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Message-ID: <881ab1a3-e68a-4053-aaf7-9aa637c0ab2c@roeck-us.net>
Date: Wed, 29 Oct 2025 11:00:14 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Marius Cristea <marius.cristea@...rochip.com>,
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>, Jonathan Corbet <corbet@....net>
Cc: linux-hwmon@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org
Subject: Re: [PATCH 2/2] hwmon: temperature: add support for EMC1812
Hi,
On 10/29/25 08:50, Marius Cristea wrote:
> This is the hwmon driver for Microchip EMC1812/13/14/15/33
> Multichannel Low-Voltage Remote Diode Sensor Family.
> 
> Signed-off-by: Marius Cristea <marius.cristea@...rochip.com>
Thanks for the patch.
Would it be possible for you to send me register dumps for the supported chips ?
I would like to write unit test code for the driver.
> ---
>   Documentation/hwmon/emc1812.rst |  68 +++
Needs to be added to Documentation/hwmon/index.rst
>   MAINTAINERS                     |   2 +
>   drivers/hwmon/Kconfig           |  11 +
>   drivers/hwmon/Makefile          |   1 +
>   drivers/hwmon/emc1812.c         | 967 ++++++++++++++++++++++++++++++++++++++++
>   5 files changed, 1049 insertions(+)
> 
> diff --git a/Documentation/hwmon/emc1812.rst b/Documentation/hwmon/emc1812.rst
> new file mode 100644
> index 0000000000000000000000000000000000000000..799111a89541c57a839a121bb3dfc12f42604bc2
> --- /dev/null
> +++ b/Documentation/hwmon/emc1812.rst
> @@ -0,0 +1,68 @@
> +.. SPDX-License-Identifier: GPL-2.0-or-later
> +
> +Kernel driver emc1802
> +=====================
> +
> +Supported chips:
> +
> +  * Microchip EMC1812, EMC1813, EMC1814, EMC1815, EMC1833
> +
> +    Addresses scanned: I2C 0x1c, 0x3c, 0x4c, 0x4d, 0x5c, 0x6c, 0x7c
> +
> +    Prefix: 'emc1812'
> +
> +    Datasheets:
> +
> +	- https://ww1.microchip.com/downloads/aemDocuments/documents/MSLD/ProductDocuments/DataSheets/EMC1812-3-4-5-33-Data-Sheet-DS20005751.pdf
> +
> +Author:
> +    Marius Cristea <marius.cristea@...rochip.com
> +
> +
> +Description
> +-----------
> +
> +The Microchip EMC181x/33 chips contain up to 4 remote temperature sensors
> +and one internal.
> +- The EMC1812 is a single channel remote temperature sensor.
> +- The EMC1813 and EMC1833 is a dual channel remote temperature sensor. The
> +remote channels for this selection of devices can support substrate diodes,
> +discrete diode-connected transistors or CPU/GPU thermal diodes.
> +- The EMC1814 is a three channel remote temperature sensor that supports
> +Anti-Parallel Diode (APD) only on one channel. For the channel that does not
> +support APD functionality, substrate diodes, discrete diode-connected
> +transistors or CPU/GPU thermal diodes are supported. For the channel that
> +supports APD, only discrete diode-connected transistors may be implemented.
> +However, if APD is disabled on the EMC1814, then the channel that supports
> +APD will be functional with substrate diodes, discrete diode-connected
> +transistors and CPU/GPU thermal diodes.
> +- The EMC1815 is a four channel remote temperature sensor. The EMC1815 and
> +EMC1833 support APD on all channels. When APD is enabled, the channels support
> +only diode-connected transistors. If APD is disabled, then the channels will
> +support substrate transistors, discrete diode-connected transistors and
> +CPU/GPU thermal diodes.
> +
> +Note: Disabling APD functionality to implement substrate diodes on devices
> +that support APD eliminates the benefit of APD (two diodes on one channel).
> +
> +The chips implement three limits for each sensor: low (tempX_min), high
> +(tempX_max) and critical (tempX_crit). The chips also implement an
> +hysteresis mechanism which applies to all limits. The relative difference
> +is stored in a single register on the chip, which means that the relative
> +difference between the limit and its hysteresis is always the same for
> +all three limits.
