Re: [PATCH v2 10/26] drm/rockchip: dw-mipi-dsi: only request HS clock when required

From: Chris Zhong
Date: Sun Jan 22 2017 - 03:11:42 EST


Hi John

Reviewed-by: Chris Zhong <zyw@xxxxxxxxxxxxxx>

On 01/22/2017 12:31 AM, John Keeping wrote:
Requesting the HS clock from the PHY before we initialize it causes an
invalid signal to be sent out since the input clock is not yet
configured. The PHY databook suggests only asserting this signal when
performing HS transfers, so let's do that.

Signed-off-by: John Keeping <john@xxxxxxxxxxxx>
---
Unchanged in v2
---
drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
index 15d33c3c8cb7..03fc096fe1bd 100644
--- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
@@ -545,13 +545,15 @@ static int dw_mipi_dsi_host_detach(struct mipi_dsi_host *host,
static void dw_mipi_message_config(struct dw_mipi_dsi *dsi,
const struct mipi_dsi_msg *msg)
{
+ bool lpm = msg->flags & MIPI_DSI_MSG_USE_LPM;
u32 val = 0;
if (msg->flags & MIPI_DSI_MSG_REQ_ACK)
val |= EN_ACK_RQST;
- if (msg->flags & MIPI_DSI_MSG_USE_LPM)
+ if (lpm)
val |= CMD_MODE_ALL_LP;
+ dsi_write(dsi, DSI_LPCLK_CTRL, lpm ? 0 : PHY_TXREQUESTCLKHS);
dsi_write(dsi, DSI_CMD_MODE_CFG, val);
}
@@ -693,6 +695,7 @@ static void dw_mipi_dsi_set_mode(struct dw_mipi_dsi *dsi,
dsi_write(dsi, DSI_PWR_UP, RESET);
dsi_write(dsi, DSI_MODE_CFG, ENABLE_VIDEO_MODE);
dw_mipi_dsi_video_mode_config(dsi);
+ dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
dsi_write(dsi, DSI_PWR_UP, POWERUP);
}
}
@@ -710,7 +713,6 @@ static void dw_mipi_dsi_init(struct dw_mipi_dsi *dsi)
| PHY_RSTZ | PHY_SHUTDOWNZ);
dsi_write(dsi, DSI_CLKMGR_CFG, TO_CLK_DIVIDSION(10) |
TX_ESC_CLK_DIVIDSION(7));
- dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
}
static void dw_mipi_dsi_dpi_config(struct dw_mipi_dsi *dsi,