https://github.com/torvalds/linux
Revision 664d58bf4d3406dc4404e29bcb8c89fd22589d57 authored by Zhuo-hao Lee on 27 August 2016, 07:39:30 UTC, committed by Wolfram Sang on 08 September 2016, 20:14:36 UTC
There are several ways to set the SDA hold time for i2c controller, including: Device Tree, built-in device properties and ACPI. However, if the SDA hold time is not specified by above method, we should read the value, where it is preset by firmware, and save it to sda_hold_time. This is needed because when i2c controller enters runtime suspend, the DW_IC_SDA_HOLD value will be reset to chipset default value. And during runtime resume, i2c_dw_init will be called to reconfigure i2c controller. If sda_hold_time is zero, the chipset default hold time will be used, that will be too short for some platforms. Therefore, to have a better tolerance, the DW_IC_SDA_HOLD value should be kept by sda_hold_time. Signed-off-by: Zhuo-hao Lee <zhuo-hao.lee@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
1 parent 30851a7
Tip revision: 664d58bf4d3406dc4404e29bcb8c89fd22589d57 authored by Zhuo-hao Lee on 27 August 2016, 07:39:30 UTC
i2c: designware: save the preset value of DW_IC_SDA_HOLD
i2c: designware: save the preset value of DW_IC_SDA_HOLD
Tip revision: 664d58b
| File | Mode | Size |
|---|---|---|
| Documentation | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | -rw-r--r-- | 59 bytes |
| .get_maintainer.ignore | -rw-r--r-- | 31 bytes |
| .gitignore | -rw-r--r-- | 1.3 KB |
| .mailmap | -rw-r--r-- | 7.1 KB |
| COPYING | -rw-r--r-- | 18.3 KB |
| CREDITS | -rw-r--r-- | 95.5 KB |
| Kbuild | -rw-r--r-- | 2.8 KB |
| Kconfig | -rw-r--r-- | 252 bytes |
| MAINTAINERS | -rw-r--r-- | 362.8 KB |
| Makefile | -rw-r--r-- | 56.8 KB |
| README | -rw-r--r-- | 18.1 KB |
| REPORTING-BUGS | -rw-r--r-- | 7.3 KB |
Computing file changes ...
