[PATCH v2 03/12] phy: phy-mtk-dp: Allow probing with devicetree match

[AngeloGioacchino Del Regno]

Make it possible to decouple the registration of the DisplayPort
PHY driver from the DisplayPort IP driver by adding a devicetree
match to probe the PHY, registering an OF PHY provider and this
device's own MMIO regmap - if, and only if, this PHY driver was
registered with an OF match.

In order to retain compatibility with older devicetrees that are
not declaring the DisplayPort PHY as a separate node, the legacy
code was moved in a `mtk_dp_phy_legacy_probe()` function, which
gets called if the driver was registered by the DisplayPort one.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
---
 drivers/phy/mediatek/phy-mtk-dp.c | 84 +++++++++++++++++++++++++++----
 1 file changed, 74 insertions(+), 10 deletions(-)

diff --git a/drivers/phy/mediatek/phy-mtk-dp.c b/drivers/phy/mediatek/phy-mtk-dp.c
index bf7b3a95e72d..b042ab67ebaf 100644
--- a/drivers/phy/mediatek/phy-mtk-dp.c
+++ b/drivers/phy/mediatek/phy-mtk-dp.c
@@ -79,6 +79,7 @@
 				 XTP_LN_TX_LCTXCP1_SW3_PRE0_DEFAULT)
 
 struct mtk_dp_phy {
+	struct device *dev;
 	struct regmap *regmap;
 };
 
@@ -160,43 +161,106 @@ static const struct phy_ops mtk_dp_phy_dev_ops = {
 	.owner = THIS_MODULE,
 };
 
+static void mtk_dp_phy_legacy_remove_lookup(void *data)
+{
+	struct phy *phy = data;
+	struct mtk_dp_phy *dp_phy = phy_get_drvdata(phy);
+
+	phy_remove_lookup(phy, "dp", dev_name(dp_phy->dev));
+}
+
+static int mtk_dp_phy_legacy_probe(struct platform_device *pdev, struct mtk_dp_phy *dp_phy)
+{
+	struct device *dev = &pdev->dev;
+	struct phy *phy;
+	int ret;
+
+	dp_phy->regmap = *(struct regmap **)dev->platform_data;
+	if (!dp_phy->regmap)
+		return dev_err_probe(dev, -EINVAL, "No platform data available\n");
+
+	phy = devm_phy_create(dev, NULL, &mtk_dp_phy_dev_ops);
+	if (IS_ERR(phy))
+		return dev_err_probe(dev, PTR_ERR(phy),
+				     "Failed to create DP PHY\n");
+
+	phy_set_drvdata(phy, dp_phy);
+	phy_create_lookup(phy, "dp", dev_name(dev));
+
+	ret = devm_add_action_or_reset(dev, mtk_dp_phy_legacy_remove_lookup, phy);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static const struct regmap_config mtk_dp_phy_regmap_cfg = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.disable_locking = true,
+};
+
 static int mtk_dp_phy_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
+	struct phy_provider *provider;
 	struct mtk_dp_phy *dp_phy;
+	void __iomem *base;
 	struct phy *phy;
-	struct regmap *regs;
-
-	regs = *(struct regmap **)dev->platform_data;
-	if (!regs)
-		return dev_err_probe(dev, -EINVAL,
-				     "No data passed, requires struct regmap**\n");
 
 	dp_phy = devm_kzalloc(dev, sizeof(*dp_phy), GFP_KERNEL);
 	if (!dp_phy)
 		return -ENOMEM;
 
-	dp_phy->regmap = regs;
+	dp_phy->dev = dev;
+
+	/* If there's no devicetree, go for legacy pdev probe */
+	if (!dev->of_node)
+		return mtk_dp_phy_legacy_probe(pdev, dp_phy);
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	dp_phy->regmap = devm_regmap_init_mmio(dev, base, &mtk_dp_phy_regmap_cfg);
+	if (IS_ERR(dp_phy->regmap))
+		return PTR_ERR(dp_phy->regmap);
+
 	phy = devm_phy_create(dev, NULL, &mtk_dp_phy_dev_ops);
 	if (IS_ERR(phy))
 		return dev_err_probe(dev, PTR_ERR(phy),
 				     "Failed to create DP PHY\n");
 
 	phy_set_drvdata(phy, dp_phy);
-	if (!dev->of_node)
-		phy_create_lookup(phy, "dp", dev_name(dev));
+
+	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+	if (IS_ERR(provider))
+		return PTR_ERR(provider);
+
+	ret = devm_pm_runtime_enable(dev);
+	if (ret)
+		return ret;
 
 	return 0;
 }
 
+static const struct of_device_id mtk_dp_phy_of_match[] = {
+	{ .compatible = "mediatek,mt8195-dp-phy" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mtk_dp_phy_of_match);
+
 static struct platform_driver mtk_dp_phy_driver = {
 	.probe = mtk_dp_phy_probe,
 	.driver = {
 		.name = "mediatek-dp-phy",
+		.of_match_table = mtk_dp_phy_of_match,
 	},
 };
 module_platform_driver(mtk_dp_phy_driver);
 
+MODULE_AUTHOR("AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>");
 MODULE_AUTHOR("Markus Schneider-Pargmann <msp at baylibre.com>");
-MODULE_DESCRIPTION("MediaTek DP PHY Driver");
+MODULE_DESCRIPTION("MediaTek DisplayPort PHY Driver");
 MODULE_LICENSE("GPL");
-- 
2.54.0