Re: [PATCH] drm/bridge/synopsys: dsi: Add 1.31 version support

From: Andrzej Hajda
Date: Mon Feb 05 2018 - 08:03:48 EST


On 22.01.2018 16:08, Philippe Cornu wrote:
> From: Philippe CORNU <philippe.cornu@xxxxxx>
>
> Add support for the Synopsys DesignWare MIPI DSI version 1.31
> Two registers need to be updated/added for supporting 1.31:
> * PHY_TMR_CFG 0x9c (updated)
> 1.30 [31:24] phy_hs2lp_time
> [23:16] phy_lp2hs_time
> [14: 0] max_rd_time
>
> 1.31 [25:16] phy_hs2lp_time
> [ 9: 0] phy_lp2hs_time
>
> * PHY_TMR_RD_CFG 0xf4 (new)
> 1.31 [14: 0] max_rd_time
>
> Signed-off-by: Philippe Cornu <philippe.cornu@xxxxxx>
> ---
> drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 52 +++++++++++++++++++++++----
> 1 file changed, 46 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> index 735f38429c06..20a2ca14a7ad 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> @@ -25,7 +25,13 @@
> #include <drm/bridge/dw_mipi_dsi.h>
> #include <video/mipi_display.h>
>
> +#define HWVER_130 0x31333000 /* IP version 1.30 */
> +#define HWVER_131 0x31333100 /* IP version 1.31 */
> +#define HWVER_OLDEST HWVER_130
> +#define HWVER_NEWEST HWVER_131
> +
> #define DSI_VERSION 0x00
> +#define VERSION GENMASK(31, 8)
>
> #define DSI_PWR_UP 0x04
> #define RESET 0
> @@ -161,11 +167,12 @@
> #define PHY_CLKHS2LP_TIME(lbcc) (((lbcc) & 0x3ff) << 16)
> #define PHY_CLKLP2HS_TIME(lbcc) ((lbcc) & 0x3ff)
>
> -/* TODO Next register is slightly different between 1.30 & 1.31 IP version */
> #define DSI_PHY_TMR_CFG 0x9c
> -#define PHY_HS2LP_TIME(lbcc) (((lbcc) & 0xff) << 24)
> -#define PHY_LP2HS_TIME(lbcc) (((lbcc) & 0xff) << 16)
> -#define MAX_RD_TIME(lbcc) ((lbcc) & 0x7fff)
> +#define PHY_HS2LP_TIME_V130(lbcc) (((lbcc) & 0xff) << 24)
> +#define PHY_LP2HS_TIME_V130(lbcc) (((lbcc) & 0xff) << 16)
> +#define MAX_RD_TIME_V130(lbcc) ((lbcc) & 0x7fff)
> +#define PHY_HS2LP_TIME_V131(lbcc) (((lbcc) & 0x3ff) << 16)
> +#define PHY_LP2HS_TIME_V131(lbcc) ((lbcc) & 0x3ff)
>
> #define DSI_PHY_RSTZ 0xa0
> #define PHY_DISFORCEPLL 0
> @@ -204,7 +211,9 @@
> #define DSI_INT_ST1 0xc0
> #define DSI_INT_MSK0 0xc4
> #define DSI_INT_MSK1 0xc8
> +
> #define DSI_PHY_TMR_RD_CFG 0xf4
> +#define MAX_RD_TIME_V131(lbcc) ((lbcc) & 0x7fff)
>
> #define PHY_STATUS_TIMEOUT_US 10000
> #define CMD_PKT_STATUS_TIMEOUT_US 20000
> @@ -215,6 +224,7 @@ struct dw_mipi_dsi {
> struct drm_bridge *panel_bridge;
> struct device *dev;
> void __iomem *base;
> + u32 hw_version;
>
> struct clk *pclk;
> struct clk *px_clk;
> @@ -616,8 +626,14 @@ static void dw_mipi_dsi_dphy_timing_config(struct dw_mipi_dsi *dsi)
> * note: DSI_PHY_TMR_CFG.MAX_RD_TIME should be in line with
> * DSI_CMD_MODE_CFG.MAX_RD_PKT_SIZE_LP (see CMD_MODE_ALL_LP)
> */
> - dsi_write(dsi, DSI_PHY_TMR_CFG, PHY_HS2LP_TIME(0x40)
> - | PHY_LP2HS_TIME(0x40) | MAX_RD_TIME(10000));
> + if (dsi->hw_version == HWVER_131) {
> + dsi_write(dsi, DSI_PHY_TMR_CFG, PHY_HS2LP_TIME_V131(0x40) |
> + PHY_LP2HS_TIME_V131(0x40));
> + dsi_write(dsi, DSI_PHY_TMR_RD_CFG, MAX_RD_TIME_V131(10000));
> + } else {
> + dsi_write(dsi, DSI_PHY_TMR_CFG, PHY_HS2LP_TIME_V130(0x40) |
> + PHY_LP2HS_TIME_V130(0x40) | MAX_RD_TIME_V130(10000));
> + }
>
> dsi_write(dsi, DSI_PHY_TMR_LPCLK_CFG, PHY_CLKHS2LP_TIME(0x40)
> | PHY_CLKLP2HS_TIME(0x40));
> @@ -791,6 +807,28 @@ static const struct drm_bridge_funcs dw_mipi_dsi_bridge_funcs = {
> .attach = dw_mipi_dsi_bridge_attach,
> };
>
> +static void dsi_get_version(struct dw_mipi_dsi *dsi)
> +{
> + u32 hw_version;
> +
> + clk_prepare_enable(dsi->pclk);
> + hw_version = dsi_read(dsi, DSI_VERSION) & VERSION;
> + clk_disable_unprepare(dsi->pclk);
> +
> + if (hw_version > HWVER_NEWEST) {
> + DRM_DEBUG("hw version: use 0x%08x for this recent 0x%08x\n",
> + HWVER_NEWEST, hw_version);
> + hw_version = HWVER_NEWEST;
> +
> + } else if (hw_version < HWVER_OLDEST) {
> + DRM_DEBUG("hw version: use 0x%08x for this old 0x%08x\n",
> + HWVER_OLDEST, hw_version);
> + hw_version = HWVER_OLDEST;
> + }
> +
> + dsi->hw_version = hw_version;
> +}
> +
> static struct dw_mipi_dsi *
> __dw_mipi_dsi_probe(struct platform_device *pdev,
> const struct dw_mipi_dsi_plat_data *plat_data)
> @@ -870,6 +908,8 @@ __dw_mipi_dsi_probe(struct platform_device *pdev,
> clk_disable_unprepare(dsi->pclk);
> }
>
> + dsi_get_version(dsi);
> +
> pm_runtime_enable(dev);

Two questions:
1. You have generally two variants:
- older than 131,
- not older than 131.
Wouldn't be better to just assume that since 131 registers slightly differ?
So you just stores:
ÂÂÂ dsi->hw_version = dsi_read(dsi, DSI_VERSION) & VERSION;
And if neccessary performs comparison:
ÂÂÂ if (dsi->hw_version >= HWVER_131)
ÂÂÂ ÂÂÂ ...
ÂÂÂ else
ÂÂÂ ÂÂÂ ...

This way you can remove these HWVER_(NEWEST|OLDEST).

2. You are using pm_runtime, but not in dsi_get_version. I guess it is
SoC dependant but I suppose performing registry read should be safer
after runtime_get.

Regards
Andrzej

>
> dsi->dsi_host.ops = &dw_mipi_dsi_host_ops;