Re: [PATCH] ARM: dts: NSP: Use hardware I2C for BCM958625HR

From: Ray Jui
Date: Fri Dec 13 2019 - 17:11:33 EST




On 2019-12-13 11:51 a.m., Florian Fainelli wrote:
Now that the i2c-bcm-iproc driver has been fixed to permit reading more
than 63 bytes in a single transaction with commit fd01eecdf959 ("i2c:
iproc: Fix i2c master read more than 63 bytes") we no longer need to
bitbang i2c over GPIOs which was necessary before to allow the
PHYLINK/SFP subsystems to read SFP modules.


This is good to hear!

Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
---
arch/arm/boot/dts/bcm958625hr.dts | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/arch/arm/boot/dts/bcm958625hr.dts b/arch/arm/boot/dts/bcm958625hr.dts
index a2c9de35ddfb..536fb24f38bb 100644
--- a/arch/arm/boot/dts/bcm958625hr.dts
+++ b/arch/arm/boot/dts/bcm958625hr.dts
@@ -55,18 +55,9 @@
priority = <200>;
};
- /* Hardware I2C block cannot do more than 63 bytes per transfer,
- * which would prevent reading from a SFP's EEPROM (256 byte).
- */
- i2c1: i2c {
- compatible = "i2c-gpio";
- sda-gpios = <&gpioa 5 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
- scl-gpios = <&gpioa 4 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
- };
-

So I suppose GPIO 4 and 5 from the 'gpioa' controller are tied to the same SCL/SDA pins from i2c0 and they are internally muxed, right?

Is the mux to GPIO done automatically when pins are configured as GPIO, and therefore you don't require any additional changes to pinmux to make this work, after changing it back to use real I2C0 block below?

sfp: sfp {
compatible = "sff,sfp";
- i2c-bus = <&i2c1>;
+ i2c-bus = <&i2c0>;
mod-def0-gpios = <&gpioa 28 GPIO_ACTIVE_LOW>;
los-gpios = <&gpioa 24 GPIO_ACTIVE_HIGH>;
tx-fault-gpios = <&gpioa 30 GPIO_ACTIVE_HIGH>;
@@ -74,6 +65,10 @@
};
};
+&i2c0 {
+ status = "okay";
+};
+
&amac0 {
status = "okay";
};


Change looks good to me.

Reviewed-by: Ray Jui <ray.jui@xxxxxxxxxxxx>

Thanks,

Ray