openwrt/target/linux/brcm2708/patches-4.4/0139-FIXUP-i2c_bcm2708-Don-t-change-module-baudrate-param.patch

From 4efc768113042d0b48fdb4e170d5469f93f6e20b Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.org>
Date: Tue, 19 Jan 2016 16:28:05 +0000
Subject: [PATCH] FIXUP i2c_bcm2708: Don't change module baudrate parameter

Overwriting the baudrate module parameter creates an apparent
forced baudrate for i2c busses after the first. Not only does this
override the baudrate from DT it also prevents the bus ID from
being initialised.

Also fix whitespace errors.
---
 drivers/i2c/busses/i2c-bcm2708.c | 48 +++++++++++++++++++++-------------------
 1 file changed, 25 insertions(+), 23 deletions(-)

--- a/drivers/i2c/busses/i2c-bcm2708.c
+++ b/drivers/i2c/busses/i2c-bcm2708.c
@@ -71,7 +71,6 @@
 
 #define DRV_NAME		"bcm2708_i2c"
 
-static unsigned int baudrate_default = CONFIG_I2C_BCM2708_BAUDRATE;
 static unsigned int baudrate;
 module_param(baudrate, uint, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
 MODULE_PARM_DESC(baudrate, "The I2C baudrate");
@@ -317,25 +316,28 @@ static int bcm2708_i2c_probe(struct plat
 	struct i2c_adapter *adap;
 	unsigned long bus_hz;
 	u32 cdiv, clk_tout;
-	
-	if (!baudrate) {
-		baudrate = baudrate_default;
-		if (pdev->dev.of_node) {
-			u32 bus_clk_rate;
-			pdev->id = of_alias_get_id(pdev->dev.of_node, "i2c");
-			if (pdev->id < 0) {
-				dev_err(&pdev->dev, "alias is missing\n");
-				return -EINVAL;
-			}
-			if (!of_property_read_u32(pdev->dev.of_node,
-						"clock-frequency", &bus_clk_rate))
-				baudrate = bus_clk_rate;
-			else
-				dev_warn(&pdev->dev,
-					"Could not read clock-frequency property\n");
+	u32 baud;
+
+	baud = CONFIG_I2C_BCM2708_BAUDRATE;
+
+	if (pdev->dev.of_node) {
+		u32 bus_clk_rate;
+		pdev->id = of_alias_get_id(pdev->dev.of_node, "i2c");
+		if (pdev->id < 0) {
+			dev_err(&pdev->dev, "alias is missing\n");
+			return -EINVAL;
 		}
+		if (!of_property_read_u32(pdev->dev.of_node,
+					"clock-frequency", &bus_clk_rate))
+			baud = bus_clk_rate;
+		else
+			dev_warn(&pdev->dev,
+				"Could not read clock-frequency property\n");
 	}
 
+	if (baudrate)
+		baud = baudrate;
+
 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!regs) {
 		dev_err(&pdev->dev, "could not get IO memory\n");
@@ -419,21 +421,21 @@ static int bcm2708_i2c_probe(struct plat
 	}
 
 	bus_hz = clk_get_rate(bi->clk);
-	cdiv = bus_hz / baudrate;
+	cdiv = bus_hz / baud;
 	if (cdiv > 0xffff) {
 		cdiv = 0xffff;
-		baudrate = bus_hz / cdiv;
+		baud = bus_hz / cdiv;
 	}
-	
- 	clk_tout = 35/1000*baudrate; //35ms timeout as per SMBus specs.
- 	if (clk_tout > 0xffff)
+
+	clk_tout = 35/1000*baud; //35ms timeout as per SMBus specs.
+	if (clk_tout > 0xffff)
 		clk_tout = 0xffff;
 	
 	bi->cdiv = cdiv;
 	bi->clk_tout = clk_tout;
 
 	dev_info(&pdev->dev, "BSC%d Controller at 0x%08lx (irq %d) (baudrate %d)\n",
-		pdev->id, (unsigned long)regs->start, irq, baudrate);
+		pdev->id, (unsigned long)regs->start, irq, baud);
 
 	return 0;