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Hello mailing list,
we have to use the linux driver "i2c-gpio" because the "i2c-at91" is marked as "BROKEN" and for our application it can as well not be used.
Here a brief description of the application:
AT91SAM9261 based embedded system running kernel 2.6.25.4, with Atmel and our own BSP patches. This system uses both SPI interfaces, one USART (for console), MMC, Sound on SPI and SSC, digital poti for contrast control and the an chip Frambuffer for a monochrome LCD (QVGA).
On the TWI interface are attached:
the AT24C04 SMB EEPROM, (@ 0x50)
two LM84 Temperature sensors (@ 0x18, 0x19)
and the Infrared temperature sensor MLX90614 manfactured by MELEXIS. (@ 0x5A)
Note: The LM84 sensors are not yet operated by the linux kernel.
Now the description of the issue we have with the I2C subsystem:
1. the EEPROM is working fine with "i2c-at91" and the "i2c-gpio" modules
2. for IR-Sensor MLX90614, a hwmon class linux driver was implemented by Linutronix on our demand. This driver works fine but delivers sporadic the error message "i2c-adapter i2c-0: sendbytes: NAK bailout." (this message is thrown by the "i2c-algo-bit" driver), or invalid temperature values ( near 0xFFFF). The invalid temperature values and as well the error message appear as reponse on bus timeout situations which are not correctly handled by the linux driver. This we find out using a I2C analyzer. In our opinion these issues come while the i2c communication is disturbed by other tasks and/or interrupt service routines (ISR) which extend the SMB clock over the permitted timeouts, leaving the IR-Sensor in an undefined or erroneous state.
The address mentioned in the driver source "Haavard Skinnemoen <hskinnemoen@xxxxxxxxx>" invalid (unknown)
Please let us now if somebody can help in fixing the i2c-gpio, or give us an other name who can help.
Thank you.
With best regards
Matthias Zacharias
Dipl.-Elektroingenieur (Univ) Projektleiter Entwicklung BMK professional electronics GmbH Â Werner-von-Siemens-Str. 6 Â D-86159 Augsburg Tel: +49(0)821/20788-715Â Fax: +49(0)821/20788-721Â www.bmk-group.de -------------------- BMK electronic solutions GmbH Werner-von-Siemens-Str. 6, Eingang 18 f D-86159 Augsburg Tel. +49 (0) 821 / 207 88 - 700 Fax +49 (0) 821 / 207 88 - 721 info@xxxxxxxxxxxxxxxx Geschäftsführer: Dipl.-oec. Alois Knöferle Sitz: Augsburg HR-Nr.: B21197 ---------------------
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