[PATCH v1 6/6] ARM: BCM5301X: Add DT for Meraki MR32

[Christian Lamparter]

Hello Florian,

On 2020-08-18 22:11, Florian Fainelli wrote:
> 
> 
> On 8/18/2020 9:39 AM, Christian Lamparter wrote:
> [snip]
>> +    i2c-gpio {
>> +        compatible = "i2c-gpio";
>> +        sda-gpios = <&chipcommon 5 GPIO_ACTIVE_HIGH>;
>> +        scl-gpios = <&chipcommon 4 GPIO_ACTIVE_HIGH>;
>> +        i2c-gpio,delay-us = <10>; /* close to 100 kHz */
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
> 
> Can you try using the hardware controller here instead of bit banging 
> i2c over gpios? GPIOs 4 and 5 are the default pins for I2C.

Ok. I gave this a try. What I did was:

I removed the i2c-gpio node and went with this in the mr32.dts:

+&i2c0 {
+       status = "okay";
+
+	clock-frequency = <100000>; /* also tried 400KHz */
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinmux_i2c>; /* editted bcm5301x.dtsi for this */
+
+       cur_mon: ina2xx at 45 {
+               compatible = "ti,ina219";
+               reg = <0x45>;
+               shunt-resistor = <60000>; /* = 60 mOhms */
+       };
+
+       meraki_eeprom: at24 at 50 {
+               compatible = "atmel,24c64";
+               reg = <0x50>;
+               pagesize = <32>;
+               read-only;
+       };
+};

I enabled CONFIG_I2C_BCM_IPROC=y and built the whole thing and moved it 
to the AP.

During boot, I now get:

|[    1.039174] bcm-iproc-i2c 18009000.i2c: bus set to 100000 Hz
|[    8.918419] i2c /dev entries driver
[...] (The i2c-bcm-iproc now causes a long "wait" during boot)
|[   59.385497] bcm-iproc-i2c 18009000.i2c: transaction timed out
|[   59.391272] ina2xx 0-0045: error configuring the device: -110
|[  110.585517] bcm-iproc-i2c 18009000.i2c: transaction timed out

Is there a special magic needed to get this working with bcm5301x's 
existing i2c0 node?

Cheers,
Christian

Here are some dumps from debugfs' pinctrl and the bcm5301x.dtsi patch

--- /sys/kernel/debug/pinctrl/pinctrl-handles ---
Requested pin control handlers their pinmux maps:
device: 18009000.i2c current state: default
   state: default
     type: MUX_GROUP controller pinctrl-ns group: i2c_grp (1) function: 
i2c (1)


--- /sys/kernel/debug/pinctrl/1800c100.cru:pinctrl/pinmux-pins ---
Pinmux settings per pin
Format: pin (name): mux_owner gpio_owner hog?
pin 0 (spi_clk): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 1 (spi_ss): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 2 (spi_mosi): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 3 (spi_miso): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 4 (i2c_scl): 18009000.i2c (GPIO UNCLAIMED) function i2c group i2c_grp
pin 5 (i2c_sda): 18009000.i2c (GPIO UNCLAIMED) function i2c group i2c_grp
pin 8 (pwm0): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 9 (pwm1): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 10 (pwm2): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 11 (pwm3): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 12 (uart1_rx): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 13 (uart1_tx): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 14 (uart1_cts): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 15 (uart1_rts): (MUX UNCLAIMED) (GPIO UNCLAIMED)
---

---
diff --git a/arch/arm/boot/dts/bcm5301x.dtsi 
b/arch/arm/boot/dts/bcm5301x.dtsi
index f7bd1587e285..9bb97deb7331 100644
--- a/arch/arm/boot/dts/bcm5301x.dtsi
+++ b/arch/arm/boot/dts/bcm5301x.dtsi
@@ -438,7 +438,7 @@ spi-pins {
  					function = "spi";
  				};

-				i2c {
+				pinmux_i2c: i2c {
  					groups = "i2c_grp";
  					function = "i2c";
  				};