[PATCH v2 2/2] drm/msm: Set CLK_IGNORE_UNUSED flag for PLL clocks

[Archit Taneja]

The DSI/HDMI PLLs in MSM require resources like interface clocks, power
domains to be enabled before we can access their registers.

The clock framework doesn't have a mechanism at the moment where we can
tie such resources to a clock, so we make sure that the KMS driver enables
these resources whenever a PLL is expected to be in use.

One place where we can't ensure the resource dependencies are met is when
the clock framework tries to disable unused clocks. The KMS driver doesn't
know when the clock framework calls the is_enabled clk_op, and hence can't
enable interface clocks/power domains beforehand.

We set the CLK_IGNORE_UNUSED flag for PLL clocks for now. This needs to be
revisited, since bootloaders can enable display, and we would want to
disable the PLL clocks if there isn't a display driver using them.

Cc: Stephen Boyd <sboyd at codeaurora.org>
Signed-off-by: Archit Taneja <architt at codeaurora.org>
---
 drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c      | 1 +
 drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm_8960.c | 1 +
 drivers/gpu/drm/msm/hdmi/hdmi_phy_8996.c        | 1 +
 drivers/gpu/drm/msm/hdmi/hdmi_pll_8960.c        | 1 +
 4 files changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c b/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c
index 598fdaf..26e3a01 100644
--- a/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c
+++ b/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c
@@ -521,6 +521,7 @@ static int pll_28nm_register(struct dsi_pll_28nm *pll_28nm)
 		.parent_names = (const char *[]){ "xo" },
 		.num_parents = 1,
 		.name = vco_name,
+		.flags = CLK_IGNORE_UNUSED,
 		.ops = &clk_ops_dsi_pll_28nm_vco,
 	};
 	struct device *dev = &pll_28nm->pdev->dev;
diff --git a/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm_8960.c b/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm_8960.c
index 38c90e1..4900845 100644
--- a/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm_8960.c
+++ b/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm_8960.c
@@ -412,6 +412,7 @@ static int pll_28nm_register(struct dsi_pll_28nm *pll_28nm)
 	struct clk_init_data vco_init = {
 		.parent_names = (const char *[]){ "pxo" },
 		.num_parents = 1,
+		.flags = CLK_IGNORE_UNUSED,
 		.ops = &clk_ops_dsi_pll_28nm_vco,
 	};
 	struct device *dev = &pll_28nm->pdev->dev;
diff --git a/drivers/gpu/drm/msm/hdmi/hdmi_phy_8996.c b/drivers/gpu/drm/msm/hdmi/hdmi_phy_8996.c
index aa94a55..143eab4 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi_phy_8996.c
+++ b/drivers/gpu/drm/msm/hdmi/hdmi_phy_8996.c
@@ -702,6 +702,7 @@ static int hdmi_8996_pll_is_enabled(struct clk_hw *hw)
 	.ops = &hdmi_8996_pll_ops,
 	.parent_names = hdmi_pll_parents,
 	.num_parents = ARRAY_SIZE(hdmi_pll_parents),
+	.flags = CLK_IGNORE_UNUSED,
 };
 
 int msm_hdmi_pll_8996_init(struct platform_device *pdev)
diff --git a/drivers/gpu/drm/msm/hdmi/hdmi_pll_8960.c b/drivers/gpu/drm/msm/hdmi/hdmi_pll_8960.c
index 92da69a..9959075 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi_pll_8960.c
+++ b/drivers/gpu/drm/msm/hdmi/hdmi_pll_8960.c
@@ -424,6 +424,7 @@ static int hdmi_pll_set_rate(struct clk_hw *hw, unsigned long rate,
 	.ops = &hdmi_pll_ops,
 	.parent_names = hdmi_pll_parents,
 	.num_parents = ARRAY_SIZE(hdmi_pll_parents),
+	.flags = CLK_IGNORE_UNUSED,
 };
 
 int msm_hdmi_pll_8960_init(struct platform_device *pdev)
-- 
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