Re: [PATCH] kernel 2.6.11.6 - I2C adaptor for ColdFire 5282 CPU
From: Jean Delvare (khali_at_linux-fr.org)
Date: 04/18/05
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- In reply to: Derek Cheung: "RE: [PATCH] kernel 2.6.11.6 - I2C adaptor for ColdFire 5282 CPU"
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Date: Mon, 18 Apr 2005 23:10:51 +0200 To: "Derek Cheung" <derek.cheung@sympatico.ca>
Hi Derek,
My comments on your code:
> + Changes:
> + v0.1 26 March 2005
> + Initial Release - developed on uClinux with 2.6.9 kernel
> + v0.2 11 April 2005
> + Coding style changes
> +
Changelogs are not welcome in kernel code.
> +#include <linux/config.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/errno.h>
> +#include <linux/i2c.h>
> +#include <linux/delay.h>
> +#include <linux/string.h>
> +#include <asm/coldfire.h>
> +#include <asm/m528xsim.h>
> +#include <asm/types.h>
> +#include "i2c-mcf5282.h"
I can't see that you need config.h, errno.h nor string.h.
> + /* printk(KERN_DEBUG "%s I2DR is %.2x \n", __FUNCTION__, *rxData); */
Please don't include dead code.
> + timeout = 500;
You use a timeout of 500 in various places. I wonder if you shouldn't
have a define for it - in case it needs to be altered later.
> + while (timeout-- && !(*MCF5282_I2C_I2SR & MCF5282_I2C_I2SR_IIF))
> + udelay(1);
> + if (timeout <= 0)
> + printk(KERN_WARNING "%s - I2C IIF never set \n", __FUNCTION__);
These constructs are error-prone. I personally prefer:
while(--timeout && ...)
...
if (!timeout)
...
> + rc += mcf5282_write_data(data->word & 0x00FF);
> + rc += mcf5282_write_data((data->word & 0x00FF) >> 8);
Looks like a bug to me.
> +static s32 mcf5282_i2c_access(struct i2c_adapter *adap, u16 addr,
> + unsigned short flags, char read_write,
> + u8 command, int size, union i2c_smbus_data *data)
> (...)
> + printk(KERN_WARNING "Not support I2C_SMBUS_PROC_CALL yet \n");
Don't use printk when you can user dev_{dbg,warn,info,err}. Also, please
no space before newline.
> +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 say you support I2C_FUNC_SMBUS_PROC_CALL and
I2C_FUNC_SMBUS_BLOCK_DATA when you in fact don't. Not supporting some
functions is no problem, just leave them out for now. You can always
submit patches later.
> --- linux-2.6.11.6/drivers/i2c/busses/i2c-mcf5282.h 1969-12-31 19:00:00.000000000 -0500
> +++ linux_dev/drivers/i2c/busses/i2c-mcf5282.h 2005-04-12 20:45:00.000000000 -0400
I see no reason to have a separate .h file for this.
> --- linux-2.6.11.6/drivers/i2c/busses/Kconfig 2005-03-25 22:28:29.000000000 -0500
> +++ linux_dev/drivers/i2c/busses/Kconfig 2005-04-12 20:45:24.000000000 -0400
> @@ -39,6 +39,16 @@ config I2C_ALI15X3
> This driver can also be built as a module. If so, the module
> will be called i2c-ali15x3.
>
> +config I2C_MCF5282
Please keep the entries in somewhat alphabetical order.
> --- linux-2.6.11.6/drivers/i2c/busses/Makefile 2005-03-25 22:28:39.000000000 -0500
> +++ linux_dev/drivers/i2c/busses/Makefile 2005-04-13 18:52:03.000000000 -0400
> @@ -40,6 +40,7 @@ obj-$(CONFIG_I2C_VIAPRO) += i2c-viapro.o
> obj-$(CONFIG_I2C_VOODOO3) += i2c-voodoo3.o
> obj-$(CONFIG_SCx200_ACB) += scx200_acb.o
> obj-$(CONFIG_SCx200_I2C) += scx200_i2c.o
> +obj-$(CONFIG_I2C_MCF5282) += i2c-mcf5282.o
Ditto.
> +#define MCF5282_I2C_I2CR_IEN (0x80) /* I2C enable */
> +#define MCF5282_I2C_I2CR_IIEN (0x40) /* interrupt enable */
> +#define MCF5282_I2C_I2CR_MSTA (0x20) /* master/slave mode */
> +#define MCF5282_I2C_I2CR_MTX (0x10) /* transmit/receive mode */
> +#define MCF5282_I2C_I2CR_TXAK (0x08) /* transmit acknowledge enable */
> +#define MCF5282_I2C_I2CR_RSTA (0x04) /* repeat start */
> +
> +#define MCF5282_I2C_I2SR_ICF (0x80) /* data transfer bit */
> +#define MCF5282_I2C_I2SR_IAAS (0x40) /* I2C addressed as a slave */
> +#define MCF5282_I2C_I2SR_IBB (0x20) /* I2C bus busy */
> +#define MCF5282_I2C_I2SR_IAL (0x10) /* aribitration lost */
> +#define MCF5282_I2C_I2SR_SRW (0x04) /* slave read/write */
> +#define MCF5282_I2C_I2SR_IIF (0x02) /* I2C interrupt */
> +#define MCF5282_I2C_I2SR_RXAK (0x01) /* received acknowledge */
Parentheses are not needed here.
Thanks,
-- Jean Delvare - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
- Previous message: Jesper Juhl: "Re: [PATCH 1/2] new valid_signal function"
- In reply to: Derek Cheung: "RE: [PATCH] kernel 2.6.11.6 - I2C adaptor for ColdFire 5282 CPU"
- Next in thread: Greg KH: "Re: [PATCH] kernel 2.6.11.6 - I2C adaptor for ColdFire 5282 CPU"
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