You may find a simiral part number in the kernel config database when your trying to bring up a chip. This can give you the false hope that maybe just a small change is needed in the driver, and you will be good to go.
This driver supports the Invensense MPU6050/9150, MPU6500/6515/6880/9250/9255, ICM20608(D)/20609/20689, ICM20602/ICM20690
But ICM20948 is not supported, the register map is entirely different.
16 bit bus mode (see EIM multiplexed mode) but 8 bit peripheral. Use AD08 and AD09 as chip select. Map peripheral to address range in device tree. Patch kernel.
&weim {
status = "okay";
ranges = <
0 0 0x08000000 0x04000000
1 0 0x0C000000 0x04000000
>;
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_weim_sja1000 &pinctrl_weim_cs &pinctrl_weim_unused
>;
sja-can-xtal@0,0 {
compatible = "nxp,sja1000";
reg = <0 0x0 0x80>;
interrupts = <31 2>;
interrupt-parent = <&gpio2>;
nxp,external-clock-frequency = <24000000>;
nxp,clock-out-frequency = <24000000>;
nxp,tx-output-config = <0x06>;
fsl,weim-cs-timing = <0x07f13039 0x00001002 0x18683372
0x00000068 0xd863ffe6 0x00000000>;
};
sja-can-slave@0,1 {
compatible = "nxp,sja1000";
reg = <1 0x0 0x80>;
interrupts = <23 2>;
interrupt-parent = <&gpio3>;
nxp,external-clock-frequency = <24000000>;
nxp,tx-output-config = <0x06>;
fsl,weim-cs-timing = <0x07f13039 0x00001002 0x18683372
0x00000068 0xd863ffe6 0x00000000>;
};
};
And patch register r/w:
Index: linux-4.14.74/drivers/net/can/sja1000/sja1000_platform.c
===================================================================
--- linux-4.14.74.orig/drivers/net/can/sja1000/sja1000_platform.c
+++ linux-4.14.74/drivers/net/can/sja1000/sja1000_platform.c
@@ -52,12 +52,14 @@ struct technologic_priv {
static u8 sp_read_reg8(const struct sja1000_priv *priv, int reg)
{
- return ioread8(priv->reg_base + reg);
+ u16 data;
+ data = ioread16(priv->reg_base + reg*2);
+ return data>>1;
}
static void sp_write_reg8(const struct sja1000_priv *priv, int reg, u8 val)
{
- iowrite8(val, priv->reg_base + reg);
+ iowrite16(val * 2, priv->reg_base + reg * 2);
}
static u8 sp_read_reg16(const struct sja1000_priv *priv, int reg)
Don’t forget to pinmux irq and reset lines.
pinctrl_mcp2515: mcp2515grp {
fsl,pins = <
/* irq */
/* MX6QDL_PAD_SD4_DAT3__GPIO2_IO11 0x000b1 */
/* rst */
MX6QDL_PAD_NANDF_CS2__GPIO6_IO15 0x000b1
>;
};
Otherwise fairly simple:
spi_can: spi_can@0 {
compatible = "microchip,mcp2515";
reg = <0>;
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_mcp2515>;
spi-max-frequency = <10000000>;
clocks = <&clk_mcp251x>;
interrupt-parent = <&gpio2>;
interrupts = <11 0x2>;
vdd-supply = <®_mcp2515>;
status = "okay";
};
If a chip is supported, this doesn’t mean that all variants support all features.
NXP PCA953x I2C GPIO multiplexer Required properties:
...
compatible: Has to contain one of the following:
...
nxp,pca9505
Looking good so far:
`CONFIG_GPIO_PCA953X_IRQ`
Say yes here to enable the pca953x to be used as an interrupt
controller. It requires the driver to be built in the kernel.
This doesn’t mean that our pca9505 supports interrupts (has a separate interrupt mask register which needs setting). Also pcal953x has a lot more irq related registers.
Use named GPIO lines:
&i2c1 {
clock-frequency = <100000>;
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_i2c1>;
status = "okay";
gpio_i2c: gpio@20 {
compatible = "microchip,mcp23017";
gpio-controller;
#gpio-cells = <2>;
reg = <0x20>;
ngpios = <14>;
gpio-line-names = "CAN1_TEN", "CAN1_TX_OFF", "CAN2_TEN","CAN2_TX_OFF",
"CAN3_TEN","CAN3_TX_OFF","CAN4_TEN", "CAN4_TX_OFF",
"SEL_SJA_CAN","","","","","","","";
pinctrl-names = "default";
pinctrl-0 = <&gpio20defaults>;
gpio20defaults: pinmux {
pins = "gpio0";
output-low;
};
};
};
Practical usage of GPIO led drivers:
leds {
compatible = "gpio-leds";
can1-err {
label = "can1-err";
gpios = <&gpio_i2c 9 GPIO_ACTIVE_LOW>;
};
can2-err {
label = "can2-err";
gpios = <&gpio_i2c 10 GPIO_ACTIVE_LOW>;
};
can3-err {
label = "can3-err";
gpios = <&gpio_i2c 11 GPIO_ACTIVE_LOW>;
};
can4-err {
label = "can4-err";
gpios = <&gpio_i2c 12 GPIO_ACTIVE_LOW>;
};
status {
label = "sw-err";
gpios = <&gpio_i2c 13 GPIO_ACTIVE_LOW>;
};
};
Setting gpios in /etc/network/interfaces (don’t
mind the pkill part):
iface can1 inet manual
pre-up gpioset --background --mode=signal $(gpiofind CAN1_TEN)=0
pre-up ip link set can1 type can bitrate 500000
pre-up echo 0 > /sys/class/leds/can1-err/brightness
pre-up echo oneshot > /sys/class/leds/can1-err/trigger
up ifconfig can1 up
up (candump can1,0~0,#FFFFFFFF > /sys/class/leds/can1-err/shot ; \
echo default-on > /sys/class/leds/can1-err/trigger) &
down ifconfig can1 down
post-down pkill -f "gpioset.*$(gpiofind CAN1_TEN)"
auto can1
Keep in mind that attaching logic analyser probes to noisy Dupont cables can lead to weird errors. Sometimes using a debugger can lead to more problems. When in doubt make sure that you have proper wiring.
&ecspi3 {
cs-gpios = <&gpio4 24 GPIO_ACTIVE_HIGH>;
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_ecspi3>;
status = "okay";
tpm_tis@0 {
compatible = "infineon,slb9670";
reg = <0>;
spi-max-frequency = <10000000>;
vdd-supply = <®_tpm>;
};
};