nvmem: raspberrypi: Add nvmem driver for reading customer OTP

[popcornmix]

This supports reading and writing OTP using the firmware mailbox interface.

It needs supporting firmware to run.

[popcornmix]

@timg236 updated with:

dtparam=nvmem_customer_writeable

Allow write access to customer otp through nvmem driver (I suspect we will want to change names, and probably where these entries are places in DT files).

[popcornmix]

@pelwell @timg236 I think this is ready for review.

[timg236]

@pelwell @timg236 I think this is ready for review.

Thanks I’ll try this out tomorrow

[pelwell]

I think you can cover all downstream dtbs by putting the changes in bcm2708-rpi.dtsi, bcm2711-rpi-ds.dtsi and bcm2712-rpi.dtsi. If we want to change upstream as well, move them to bcm2835-common.dtsi and bcm2711-rpi.dtsi.

[pelwell]

I also notice that the 2712 nvmem entries are in /soc, whereas the others are in /.

[pelwell]

See https://github.com/pelwell/linux/tree/nvmem - the output is identical. Also consider moving the 2712 nvmem nodes to /

[popcornmix]

Updated.

[pelwell]

diff --git a/arch/arm/boot/dts/broadcom/bcm2708-rpi.dtsi b/arch/arm/boot/dts/broadcom/bcm2708-rpi.dtsi
index 4302f55f57b4d..f4949a07272b6 100644
--- a/arch/arm/boot/dts/broadcom/bcm2708-rpi.dtsi
+++ b/arch/arm/boot/dts/broadcom/bcm2708-rpi.dtsi
@@ -15,6 +15,17 @@ aliases {
                i2c2 = &i2c2;
        };
 
+       __overrides__ {
+               hdmi = <&hdmi>,"status";
+               i2c2_iknowwhatimdoing = <&i2c2>,"status";
+               i2c2_baudrate = <&i2c2>,"clock-frequency:0";
+               nvmem_cust_rw = <&nvmem_cust>,"rw?";
+               sd = <&sdhost>,"status";
+               sd_poll_once = <&sdhost>,"non-removable?";
+       };
+};
+
+&soc {
        nvmem_otp: nvmem_otp {
                compatible = "raspberrypi,rpi-otp";
                firmware = <&firmware>;
@@ -28,15 +39,6 @@ nvmem_cust: nvmem_cust {
                reg = <1 8>;
                status = "okay";
        };
-
-       __overrides__ {
-               hdmi = <&hdmi>,"status";
-               i2c2_iknowwhatimdoing = <&i2c2>,"status";
-               i2c2_baudrate = <&i2c2>,"clock-frequency:0";
-               nvmem_cust_rw = <&nvmem_cust>,"rw?";
-               sd = <&sdhost>,"status";
-               sd_poll_once = <&sdhost>,"non-removable?";
-       };
 };
 
 &sdhost {
diff --git a/arch/arm/boot/dts/broadcom/bcm2711-rpi-ds.dtsi b/arch/arm/boot/dts/broadcom/bcm2711-rpi-ds.dtsi
index daa3b5dfa0bf3..b298cd8bb71ce 100644
--- a/arch/arm/boot/dts/broadcom/bcm2711-rpi-ds.dtsi
+++ b/arch/arm/boot/dts/broadcom/bcm2711-rpi-ds.dtsi
@@ -75,6 +75,21 @@ zone_dma {
                #size-cells = <1>;
                dma-ranges = <0x0  0x0 0x0  0x40000000>;
        };
+};
+
+&vc4 {
+       raspberrypi,firmware = <&firmware>;
+};
+
+&cma {
+       /* Limit cma to the lower 768MB to allow room for HIGHMEM on 32-bit */
+       alloc-ranges = <0x0 0x00000000 0x30000000>;
+};
+
+&soc {
+       /* Add the physical <-> DMA mapping for the I/O space */
+       dma-ranges = <0xc0000000  0x0 0x00000000  0x40000000>,
+                    <0x7c000000  0x0 0xfc000000  0x03800000>;
 
        nvmem_otp: nvmem_otp {
                compatible = "raspberrypi,rpi-otp";
@@ -98,21 +113,6 @@ nvmem_priv: nvmem_priv {
        };
 };
 
-&vc4 {
-       raspberrypi,firmware = <&firmware>;
-};
-
-&cma {
-       /* Limit cma to the lower 768MB to allow room for HIGHMEM on 32-bit */
-       alloc-ranges = <0x0 0x00000000 0x30000000>;
-};
-
-&soc {
-       /* Add the physical <-> DMA mapping for the I/O space */
-       dma-ranges = <0xc0000000  0x0 0x00000000  0x40000000>,
-                    <0x7c000000  0x0 0xfc000000  0x03800000>;
-};
-
 &scb {
        #size-cells = <2>;
 

[popcornmix]

Updated