spi: adi_spi3: remove spurious 500 kHz controller speed cap - #108
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The driver reads spi-max-frequency from the controller DT node as a cap applied in set_speed(). Upstream Linux DTS places spi-max-frequency only on child device nodes (the flash), not on the controller node, so the driver fell back to the 500 kHz default — throttling every transfer to 1/20th of the intended speed. The Linux adi SPI driver (spi-adi.c) never reads spi-max-frequency from the controller node at all; speed comes entirely from the per-transfer speed_hz. Default to U32_MAX so that when the controller node has no cap, the per-device spi-max-frequency governs without interference. Signed-off-by: Jie Zhang <jie.zhang@analog.com>
sipraga
reviewed
Jul 7, 2026
| fdt_addr_t addr; | ||
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| plat->max_hz = dev_read_u32_default(bus, "spi-max-frequency", 500000); | ||
| plat->max_hz = dev_read_u32_default(bus, "spi-max-frequency", U32_MAX); |
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Why parse this meaningless property at all? Why not just drop it?
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The driver reads spi-max-frequency from the controller DT node as a cap applied in set_speed(). Upstream Linux DTS places spi-max-frequency only on child device nodes (the flash), not on the controller node, so the driver fell back to the 500 kHz default — throttling every transfer to 1/20th of the intended speed.
The Linux adi SPI driver (spi-adi.c) never reads spi-max-frequency from the controller node at all; speed comes entirely from the per-transfer speed_hz. Default to U32_MAX so that when the controller node has no cap, the per-device spi-max-frequency governs without interference.