Re: [PATCH] kernel 2.6.11.6 - I2C adaptor for ColdFire 5282 CPU

From: Randy.Dunlap
Date: Tue Apr 05 2005 - 22:45:30 EST


Derek Cheung wrote:

Below please find the patch file I "diff" against Linux 2.6.11.6. It
contains the I2C adaptor for ColdFire 5282 CPU. Since most ColdFire
CPU
shares the same I2C register set, the code can be easily adopted for
other ColdFire CPUs for I2C operations.

I have tested the code on a ColdFire 5282Lite CPU board
(http://www.axman.com/Pages/cml-5282LITE.html) running uClinux 2.6.9
with LM75 and DS1621 temperature sensor chips. As advised by David
McCullough, the code will be incorporated in the next uClinux
release.

The patch contains:

linux/drivers/i2c/busses
i2c-mcf5282.c (new file)

Limit source code lines to 80 characters (including comment lines).

+static int mcf5282_read_data():

+ if (ackType == NACK)
+ *MCF5282_I2C_I2CR |= MCF5282_I2C_I2CR_TXAK; // generate NA
+ else
+ *MCF5282_I2C_I2CR &= ~MCF5282_I2C_I2CR_TXAK; // generate ACK

The 2 assignments above should begin in the same column.
Also, kernel comment style is C /* ... */, not C++ (or C99) // style.

+ if (timeout <= 0)
+ printk("%s - I2C IIF never set. Timeout is %d \n", __FUNCTION__, timeout);

All printk() calls should have a KERN_WARNING or KERN_ERR or
KERN_DEBUG level used in it...

+ if (timeout <= 0 )

No space before the closing ')'.

+static int mcf5282_write_data():

+ if (timeout <=0)
should be (add a space)
+ if (timeout <= 0)

+ if (timeout <= 0 )
Drop space before ')'

Drop the debugging printk's and DEREK_DEBUG blocks.

+ switch (size) {
+ case I2C_SMBUS_QUICK:
We usually don't indent the 'case' line to save one indent level.
It helps when using 8-space tabs.

+ // this is not yet ready!!!
Put blocks like this inside
#if 0
or
#if NOT_READY_YET
#endif
blocks.

+static u32 mcf5282_func(struct i2c_adapter *adapter)
+{
+ return(I2C_FUNC_SMBUS_QUICK |
+ I2C_FUNC_SMBUS_BYTE |
+ I2C_FUNC_SMBUS_PROC_CALL |
+ I2C_FUNC_SMBUS_BYTE_DATA |
+ I2C_FUNC_SMBUS_WORD_DATA |
+ I2C_FUNC_SMBUS_BLOCK_DATA);
+};
Don't use parens on return statements.


+static int __init i2c_mcf5282_init():
is not driver registration needed? I don't know the I2C
subsystem, so maybe not...



Big Question: does most Coldfire or I2C use volatile so heavily,
or is it just this one driver that does that? Volatile here
semms very overused.


--
~Randy
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