diff mbox series

[linux,dev-5.8,2/3] pmbus: (ucd9000) Throttle SMBus transfers to avoid poor behaviour

Message ID 20200902071736.2578715-3-andrew@aj.id.au
State New
Headers show
Series i2c: Introduce transfer throttling | expand

Commit Message

Andrew Jeffery Sept. 2, 2020, 7:17 a.m. UTC 
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 <andrew@aj.id.au>
---
 drivers/hwmon/pmbus/ucd9000.c | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
index 81f4c4f166cd..7ba400d62475 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,
 			 const struct i2c_device_id *id)
 {
@@ -502,6 +504,8 @@  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) {