drivers: memc_mcux_flexspi: force applying OVRDVAL #96957
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Enable this kconfig setting to force using a specific raw value for the OVRDVAL field in the DLLCR registers. This option gives more granularity than the 'data-valid-time' field in the dts. The unit of 'data-valid-time' is nanoseconds while the unit of OVRDVAL are raw delay cells. Normally the 'data-valid-time' on any 'nxp,imx-flexspi-device' device will set the OVRDVAL and OVRDEN fields in the DLLCR register but works only when the 'rx-clock-source' is configured to '#0 External input from DQS pad' and the frequency <= 100MHz. Signed-off-by: Andre Heinemans <[email protected]>
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| #if (CONFIG_FLASH_MCUX_FLEXSPI_FORCE_USING_OVRDVAL == 1) | ||
| data->base->DLLCR[port >> 1U] = FLEXSPI_DLLCR_OVRDEN(1) | | ||
| FLEXSPI_DLLCR_OVRDVAL(CONFIG_FLASH_MCUX_FLEXSPI_OVRDVAL); | ||
| #endif |
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Hi @AndreHeinemans-NXP, May I ask about your motivation or a specific use case for proposing these changes?
In the function FLEXSPI_SetFlashConfig(), there is a mechanism that allows override and calculates the override value based on flexspirootclk.
Did you find that this function does not meet your use case requirements?
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You are referring to 'data-valid-time' which can be configured in the dts. I tried to use it but it seems that this field is only effective when rx-clock-source=3 (external DQS). See src. In the other cases, the boolean isUnifiedConfig will be set and results in having a default value being used.
I'm am working on the NavQ95 and currently there are some problems with the DQS signal. So I need to configure the rx-clock-source to 1 (Loopback from DQS pad). Within this mode it is not possible to get the correct value set by using the 'data-valid-time'.
Besides, it allows more granularity since the unit of 'data-valid-time' is nanoseconds while the unit of OVRDVAL are raw delay cells.
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Hi @AndreHeinemans-NXP, thank you for your explanations. It is clear to me.
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Enable this kconfig setting to force using a specific raw value for the OVRDVAL field in the DLLCR registers.
This option gives more granularity than the 'data-valid-time' field in the dts. The unit of 'data-valid-time' is nanoseconds while the unit of OVRDVAL are raw delay cells.
Normally the 'data-valid-time' on any 'nxp,imx-flexspi-device' device will set the OVRDVAL and OVRDEN fields in the DLLCR register but works only when the 'rx-clock-source' is configured to '# 3 External input from DQS pad' and the frequency <= 100MHz.
This option allows this OVRDVAL value being set under all circumstances.