[PATCH 2/2] drm/imagination: add reset control support

[Parthiban Nallathambi]

On some platforms like Allwinner A133 with GE8300 includes
reset control from reset control unit. Add reset control
optionally from the devicetree.

Signed-off-by: Parthiban Nallathambi <parthi...@linumiz.com>
---
 drivers/gpu/drm/imagination/pvr_device.h |  8 ++++++++
 drivers/gpu/drm/imagination/pvr_drv.c    |  5 +++++
 drivers/gpu/drm/imagination/pvr_power.c  | 16 +++++++++++++++-
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/imagination/pvr_device.h 
b/drivers/gpu/drm/imagination/pvr_device.h
index 6d0dfacb677b..21ec7dd64415 100644
--- a/drivers/gpu/drm/imagination/pvr_device.h
+++ b/drivers/gpu/drm/imagination/pvr_device.h
@@ -23,6 +23,7 @@
 #include <linux/kernel.h>
 #include <linux/math.h>
 #include <linux/mutex.h>
+#include <linux/reset.h>
 #include <linux/spinlock_types.h>
 #include <linux/timer.h>
 #include <linux/types.h>
@@ -131,6 +132,13 @@ struct pvr_device {
         */
        struct clk *mem_clk;
 
+       /**
+        * @reset: Optional reset control
+        *
+        * This may be used on some platforms to reset the GPU module/IP.
+        */
+       struct reset_control *reset;
+
        /** @irq: IRQ number. */
        int irq;
 
diff --git a/drivers/gpu/drm/imagination/pvr_drv.c 
b/drivers/gpu/drm/imagination/pvr_drv.c
index fb17196e05f4..d9b918410ea9 100644
--- a/drivers/gpu/drm/imagination/pvr_drv.c
+++ b/drivers/gpu/drm/imagination/pvr_drv.c
@@ -36,6 +36,7 @@
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/reset.h>
 #include <linux/xarray.h>
 
 /**
@@ -1427,6 +1428,10 @@ pvr_probe(struct platform_device *plat_dev)
        pm_runtime_use_autosuspend(&plat_dev->dev);
        pvr_watchdog_init(pvr_dev);
 
+       pvr_dev->reset = 
devm_reset_control_get_optional_exclusive(&plat_dev->dev, "ahb");
+       if (PTR_ERR(pvr_dev->reset) == -EPROBE_DEFER)
+               return PTR_ERR(pvr_dev->reset);
+
        err = pvr_device_init(pvr_dev);
        if (err)
                goto err_watchdog_fini;
diff --git a/drivers/gpu/drm/imagination/pvr_power.c 
b/drivers/gpu/drm/imagination/pvr_power.c
index ba7816fd28ec..a24ed85f36c7 100644
--- a/drivers/gpu/drm/imagination/pvr_power.c
+++ b/drivers/gpu/drm/imagination/pvr_power.c
@@ -15,6 +15,7 @@
 #include <linux/mutex.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/reset.h>
 #include <linux/timer.h>
 #include <linux/types.h>
 #include <linux/workqueue.h>
@@ -252,6 +253,9 @@ pvr_power_device_suspend(struct device *dev)
        clk_disable_unprepare(pvr_dev->sys_clk);
        clk_disable_unprepare(pvr_dev->core_clk);
 
+       if (!IS_ERR(pvr_dev->reset))
+               reset_control_assert(pvr_dev->reset);
+
 err_drm_dev_exit:
        drm_dev_exit(idx);
 
@@ -270,9 +274,15 @@ pvr_power_device_resume(struct device *dev)
        if (!drm_dev_enter(drm_dev, &idx))
                return -EIO;
 
+       if (!IS_ERR(pvr_dev->reset)) {
+               err = reset_control_reset(pvr_dev->reset);
+               if (err)
+                       goto err_drm_dev_exit;
+       }
+
        err = clk_prepare_enable(pvr_dev->core_clk);
        if (err)
-               goto err_drm_dev_exit;
+               goto err_reset_exit;
 
        err = clk_prepare_enable(pvr_dev->sys_clk);
        if (err)
@@ -301,6 +311,10 @@ pvr_power_device_resume(struct device *dev)
 err_core_clk_disable:
        clk_disable_unprepare(pvr_dev->core_clk);
 
+err_reset_exit:
+       if (!IS_ERR(pvr_dev->reset))
+               reset_control_assert(pvr_dev->reset);
+
 err_drm_dev_exit:
        drm_dev_exit(idx);
 

-- 
2.39.2