openwrtv4/target/linux/brcm2708/patches-3.10/0036-set-i2c-speed-via-module-parameter-or-menuconfig.-Th.patch

From ec78c7da4fe9f7289cdc3e948b70a43c900f2be4 Mon Sep 17 00:00:00 2001
From: popcornmix <popcornmix@gmail.com>
Date: Wed, 3 Oct 2012 20:08:19 +0100
Subject: [PATCH 036/196] set i2c speed via module-parameter or menuconfig.
 Thanks FrankBoesing

---
 drivers/i2c/busses/Kconfig       | 11 +++++++++++
 drivers/i2c/busses/i2c-bcm2708.c | 12 ++++++++----
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 290aee4..abaff1a 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -355,6 +355,17 @@ config I2C_BCM2708
 	  support for the BCM2708. BSC is a Broadcom proprietary bus compatible
 	  with I2C/TWI/SMBus.
 
+config I2C_BCM2708_BAUDRATE
+    prompt "BCM2708 I2C baudrate"
+	depends on I2C_BCM2708
+    int
+    default 100000
+    help
+      Set the I2C baudrate. This will alter the default value. A
+      different baudrate can be set by using a module parameter as well. If
+      no parameter is provided when loading, this is the value that will be
+      used.
+
 config I2C_BLACKFIN_TWI
 	tristate "Blackfin TWI I2C support"
 	depends on BLACKFIN
diff --git a/drivers/i2c/busses/i2c-bcm2708.c b/drivers/i2c/busses/i2c-bcm2708.c
index 7cae615..3391889 100644
--- a/drivers/i2c/busses/i2c-bcm2708.c
+++ b/drivers/i2c/busses/i2c-bcm2708.c
@@ -66,11 +66,15 @@
 #define BSC_S_DONE		0x00000002
 #define BSC_S_TA		0x00000001
 
-#define I2C_CLOCK_HZ	100000 /* FIXME: get from DT */
 #define I2C_TIMEOUT_MS	150
 
 #define DRV_NAME	"bcm2708_i2c"
 
+static unsigned int baudrate = CONFIG_I2C_BCM2708_BAUDRATE;
+module_param(baudrate, uint, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
+MODULE_PARM_DESC(baudrate, "The I2C baudrate");
+
+
 struct bcm2708_i2c {
 	struct i2c_adapter adapter;
 
@@ -148,7 +152,7 @@ static inline void bcm2708_bsc_setup(struct bcm2708_i2c *bi)
 	u32 c = BSC_C_I2CEN | BSC_C_INTD | BSC_C_ST | BSC_C_CLEAR_1;
 
 	bus_hz = clk_get_rate(bi->clk);
-	cdiv = bus_hz / I2C_CLOCK_HZ;
+	cdiv = bus_hz / baudrate;
 
 	if (bi->msg->flags & I2C_M_RD)
 		c |= BSC_C_INTR | BSC_C_READ;
@@ -331,8 +335,8 @@ static int bcm2708_i2c_probe(struct platform_device *pdev)
 		goto out_free_irq;
 	}
 
-	dev_info(&pdev->dev, "BSC%d Controller at 0x%08lx (irq %d)\n",
-		pdev->id, (unsigned long)regs->start, irq);
+	dev_info(&pdev->dev, "BSC%d Controller at 0x%08lx (irq %d) (baudrate %dk)\n",
+		pdev->id, (unsigned long)regs->start, irq, baudrate/1000);
 
 	return 0;
 
-- 
1.9.1