[PATCH] ARM: dts: imx6sx: document SION necessity of ENET1_REF_CLK1

[Christoph Fritz]

On Wed, 2016-08-17 at 11:25 +0200, Christoph Fritz wrote:
> Signed-off-by: Christoph Fritz <chf.fritz at googlemail.com>
> ---
>  arch/arm/boot/dts/imx6sx-pinfunc.h | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/imx6sx-pinfunc.h b/arch/arm/boot/dts/imx6sx-pinfunc.h
> index bb9c6b7..42c4c80 100644
> --- a/arch/arm/boot/dts/imx6sx-pinfunc.h
> +++ b/arch/arm/boot/dts/imx6sx-pinfunc.h
> @@ -308,6 +308,20 @@
>  #define MX6SX_PAD_ENET1_RX_CLK__VDEC_DEBUG_35                     0x008C 0x03D4 0x0000 0x8 0x0
>  #define MX6SX_PAD_ENET1_RX_CLK__PCIE_CTRL_DEBUG_29                0x008C 0x03D4 0x0000 0x9 0x0
>  #define MX6SX_PAD_ENET1_TX_CLK__ENET1_TX_CLK                      0x0090 0x03D8 0x0000 0x0 0x0
> +/*
> + * SION bit is necessary for ENET1_REF_CLK1 (ENET2_REF_CLK2 untested) if it is
> + * used as clock output of IMX6SX_CLK_ENET_REF (ENET1_TX_CLK) to e.g. supply a
> + * PHY in RMII mode. This configuration is valid if:
> + *  - bit 1 in field IMX6SX_GPR1_FEC_CLOCK_PAD_DIR_MASK is set
> + *  - bit 1 in field IMX6SX_GPR1_FEC_CLOCK_MUX_SEL_MASK unset
> + * It seems to be a silicon bug that in this configuration ENET1_TX reference
> + * clock isn't provided automatically.  According to i.MX6SX reference manual
> + * (IOMUXC_GPR_GPR1 field descriptions: ENET1_CLK_SEL, Rev. 0 from 2/2015) it
> + * should be the case.
> + * So this might have unwanted side effects for other hardware units that are
> + * also connected to that pin and using respective function as input (e.g.
> + * UART1's DTR handling on MX6SX_PAD_ENET1_TX_CLK__UART1_DTR_B).
> + */
>  #define MX6SX_PAD_ENET1_TX_CLK__ENET1_REF_CLK1                    0x0090 0x03D8 0x0760 0x1 0x1
>  #define MX6SX_PAD_ENET1_TX_CLK__AUDMUX_AUD4_RXD                   0x0090 0x03D8 0x0644 0x2 0x1
>  #define MX6SX_PAD_ENET1_TX_CLK__UART1_DTR_B                       0x0090 0x03D8 0x0000 0x3 0x0

@Uwe and Fabio: Can I get your Ack on this?
@Shawn: Can you queue this patch for upstream?