linux-kernel - [PATCH 2/4] i2c: nomadik: support Mobileye EyeQ6H I2C controller

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Message-Id: <20241008-mbly-i2c-v1-2-a06c1317a2f7@bootlin.com>
Date: Tue, 08 Oct 2024 12:29:41 +0200
From: Théo Lebrun <theo.lebrun@...tlin.com>
To: Linus Walleij <linus.walleij@...aro.org>, 
 Andi Shyti <andi.shyti@...nel.org>, Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org, linux-i2c@...r.kernel.org, 
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Vladimir Kondratiev <vladimir.kondratiev@...ileye.com>, 
 Grégory Clement <gregory.clement@...tlin.com>, 
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
 Tawfik Bayouk <tawfik.bayouk@...ileye.com>, 
 Théo Lebrun <theo.lebrun@...tlin.com>
Subject: [PATCH 2/4] i2c: nomadik: support Mobileye EyeQ6H I2C controller

Add EyeQ6H support to the nmk-i2c AMBA driver. It shares the same quirk
as EyeQ5: the memory bus only supports 32-bit accesses. Avoid writeb()
and readb() by reusing the same `priv->has_32b_bus` flag.

It does NOT need to write speed-mode specific value into a register;
therefore it does not depend on the mobileye,olb DT property.

Refactoring is done using is_eyeq5 and is_eyeq6h boolean local
variables. Sort variables in reverse christmas tree to try and
introduce some logic into the ordering.

Signed-off-by: Théo Lebrun <theo.lebrun@...tlin.com>
---
 drivers/i2c/busses/i2c-nomadik.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
index ad0f02acdb1215a1c04729f97bb14a4d93f88456..ea511d3a58073eaedb63850026e05b59427a69c6 100644
--- a/drivers/i2c/busses/i2c-nomadik.c
+++ b/drivers/i2c/busses/i2c-nomadik.c
@@ -6,10 +6,10 @@
  * I2C master mode controller driver, used in Nomadik 8815
  * and Ux500 platforms.
  *
- * The Mobileye EyeQ5 platform is also supported; it uses
+ * The Mobileye EyeQ5 and EyeQ6H platforms are also supported; they use
  * the same Ux500/DB8500 IP block with two quirks:
  *  - The memory bus only supports 32-bit accesses.
- *  - A register must be configured for the I2C speed mode;
+ *  - (only EyeQ5) A register must be configured for the I2C speed mode;
  *    it is located in a shared register region called OLB.
  *
  * Author: Srinidhi Kasagar <srinidhi.kasagar@...ricsson.com>
@@ -1046,8 +1046,6 @@ static int nmk_i2c_eyeq5_probe(struct nmk_i2c_dev *priv)
 	struct regmap *olb;
 	unsigned int id;
 
-	priv->has_32b_bus = true;
-
 	olb = syscon_regmap_lookup_by_phandle_args(np, "mobileye,olb", 1, &id);
 	if (IS_ERR(olb))
 		return PTR_ERR(olb);
@@ -1070,13 +1068,15 @@ static int nmk_i2c_eyeq5_probe(struct nmk_i2c_dev *priv)
 
 static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id)
 {
-	int ret = 0;
-	struct nmk_i2c_dev *priv;
-	struct device_node *np = adev->dev.of_node;
-	struct device *dev = &adev->dev;
-	struct i2c_adapter *adap;
 	struct i2c_vendor_data *vendor = id->data;
+	struct device_node *np = adev->dev.of_node;
+	bool is_eyeq6h = of_device_is_compatible(np, "mobileye,eyeq6h-i2c");
+	bool is_eyeq5 = of_device_is_compatible(np, "mobileye,eyeq5-i2c");
 	u32 max_fifo_threshold = (vendor->fifodepth / 2) - 1;
+	struct device *dev = &adev->dev;
+	struct nmk_i2c_dev *priv;
+	struct i2c_adapter *adap;
+	int ret = 0;
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
@@ -1084,10 +1084,10 @@ static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id)
 
 	priv->vendor = vendor;
 	priv->adev = adev;
-	priv->has_32b_bus = false;
+	priv->has_32b_bus = is_eyeq5 || is_eyeq6h;
 	nmk_i2c_of_probe(np, priv);
 
-	if (of_device_is_compatible(np, "mobileye,eyeq5-i2c")) {
+	if (is_eyeq5) {
 		ret = nmk_i2c_eyeq5_probe(priv);
 		if (ret)
 			return dev_err_probe(dev, ret, "failed OLB lookup\n");

-- 
2.46.2