Linux Kernel : v4.1.6, Driver selected for the device : m25p80.c
Processor : AM3358 - 800 Mhz, running on Custom Board
Pin Mux / DTS has following entries for SPI
AM33xx.dtsi:-
spi0: spi@48030000 {
compatible = "ti,omap4-mcspi";
#address-cells = <1>;
#size-cells = <0>;
reg = <0x48030000 0x400>;
interrupts = <65>;
ti,spi-num-cs = <2>;
ti,hwmods = "spi0";
//ti,pindir-d0-out-d1-in = <1>;
dmas = <&edma 16
&edma 17
&edma 18
&edma 19>;
dma-names = "tx0", "rx0", "tx1", "rx1";
status = "disabled";
};
AM335x-bone-common.dtsi:-
spi0_pins: pinmux_spi0_pins {
pinctrl-single,pins = <
0x150 0x10 /* (A17) spi0_sclk.spi0_sclk */
0x154 0x30 /* (B17) spi0_d0.spi0_d0 */
0x158 0x30 /* (B16) spi0_d1.spi0_d1 */
0x15c 0x10 /* (A16) spi0_cs0.spi0_cs0 */
>;
};
&spi0 {
pinctrl-names = "default";
pinctrl-0 = <&spi0_pins>;
status = "okay";
spi-flash@0 {
#address-cells = <1>;
#size-cells = <1>;
compatible = "micron,n25q256a";
reg = <0>;
spi-max-frequency = <24000000>;
spi-cpha;
spi-cpol;
status = "okay";
};
};
m25p80 driver while probing always returns 0 for JEDEC ID response command (0x9e/0x9f). Upon module probing I am expecting the JEDEC ID of the device as 0x20BA19.
I have verified the hardware connectivity between processor and SPI slave chip. It is intact. CS is native, no extra GPIO are used. Using oscilloscope i can see CLK, CS, D0 and D1 waveforms when module probing starts. But JEDEC id is always returned as Zero. Tried probing the device with different frequencies (5, 10, 15, 20, 24 Mhz) and also tried swapping D0 and D1 pins both in hardware and software, but the result remained same, Cannot read JEDEC ID of the device, with out which i cannot get the device handle to communicate from the User space. Please help...
