From: Eddie James <eajames@linux.ibm.com>
To: openbmc@lists.ozlabs.org
Cc: Andrew Jeffery <andrew@aj.id.au>
Subject: [PATCH linux dev-5.10 05/14] pmbus: (core) Add a one-shot retry in pmbus_set_page()
Date: Wed, 11 Aug 2021 10:42:23 -0500 [thread overview]
Message-ID: <20210811154232.12649-6-eajames@linux.ibm.com> (raw)
In-Reply-To: <20210811154232.12649-1-eajames@linux.ibm.com>
From: Andrew Jeffery <andrew@aj.id.au>
From extensive testing and tracing it was discovered that the MAX31785
occasionally fails to switch pages despite ACK'ing the PAGE PMBus data
write. I suspect this behaviour had been seen on other devices as well,
as pmbus_set_page() already read-back the freshly set value and errored
out if it wasn't what we requested.
In the case of the MAX31785 it was shown that a one-shot retry was
enough to get the PAGE write to stick if the inital command failed. To
improve robustness, only error out if the one-shot retry also fails to
stick.
OpenBMC-Staging-Count: 1
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>
---
drivers/hwmon/pmbus/pmbus_core.c | 31 ++++++++++++++++++++-----------
1 file changed, 20 insertions(+), 11 deletions(-)
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index def8be831456..1a13d6d3f8b5 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -151,25 +151,34 @@ int pmbus_set_page(struct i2c_client *client, int page, int phase)
if (!(data->info->func[page] & PMBUS_PAGE_VIRTUAL) &&
data->info->pages > 1 && page != data->currpage) {
+ int i;
+
dev_dbg(&client->dev, "Want page %u, %u cached\n", page,
data->currpage);
- rv = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
- if (rv < 0) {
+ for (i = 0; i < 2; i++) {
rv = i2c_smbus_write_byte_data(client, PMBUS_PAGE,
page);
- dev_dbg(&client->dev,
- "Failed to set page %u, performed one-shot retry %s: %d\n",
- page, rv ? "and failed" : "with success", rv);
+ if (rv)
+ continue;
+
+ rv = i2c_smbus_read_byte_data(client, PMBUS_PAGE);
if (rv < 0)
- return rv;
- }
+ continue;
- rv = i2c_smbus_read_byte_data(client, PMBUS_PAGE);
- if (rv < 0)
- return rv;
+ /* Success, exit loop */
+ if (rv == page)
+ break;
+
+ rv = i2c_smbus_read_byte_data(client, PMBUS_STATUS_CML);
+ if (rv < 0)
+ continue;
+
+ if (rv & PB_CML_FAULT_INVALID_DATA)
+ return -EIO;
+ }
- if (rv != page)
+ if (i == 2)
return -EIO;
}
data->currpage = page;
--
2.27.0
next prev parent reply other threads:[~2021-08-11 15:46 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-11 15:42 [PATCH linux dev-5.10 00/14] Rainier and Everest system fixes Eddie James
2021-08-11 15:42 ` [PATCH linux dev-5.10 01/14] i2c: Allow throttling of transfers to client devices Eddie James
2021-08-11 15:42 ` [PATCH linux dev-5.10 02/14] pmbus: (ucd9000) Throttle SMBus transfers to avoid poor behaviour Eddie James
2021-08-11 15:42 ` [PATCH linux dev-5.10 03/14] ucd9000: Add a throttle delay attribute in debugfs Eddie James
2021-08-11 15:42 ` [PATCH linux dev-5.10 04/14] fsi: run clock at 100MHz Eddie James
2021-08-11 15:42 ` Eddie James [this message]
2021-08-11 15:42 ` [PATCH linux dev-5.10 06/14] pmbus: (max31785) Add a local pmbus_set_page() implementation Eddie James
2021-08-11 16:13 ` Matthew Barth
2021-08-11 15:42 ` [PATCH linux dev-5.10 07/14] pmbus: (max31785) Retry enabling fans after writing MFR_FAN_CONFIG Eddie James
2021-08-11 16:14 ` Matthew Barth
2021-08-11 15:42 ` [PATCH linux dev-5.10 08/14] ARM: dts: aspeed: Rainier: Add fan controller properties Eddie James
2021-08-11 16:14 ` Matthew Barth
2021-08-11 15:42 ` [PATCH linux dev-5.10 09/14] ARM: dts: aspeed: Everest: " Eddie James
2021-08-11 16:15 ` Matthew Barth
2021-08-11 15:42 ` [PATCH linux dev-5.10 10/14] ARM: dts: aspeed: Rainier 4U: Delete fan dual-tach properties Eddie James
2021-08-11 16:17 ` Matthew Barth
2021-08-11 15:42 ` [PATCH linux dev-5.10 11/14] ARM: dts: aspeed: Add Rainier 2U and 4U device trees for pass 1 hardware Eddie James
2021-08-11 15:42 ` [PATCH linux dev-5.10 12/14] fsi: sbefifo: Increase command timeouts to 30 seconds Eddie James
2021-08-11 15:42 ` [PATCH linux dev-5.10 13/14] fsi: occ: Add dynamic debug to dump command and response Eddie James
2021-08-11 15:42 ` [PATCH linux dev-5.10 14/14] fsi: sbefifo: Use interruptible mutex locking Eddie James
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