| Lokesh Vutla | 0b1b60c | 2013-04-17 20:49:40 +0000 | [diff] [blame] | 1 | README on how reset time on OMAPs should be calculated |
| 2 | |
| 3 | CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC: |
| 4 | Most OMAPs' provide a way to specify the time for |
| 5 | which the reset should be held low while the voltages |
| 6 | and Oscillator outputs stabilize. |
| 7 | |
| 8 | This time is mostly board and PMIC dependent. Hence the |
| 9 | boards are expected to specify a pre-computed time |
| 10 | using the above option, (the details on how to compute |
| 11 | the value are given below) without which a default time |
| 12 | as specified by CONFIG_DEFAULT_OMAP_RESET_TIME_MAX_USEC |
| 13 | is used. |
| 14 | |
| 15 | The value for CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC |
| 16 | can be computed using a summation of the below 3 parameters |
| 17 | -1- Time taken by the Osciallator to stop and restart |
| 18 | -2- PMIC OTP time |
| 19 | -3- Voltage ramp time, which can be derived using the |
| 20 | PMIC slew rate and value of voltage ramp needed. |