> +
> +This implementation detail implies the following:
> +
> +* When setting a limit, its hysteresis will automatically follow, the
> +  difference staying unchanged. For example, if the old critical limit was
> +  80 degrees C, and the hysteresis was 75 degrees C, and you change the
> +  critical limit to 90 degrees C, then the hysteresis will automatically
> +  change to 85 degrees C.
> +* The hysteresis values can't be set independently. We decided to make
> +  only tempX_crit_hyst writable, while all other hysteresis attributes
> +  are read-only. Setting tempX_crit_hyst writes the difference between
> +  tempX_crit_hyst and tempX_crit into the chip, and the same relative
> +  hysteresis applies automatically to all other limits.
> +* The limits should be set before the hysteresis. At power up the device
> +  starts with a 10 degree written into hysteresis register.
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 85c236df781e47c78deeb7ef4d80bc94bba604c4..fcb712549ea679d49fde8c97840af9528b52d52b 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -16651,6 +16651,8 @@ M:	Marius Cristea <marius.cristea@...rochip.com>
>   L:	linux-hwmon@...r.kernel.org
>   S:	Supported
>   F:	Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml
> +F:	Documentation/hwmon/emc1812.rst
> +F:	drivers/hwmon/emc1812.c
>   
>   MICROCHIP I2C DRIVER
>   M:	Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 2760feb9f83b5d3b990b27acff572e587b373e9d..3b53572fd8bfbd752c2235ca429c4f74b1db3095 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -2042,6 +2042,17 @@ config SENSORS_EMC1403
>   	  Threshold values can be configured using sysfs.
>   	  Data from the different diodes are accessible via sysfs.
>   
> +config SENSORS_EMC1812
> +	tristate "Microchip Technology EMC1812 driver"
> +	depends on I2C
> +	select REGMAP_I2C
> +	help
> +	  If you say yes here to build support for Microchip Technology's
> +	  EMC181X/33  Multichannel Low-Voltage Remote Diode Sensor Family.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called emc1812.
> +
>   config SENSORS_EMC2103
>   	tristate "SMSC EMC2103"
>   	depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 73b2abdcc6dd9cfae4c84b350febc5d8c191e385..e93e4051e99db698dbaae97ac4841e6d810ee8c4 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -73,6 +73,7 @@ obj-$(CONFIG_SENSORS_DRIVETEMP)	+= drivetemp.o
>   obj-$(CONFIG_SENSORS_DS620)	+= ds620.o
>   obj-$(CONFIG_SENSORS_DS1621)	+= ds1621.o
>   obj-$(CONFIG_SENSORS_EMC1403)	+= emc1403.o
> +obj-$(CONFIG_SENSORS_EMC1812)	+= emc1812.o
>   obj-$(CONFIG_SENSORS_EMC2103)	+= emc2103.o
>   obj-$(CONFIG_SENSORS_EMC2305)	+= emc2305.o
>   obj-$(CONFIG_SENSORS_EMC6W201)	+= emc6w201.o
> diff --git a/drivers/hwmon/emc1812.c b/drivers/hwmon/emc1812.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..78038dace1fd218346beae7c7d7447f68072d0f4
> --- /dev/null
> +++ b/drivers/hwmon/emc1812.c
> @@ -0,0 +1,967 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * HWMON driver for Microchip EMC1812/13/14/15/33 Multichannel high-accuracy
> + * 2-wire low-voltage remote diode temperature monitor family.
