On 11/4/24 00:43, Jerome Brunet wrote:
+/*
+ * PMBus write protect forced mode:
+ * PMBus may come up with a variety of write protection configuration.
+ * 'pmbus_wp' may be used if a particular write protection is necessary.
+ * The ability to actually alter the protection may also depend on the chip
+ * so the actual runtime write protection configuration may differ from
+ * the requested one. pmbus_core currently support the following value:
+ * - 0: write protection removed
+ * - 1: write protection fully enabled, including OPERATION and VOUT_COMMAND
+ * registers. Chips essentially become read-only with this.
Would it be desirable to also suppport the ability to set the output voltage
but not limits (PB_WP_VOUT) ?
I was starting simple, it is doable sure.
It is not something I will be able to test on actual since does not
support that.
Do you want me to add "2: write protection enable execpt for VOUT_COMMAND." ?
Please add it. I have a number of PMBus test boards and will be able to test it.
Thee are three options, though. Per specification:
1000 0000 Disable all writes except to the WRITE_PROTECT command
0100 0000 Disable all writes except to the WRITE_PROTECT, OPERATION and
PAGE commands
0010 0000 Disable all writes except to the WRITE_PROTECT, OPERATION,
PAGE, ON_OFF_CONFIG and VOUT_COMMAND commands
The driver uses OPERATION and VOUT_COMMAND, so we should have options
to disable them separately. It may be desirable, for example, to be able
to turn on a regulator but not to change the voltages. Also, since
full write protection also disables writes to the page register,
the impact of full write protection on multi-page chips needs to be
documented.
Thanks,
Guenter
