linux-kernel - [PATCH v2 4/7] drm/rockchip: dsi: Support optional AHB clock

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Date: Thu,  9 May 2024 14:07:12 +0200
From: Alex Bee <knaerzche@...il.com>
To: Sandy Huang <hjc@...k-chips.com>,
	Heiko Stübner <heiko@...ech.de>,
	Andy Yan <andy.yan@...k-chips.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>,
	Daniel Vetter <daniel@...ll.ch>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...nel.org>
Cc: dri-devel@...ts.freedesktop.org,
	devicetree@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-rockchip@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-clk@...r.kernel.org,
	Alex Bee <knaerzche@...il.com>
Subject: [PATCH v2 4/7] drm/rockchip: dsi: Support optional AHB clock

Some integrations of the IP additionally have an AHB clock which has to be
enabled before accessing the registers is possible.

Add support for it as an optional clock.

Signed-off-by: Alex Bee <knaerzche@...il.com>
---
changes since v1:
 - new patch

 .../gpu/drm/rockchip/dw-mipi-dsi-rockchip.c   | 25 +++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
index 4cc8ed8f4fbd..6ed64cc35275 100644
--- a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
@@ -265,6 +265,7 @@ struct dw_mipi_dsi_rockchip {
 	struct clk *pllref_clk;
 	struct clk *grf_clk;
 	struct clk *phy_cfg_clk;
+	struct clk *ahb_clk;
 
 	/* dual-channel */
 	bool is_slave;
@@ -1153,7 +1154,15 @@ static int dw_mipi_dsi_dphy_init(struct phy *phy)
 			goto err_init;
 		}
 
+		ret = clk_prepare_enable(dsi->ahb_clk);
+		if (ret) {
+			clk_disable_unprepare(dsi->grf_clk);
+			clk_disable_unprepare(dsi->pclk);
+			goto err_init;
+		}
+
 		ret = dsi->cdata->dphy_rx_init(phy);
+		clk_disable_unprepare(dsi->ahb_clk);
 		clk_disable_unprepare(dsi->grf_clk);
 		clk_disable_unprepare(dsi->pclk);
 		if (ret < 0)
@@ -1240,6 +1249,12 @@ static int dw_mipi_dsi_dphy_power_on(struct phy *phy)
 		goto err_phy_cfg_clk;
 	}
 
+	ret = clk_prepare_enable(dsi->ahb_clk);
+	if (ret) {
+		DRM_DEV_ERROR(dsi->dev, "Failed to enable ahb_clk: %d\n", ret);
+		goto err_ahb_clk;
+	}
+
 	/* do soc-variant specific init */
 	if (dsi->cdata->dphy_rx_power_on) {
 		ret = dsi->cdata->dphy_rx_power_on(phy);
@@ -1269,6 +1284,8 @@ static int dw_mipi_dsi_dphy_power_on(struct phy *phy)
 	return ret;
 
 err_pwr_on:
+	clk_disable_unprepare(dsi->ahb_clk);
+err_ahb_clk:
 	clk_disable_unprepare(dsi->phy_cfg_clk);
 err_phy_cfg_clk:
 	clk_disable_unprepare(dsi->grf_clk);
@@ -1296,6 +1313,7 @@ static int dw_mipi_dsi_dphy_power_off(struct phy *phy)
 			DRM_DEV_ERROR(dsi->dev, "hardware-specific phy shutdown failed: %d\n", ret);
 	}
 
+	clk_disable_unprepare(dsi->ahb_clk);
 	clk_disable_unprepare(dsi->grf_clk);
 	clk_disable_unprepare(dsi->pclk);
 
@@ -1429,6 +1447,13 @@ static int dw_mipi_dsi_rockchip_probe(struct platform_device *pdev)
 		}
 	}
 
+	dsi->ahb_clk = devm_clk_get_optional(dev, "ahb");
+	if (IS_ERR(dsi->ahb_clk)) {
+		ret = PTR_ERR(dsi->ahb_clk);
+		DRM_DEV_ERROR(dev, "Unable to get ahb_clk: %d\n", ret);
+		return ret;
+	}
+
 	dsi->grf_regmap = syscon_regmap_lookup_by_phandle(np, "rockchip,grf");
 	if (IS_ERR(dsi->grf_regmap)) {
 		DRM_DEV_ERROR(dev, "Unable to get rockchip,grf\n");
-- 
2.43.2