On Tue, Jun 30, 2020 at 05:43:50PM +0000, Chu Lin wrote: > Per max6581, reg 4d and reg 4e is used for temperature read offset. > This patch will let the user specify the temperature read offset for > max6581. This patch is tested on max6581 and only applies to max6581. > > Testing: > dts: temperature-read-offset = <0xde 0x0>; This should not be implemented this way. Instead, the standard tempX_offset attribute should be used, with appropriate code to determine affected channels (since there is only one offset value, and since it can be enabled per channel). A secondary question is if and how to set the temperature offset via devicetree; that will have to be documented and approved by a DT maintainer. I would think, though, that the offset should be specified in milli-degrees C and not as raw chip data. Thanks, Guenter > > verify: iotools smbus_read8 <vbus> 0x4d 0x4e > 0x6F > > Signed-off-by: Chu Lin <linchuyuan@xxxxxxxxxx> > --- > drivers/hwmon/max6697.c | 19 +++++++++++++++++-- > include/linux/platform_data/max6697.h | 4 ++++ > 2 files changed, 21 insertions(+), 2 deletions(-) > > diff --git a/drivers/hwmon/max6697.c b/drivers/hwmon/max6697.c > index 743752a2467a..16c0f0995a12 100644 > --- a/drivers/hwmon/max6697.c > +++ b/drivers/hwmon/max6697.c > @@ -493,8 +493,13 @@ static void max6697_get_config_of(struct device_node *node, > } > prop = of_get_property(node, "transistor-ideality", &len); > if (prop && len == 2 * sizeof(u32)) { > - pdata->ideality_mask = be32_to_cpu(prop[0]); > - pdata->ideality_value = be32_to_cpu(prop[1]); > + pdata->ideality_mask = be32_to_cpu(prop[0]); > + pdata->ideality_value = be32_to_cpu(prop[1]); > + } > + prop = of_get_property(node, "temperature-read-offset", &len); > + if (prop && len == 2 * sizeof(u32)) { > + pdata->offset_mask = be32_to_cpu(prop[0]); > + pdata->offset_value = be32_to_cpu(prop[1]); > } > } > > @@ -586,6 +591,16 @@ static int max6697_init_chip(struct max6697_data *data, > pdata->ideality_mask >> 1); > if (ret < 0) > return ret; > + ret = i2c_smbus_write_byte_data(client, > + MAX6581_REG_OFFSET, > + pdata->offset_value); > + if (ret < 0) > + return ret; > + ret = i2c_smbus_write_byte_data(client, > + MAX6581_REG_OFFSET_SELECT, > + pdata->offset_mask >> 1); > + if (ret < 0) > + return ret; > } > done: > data->update_interval = factor * MAX6697_CONV_TIME; > diff --git a/include/linux/platform_data/max6697.h b/include/linux/platform_data/max6697.h > index 6fbb70005541..ff98adfe9d8d 100644 > --- a/include/linux/platform_data/max6697.h > +++ b/include/linux/platform_data/max6697.h > @@ -28,6 +28,10 @@ struct max6697_platform_data { > u8 ideality_value; /* transistor ideality as per > * MAX6581 datasheet > */ > + u8 offset_mask; /* set bit to 0 to disable */ > + u8 offset_value; /* temperature read offset as > + * MAX6581 datasheet > + */ > }; > > #endif /* MAX6697_H */ > -- > 2.27.0.212.ge8ba1cc988-goog >