drm/vc4: Turn the V3D clock on at runtime.

For the Raspberry Pi's bindings, the power domain also implicitly
turns on the clock and deasserts reset, but for the new Cygnus port we
start representing the clock in the devicetree.

v2: Document the clock-names property, check for -ENOENT for no clock
    in DT.
v3: Drop NULL checks around clk calls which embed NULL checks.
v4: Drop clk-names (feedback by Rob Herring)

Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Rob Herring <robh@kernel.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20170428224223.21904-1-eric@anholt.net

diff --git a/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt b/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt
index ca02d3e4db91738ac5d87d7e235e0f9de8a56b5e..bc1756f4f7918f3231985626bb43938be393f4ac 100644 (file)
--- a/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt
+++ b/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt
@@ -59,6 +59,9 @@ Required properties for V3D:
 - interrupts:  The interrupt number
                  See bindings/interrupt-controller/brcm,bcm2835-armctrl-ic.txt
 
+Optional properties for V3D:
+- clocks:      The clock the unit runs on
+
 Required properties for DSI:
 - compatible:  Should be "brcm,bcm2835-dsi0" or "brcm,bcm2835-dsi1"
 - reg:         Physical base address and length of the DSI block's registers

diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index b0967e2f7e8822e07201ef75d2b171c9df904544..92eb7d811bf211e992dc69fdacc1505e180c5522 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -200,6 +200,7 @@ struct vc4_v3d {
        struct vc4_dev *vc4;
        struct platform_device *pdev;
        void __iomem *regs;
+       struct clk *clk;
 };
 
 struct vc4_hvs {

diff --git a/drivers/gpu/drm/vc4/vc4_v3d.c b/drivers/gpu/drm/vc4/vc4_v3d.c
index a88078d7c9d141ec4a50ddce558a213068fcd169..7500820e5cd5132413b019ade883b51a09d565e2 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_v3d.c
+++ b/drivers/gpu/drm/vc4/vc4_v3d.c
@@ -16,6 +16,7 @@
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include "linux/clk.h"
 #include "linux/component.h"
 #include "linux/pm_runtime.h"
 #include "vc4_drv.h"
@@ -305,6 +306,8 @@ static int vc4_v3d_runtime_suspend(struct device *dev)
        drm_gem_object_put_unlocked(&vc4->bin_bo->base.base);
        vc4->bin_bo = NULL;
 
+       clk_disable_unprepare(v3d->clk);
+
        return 0;
 }
 
@@ -318,6 +321,10 @@ static int vc4_v3d_runtime_resume(struct device *dev)
        if (ret)
                return ret;
 
+       ret = clk_prepare_enable(v3d->clk);
+       if (ret != 0)
+               return ret;
+
        vc4_v3d_init_hw(vc4->dev);
        vc4_irq_postinstall(vc4->dev);
 
@@ -348,15 +355,37 @@ static int vc4_v3d_bind(struct device *dev, struct device *master, void *data)
        vc4->v3d = v3d;
        v3d->vc4 = vc4;
 
+       v3d->clk = devm_clk_get(dev, NULL);
+       if (IS_ERR(v3d->clk)) {
+               int ret = PTR_ERR(v3d->clk);
+
+               if (ret == -ENOENT) {
+                       /* bcm2835 didn't have a clock reference in the DT. */
+                       ret = 0;
+                       v3d->clk = NULL;
+               } else {
+                       if (ret != -EPROBE_DEFER)
+                               dev_err(dev, "Failed to get V3D clock: %d\n",
+                                       ret);
+                       return ret;
+               }
+       }
+
        if (V3D_READ(V3D_IDENT0) != V3D_EXPECTED_IDENT0) {
                DRM_ERROR("V3D_IDENT0 read 0x%08x instead of 0x%08x\n",
                          V3D_READ(V3D_IDENT0), V3D_EXPECTED_IDENT0);
                return -EINVAL;
        }
 
+       ret = clk_prepare_enable(v3d->clk);
+       if (ret != 0)
+               return ret;
+
        ret = vc4_allocate_bin_bo(drm);
-       if (ret)
+       if (ret) {
+               clk_disable_unprepare(v3d->clk);
                return ret;
+       }
 
        /* Reset the binner overflow address/size at setup, to be sure
         * we don't reuse an old one.