[PATCH 03/23] drm: omapdrm: dss: reset dsi module during initialization

Sebastian Reichel
2016-03-08T16:50:13Z

From: Tomi Valkeinen <tomi.valkeinen@ti.com>

The Nokia N950's bootloader leaves the DSI module
in a non-working state. Work around this by resetting
the DSI module before using it.

Signed-off-By: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-By: Sebastian Reichel <sre@kernel.org>
Tested-By: Sebastian Reichel <sre@kernel.org>
---
drivers/gpu/drm/omapdrm/dss/dsi.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)

diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c
index 43be4b2a7b05..363a61e6aca7 100644
--- a/drivers/gpu/drm/omapdrm/dss/dsi.c
+++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
@@ -5274,6 +5274,28 @@ static int dsi_init_pll_data(struct platform_device *dsidev)
return 0;
}

+static int _dsi_wait_reset(struct platform_device *dsidev)
+{
+ int t = 0;
+
+ while (REG_GET(dsidev, DSI_SYSSTATUS, 0, 0) == 0) {
+ if (++t > 5) {
+ DSSERR("soft reset failed\n");
+ return -ENODEV;
+ }
+ udelay(1);
+ }
+
+ return 0;
+}
+
+static int _dsi_reset(struct platform_device *dsidev)
+{
+ /* Soft reset */
+ dsi_write_reg(dsidev, DSI_SYSCONFIG, 0x2);
+ return _dsi_wait_reset(dsidev);
+}
+
/* DSI1 HW IP initialisation */
static int dsi_bind(struct device *dev, struct device *master, void *data)
{
@@ -5432,6 +5454,8 @@ static int dsi_bind(struct device *dev, struct device *master, void *data)
if (r)
goto err_runtime_get;

+ _dsi_reset(dsidev);
+
rev = dsi_read_reg(dsidev, DSI_REVISION);
dev_dbg(&dsidev->dev, "OMAP DSI rev %d.%d\n",
FLD_GET(rev, 7, 4), FLD_GET(rev, 3, 0));
--
2.7.0