The linux pmbus driver scans all possible pages and does not reset the
current page after the scan, making all future page reads fail as out of range
on devices with a single page.
This change resets out of range pages immediately on write.
Also added a qtest for simultaneous writes to all pages.
Reviewed-by: Hao Wu <wuhaotsh@google.com>
Signed-off-by: Titus Rwantare <titusr@google.com>
Message-ID: <20231023-staging-pmbus-v3-v4-8-07a8cb7cd20a@google.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
PMBus devices can send and receive variable length data using the
block read and write format, with the first byte in the payload
denoting the length.
This is mostly used for strings and on-device logs. Devices can
respond to a block read with an empty string.
Reviewed-by: Hao Wu <wuhaotsh@google.com>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Titus Rwantare <titusr@google.com>
Message-ID: <20231023-staging-pmbus-v3-v4-1-07a8cb7cd20a@google.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
QOM object instance should not modify its class state (because
all other objects instanciated from this class get affected).
Instead of modifying the PMBusDeviceClass 'device_num_pages' field
the first time a instance is initialized (in pmbus_pages_alloc),
introduce a new pmbus_pages_num() helper which returns the page
number from the class without modifying the class state.
The code logic become slighly simplified.
Inspired-by: Bernhard Beschow <shentey@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230523064408.57941-4-philmd@linaro.org>
Current implementation of the pmbus core driver treats the read request
for page 255 as invalid request and sets the invalid command bit (bit 7)
in the STATUS_CML register. As per the PMBus specification it is a valid
request.
Refer to the PMBus specification, revision 1.3.1, section 11.10 PAGE,
on the page 58:
"Setting the PAGE to FFh means that all subsequent comands are to be
applied to all outputs.
Some commands, such as READ_TEMPERATURE, may use a common sensor but
be available on all pages of a device. Such implementations are the
decision of each device manufacturer or are specified in a PMBus
Application Profile. Consult the manufacturer's documents or the
Application Profile Specification as needed."
For e.g.,
The VOUT_MODE is a valid command for page 255 for maxim 31785 device.
refer to Table 1. PMBus Command Codes on page 14 in the datasheet.
https://datasheets.maximintegrated.com/en/ds/MAX31785.pdf
Fixes: 38870253f1 ("hw/i2c: pmbus: fix error returns and guard against out of range accesses")
Signed-off-by: Maheswara Kurapati <quic_mkurapat@quicinc.com>
Signed-off-by: Jae Hyun Yoo <quic_jaehyoo@quicinc.com>
Reviewed-by: Titus Rwantare <titusr@google.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20220627154703.148943-4-quic_jaehyoo@quicinc.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
