[PATCH v3 2/8] drm/msm/dsi: 28nm 8960 PHY: Get ref clock from the DT

[Matthias Kaehlcke <mka@chromium.org>]

Get the ref clock of the PHY from the device tree instead of
hardcoding its name and rate. Use default values if the ref
clock is not specified.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---
Changes in v3:
- use default name and rate if the ref clock is not specified
  in the DT
- store vco_ref_clk_name instead of vco_ref_clk
- fixed check for EPROBE_DEFER
- renamed VCO_REF_CLK_RATE to VCO_REF_CLK_DEFAULT_RATE

Changes in v2:
- patch added to the series
---
 .../gpu/drm/msm/dsi/pll/dsi_pll_28nm_8960.c   | 28 +++++++++++++++----
 1 file changed, 23 insertions(+), 5 deletions(-)

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 49008451085b8..3af678d3317f6 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
@@ -47,9 +47,9 @@
 
 #define NUM_PROVIDED_CLKS	2
 
-#define VCO_REF_CLK_RATE	27000000
-#define VCO_MIN_RATE		600000000
-#define VCO_MAX_RATE		1200000000
+#define VCO_REF_CLK_DEFAULT_RATE	27000000
+#define VCO_MIN_RATE			600000000
+#define VCO_MAX_RATE			1200000000
 
 #define DSI_BYTE_PLL_CLK	0
 #define DSI_PIXEL_PLL_CLK	1
@@ -75,6 +75,8 @@ struct dsi_pll_28nm {
 	struct platform_device *pdev;
 	void __iomem *mmio;
 
+	const char *vco_ref_clk_name;
+
 	/* custom byte clock divider */
 	struct clk_bytediv *bytediv;
 
@@ -125,7 +127,10 @@ static int dsi_pll_28nm_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 	DBG("rate=%lu, parent's=%lu", rate, parent_rate);
 
 	temp = rate / 10;
-	val = VCO_REF_CLK_RATE / 10;
+	if (parent_rate)
+		val = parent_rate / 10;
+	else
+		val = VCO_REF_CLK_DEFAULT_RATE / 10;
 	fb_divider = (temp * VCO_PREF_DIV_RATIO) / val;
 	fb_divider = fb_divider / 2 - 1;
 	pll_write(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_1,
@@ -410,7 +415,7 @@ static int pll_28nm_register(struct dsi_pll_28nm *pll_28nm)
 {
 	char *clk_name, *parent_name, *vco_name;
 	struct clk_init_data vco_init = {
-		.parent_names = (const char *[]){ "pxo" },
+		.parent_names = &pll_28nm->vco_ref_clk_name,
 		.num_parents = 1,
 		.flags = CLK_IGNORE_UNUSED,
 		.ops = &clk_ops_dsi_pll_28nm_vco,
@@ -494,6 +499,7 @@ struct msm_dsi_pll *msm_dsi_pll_28nm_8960_init(struct platform_device *pdev,
 {
 	struct dsi_pll_28nm *pll_28nm;
 	struct msm_dsi_pll *pll;
+	struct clk *vco_ref_clk;
 	int ret;
 
 	if (!pdev)
@@ -506,6 +512,18 @@ struct msm_dsi_pll *msm_dsi_pll_28nm_8960_init(struct platform_device *pdev,
 	pll_28nm->pdev = pdev;
 	pll_28nm->id = id + 1;
 
+	vco_ref_clk = devm_clk_get(&pdev->dev, "ref");
+	if (!IS_ERR(vco_ref_clk)) {
+		pll_28nm->vco_ref_clk_name = __clk_get_name(vco_ref_clk);
+	} else {
+		ret = PTR_ERR(vco_ref_clk);
+		if (ret == -EPROBE_DEFER)
+			return ERR_PTR(ret);
+
+		dev_warn(&pdev->dev, "'ref' clock is not specified, using default name\n");
+		pll_28nm->vco_ref_clk_name = "pxo";
+	}
+
 	pll_28nm->mmio = msm_ioremap(pdev, "dsi_pll", "DSI_PLL");
 	if (IS_ERR_OR_NULL(pll_28nm->mmio)) {
 		dev_err(&pdev->dev, "%s: failed to map pll base\n", __func__);
-- 
2.20.0.rc1.387.gf8505762e3-goog