> + *
> + * Copyright (C) 2025 Microchip Technology Inc. and its subsidiaries
> + *
> + * Author: Marius Cristea <marius.cristea@...rochip.com>
> + *
> + * Datasheet can be found here:
> + * https://ww1.microchip.com/downloads/aemDocuments/documents/MSLD/ProductDocuments/DataSheets/EMC1812-3-4-5-33-Data-Sheet-DS20005751.pdf
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/bitops.h>
> +#include <linux/bits.h>
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/hwmon.h>
> +#include <linux/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/math64.h>
> +#include <linux/property.h>
> +#include <linux/regmap.h>
> +#include <linux/string.h>
> +#include <linux/units.h>
> +
> +/* EMC1812 Registers Addresses */
> +#define EMC1812_STATUS_ADDR				0x02
> +#define EMC1812_CONFIG_LO_ADDR				0x03
> +
> +#define EMC1812_CFG_ADDR				0x09
> +#define EMC1812_CONV_ADDR				0x0A
> +#define EMC1812_INT_DIODE_HIGH_LIMIT_ADDR		0x0B
> +#define EMC1812_INT_DIODE_LOW_LIMIT_ADDR		0x0C
> +#define EMC1812_EXT1_HIGH_LIMIT_HIGH_BYTE_ADDR		0x0D
> +#define EMC1812_EXT1_LOW_LIMIT_HIGH_BYTE_ADDR		0x0E
> +#define EMC1812_ONE_SHOT_ADDR				0x0F
> +
> +#define EMC1812_EXT1_HIGH_LIMIT_LOW_BYTE_ADDR		0x13
> +#define EMC1812_EXT1_LOW_LIMIT_LOW_BYTE_ADDR		0x14
> +#define EMC1812_EXT2_HIGH_LIMIT_HIGH_BYTE_ADDR		0x15
> +#define EMC1812_EXT2_LOW_LIMIT_HIGH_BYTE_ADDR		0x16
> +#define EMC1812_EXT2_HIGH_LIMIT_LOW_BYTE_ADDR		0x17
> +#define EMC1812_EXT2_LOW_LIMIT_LOW_BYTE_ADDR		0x18
> +#define EMC1812_EXT1_THERM_LIMIT_ADDR			0x19
> +#define EMC1812_EXT2_THERM_LIMIT_ADDR			0x1A
> +#define EMC1812_EXT_DIODE_FAULT_STATUS_ADDR		0x1B
> +
> +#define EMC1812_DIODE_FAULT_MASK_ADDR			0x1F
> +#define EMC1812_INT_DIODE_THERM_LIMIT_ADDR		0x20
> +#define EMC1812_THRM_HYS_ADDR				0x21
> +#define EMC1812_CONSEC_ALERT_ADDR			0x22
> +
> +#define EMC1812_EXT1_BETA_CONFIG_ADDR			0x25
> +#define EMC1812_EXT2_BETA_CONFIG_ADDR			0x26
> +#define EMC1812_EXT1_IDEALITY_FACTOR_ADDR		0x27
> +#define EMC1812_EXT2_IDEALITY_FACTOR_ADDR		0x28
> +
> +#define EMC1812_EXT3_HIGH_LIMIT_HIGH_BYTE_ADDR		0x2C
> +#define EMC1812_EXT3_LOW_LIMIT_HIGH_BYTE_ADDR		0x2D
> +#define EMC1812_EXT3_HIGH_LIMIT_LOW_BYTE_ADDR		0x2E
> +#define EMC1812_EXT3_LOW_LIMIT_LOW_BYTE_ADDR		0x2F
> +#define EMC1812_EXT3_THERM_LIMIT_ADDR			0x30
> +#define EMC1812_EXT3_IDEALITY_FACTOR_ADDR		0x31
> +
> +#define EMC1812_EXT4_HIGH_LIMIT_HIGH_BYTE_ADDR		0x34
> +#define EMC1812_EXT4_LOW_LIMIT_HIGH_BYTE_ADDR		0x35
> +#define EMC1812_EXT4_HIGH_LIMIT_LOW_BYTE_ADDR		0x36
> +#define EMC1812_EXT4_LOW_LIMIT_LOW_BYTE_ADDR		0x37
> +#define EMC1812_EXT4_THERM_LIMIT_ADDR			0x38
> +#define EMC1812_EXT4_IDEALITY_FACTOR_ADDR		0x39
> +#define EMC1812_HIGH_LIMIT_STATUS_ADDR			0x3A
> +#define EMC1812_LOW_LIMIT_STATUS_ADDR			0x3B
> +#define EMC1812_THERM_LIMIT_STATUS_ADDR			0x3C
> +#define EMC1812_ROC_GAIN_ADDR				0x3D
> +#define EMC1812_ROC_CONFIG_ADDR				0x3E
> +#define EMC1812_ROC_STATUS_ADDR				0x3F
> +#define EMC1812_R1_RESH_ADDR				0x40
> +#define EMC1812_R1_LIMH_ADDR				0x41
> +#define EMC1812_R1_LIML_ADDR				0x42
> +#define EMC1812_R1_SMPL_ADDR				0x43
