Re: [PATCH] drm/msm/dsi: Parse lane swap information from DT

From: Archit Taneja
Date: Sun Sep 06 2015 - 08:12:41 EST

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@xxxxxxxxxxxxxx>
---
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


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