From: Lucas Stach <l.stach@pengutronix.de>
Date: Fri, 19 Jan 2018 15:05:40 +0100
Subject: drm/etnaviv: add support for slave interface clock
Git-commit: 65f037e8e9085b9d6d76e5894c1e5353602202be
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

The slave interface clock is a clock input found on newer cores to gate
the register interface. For now we simply ungate it when the GPU is in
active state.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/etnaviv/etnaviv_gpu.c |   13 +++++++++++++
 drivers/gpu/drm/etnaviv/etnaviv_gpu.h |    1 +
 2 files changed, 14 insertions(+)

--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -1383,6 +1383,12 @@ static int etnaviv_gpu_clk_enable(struct
 {
 	int ret;
 
+	if (gpu->clk_reg) {
+		ret = clk_prepare_enable(gpu->clk_reg);
+		if (ret)
+			return ret;
+	}
+
 	if (gpu->clk_bus) {
 		ret = clk_prepare_enable(gpu->clk_bus);
 		if (ret)
@@ -1421,6 +1427,8 @@ static int etnaviv_gpu_clk_disable(struc
 		clk_disable_unprepare(gpu->clk_core);
 	if (gpu->clk_bus)
 		clk_disable_unprepare(gpu->clk_bus);
+	if (gpu->clk_reg)
+		clk_disable_unprepare(gpu->clk_reg);
 
 	return 0;
 }
@@ -1676,6 +1684,11 @@ static int etnaviv_gpu_platform_probe(st
 	}
 
 	/* Get Clocks: */
+	gpu->clk_reg = devm_clk_get(&pdev->dev, "reg");
+	DBG("clk_reg: %p", gpu->clk_reg);
+	if (IS_ERR(gpu->clk_reg))
+		gpu->clk_reg = NULL;
+
 	gpu->clk_bus = devm_clk_get(&pdev->dev, "bus");
 	DBG("clk_bus: %p", gpu->clk_bus);
 	if (IS_ERR(gpu->clk_bus))
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
@@ -147,6 +147,7 @@ struct etnaviv_gpu {
 
 	/* Power Control: */
 	struct clk *clk_bus;
+	struct clk *clk_reg;
 	struct clk *clk_core;
 	struct clk *clk_shader;