> +#define EMC1812_R2_RESH_ADDR				0x44
> +#define EMC1812_R2_3_RESL_ADDR				0x45
> +#define EMC1812_R2_LIMH_ADDR				0x46
> +#define EMC1812_R2_LIML_ADDR				0x47
> +#define EMC1812_R2_SMPL_ADDR				0x48
> +#define EMC1812_PER_MAXTH_1_ADDR			0x49
> +#define EMC1812_PER_MAXT1L_ADDR				0x4A
> +#define EMC1812_PER_MAXTH_2_ADDR			0x4B
> +#define EMC1812_PER_MAXT2_3L_ADDR			0x4C
> +#define EMC1812_GBL_MAXT1H_ADDR				0x4D
> +#define EMC1812_GBL_MAXT1L_ADDR				0x4E
> +#define EMC1812_GBL_MAXT2H_ADDR				0x4F
> +#define EMC1812_GBL_MAXT2L_ADDR				0x50
> +#define EMC1812_FILTER_SEL_ADDR				0x51
> +
> +#define EMC1812_INT_HIGH_BYTE_ADDR		0x60
> +#define EMC1812_INT_LOW_BYTE_ADDR		0x61
> +#define EMC1812_EXT1_HIGH_BYTE_ADDR		0x62
> +#define EMC1812_EXT1_LOW_BYTE_ADDR		0x63
> +#define EMC1812_EXT2_HIGH_BYTE_ADDR		0x64
> +#define EMC1812_EXT2_LOW_BYTE_ADDR		0x65
> +#define EMC1812_EXT3_HIGH_BYTE_ADDR		0x66
> +#define EMC1812_EXT3_LOW_BYTE_ADDR		0x67
> +#define EMC1812_EXT4_HIGH_BYTE_ADDR		0x68
> +#define EMC1812_EXT4_LOW_BYTE_ADDR		0x69
> +#define EMC1812_HOTTEST_DIODE_HIGH_BYTE_ADDR	0x6A
> +#define EMC1812_HOTTEST_DIODE_LOW_BYTE_ADDR	0x6B
> +#define EMC1812_HOTTEST_STATUS_ADDR		0x6C
> +#define EMC1812_HOTTEST_CFG_ADDR		0x6D
> +
> +#define EMC1812_PRODUCT_ID_ADDR			0xFD
> +#define EMC1812_MANUFACTURER_ID_ADDR		0xFE
> +#define EMC1812_REVISION_ADDR			0xFF
> +
> +/* EMC1812 Config Bits */
> +#define EMC1812_CFG_MSKAL			BIT(7)
> +#define EMC1812_CFG_RS				BIT(6)
> +#define EMC1812_CFG_ATTHM			BIT(5)
> +#define EMC1812_CFG_RECD12			BIT(4)
> +#define EMC1812_CFG_RECD34			BIT(3)
> +#define EMC1812_CFG_RANGE			BIT(2)
> +#define EMC1812_CFG_DA_ENA			BIT(1)
> +#define EMC1812_CFG_APDD			BIT(0)
> +
> +/* EMC1812 Status Bits */
> +#define EMC1812_STATUS_ROCF			BIT(7)
> +#define EMC1812_STATUS_HOTCHG			BIT(6)
> +#define EMC1812_STATUS_BUSY			BIT(5)
> +#define EMC1812_STATUS_HIGH			BIT(4)
> +#define EMC1812_STATUS_LOW			BIT(3)
> +#define EMC1812_STATUS_FAULT			BIT(2)
> +#define EMC1812_STATUS_ETHRM			BIT(1)
> +#define EMC1812_STATUS_ITHRM			BIT(0)
> +
> +#define EMC1812_BETA_LOCK_VAL			0x0F
> +
> +#define EMC1812_TEMP_CH_ADDR(index)		(0x60 + 2 * (index))
> +
> +#define EMC1812_FILTER_MASK_LEN			2
> +
> +#define EMC1812_PID				0x81
> +#define EMC1813_PID				0x87
> +#define EMC1814_PID				0x84
> +#define EMC1815_PID				0x85
> +#define EMC1833_PID				0x83
> +
> +/* The maximum number of channels a member of the family can have */
> +#define EMC1812_MAX_NUM_CHANNELS		5
> +#define EMC1812_TEMP_OFFSET			64
> +
> +#define EMC1812_DEFAULT_IDEALITY_FACTOR		0x12
> +
> +static const struct hwmon_channel_info * const emc1812_info[] = {
> +	HWMON_CHANNEL_INFO(chip, HWMON_C_UPDATE_INTERVAL),
> +	HWMON_CHANNEL_INFO(temp,
> +			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
> +			   HWMON_T_CRIT | HWMON_T_MIN_HYST | HWMON_T_MAX_HYST |
> +			   HWMON_T_CRIT_HYST | HWMON_T_MIN_ALARM |
> +			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM | HWMON_T_FAULT |
> +			   HWMON_T_LABEL,
> +
The internal sensor does not have a fault condition, so HWMON_T_FAULT
should be dropped here.
