From cf899ada48e0d2dcdcec2b65bb72a612083736eb Mon Sep 17 00:00:00 2001
From: Joel Stanley <joel@jms.id.au>
Date: Fri, 6 Oct 2017 15:37:18 +1030
Subject: [PATCH] ARM: dts: aspeed-evb: Enable EEPROM i2c slave
This enables I2C2 (/dev/i2c1 in Linux) and I2C3 (/dev/i2c2).
To test, do the following from userspace:
# echo slave-24c02 0x1064 > /sys/bus/i2c/devices/i2c-1/new-device
# echo 24c02 0x64 > /sys/bus/i2c/devices/i2c-2/new_device
See the documentation for more details:
Documentation/i2c/slave-eeprom-backend
Documentation/i2c/slave-interface
Signed-off-by: Joel Stanley <joel@jms.id.au>
---
arch/arm/boot/dts/aspeed-ast2500-evb.dts | 8 ++++++++
arch/arm/configs/aspeed_g5_defconfig | 2 ++
2 files changed, 10 insertions(+)
@@ -79,6 +79,14 @@
};
};
+&i2c1 {
+ status = "okay";
+};
+
+&i2c2 {
+ status = "okay";
+};
+
&i2c7 {
status = "okay";
@@ -121,6 +121,8 @@ CONFIG_I2C_MUX=y
CONFIG_I2C_MUX_PCA9541=y
CONFIG_I2C_MUX_PCA954x=y
CONFIG_I2C_ASPEED=y
+CONFIG_I2C_SLAVE=y
+CONFIG_I2C_SLAVE_EEPROM=y
CONFIG_GPIOLIB=y
CONFIG_GPIO_SYSFS=y
CONFIG_GPIO_ASPEED=y
--
2.14.1
Hello, Back when reviewing the upstream i2c driver I used the slave-eeprom support in the kernel to test the slave support. I've had some questions about this recently, so here are the steps I used on my ast2500 EVB. Grab a recent Linux kernel with ASPEED i2c support. I used 4.14 with my in-progress clock driver applied, but dev-4.10 should work too. 1. Connect I2C1 and I2C2 SCL and SDA lines The pins are on the south edge of the board, towards the south-west corner when reading the ASPEED Technolgoy Inc silkscreen up the correct way. A jumper should be able to reach between them. 2. Apply the attached patch to your tree $ cd linux-aspeed $ patch -p1 < 0001-ARM-dts-aspeed-evb-Enable-EEPROM-i2c-slave.patch 3. Build the kernel and fit image. Use your favourite FIT and initrd or root file system. $ cd linux-aspeed $ make aspeed_g5_defconfig $ make $ mkimage -f evb.fit evb 4. Boot the 'evb' fit image on your evb 5. Bind some drivers # echo slave-24c02 0x1064 > /sys/bus/i2c/devices/i2c-1/new-device # i2cdetect -y 1 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- UU -- -- -- -- -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- -- # echo 24c02 0x64 > /sys/bus/i2c/devices/i2c-2/new_device # i2cdetect -y 2 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- UU -- -- -- -- -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- -- 6. Find the eeprom sysfs files # find /sys/devices/ -name slave-eeprom /sys/devices/platform/ahb/ahb:apb/ahb:apb:i2c@1e78a000/1e78a0c0.i2c-bus/i2c-2/2-0064/slave-eeprom And the 'host' side of the eeprom is here. The one on bus i2c-3 is the real EEPROM; ignore it. # find /sys/devices -name eeprom /sys/devices/platform/ahb/ahb:apb/ahb:apb:i2c@1e78a000/1e78a0c0.i2c-bus/i2c-2/2-0064/eeprom /sys/devices/platform/ahb/ahb:apb/ahb:apb:i2c@1e78a000/1e78a100.i2c-bus/i2c-3/3-0050/eeprom 7. Create some environment variables: HOST=/sys/devices/platform/ahb/ahb:apb/ahb:apb:i2c@1e78a000/1e78a0c0.i2c-bus/i2c-2/2-0064/eeprom SLAVE=/sys/devices/platform/ahb/ahb:apb/ahb:apb:i2c@1e78a000/1e78a0c0.i2c-bus/i2c-2/2-0064/slave-eeprom 8. Write to one, and see it appear in the other # echo "How about a nice game of chess?" > $SLAVE # cat $HOST How about a nice game of chess? # hexdump -C $HOST 00000000 48 6f 77 20 61 62 6f 75 74 20 61 20 6e 69 63 65 |How about a nice| 00000010 20 67 61 6d 65 20 6f 66 20 63 68 65 73 73 3f 0a | game of chess?.| 00000020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| # echo "You have no chance to survive make your time" > $HOST # hexdump -C $SLAVE 00000000 59 6f 75 20 68 61 76 65 20 6e 6f 20 63 68 61 6e |You have no chan| 00000010 63 65 20 74 6f 20 73 75 72 76 69 76 65 20 6d 61 |ce to survive ma| 00000020 6b 65 20 79 6f 75 72 20 74 69 6d 65 0a 00 00 00 |ke your time....| 00000030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| Cheers, Joel