OSD335x C-SiP + WL1835MOD No WiFi

Has anyone else attempted to use the WL1835MOD module with the OSD335x C-SiP running 1.8v on the VDDSHV5 pin group and no level shifter, like in the IoT article?

Enabling IoT with OSD335x using Wi-Fi and Bluetooth

Our custom board runs nicely but the WiFi will not come up. Using a stock Beaglebone Blue image, which matches the pinout in or schematic, the Bluetooth works and the OSD335x C-SiP attempts to enable the WiFi, but the WL1835MOD doesn’t seem to respond on the MMC2. The kernel reports an error and the wl_en turns off.
The error the kernel reads:
wl1271_sdio mmc2:0001:2: sdio write failed (-110)

We have verified the following:

-Using an unmodified bone-debian-9.9-iot-armhf-2019-08-03-4gb.img.xz image with the Beaglebone Blue EEPROM dump.

-Bluetooth can detect Bluetooth devices in the area

-32khz crystal is producing clean output.

-3.3v on VBAT and 1.8 on VIO

-Verified some toggling 1.8v to 0v readings on mmc2, wl_en and IRQ pins during boot with no noise.

-MMC2 clock is cycling cleanly

-Lowering MMC speed to 1Mhz with max-frequency = <1000000>; in the device tree

-Moved the WL1835MOD to a Beaglebone Blue and connected to a WiFi network to check it was working OK and not a dud module.

-Using a different custom device tree overlay we were able to confirm the chip can control the pins independently as GPIO with no strange behaviour.

-Enabling MMC debug kernel option shows its trying to send CMD53(log below)

-Our schematic matches the one in the IoT article (Pin names, not pin numbers due to it being for OSD335x-SM)

The only difference with our schematic and the Beaglebone Blue is the level shifter is removed. Is there something else that could be checked? Attached is the WiFi schematic.

Thanks for any help,
Peter

Aug 4 02:11:05 beaglebone kernel: [ 40.807142] mmc2: req done (CMD53): 0: 00001000 00000000 00000000 00000000
Aug 4 02:11:05 beaglebone kernel: [ 40.807170] mmc2: 0 bytes transferred: -110
Aug 4 02:11:05 beaglebone kernel: [ 40.807641] ————[ cut here ]————
Aug 4 02:11:05 beaglebone kernel: [ 40.807694] WARNING: CPU: 0 PID: 153 at drivers/net/wireless/ti/wlcore/sdio.c:145 wl12xx_sdio_raw_write+0x1
34/0x1c0 [wlcore_sdio]()
Aug 4 02:11:05 beaglebone kernel: [ 40.807702] Modules linked in: wl18xx wlcore hci_uart btbcm btqca bluetooth wlcore_sdio usb_f_mass_storage
usb_f_acm u_serial usb_f_ecm usb_f_rndis u_ether libcomposite evdev iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack
iptable_mangle iptable_filter uio_pdrv_genirq uio spidev pru_rproc pruss pruss_intc tieqep ip_tables x_tables
Aug 4 02:11:05 beaglebone kernel: [ 40.809318] CPU: 0 PID: 153 Comm: kworker/0:3 Not tainted 4.4.155-ti-rt-r155+ #24
Aug 4 02:11:05 beaglebone kernel: [ 40.809332] Hardware name: Generic AM33XX (Flattened Device Tree)
Aug 4 02:11:05 beaglebone kernel: [ 40.809364] Workqueue: events request_firmware_work_func
Aug 4 02:11:05 beaglebone kernel: [ 40.809414] [<c0019420>] (unwind_backtrace) from [<c00153f8>] (show_stack+0x20/0x24)
Aug 4 02:11:05 beaglebone kernel: [ 40.809432] [<c00153f8>] (show_stack) from [<c0505018>] (dump_stack+0x24/0x28)
Aug 4 02:11:05 beaglebone kernel: [ 40.809456] [<c0505018>] (dump_stack) from [<c0040bac>] (warn_slowpath_common+0x94/0xc0)
Aug 4 02:11:05 beaglebone kernel: [ 40.809473] [<c0040bac>] (warn_slowpath_common) from [<c0040cdc>] (warn_slowpath_null+0x2c/0x34)
Aug 4 02:11:05 beaglebone kernel: [ 40.809501] [<c0040cdc>] (warn_slowpath_null) from [<bf129354>] (wl12xx_sdio_raw_write+0x134/0x1c0 [wlcore_
sdio])
Aug 4 02:11:05 beaglebone kernel: [ 40.809789] [<bf129354>] (wl12xx_sdio_raw_write [wlcore_sdio]) from [<bf209014>] (wlcore_set_partition+0xdc
/0x568 [wlcore])
Aug 4 02:11:05 beaglebone kernel: [ 40.809961] [<bf209014>] (wlcore_set_partition [wlcore]) from [<bf1fde88>] (wl12xx_set_power_on+0x8c/0x178
[wlcore])
Aug 4 02:11:05 beaglebone kernel: [ 40.810099] [<bf1fde88>] (wl12xx_set_power_on [wlcore]) from [<bf202fcc>] (wlcore_nvs_cb+0x12c/0xa68 [wlcor
e])
Aug 4 02:11:05 beaglebone kernel: [ 40.810179] [<bf202fcc>] (wlcore_nvs_cb [wlcore]) from [<c060add8>] (request_firmware_work_func+0x50/0x8c)
Aug 4 02:11:05 beaglebone kernel: [ 40.810204] [<c060add8>] (request_firmware_work_func) from [<c005b414>] (process_one_work+0x158/0x488)
Aug 4 02:11:05 beaglebone kernel: [ 40.810220] [<c005b414>] (process_one_work) from [<c005c04c>] (worker_thread+0x6c/0x568)
Aug 4 02:11:05 beaglebone kernel: [ 40.810238] [<c005c04c>] (worker_thread) from [<c0061464>] (kthread+0x120/0x128)
Aug 4 02:11:05 beaglebone kernel: [ 40.810257] [<c0061464>] (kthread) from [<c0010ef8>] (ret_from_fork+0x14/0x3c)
Aug 4 02:11:05 beaglebone kernel: [ 40.810267] —[ end trace 0000000000000002 ]—
Aug 4 02:11:05 beaglebone kernel: [ 40.810285] wl1271_sdio mmc2:0001:2: sdio write failed (-110)