[PATCH 5/9] hw/i2c: pmbus: Page #255 is valid page for read requests.

[Jae Hyun Yoo]

From: Maheswara Kurapati <quic_mkurapat@quicinc.com>

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 socuments or the Applicatin 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: 38870253f1d1 ("hw/i2c: pmbus: fix error returns and guard against out of 
range accesses")

Signed-off-by: Maheswara Kurapati <quic_mkurapat@quicinc.com>
---
 hw/i2c/pmbus_device.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/hw/i2c/pmbus_device.c b/hw/i2c/pmbus_device.c
index 62885fa6a15e..7db3343a83b6 100644
--- a/hw/i2c/pmbus_device.c
+++ b/hw/i2c/pmbus_device.c
@@ -291,7 +291,6 @@ static uint8_t pmbus_receive_byte(SMBusDevice *smd)
         qemu_log_mask(LOG_GUEST_ERROR,
                       "%s: tried to read from all pages\n",
                       __func__);
-        pmbus_cml_error(pmdev);
     } else if (pmdev->page > pmdev->num_pages - 1) {
         qemu_log_mask(LOG_GUEST_ERROR,
                       "%s: page %d is out of range\n",
-- 
2.25.1