> +			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
> +			   HWMON_T_CRIT | HWMON_T_MIN_HYST | HWMON_T_MAX_HYST |
> +			   HWMON_T_CRIT_HYST | HWMON_T_MIN_ALARM |
> +			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM | HWMON_T_FAULT |
> +			   HWMON_T_LABEL,
> +
> +			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
> +			   HWMON_T_CRIT | HWMON_T_MIN_HYST | HWMON_T_MAX_HYST |
> +			   HWMON_T_CRIT_HYST | HWMON_T_MIN_ALARM |
> +			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM | HWMON_T_FAULT |
> +			   HWMON_T_LABEL,
> +
> +			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
> +			   HWMON_T_CRIT | HWMON_T_MIN_HYST | HWMON_T_MAX_HYST |
> +			   HWMON_T_CRIT_HYST | HWMON_T_MIN_ALARM |
> +			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM | HWMON_T_FAULT |
> +			   HWMON_T_LABEL,
> +
> +			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
> +			   HWMON_T_CRIT | HWMON_T_MIN_HYST | HWMON_T_MAX_HYST |
> +			   HWMON_T_CRIT_HYST | HWMON_T_MIN_ALARM |
> +			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM | HWMON_T_FAULT |
> +			   HWMON_T_LABEL
> +			   ),
> +	NULL
> +};
> +
> +/**
> + * struct emc1812_features - features of a emc1812 instance
> + * @name:		chip's name
> + * @phys_channels:	number of physical channels supported by the chip
> + */
> +struct emc1812_features {
> +	const char	*name;
> +	u8		phys_channels;
> +};
> +
> +static const struct emc1812_features emc1833_chip_config = {
> +	.name = "emc1833",
> +	.phys_channels = 3,
> +};
> +
> +static const struct emc1812_features emc1812_chip_config = {
> +	.name = "emc1812",
> +	.phys_channels = 2,
> +};
> +
> +static const struct emc1812_features emc1813_chip_config = {
> +	.name = "emc1813",
> +	.phys_channels = 3,
> +};
> +
> +static const struct emc1812_features emc1814_chip_config = {
> +	.name = "emc1814",
> +	.phys_channels = 4,
> +};
> +
> +static const struct emc1812_features emc1815_chip_config = {
> +	.name = "emc1815",
> +	.phys_channels = 5,
> +};
> +
> +enum emc1812_limit_type {temp_min, temp_max};
> +
> +static u8 emc1812_temp_map[] = {
> +	[hwmon_temp_min] = temp_min,
> +	[hwmon_temp_max] = temp_max,
> +};
> +
> +static u8 emc1812_temp_crit_regs[] = {
> +	[0] = EMC1812_INT_DIODE_THERM_LIMIT_ADDR,
> +	[1] = EMC1812_EXT1_THERM_LIMIT_ADDR,
> +	[2] = EMC1812_EXT2_THERM_LIMIT_ADDR,
