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Diffstat (limited to 'meta-openbmc-machines/meta-openpower/meta-rackspace/meta-barreleye/recipes-kernel/linux/linux-obmc/readme_adm1278.txt')
| -rw-r--r-- | meta-openbmc-machines/meta-openpower/meta-rackspace/meta-barreleye/recipes-kernel/linux/linux-obmc/readme_adm1278.txt | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/meta-openbmc-machines/meta-openpower/meta-rackspace/meta-barreleye/recipes-kernel/linux/linux-obmc/readme_adm1278.txt b/meta-openbmc-machines/meta-openpower/meta-rackspace/meta-barreleye/recipes-kernel/linux/linux-obmc/readme_adm1278.txt new file mode 100644 index 000000000..e86d97744 --- /dev/null +++ b/meta-openbmc-machines/meta-openpower/meta-rackspace/meta-barreleye/recipes-kernel/linux/linux-obmc/readme_adm1278.txt @@ -0,0 +1,78 @@ +README for adm1278 hwmon driver +================================== +Yi Li <shliyi@cn.ibm.com> + + +This is a temporary kernel patch to enable hwmon driver for adm1278 chip on Barreleye. +When this patch is merged into linux kernel, this patch will be removed from openbmc. + +The adm1278 driver is created according to datasheet: +http://www.analog.com/media/en/technical-documentation/data-sheets/ADM1278.pdf + +The patch heavily re-used adm1278 enabling code from: https://github.com/facebook/openbmc/blob/master/meta-aspeed/recipes-kernel/linux/files/patch-2.6.28.9/0000-linux-openbmc.patch. + +This patch has been tested on barreleye, by following these steps: + +1) There are 3 adm1278 devices on Barreleye + +I2C5: P12v_a for CPU0 +I2C6: P12v_b for CPU1 +I2C7: P12v_c for HDD and IO Board + +2) adm1278 driver is based on adm1275.c, which depends on pmbus. This patch builds +adm1275 and pmbus into kernel. + +3) When kernel booted, initialize the adm1278 devices: + +root@barreleye:~# echo adm1278 0x10 > /sys/class/i2c-adapter/i2c-4/new_device +root@barreleye:~# echo adm1278 0x10 > /sys/class/i2c-adapter/i2c-5/new_device +root@barreleye:~# echo adm1278 0x10 > /sys/class/i2c-adapter/i2c-6/new_device + +There will be three new hwmon sysfs entries created: + +root@barreleye:~# ls /sys/class/hwmon/hwmon3/ +curr1_highest in1_highest in1_reset_history in2_min_alarm power1_label temp1_input +curr1_input in1_input in2_highest in2_reset_history power1_max temp1_max +curr1_label in1_label in2_input name power1_reset_history temp1_max_alarm +curr1_max in1_max in2_label power/ subsystem/ temp1_reset_history +curr1_max_alarm in1_max_alarm in2_max power1_alarm temp1_crit uevent +curr1_reset_history in1_min in2_max_alarm power1_input temp1_crit_alarm +device/ in1_min_alarm in2_min power1_input_highest temp1_highest +root@barreleye:~# ls /sys/class/hwmon/hwmon4/ +curr1_highest in1_highest in1_reset_history in2_min_alarm power1_label temp1_input +curr1_input in1_input in2_highest in2_reset_history power1_max temp1_max +curr1_label in1_label in2_input name power1_reset_history temp1_max_alarm +curr1_max in1_max in2_label power/ subsystem/ temp1_reset_history +curr1_max_alarm in1_max_alarm in2_max power1_alarm temp1_crit uevent +curr1_reset_history in1_min in2_max_alarm power1_input temp1_crit_alarm +device/ in1_min_alarm in2_min power1_input_highest temp1_highest +root@barreleye:~# ls /sys/class/hwmon/hwmon5/ +curr1_highest in1_highest in1_reset_history in2_min_alarm power1_label temp1_input +curr1_input in1_input in2_highest in2_reset_history power1_max temp1_max +curr1_label in1_label in2_input name power1_reset_history temp1_max_alarm +curr1_max in1_max in2_label power/ subsystem/ temp1_reset_history +curr1_max_alarm in1_max_alarm in2_max power1_alarm temp1_crit uevent +curr1_reset_history in1_min in2_max_alarm power1_input temp1_crit_alarm +device/ in1_min_alarm in2_min power1_input_highest temp1_highest + +4) For details of what each hwmon sysfs attributes mean, please refer to: +https://www.kernel.org/doc/Documentation/hwmon/pmbus +For short, 'curr1_*' refers to 'IOUT', 'in1_*' refers to 'vin', 'in2_*' refers to 'vout', 'power1_*' refers to 'input power', +'temp1_*' for 'temperature'. + +5) Remaining issue: + +5.1) Currently, i2c_aspeed driver does not handle "i2c_smbus_read_block_data()" correctly. So this patch has to bypass some detection code. +We need to fix this issue when the patch is merged to kernel. +5.2) According to adm1278 datasheet, there is a sense resistor used to measure power and current. The resistor will affect conversion between +adm1278 register value to real-world value for current and power. I am not very sure about the resistor value. So using 1 mili-ohms (or 1000 micro-ohms) as default value. When build the adm1275 driver as kernel module, we can set this resistor value by: + +# insmod adm1275.ko r_sense=500 + +This will set the 'sense resistor' to 500 micro-ohms. +5.3) Some of the sensor value, e.g, 'temp1_input' seems not reasonable, e.g: + +root@barreleye:~# cat /sys/class/hwmon/hwmon4/temp1_input +-270952 + +Need further check on that. |
