The sht21 temperature and humidity sensor holds the i2c bus while
an ADC conversion is in progress. For example, a temperature
measurement is requested, a read operation is started, and the
sht21 doesn't respond to the read request until the result of
the measurement is ready. The conversion time isn't constant.
On rare occations (one in hundreds of samples) the timeout in the
i2c driver expires returning an error.
The example code from Sensirion, the sht21's manufacturer, suggests
a bus timeout of 1 second to accommodate the sht21. This commit
increases the bus timeout to 1 second. The timeout is only reached
when chips do not respond normally, so the change doesn't affect the
performance of any other drivers.
Change-Id: I57b0f958a5d0b69b221af380b771fe67401ff604
On the AM335X, writes to the padconf registers must be done in privileged
mode. To allow userspace drivers to dynamically change the padconf at
runtime, a kernel call has been added.
Change-Id: I4b25d2879399b1785a360912faa0e90b5c258533
Implement changes based on Kees comments on the code review:
http://gerrit-minix.few.vu.nl/#/c/676/
Changes:
- use spin API instead of micro_delay() for busy-wait loops.
- use read16/write16/set16 from mmio.h to access I2C registers.
- reduce the timeout for soft reset.
- in read/write, don't mix variable declaration and initialization.
- after transfer, wait for access ready instead of blindly delaying.
- rename constants am335x, dm37xx to AM335X_I2C_BUS, DM37XX_I2C_BUS.
- rename ADDRESS_MASK to MAX_I2C_SA_MASK for clairity.
- rename omap_i2c_claim_bus() to omap_i2c_bus_is_free().
Change-Id: Ic221e6134e024ea0a6690f21cff208a728286948
