From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Chou <thomas@wytron.com.tw>
Date: Mon, 12 Jul 2010 13:51:48 +0800
Subject: [U-Boot] [PATCH] i2c: fix SDA contention in read_byte()
In-Reply-To: <4C3AA15E.6070203@emk-elektronik.de>
References: <1278396866-5571-1-git-send-email-thomas@wytron.com.tw>	<AANLkTikUom99jC9Wjc0jejiG814_zsGIq7DmjtAMp8Go@mail.gmail.com>	<4C3409F6.9000902@emk-elektronik.de>
	<4C3A96AF.9080109@wytron.com.tw>
	<4C3AA15E.6070203@emk-elektronik.de>
Message-ID: <4C3AAD74.7090307@wytron.com.tw>
List-Id: <u-boot.lists.denx.de>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
To: u-boot@lists.denx.de

Reinhard Meyer wrote:
> Its even simpler, provided the  hardware can do open collector. Here was 
> my solution for AVR32AP7000:
> 

Then we could add a config for open drain similar to that of linux driver.

# ifndef I2C_SDA
#  ifdef CONFIG_SOFT_I2C_GPIO_SDA_IS_OPEN_DRAIN
#   define I2C_SDA(bit) gpio_set_value(CONFIG_SOFT_I2C_GPIO_SDA, bit)
#  else
#   define I2C_SDA(bit) \
     if (bit) {                        \
         gpio_direction_input(CONFIG_SOFT_I2C_GPIO_SDA);    \
     } else {                        \
         gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SDA, 0);\
     }
#  endif
# endif

BTW, will you be interested in using common gpio framework for avr32 family?

Cheers,
Thomas