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Subject[PATCH] drm: mxsfb: Add interconnect path request
Date
Add interconnect support to mxsfb so that it is able to request enough
bandwidth to DDR for display output to work.

Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
---
drivers/gpu/drm/mxsfb/mxsfb_drv.c | 33 +++++++++++++++++++++++++++++++
drivers/gpu/drm/mxsfb/mxsfb_drv.h | 2 ++
drivers/gpu/drm/mxsfb/mxsfb_kms.c | 13 ++++++++++++
3 files changed, 48 insertions(+)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
index 6faf17b6408d..b05e8e5f1e38 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
@@ -15,6 +15,7 @@
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
+#include <linux/interconnect.h>

#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge.h>
@@ -311,6 +312,34 @@ static const struct of_device_id mxsfb_dt_ids[] = {
};
MODULE_DEVICE_TABLE(of, mxsfb_dt_ids);

+
+static int mxsfb_init_icc(struct platform_device *pdev)
+{
+ struct drm_device *drm = platform_get_drvdata(pdev);
+ struct mxsfb_drm_private *mxsfb = drm->dev_private;
+ int ret;
+
+ /* Optional interconnect request */
+ mxsfb->icc_path = devm_of_icc_get(&pdev->dev, "lcdif-dram");
+ if (IS_ERR(mxsfb->icc_path)) {
+ ret = PTR_ERR(mxsfb->icc_path);
+ if (ret == -EPROBE_DEFER)
+ return ret;
+
+ mxsfb->icc_path = NULL;
+ dev_dbg(drm->dev,
+ "No interconnect may cause display underflows!\n");
+ }
+
+ ret = icc_set_bw(mxsfb->icc_path, 0, MBps_to_icc(700));
+ if (ret) {
+ dev_err(drm->dev, "%s: icc_set_bw failed: %d\n", __func__, ret);
+ return ret;
+ }
+
+ return 0;
+}
+
static int mxsfb_probe(struct platform_device *pdev)
{
struct drm_device *drm;
@@ -329,6 +358,10 @@ static int mxsfb_probe(struct platform_device *pdev)
if (ret)
goto err_free;

+ ret = mxsfb_init_icc(pdev);
+ if (ret)
+ goto err_free;
+
ret = drm_dev_register(drm, 0);
if (ret)
goto err_unload;
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.h b/drivers/gpu/drm/mxsfb/mxsfb_drv.h
index 399d23e91ed1..d74ff4818e62 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_drv.h
+++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.h
@@ -41,6 +41,8 @@ struct mxsfb_drm_private {
struct drm_encoder encoder;
struct drm_connector *connector;
struct drm_bridge *bridge;
+
+ struct icc_path *icc_path;
};

static inline struct mxsfb_drm_private *
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
index 3e1bb0aefb87..8925ee7deeaa 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
@@ -13,6 +13,7 @@
#include <linux/iopoll.h>
#include <linux/pm_runtime.h>
#include <linux/spinlock.h>
+#include <linux/interconnect.h>

#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
@@ -310,6 +311,12 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc *crtc,
struct mxsfb_drm_private *mxsfb = to_mxsfb_drm_private(crtc->dev);
struct drm_device *drm = mxsfb->drm;
dma_addr_t paddr;
+ int ret;
+
+ ret = icc_enable(mxsfb->icc_path);
+ if (ret)
+ dev_err_ratelimited(drm->dev, "%s: icc_enable failed: %d\n",
+ __func__, ret);

pm_runtime_get_sync(drm->dev);
mxsfb_enable_axi_clk(mxsfb);
@@ -334,6 +341,7 @@ static void mxsfb_crtc_atomic_disable(struct drm_crtc *crtc,
struct mxsfb_drm_private *mxsfb = to_mxsfb_drm_private(crtc->dev);
struct drm_device *drm = mxsfb->drm;
struct drm_pending_vblank_event *event;
+ int ret;

mxsfb_disable_controller(mxsfb);

@@ -349,6 +357,11 @@ static void mxsfb_crtc_atomic_disable(struct drm_crtc *crtc,

mxsfb_disable_axi_clk(mxsfb);
pm_runtime_put_sync(drm->dev);
+
+ ret = icc_disable(mxsfb->icc_path);
+ if (ret)
+ dev_err_ratelimited(drm->dev, "%s: icc_disable failed: %d\n",
+ __func__, ret);
}

static int mxsfb_crtc_enable_vblank(struct drm_crtc *crtc)
--
2.20.1
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