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Wed, 11 Aug 2021 15:42:34 +0000 (GMT) Received: from v0005c16.aus.stglabs.ibm.com (unknown [9.211.42.251]) by b03ledav003.gho.boulder.ibm.com (Postfix) with ESMTP; Wed, 11 Aug 2021 15:42:34 +0000 (GMT) From: Eddie James To: openbmc@lists.ozlabs.org Subject: [PATCH linux dev-5.10 02/14] pmbus: (ucd9000) Throttle SMBus transfers to avoid poor behaviour Date: Wed, 11 Aug 2021 10:42:20 -0500 Message-Id: <20210811154232.12649-3-eajames@linux.ibm.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210811154232.12649-1-eajames@linux.ibm.com> References: <20210811154232.12649-1-eajames@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: aqr_ydu8YvhlfawAwS3BKX0OhdLsSoke X-Proofpoint-ORIG-GUID: aqr_ydu8YvhlfawAwS3BKX0OhdLsSoke X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391, 18.0.790 definitions=2021-08-11_05:2021-08-11, 2021-08-11 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 priorityscore=1501 mlxlogscore=999 spamscore=0 impostorscore=0 adultscore=0 clxscore=1015 suspectscore=0 mlxscore=0 lowpriorityscore=0 malwarescore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2107140000 definitions=main-2108110104 X-BeenThere: openbmc@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development list for OpenBMC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrew Jeffery Errors-To: openbmc-bounces+openbmc=archiver.kernel.org@lists.ozlabs.org Sender: "openbmc" From: Andrew Jeffery Short turn-around times between transfers to UCD9000 devices can lead to problematic behaviour, including unnecessary clock stretching, bus lockups and potential corruption of the device's volatile state. Introduce transfer throttling for the device with a minimum access delay of 1ms. Signed-off-by: Andrew Jeffery --- drivers/hwmon/pmbus/ucd9000.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c index a15e6fe3e425..9687bc3609d1 100644 --- a/drivers/hwmon/pmbus/ucd9000.c +++ b/drivers/hwmon/pmbus/ucd9000.c @@ -487,6 +487,8 @@ static int ucd9000_init_debugfs(struct i2c_client *client, } #endif /* CONFIG_DEBUG_FS */ +#define UCD9000_SMBUS_THROTTLE_US 1000 + static int ucd9000_probe(struct i2c_client *client) { u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1]; @@ -501,6 +503,8 @@ static int ucd9000_probe(struct i2c_client *client) I2C_FUNC_SMBUS_BLOCK_DATA)) return -ENODEV; + i2c_smbus_throttle_client(client, UCD9000_SMBUS_THROTTLE_US); + ret = i2c_smbus_read_block_data(client, UCD9000_DEVICE_ID, block_buffer); if (ret < 0) { -- 2.27.0