[PATCH 2/2] gpu: host1x: Support module reset

[Thierry Reding <thierry.reding@gmail.com>]

From: Thierry Reding <treding@nvidia.com>

Newer versions of Tegra come with early boot software that aggressively
puts various modules in reset. Add support to the host1x driver to take
the module out of reset on probe, and assert reset on removal.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/gpu/host1x/dev.c | 18 +++++++++++++++++-
 drivers/gpu/host1x/dev.h |  2 ++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
index 6c17c4900166..f5dd6a06f798 100644
--- a/drivers/gpu/host1x/dev.c
+++ b/drivers/gpu/host1x/dev.c
@@ -168,6 +168,13 @@ static int host1x_probe(struct platform_device *pdev)
 		return err;
 	}
 
+	host->rst = devm_reset_control_get(&pdev->dev, "host1x");
+	if (IS_ERR(host->rst)) {
+		err = PTR_ERR(host->clk);
+		dev_err(&pdev->dev, "failed to get reset: %d\n", err);
+		return err;
+	}
+
 	err = host1x_channel_list_init(host);
 	if (err) {
 		dev_err(&pdev->dev, "failed to initialize channel list\n");
@@ -180,10 +187,16 @@ static int host1x_probe(struct platform_device *pdev)
 		return err;
 	}
 
+	err = reset_control_deassert(host->rst);
+	if (err < 0) {
+		dev_err(&pdev->dev, "failed to deassert reset: %d\n", err);
+		goto fail_unprepare_disable;
+	}
+
 	err = host1x_syncpt_init(host);
 	if (err) {
 		dev_err(&pdev->dev, "failed to initialize syncpts\n");
-		goto fail_unprepare_disable;
+		goto fail_reset_assert;
 	}
 
 	err = host1x_intr_init(host, syncpt_irq);
@@ -204,6 +217,8 @@ static int host1x_probe(struct platform_device *pdev)
 	host1x_intr_deinit(host);
 fail_deinit_syncpt:
 	host1x_syncpt_deinit(host);
+fail_reset_assert:
+	reset_control_assert(host->rst);
 fail_unprepare_disable:
 	clk_disable_unprepare(host->clk);
 	return err;
@@ -216,6 +231,7 @@ static int host1x_remove(struct platform_device *pdev)
 	host1x_unregister(host);
 	host1x_intr_deinit(host);
 	host1x_syncpt_deinit(host);
+	reset_control_deassert(host->rst);
 	clk_disable_unprepare(host->clk);
 
 	return 0;
diff --git a/drivers/gpu/host1x/dev.h b/drivers/gpu/host1x/dev.h
index 862285f2cfb8..758cd3feb545 100644
--- a/drivers/gpu/host1x/dev.h
+++ b/drivers/gpu/host1x/dev.h
@@ -19,6 +19,7 @@
 
 #include <linux/device.h>
 #include <linux/platform_device.h>
+#include <linux/reset.h>
 
 #include "channel.h"
 #include "syncpt.h"
@@ -107,6 +108,7 @@ struct host1x {
 	struct host1x_syncpt_base *bases;
 	struct device *dev;
 	struct clk *clk;
+	struct reset_control *rst;
 
 	struct mutex intr_mutex;
 	int intr_syncpt_irq;
-- 
2.12.0

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