linux-kernel - [PATCH V2 1/5] soc: imx: imx8m-blk-ctrl: Fix imx8mm mipi reset

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Date:   Sat,  6 Nov 2021 10:54:23 -0500
From:   Adam Ford <aford173@...il.com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     tharvey@...eworks.com, frieder.schrempf@...tron.de,
        linux-media@...r.kernel.org, laurent.pinchart@...asonboard.com,
        aford@...conembedded.com, cstevens@...conembedded.com,
        jagan@...rulasolutions.com, Adam Ford <aford173@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Peng Fan <peng.fan@....com>,
        Lucas Stach <l.stach@...gutronix.de>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH V2 1/5] soc: imx: imx8m-blk-ctrl: Fix imx8mm mipi reset

Most of the blk-ctrl reset bits are found in one register, however
there are two bits in offset 8 for pulling the MIPI DPHY out of reset
and these need to be set when IMX8MM_DISPBLK_PD_MIPI_CSI is brought
out of reset or the MIPI_CSI hangs.

Fixes: 926e57c065df ("soc: imx: imx8m-blk-ctrl: add DISP blk-ctrl")
Signed-off-by: Adam Ford <aford173@...il.com>
---

V2:  Make a note that the extra register is only for Mini/Nano DISPLAY_BLK_CTRL
     Rename the new register to mipi_phy_rst_mask
     Encapsulate the edits to this register with an if-statement

 drivers/soc/imx/imx8m-blk-ctrl.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/soc/imx/imx8m-blk-ctrl.c b/drivers/soc/imx/imx8m-blk-ctrl.c
index 519b3651d1d9..581eb4bc7f7d 100644
--- a/drivers/soc/imx/imx8m-blk-ctrl.c
+++ b/drivers/soc/imx/imx8m-blk-ctrl.c
@@ -17,6 +17,7 @@
 
 #define BLK_SFT_RSTN	0x0
 #define BLK_CLK_EN	0x4
+#define BLK_MIPI_RESET_DIV	0x8 /* Mini/Nano DISPLAY_BLK_CTRL only */
 
 struct imx8m_blk_ctrl_domain;
 
@@ -36,6 +37,15 @@ struct imx8m_blk_ctrl_domain_data {
 	const char *gpc_name;
 	u32 rst_mask;
 	u32 clk_mask;
+
+	/*
+	 * i.MX8M Mini and Nano have a third DISPLAY_BLK_CTRL register
+	 * which is used to control the reset for the MIPI Phy.
+	 * Since it's only present in certain circumstances,
+	 * an if-statement should be used before setting and clearing this
+	 * register.
+	 */
+	u32 mipi_phy_rst_mask;
 };
 
 #define DOMAIN_MAX_CLKS 3
@@ -78,6 +88,8 @@ static int imx8m_blk_ctrl_power_on(struct generic_pm_domain *genpd)
 
 	/* put devices into reset */
 	regmap_clear_bits(bc->regmap, BLK_SFT_RSTN, data->rst_mask);
+	if (data->mipi_phy_rst_mask)
+		regmap_clear_bits(bc->regmap, BLK_MIPI_RESET_DIV, data->mipi_phy_rst_mask);
 
 	/* enable upstream and blk-ctrl clocks to allow reset to propagate */
 	ret = clk_bulk_prepare_enable(data->num_clks, domain->clks);
@@ -99,6 +111,8 @@ static int imx8m_blk_ctrl_power_on(struct generic_pm_domain *genpd)
 
 	/* release reset */
 	regmap_set_bits(bc->regmap, BLK_SFT_RSTN, data->rst_mask);
+	if (data->mipi_phy_rst_mask)
+		regmap_set_bits(bc->regmap, BLK_MIPI_RESET_DIV, data->mipi_phy_rst_mask);
 
 	/* disable upstream clocks */
 	clk_bulk_disable_unprepare(data->num_clks, domain->clks);
@@ -120,6 +134,9 @@ static int imx8m_blk_ctrl_power_off(struct generic_pm_domain *genpd)
 	struct imx8m_blk_ctrl *bc = domain->bc;
 
 	/* put devices into reset and disable clocks */
+	if (data->mipi_phy_rst_mask)
+		regmap_clear_bits(bc->regmap, BLK_MIPI_RESET_DIV, data->mipi_phy_rst_mask);
+
 	regmap_clear_bits(bc->regmap, BLK_SFT_RSTN, data->rst_mask);
 	regmap_clear_bits(bc->regmap, BLK_CLK_EN, data->clk_mask);
 
@@ -488,6 +505,7 @@ static const struct imx8m_blk_ctrl_domain_data imx8mm_disp_blk_ctl_domain_data[]
 		.gpc_name = "mipi-csi",
 		.rst_mask = BIT(3) | BIT(4),
 		.clk_mask = BIT(10) | BIT(11),
+		.mipi_phy_rst_mask = BIT(16) | BIT(17),
 	},
 };
 
-- 
2.32.0