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Message-ID: <D99582E5322435468A77E74BB0039E7B1D1655BFBB@SRV02.hamburg.garz-fricke.de>
Date: Wed, 23 Nov 2011 10:31:44 +0100
From: Carsten Behling <carsten.behling@...z-fricke.com>
To: "Voss, Nikolaus" <N.Voss@...nmann.de>
CC: "'linux-i2c@...r.kernel.org'" <linux-i2c@...r.kernel.org>,
"'linux-arm-kernel@...ts.infradead.org'"
<linux-arm-kernel@...ts.infradead.org>,
"'linux-kernel@...r.kernel.org'" <linux-kernel@...r.kernel.org>
Subject: AW: [PATCH v5 3/4] drivers/i2c/busses/i2c-at91.c: add new driver
> this case is already catched in at91_do_twi_transfer():
Sorry, I did not found this code in your patch.
(http://www.mail-archive.com/linux-i2c@vger.kernel.org/msg06556.html):
> + if (is_read) {
> + if (!dev->buf_len)
> + at91_twi_write(dev, AT91_TWI_CR,
> + AT91_TWI_START | AT91_TWI_STOP);
> + else
> + at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_START);
> + at91_twi_write(dev, AT91_TWI_IER,
> + AT91_TWI_TXCOMP | AT91_TWI_RXRDY);
> + } else {
> + at91_twi_write_next_byte(dev);
> + at91_twi_write(dev, AT91_TWI_IER,
> + AT91_TWI_TXCOMP | AT91_TWI_TXRDY);
> + }
Is there a more recent version ?
Mit freundlichen Grüßen / Best regards
Carsten Behling
Development Engineer
Garz & Fricke GmbH
Tempowerkring 2, 21079 Hamburg - Germany
Amtsgericht Hamburg HRB 60514
Geschäftsführer: Manfred Garz, Matthias Fricke
Phone: +49 (0) 40 791 899 - 56
Fax: +49 40 / 791 899 - 39
www.garz-fricke.com
-----Ursprüngliche Nachricht-----
Von: Voss, Nikolaus [mailto:N.Voss@...nmann.de]
Gesendet: Dienstag, 22. November 2011 17:26
An: Carsten Behling
Cc: 'linux-i2c@...r.kernel.org'; 'linux-arm-kernel@...ts.infradead.org'; 'linux-kernel@...r.kernel.org'
Betreff: RE: [PATCH v5 3/4] drivers/i2c/busses/i2c-at91.c: add new driver
Hi,
Carsten Behling wrote on 2011-11-22:
> +static void at91_twi_read_next_byte(struct at91_twi_dev *dev)
> +{
> + *dev->buf = at91_twi_read(dev, AT91_TWI_RHR) & 0xff;
> +
> + /* send stop if second but last byte has been read */
> + if (--dev->buf_len == 1)
> + at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
>
>
>
> If dev->buf_len =1 at the beginning of a read transfer, a stop condition will
> never be send.
this case is already catched in at91_do_twi_transfer():
+ if (dev->msg->flags & I2C_M_RD) {
+ unsigned start_flags = AT91_TWI_START;
+
+ /* if only one byte is to be read, immediately stop transfer */
+ if (dev->buf_len <= 1 && !(dev->msg->flags & I2C_M_RECV_LEN))
+ start_flags |= AT91_TWI_STOP;
+ at91_twi_write(dev, AT91_TWI_CR, start_flags);
Thanks for reviewing,
Niko
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