PROCESSOR-SDK-AM437X: Set QSPI clock

kazuki

Prodigy 40 points

Part Number: PROCESSOR-SDK-AM437X
Other Parts Discussed in Thread: AM4376

Tool/software:

We are developing the custom board with AM4376 based on AM437x-EVM.

SDK : PROCESSOR-SDK-AM437X-06.03.00.106

Our custom board has the QSPI flash and we modify device tree as below.

&qspi {
	status = "okay";
	spi-max-frequency = <48000000>;

	m25p80@0 {
		compatible = "w25q512jv", "jedec,spi-nor";
		spi-max-frequency = <48000000>;
		reg = <0>;
		spi-cpol;
		spi-cpha;
		spi-tx-bus-width = <1>;
		spi-rx-bus-width = <4>;
		#address-cells = <1>;
		#size-cells = <1>;

We set the clock to 48MHz.

We probed the clock, the clock is about 16MHz.

Could you please let us know why the clock is different from the device tree setting?

Best regards,

Thank you.

1 day ago

0 kazuki 6 hours ago

Prodigy 40 points

We found the below patch for u-boot.

https://git.ti.com/cgit/ti-u-boot/ti-u-boot/commit/drivers/spi/ti_qspi.c?id=a6e562fe36b2bae780589a81a11fceb6e1b4a9f7

We modified the driver of kernel with reference to this patch.

--- a/drivers/spi/spi-ti-qspi.c
+++ b/drivers/spi/spi-ti-qspi.c
@@ -163,7 +163,7 @@ static int ti_qspi_setup(struct spi_device *spi)
 		return -EINVAL;
 	}
 
-	clk_rate = clk_get_rate(qspi->fclk);
+	clk_rate = (QSPI_FCLK / 4);
 
 	clk_div = DIV_ROUND_UP(clk_rate, qspi->spi_max_frequency) - 1;

Could you please check if this modification is correct or not?

After our modification, the clock of QSPI output became 48MHz.

Best regards,

Processors

Processors forum

PROCESSOR-SDK-AM437X: Set QSPI clock