> +	[3] = EMC1812_EXT3_THERM_LIMIT_ADDR,
> +	[4] = EMC1812_EXT4_THERM_LIMIT_ADDR,
> +};
> +
> +static u8 emc1812_limit_regs[][2] = {
> +	[0] = {
> +		[temp_min] = EMC1812_INT_DIODE_LOW_LIMIT_ADDR,
> +		[temp_max] = EMC1812_INT_DIODE_HIGH_LIMIT_ADDR,
> +	},
> +	[1] = {
> +		[temp_min] = EMC1812_EXT1_LOW_LIMIT_HIGH_BYTE_ADDR,
> +		[temp_max] = EMC1812_EXT1_HIGH_LIMIT_HIGH_BYTE_ADDR,
> +	},
> +	[2] = {
> +		[temp_min] = EMC1812_EXT2_LOW_LIMIT_HIGH_BYTE_ADDR,
> +		[temp_max] = EMC1812_EXT2_HIGH_LIMIT_HIGH_BYTE_ADDR,
> +	},
> +	[3] = {
> +		[temp_min] = EMC1812_EXT3_LOW_LIMIT_HIGH_BYTE_ADDR,
> +		[temp_max] = EMC1812_EXT3_HIGH_LIMIT_HIGH_BYTE_ADDR,
> +	},
> +	[4] = {
> +		[temp_min] = EMC1812_EXT4_LOW_LIMIT_HIGH_BYTE_ADDR,
> +		[temp_max] = EMC1812_EXT4_HIGH_LIMIT_HIGH_BYTE_ADDR,
> +	},
> +};
> +
> +static u8 emc1812_limit_regs_low[][3] = {
> +	[0] = {
> +		[temp_min] = 0xff,
> +		[temp_max] = 0xff,
> +	},
> +	[1] = {
> +		[temp_min] = EMC1812_EXT1_LOW_LIMIT_LOW_BYTE_ADDR,
> +		[temp_max] = EMC1812_EXT1_HIGH_LIMIT_LOW_BYTE_ADDR,
> +	},
> +	[2] = {
> +		[temp_min] = EMC1812_EXT2_LOW_LIMIT_LOW_BYTE_ADDR,
> +		[temp_max] = EMC1812_EXT2_HIGH_LIMIT_LOW_BYTE_ADDR,
> +	},
> +	[3] = {
> +		[temp_min] = EMC1812_EXT3_LOW_LIMIT_LOW_BYTE_ADDR,
> +		[temp_max] = EMC1812_EXT3_HIGH_LIMIT_LOW_BYTE_ADDR,
> +	},
> +	[4] = {
> +		[temp_min] = EMC1812_EXT4_LOW_LIMIT_LOW_BYTE_ADDR,
> +		[temp_max] = EMC1812_EXT4_HIGH_LIMIT_LOW_BYTE_ADDR,
> +	},
> +};
> +
> +/* Lookup table for temperature conversion times in msec */
> +static const u16 emc1812_conv_time[] = {
> +	16000, 8000, 4000, 2000, 1000, 500, 250, 125, 62, 31, 16
> +};
> +
> +/**
> + * struct emc1812_data - information about chip parameters
> + * @client:		i2c client
Unused.
> + * @hwmon_dev:		hwmon device
Unused.
> + * @labels:		labels of the channels
> + * @active_ch_mask:	active channels
> + * @chip:		pointer to structure holding chip features
> + * @freq_idx:		index representing the current sampling frequency
Unused.
> + * @regmap:		device register map
> + * @recd34_en:		state of Resistance Error Correction (REC) on channels 3 and 4
> + * @recd12_en:		state of Resistance Error Correction (REC) on channels 1 and 2
> + * @lock:		synchronize access to driver's state members
Unused.
> + * @apdd_en:		state of anti-parallel diode mode
> + * @num_channels:	number of active physical channels
Unused.
