3_SCL = >>>> IOMUX_PAD(0x03FC, 0x00B4, 2, 0x07B8, 2, 0), >>>> + MX6_PAD_KEY_COL4__I2C3_SCL = >>>> IOMUX_PAD(0x03FC, 0x00B4, IOMUX_CONFIG_SION | 2, 0x07B8, 2, 0), >>>> MX6_PAD_KEY_COL4__USDHC2_LCTL = >>>> IOMUX_PAD(0x03FC, 0x00B4, 3, 0x0000, 0, 0), >>>> MX6_PAD_KEY_COL4__AUDMUX_AUD5_RXC = >>>> IOMUX_PAD(0x03FC, 0x00B4, 4, 0x0664, 0, 0), >>>> MX6_PAD_KEY_COL4__GPIO2_IO_14 = >>>> IOMUX_PAD(0x03FC, 0x00B4, 5, 0x0000, 0, 0), >>>> @@ -467,7 +467,7 @@ enum { >>>> >>>> MX6_PAD_KEY_ROW4__KPP_ROW_4 = >>>> IOMUX_PAD(0x0410, 0x00C8, 0, 0x0000, 0, 0), >>>> MX6_PAD_KEY_ROW4__ENET2_MDIO = >>>> IOMUX_PAD(0x0410, 0x00C8, 1, 0x0770, 3, 0), >>>> - MX6_PAD_KEY_ROW4__I2C3_SDA = >>>> IOMUX_PAD(0x0410, 0x00C8, 2, 0x07BC, 2, 0), >>>> + MX6_PAD_KEY_ROW4__I2C3_SDA = >>>> IOMUX_PAD(0x0410, 0x00C8, IOMUX_CONFIG_SION | 2, 0x07BC, 2, 0), >>>> MX6_PAD_KEY_ROW4__USDHC1_LCTL = >>>> IOMUX_PAD(0x0410, 0x00C8, 3, 0x0000, 0, 0), >>>> MX6_PAD_KEY_ROW4__AUDMUX_AUD5_RXFS = >>>> IOMUX_PAD(0x0410, 0x00C8, 4, 0x0668, 0, 0), >>>> MX6_PAD_KEY_ROW4__GPIO2_IO_19 = >>>> IOMUX_PAD(0x0410, 0x00C8, 5, 0x0000, 0, 0), >>>> >>> Usually the SCL is output-only, driven by the I2C master. Why do you >>> need to enable SION bit on SCL, if the pin will be used as output-only? >>> >> Right - I do not see why SION should be set. >> >> Regards, >> Stefano Babic >> > > Setting SION to both SDA and SCL is required by i.MX6 reference manual. You > can find the information below from i2c chapter. > > 34.2 External Signals > This section discusses I2C signals that connect off-chip. > For I2C compliance, all devices connected to the I2Cn_SCL and I2Cn_SDA > signals must > have open-drain or open-collector outputs. The logic AND function is > implemented on > both lines with external pull-up resistors. > Inputs of I2Cn_SCL and I2Cn_SDA also need to be manually enabled by setting > the > SION bit in the IOMUX after the corresponding PADs are selected as I2C > function. >
Checked in manual, thanks for link. However, I have still a couple of questions. The controller can work as slave or as master, and according to the manual, the slave is the default after a reset. I understand that putting the controller into slave mode must require the SION bit set. Anyway, you are using I2C3 as master in your patch 4/4. Is it still mandatory even in this case to set the SION bit ? The manual states that to use the signal as input the SION bit must be set, but as far as I see in the patchset SCL is output only. Best regards, Stefano Babic -- ===================================================================== DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: [email protected] ===================================================================== _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
