drm/msm/dsi: Parse lane swap information from DT

Lane swap configuration is based on the board design.
This change allows the DSI host to get this information
from device tree, instead of hardcoding in driver.

Signed-off-by: Hai Li <hali@codeaurora.org>
---
 Documentation/devicetree/bindings/drm/msm/dsi.txt | 13 ++++++
 drivers/gpu/drm/msm/dsi/dsi_host.c                | 49 +++++++++++++++++------
 2 files changed, 49 insertions(+), 13 deletions(-)

Hi,

On 9/4/2015 12:00 AM, Hai Li wrote:
> Lane swap configuration is based on the board design.
> This change allows the DSI host to get this information
> from device tree, instead of hardcoding in driver.
>
> Signed-off-by: Hai Li <hali@codeaurora.org>
> ---
>   Documentation/devicetree/bindings/drm/msm/dsi.txt | 13 ++++++
>   drivers/gpu/drm/msm/dsi/dsi_host.c                | 49 +++++++++++++++++------
>   2 files changed, 49 insertions(+), 13 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/drm/msm/dsi.txt b/Documentation/devicetree/bindings/drm/msm/dsi.txt
> index d56923c..febcc51 100644
> --- a/Documentation/devicetree/bindings/drm/msm/dsi.txt
> +++ b/Documentation/devicetree/bindings/drm/msm/dsi.txt
> @@ -44,6 +44,17 @@ Optional properties:
>   - port: DSI controller output port. This contains one endpoint subnode, with its
>     remote-endpoint set to the phandle of the connected panel's endpoint.
>     See Documentation/devicetree/bindings/graph.txt for device graph info.
> +- qcom,dsi-logical-lane-swap: Character string to swap logical lane to physical
> +  lane mapping. Supported lane mappings:
> +  "0123": Logic 0->Phys 0; Logic 1->Phys 1; Logic 2->Phys 2; Logic 3->Phys 3;
> +  "3012": Logic 3->Phys 0; Logic 0->Phys 1; Logic 1->Phys 2; Logic 2->Phys 3;
> +  "2301": Logic 2->Phys 0; Logic 3->Phys 1; Logic 0->Phys 2; Logic 1->Phys 3;
> +  "1230": Logic 1->Phys 0; Logic 2->Phys 1; Logic 3->Phys 2; Logic 0->Phys 3;
> +  "0321": Logic 0->Phys 0; Logic 3->Phys 1; Logic 2->Phys 2; Logic 1->Phys 3;
> +  "1032": Logic 1->Phys 0; Logic 0->Phys 1; Logic 3->Phys 2; Logic 2->Phys 3;
> +  "2103": Logic 2->Phys 0; Logic 1->Phys 1; Logic 0->Phys 2; Logic 3->Phys 3;
> +  "3210": Logic 3->Phys 0; Logic 2->Phys 1; Logic 1->Phys 2; Logic 0->Phys 3;
> +  Default value is "0123", which means no lane swap.
>
>   DSI PHY:
>   Required properties:
> @@ -129,6 +140,8 @@ Example:
>   				remote-endpoint = <&panel_in>;
>   			};
>   		};
> +
> +		qcom,dsi-logical-lane-swap = "0123";
>   	};

I think we could keep this in the output port DT node instead,
since it is more of a property of how it connects to the panel.

There is a more generic way to represent lane info. It would be nice to
have a look at what's done here:

http://marc.info/?l=linux-omap&m=133605367610068&w=2

and it's usage here:

http://lxr.free-electrons.com/source/arch/arm/boot/dts/omap4-sdp.dts#L647

Thanks,
Archit


>
>   	mdss_dsi_phy0: qcom,mdss_dsi_phy@fd922a00 {
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 8d82973f..eaba417 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -131,6 +131,7 @@ struct msm_dsi_host {
>   	enum mipi_dsi_pixel_format format;
>   	unsigned long mode_flags;
>
> +	u32 dlane_swap;
>   	u32 dma_cmd_ctrl_restore;
>
>   	bool registered;
> @@ -684,19 +685,9 @@ static void dsi_ctrl_config(struct msm_dsi_host *msm_host, bool enable,
>   	data = DSI_CTRL_CLK_EN;
>
>   	DBG("lane number=%d", msm_host->lanes);
> -	if (msm_host->lanes == 2) {
> -		data |= DSI_CTRL_LANE1 | DSI_CTRL_LANE2;
> -		/* swap lanes for 2-lane panel for better performance */
> -		dsi_write(msm_host, REG_DSI_LANE_SWAP_CTRL,
> -			DSI_LANE_SWAP_CTRL_DLN_SWAP_SEL(LANE_SWAP_1230));
> -	} else {
> -		/* Take 4 lanes as default */
> -		data |= DSI_CTRL_LANE0 | DSI_CTRL_LANE1 | DSI_CTRL_LANE2 |
> -			DSI_CTRL_LANE3;
> -		/* Do not swap lanes for 4-lane panel */
> -		dsi_write(msm_host, REG_DSI_LANE_SWAP_CTRL,
> -			DSI_LANE_SWAP_CTRL_DLN_SWAP_SEL(LANE_SWAP_0123));
> -	}
> +	data |= ((DSI_CTRL_LANE0 << msm_host->lanes) - DSI_CTRL_LANE0);
> +	dsi_write(msm_host, REG_DSI_LANE_SWAP_CTRL,
> +		DSI_LANE_SWAP_CTRL_DLN_SWAP_SEL(msm_host->dlane_swap));
>
>   	if (!(flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
>   		dsi_write(msm_host, REG_DSI_LANE_CTRL,
> @@ -1289,6 +1280,9 @@ static int dsi_host_attach(struct mipi_dsi_host *host,
>   	struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
>   	int ret;
>
> +	if (dsi->lanes > 4 || dsi->channel > 3)
> +		return -EINVAL;
> +
>   	msm_host->channel = dsi->channel;
>   	msm_host->lanes = dsi->lanes;
>   	msm_host->format = dsi->format;
> @@ -1344,6 +1338,33 @@ static struct mipi_dsi_host_ops dsi_host_ops = {
>   	.transfer = dsi_host_transfer,
>   };
>
> +static void dsi_parse_dlane_swap(struct msm_dsi_host *msm_host,
> +				struct device_node *np)
> +{
> +	const char *lane_swap;
> +
> +	lane_swap = of_get_property(np, "qcom,dsi-logical-lane-swap", NULL);
> +
> +	if (!lane_swap)
> +		msm_host->dlane_swap = LANE_SWAP_0123;
> +	else if (!strncmp(lane_swap, "3012", 5))
> +		msm_host->dlane_swap = LANE_SWAP_3012;
> +	else if (!strncmp(lane_swap, "2301", 5))
> +		msm_host->dlane_swap = LANE_SWAP_2301;
> +	else if (!strncmp(lane_swap, "1230", 5))
> +		msm_host->dlane_swap = LANE_SWAP_1230;
> +	else if (!strncmp(lane_swap, "0321", 5))
> +		msm_host->dlane_swap = LANE_SWAP_0321;
> +	else if (!strncmp(lane_swap, "1032", 5))
> +		msm_host->dlane_swap = LANE_SWAP_1032;
> +	else if (!strncmp(lane_swap, "2103", 5))
> +		msm_host->dlane_swap = LANE_SWAP_2103;
> +	else if (!strncmp(lane_swap, "3210", 5))
> +		msm_host->dlane_swap = LANE_SWAP_3210;
> +	else
> +		msm_host->dlane_swap = LANE_SWAP_0123;
> +}
> +
>   static int dsi_host_parse_dt(struct msm_dsi_host *msm_host)
>   {
>   	struct device *dev = &msm_host->pdev->dev;
> @@ -1358,6 +1379,8 @@ static int dsi_host_parse_dt(struct msm_dsi_host *msm_host)
>   		return ret;
>   	}
>
> +	dsi_parse_dlane_swap(msm_host, np);
> +
>   	/*
>   	 * Get the first endpoint node. In our case, dsi has one output port
>   	 * to which the panel is connected. Don't return an error if a port
>