linux-kernel - Re: [rtc-linux] [PATCH] rtc: rtc-max6900: SMBus support.

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Message-ID: <20100115163712.3e54861d@linux.lan.towertech.it>
Date:	Fri, 15 Jan 2010 16:37:12 +0100
From:	Alessandro Zummo <a.zummo@...ertech.it>
To:	rtc-linux@...glegroups.com
Cc:	lethal@...ux-sh.org, Dale Farnsworth <dale@...nsworth.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [rtc-linux] [PATCH] rtc: rtc-max6900: SMBus support.

On Thu, 14 Jan 2010 20:32:35 +0900
Paul Mundt <lethal@...ux-sh.org> wrote:

> The current rtc-max6900 driver only supports getting and setting the time
> through bursting, which requires a controller capable of such. As
> bursting is merely an optimization, we can also opt for the non-burst
> fallback path that pokes at the date/time registers individually.

 almost ok, review below.


> -static int max6900_i2c_read_regs(struct i2c_client *client, u8 *buf)
> +static unsigned int smbus_mode;	/* disabled by default, prefer bursting */

 that one should be per-device.

> +static int max6900_i2c_smbus_read(struct i2c_client *client, u8 *buf)
> +{
> +	int rc = 0, i;

 no need to init rc

> +static int max6900_i2c_smbus_write(struct i2c_client *client, u8 const *buf)
> +{
> +	int rc = 0, i;
> +
> +	for (i = 0; i < MAX6900_REG_LEN; i++)
> +		rc |= i2c_smbus_write_byte_data(client,
> +				MAX6900_REG_WRITE(i), buf[i]);

 please check rc at each write.

 you might want to check if you'll have troubles if you read/write
 when the minutes are changing.

 you might also want to investigate block SMbus messages. 

-- 

 Best regards,

 Alessandro Zummo,
  Tower Technologies - Torino, Italy

  http://www.towertech.it

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