On Wed, 15 Feb 2017 11:38:45 +0800, Chris Zhong wrote:Also, we can not get error number from "ret" here.
On 01/29/2017 09:24 PM, John Keeping wrote:Nice catch, I'll fix this.
In order to fully reset the state of the MIPI controller we must assertAccording to [0], I think it should be -ENOENT here.
this reset.
This is slightly more complicated than it could be in order to maintain
compatibility with device trees that do not specify the reset property.
Signed-off-by: John Keeping <john@xxxxxxxxxxxx>
Reviewed-by: Chris Zhong <zyw@xxxxxxxxxxxxxx>
---
v3:
- Add Chris' Reviewed-by
Unchanged in v2
drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
index 58cb8ace2fe8..cf3ca6b0cbdb 100644
--- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
@@ -13,6 +13,7 @@
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/regmap.h>
+#include <linux/reset.h>
#include <linux/mfd/syscon.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_crtc.h>
@@ -1124,6 +1125,7 @@ static int dw_mipi_dsi_bind(struct device *dev, struct device *master,
of_match_device(dw_mipi_dsi_dt_ids, dev);
const struct dw_mipi_dsi_plat_data *pdata = of_id->data;
struct platform_device *pdev = to_platform_device(dev);
+ struct reset_control *apb_rst;
struct drm_device *drm = data;
struct dw_mipi_dsi *dsi;
struct resource *res;
@@ -1162,6 +1164,34 @@ static int dw_mipi_dsi_bind(struct device *dev, struct device *master,
return ret;
}
+ /*
+ * Note that the reset was not defined in the initial device tree, so
+ * we have to be prepared for it not being found.
+ */
+ apb_rst = devm_reset_control_get(dev, "apb");
+ if (IS_ERR(apb_rst)) {
+ if (PTR_ERR(apb_rst) == -ENODEV) {
[0]
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=3d81216fde465e76c5eae98f61d3666163634395
commit 3d81216fde465e76c5eae98f61d3666163634395
Author: Alban Bedel <albeu@xxxxxxx>
Date: Tue Sep 1 17:28:31 2015 +0200
reset: Fix of_reset_control_get() for consistent return values
When of_reset_control_get() is called without connection ID it returns
-ENOENT when the 'resets' property doesn't exists or is an empty entry.
However when a connection ID is given it returns -EINVAL when the
'resets'
property doesn't exists or the requested name can't be found. This is
because the error code returned by of_property_match_string() is just
passed down as an index to of_parse_phandle_with_args(), which then
returns -EINVAL.
To get a consistent return value with both code paths we must return
-ENOENT when of_property_match_string() fails.
Signed-off-by: Alban Bedel <albeu@xxxxxxx>
Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
+ apb_rst = NULL;
+ } else {
+ dev_err(dev, "Unable to get reset control: %d\n", ret);
+ return PTR_ERR(apb_rst);
+ }
+ }
+
+ if (apb_rst) {
+ ret = clk_prepare_enable(dsi->pclk);
+ if (ret) {
+ dev_err(dev, "%s: Failed to enable pclk\n", __func__);
+ return ret;
+ }
+
+ reset_control_assert(apb_rst);
+ usleep_range(10, 20);
+ reset_control_deassert(apb_rst);
+
+ clk_disable_unprepare(dsi->pclk);
+ }
+
ret = clk_prepare_enable(dsi->pllref_clk);
if (ret) {
dev_err(dev, "%s: Failed to enable pllref_clk\n", __func__);