I have been trying to bring up the SDIO WiFi card on the sdmmc3 / sdhci2@700b0400 interface. I haven’t gotten the card detected yet.
Can someone please help me understand the following properties?
-mmc-ocr-mask: Specify OCR register masking details
What register is this and what is its purpose? Does the above mask need to change if an SDIO WiFi device is connected to the sdmmc3 controller?
- default-drv-type: Drive strength to select for SDIO devices is encoded as 8-bit char as follows
Drive strength Type B: 0x0
Drive strength Type A: 0x1
Drive strength Type C: 0x2
Drive strength Type D: 0x3
Do I need to set this to a particular value for SDIO WiFi device?
- fixed-clock-freq: The first element is for ID mode. The rest of the entries are for different modes indexed as per ios timings.
ID MODE 0
MMC_TIMING_LEGACY 1
MMC_TIMING_MMC_HS 2
MMC_TIMING_SD_HS 3
MMC_TIMING_UHS_SDR12 4
MMC_TIMING_UHS_SDR25 5
MMC_TIMING_UHS_SDR50 6
MMC_TIMING_UHS_SDR104 7
MMC_TIMING_UHS_DDR50 8
MMC_TIMING_MMC_HS200 9
MMC_TIMING_MMC_HS400 10
Example for setting fixed-clock-freq
from the device tree bindings document: fixed-clock-freq = <25500000 25500000 24000000 47000000 24000000 47000000 94000000 204000000 0 0 0>;
Is this fixed-clock-freq
applicable only to MMC storage device or also to SDIO devices like WiFi modules?
Also what is the ID MODE?
In the example it can be seen that some values are set to 0. When should a value be set to zero? Also should these values be set according to the device being connected to the interface? For example, the WiFi module I use has a max SDIO clock freq of 100 MHz for SDR50. So should I set 100 against MMC_TIMING_UHS_SDR50
-nvidia,min-tap-delay: Defines minimum tap delay in picoseconds seen on a SOC.
This value is SOC specific and used to compute lowerthreshold, upperthreshold, fixed_tap values needed for post auto-tuning correction algorithm.
-nvidia,max-tap-delay: Defines maximum tap delay in picoseconds seen on a SOC.
This value is SOC specific and used to compute lowerthreshold, upperthreshold, fixed_tap values needed for post auto-tuning correction algorithm.
Should these values change to suit the SDIO WiFi module?
Will appreciate any help. Thanks.