[PATCH v4 3/8] drm/msm/dsi: 28nm PHY: Get ref clock from the DT

[Matthias Kaehlcke <mka@xxxxxxxxxxxx>]

Get the ref clock of the PHY from the device tree instead of
hardcoding its name and rate.

Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
---
Changes in v4:
- always use parent rate in dsi_pll_28nm_clk_set_rate() and
   dsi_pll_28nm_clk_recalc_rate()
- pass name of VCO ref clock to pll_28nm_register() instead of
  storing it in a struct field
- updated commit message

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
- dsi_pll_28nm_clk_set_rate: changed data type of ref_clk_rate to
  unsigned long
- fixed check for EPROBE_DEFER
- renamed VCO_REF_CLK_RATE to VCO_REF_CLK_DEFAULT_RATE

Changes in v2:
- patch added to the series
---
 drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c | 36 +++++++++++++++-------
 1 file changed, 25 insertions(+), 11 deletions(-)

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 26e3a01a99c2b..7777340b03e8d 100644
--- a/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c
+++ b/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c
@@ -40,7 +40,6 @@
 
 #define NUM_PROVIDED_CLKS		2
 
-#define VCO_REF_CLK_RATE		19200000
 #define VCO_MIN_RATE			350000000
 #define VCO_MAX_RATE			750000000
 
@@ -166,17 +165,17 @@ static int dsi_pll_28nm_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 	pll_write(base + REG_DSI_28nm_PHY_PLL_LPFC1_CFG, 0x70);
 	pll_write(base + REG_DSI_28nm_PHY_PLL_LPFC2_CFG, 0x15);
 
-	rem = rate % VCO_REF_CLK_RATE;
+	rem = rate % parent_rate;
 	if (rem) {
 		refclk_cfg = DSI_28nm_PHY_PLL_REFCLK_CFG_DBLR;
 		frac_n_mode = 1;
-		div_fbx1000 = rate / (VCO_REF_CLK_RATE / 500);
-		gen_vco_clk = div_fbx1000 * (VCO_REF_CLK_RATE / 500);
+		div_fbx1000 = rate / (parent_rate / 500);
+		gen_vco_clk = div_fbx1000 * (parent_rate / 500);
 	} else {
 		refclk_cfg = 0x0;
 		frac_n_mode = 0;
-		div_fbx1000 = rate / (VCO_REF_CLK_RATE / 1000);
-		gen_vco_clk = div_fbx1000 * (VCO_REF_CLK_RATE / 1000);
+		div_fbx1000 = rate / (parent_rate / 1000);
+		gen_vco_clk = div_fbx1000 * (parent_rate / 1000);
 	}
 
 	DBG("refclk_cfg = %d", refclk_cfg);
@@ -265,7 +264,7 @@ static unsigned long dsi_pll_28nm_clk_recalc_rate(struct clk_hw *hw,
 	void __iomem *base = pll_28nm->mmio;
 	u32 sdm0, doubler, sdm_byp_div;
 	u32 sdm_dc_off, sdm_freq_seed, sdm2, sdm3;
-	u32 ref_clk = VCO_REF_CLK_RATE;
+	u32 ref_clk = parent_rate;
 	unsigned long vco_rate;
 
 	VERB("parent_rate=%lu", parent_rate);
@@ -273,7 +272,7 @@ static unsigned long dsi_pll_28nm_clk_recalc_rate(struct clk_hw *hw,
 	/* Check to see if the ref clk doubler is enabled */
 	doubler = pll_read(base + REG_DSI_28nm_PHY_PLL_REFCLK_CFG) &
 			DSI_28nm_PHY_PLL_REFCLK_CFG_DBLR;
-	ref_clk += (doubler * VCO_REF_CLK_RATE);
+	ref_clk += (doubler * ref_clk);
 
 	/* see if it is integer mode or sdm mode */
 	sdm0 = pll_read(base + REG_DSI_28nm_PHY_PLL_SDM_CFG0);
@@ -514,11 +513,12 @@ static void dsi_pll_28nm_destroy(struct msm_dsi_pll *pll)
 	pll_28nm->clk_data.clk_num = 0;
 }
 
-static int pll_28nm_register(struct dsi_pll_28nm *pll_28nm)
+static int pll_28nm_register(struct dsi_pll_28nm *pll_28nm,
+			     const char *ref_clk_name)
 {
 	char clk_name[32], parent1[32], parent2[32], vco_name[32];
 	struct clk_init_data vco_init = {
-		.parent_names = (const char *[]){ "xo" },
+		.parent_names = &ref_clk_name,
 		.num_parents = 1,
 		.name = vco_name,
 		.flags = CLK_IGNORE_UNUSED,
@@ -593,6 +593,8 @@ struct msm_dsi_pll *msm_dsi_pll_28nm_init(struct platform_device *pdev,
 {
 	struct dsi_pll_28nm *pll_28nm;
 	struct msm_dsi_pll *pll;
+	struct clk *vco_ref_clk;
+	const char *vco_ref_clk_name;
 	int ret;
 
 	if (!pdev)
@@ -605,6 +607,18 @@ struct msm_dsi_pll *msm_dsi_pll_28nm_init(struct platform_device *pdev,
 	pll_28nm->pdev = pdev;
 	pll_28nm->id = id;
 
+	vco_ref_clk = devm_clk_get(&pdev->dev, "ref");
+	if (!IS_ERR(vco_ref_clk)) {
+		vco_ref_clk_name = __clk_get_name(vco_ref_clk);
+	} else {
+		ret = PTR_ERR(vco_ref_clk);
+		if (ret == -EPROBE_DEFER)
+			ERR_PTR(ret);
+
+		dev_warn(&pdev->dev, "'ref' clock is not specified, using default name\n");
+		vco_ref_clk_name = "xo";
+	}
+
 	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__);
@@ -637,7 +651,7 @@ struct msm_dsi_pll *msm_dsi_pll_28nm_init(struct platform_device *pdev,
 		return ERR_PTR(-EINVAL);
 	}
 
-	ret = pll_28nm_register(pll_28nm);
+	ret = pll_28nm_register(pll_28nm, vco_ref_clk_name);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to register PLL: %d\n", ret);
 		return ERR_PTR(ret);
-- 
2.20.0.rc1.387.gf8505762e3-goog