2022-04-22 08:25:16

by Adam Wujek

Subject: [PATCH] hwmod: (pmbus) disable PEC if not enabled

Explicitly disable PEC when the client does not support it.
Without the explicit disable, when the device with the PEC support is removed
later when a device without PEC support is inserted into the same address,
the driver uses the old value of client->flags which contains the I2C_CLIENT_PEC
flag. As a consequence the PEC is used when it should not.

Signed-off-by: Adam Wujek <[email protected]>
---
drivers/hwmon/pmbus/pmbus_core.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index 82c3754e21e3..f8ca36759b0a 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -2014,6 +2014,8 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data,
ret = i2c_smbus_read_byte_data(client, PMBUS_CAPABILITY);
if (ret >= 0 && (ret & PB_CAPABILITY_ERROR_CHECK))
client->flags |= I2C_CLIENT_PEC;
+ else
+ client->flags &= ~I2C_CLIENT_PEC;

pmbus_clear_faults(client);

--
2.17.1

2022-04-22 18:25:15

by Guenter Roeck

Subject: Re: [PATCH] hwmod: (pmbus) disable PEC if not enabled

On 4/19/22 13:53, Adam Wujek wrote:
> Explicitly disable PEC when the client does not support it.
> Without the explicit disable, when the device with the PEC support is removed
> later when a device without PEC support is inserted into the same address,
> the driver uses the old value of client->flags which contains the I2C_CLIENT_PEC
> flag. As a consequence the PEC is used when it should not.
>
> Signed-off-by: Adam Wujek <[email protected]>
> ---
> drivers/hwmon/pmbus/pmbus_core.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index 82c3754e21e3..f8ca36759b0a 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -2014,6 +2014,8 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data,
> ret = i2c_smbus_read_byte_data(client, PMBUS_CAPABILITY);
> if (ret >= 0 && (ret & PB_CAPABILITY_ERROR_CHECK))
> client->flags |= I2C_CLIENT_PEC;
> + else
> + client->flags &= ~I2C_CLIENT_PEC;
>

I just realized that this patch is not based on the latest
kernel version. Please rebase.

Guenter

2022-04-22 21:44:57

by Guenter Roeck

Subject: Re: [PATCH] hwmod: (pmbus) disable PEC if not enabled

On 4/19/22 13:53, Adam Wujek wrote:
> Explicitly disable PEC when the client does not support it.
> Without the explicit disable, when the device with the PEC support is removed
> later when a device without PEC support is inserted into the same address,
> the driver uses the old value of client->flags which contains the I2C_CLIENT_PEC
> flag. As a consequence the PEC is used when it should not.
>

How can that happen ? I would assume the I2C device gets deleted and re-created
in that case, which should clear the PEC flag.

Guenter

> Signed-off-by: Adam Wujek <[email protected]>
> ---
> drivers/hwmon/pmbus/pmbus_core.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index 82c3754e21e3..f8ca36759b0a 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -2014,6 +2014,8 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data,
> ret = i2c_smbus_read_byte_data(client, PMBUS_CAPABILITY);
> if (ret >= 0 && (ret & PB_CAPABILITY_ERROR_CHECK))
> client->flags |= I2C_CLIENT_PEC;
> + else
> + client->flags &= ~I2C_CLIENT_PEC;
>
> pmbus_clear_faults(client);
>
> --
> 2.17.1
>
>