> + */
> +struct emc1812_data {
> +	struct i2c_client *client;
> +	struct device *hwmon_dev;
> +	const char *labels[EMC1812_MAX_NUM_CHANNELS];
> +	unsigned long active_ch_mask;
> +	const struct emc1812_features *chip;
> +	unsigned int freq_idx;
> +	struct regmap *regmap;
> +	bool recd34_en;
> +	bool recd12_en;
> +	struct mutex lock;	 /* Synchronize access to driver's state members */
> +	bool apdd_en;
> +	u8 num_channels;
> +};
> +
> +/* emc1812 regmap configuration */
> +static const struct regmap_range emc1812_regmap_writable_ranges[] = {
> +	regmap_reg_range(EMC1812_CFG_ADDR, EMC1812_ONE_SHOT_ADDR),
> +	regmap_reg_range(EMC1812_EXT1_HIGH_LIMIT_LOW_BYTE_ADDR,
> +			 EMC1812_EXT_DIODE_FAULT_STATUS_ADDR),
> +	regmap_reg_range(EMC1812_DIODE_FAULT_MASK_ADDR, EMC1812_CONSEC_ALERT_ADDR),
> +	regmap_reg_range(EMC1812_EXT1_BETA_CONFIG_ADDR, EMC1812_FILTER_SEL_ADDR),
> +	regmap_reg_range(EMC1812_HOTTEST_STATUS_ADDR, EMC1812_HOTTEST_CFG_ADDR),
> +};
> +
> +static const struct regmap_access_table emc1812_regmap_wr_table = {
> +	.yes_ranges = emc1812_regmap_writable_ranges,
> +	.n_yes_ranges = ARRAY_SIZE(emc1812_regmap_writable_ranges),
> +};
> +
> +static const struct regmap_range emc1812_regmap_rd_ranges[] = {
> +	regmap_reg_range(EMC1812_STATUS_ADDR, EMC1812_CONFIG_LO_ADDR),
> +	regmap_reg_range(EMC1812_CFG_ADDR, EMC1812_ONE_SHOT_ADDR),
> +	regmap_reg_range(EMC1812_EXT1_HIGH_LIMIT_LOW_BYTE_ADDR,
> +			 EMC1812_EXT_DIODE_FAULT_STATUS_ADDR),
> +	regmap_reg_range(EMC1812_DIODE_FAULT_MASK_ADDR, EMC1812_CONSEC_ALERT_ADDR),
> +	regmap_reg_range(EMC1812_EXT1_BETA_CONFIG_ADDR, EMC1812_FILTER_SEL_ADDR),
> +	regmap_reg_range(EMC1812_INT_HIGH_BYTE_ADDR, EMC1812_HOTTEST_CFG_ADDR),
> +	regmap_reg_range(EMC1812_PRODUCT_ID_ADDR, EMC1812_REVISION_ADDR),
> +};
> +
> +static const struct regmap_access_table emc1812_regmap_rd_table = {
> +	.yes_ranges = emc1812_regmap_rd_ranges,
> +	.n_yes_ranges = ARRAY_SIZE(emc1812_regmap_rd_ranges),
> +};
> +
> +static bool emc1812_is_volatile_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case EMC1812_STATUS_ADDR:
> +	case EMC1812_EXT_DIODE_FAULT_STATUS_ADDR:
> +	case EMC1812_DIODE_FAULT_MASK_ADDR:
> +	case EMC1812_EXT1_BETA_CONFIG_ADDR:
> +	case EMC1812_EXT2_BETA_CONFIG_ADDR:
> +	case EMC1812_HIGH_LIMIT_STATUS_ADDR:
> +	case EMC1812_LOW_LIMIT_STATUS_ADDR:
> +	case EMC1812_THERM_LIMIT_STATUS_ADDR:
> +	case EMC1812_ROC_STATUS_ADDR:
> +	case EMC1812_PER_MAXTH_1_ADDR:
> +	case EMC1812_PER_MAXT1L_ADDR:
> +	case EMC1812_PER_MAXTH_2_ADDR:
> +	case EMC1812_PER_MAXT2_3L_ADDR:
> +	case EMC1812_GBL_MAXT1H_ADDR:
> +	case EMC1812_GBL_MAXT1L_ADDR:
> +	case EMC1812_GBL_MAXT2H_ADDR:
> +	case EMC1812_GBL_MAXT2L_ADDR:
> +	case EMC1812_INT_HIGH_BYTE_ADDR:
> +	case EMC1812_INT_LOW_BYTE_ADDR:
> +	case EMC1812_EXT1_HIGH_BYTE_ADDR:
> +	case EMC1812_EXT1_LOW_BYTE_ADDR:
> +	case EMC1812_EXT2_HIGH_BYTE_ADDR:
> +	case EMC1812_EXT2_LOW_BYTE_ADDR:
> +	case EMC1812_EXT3_HIGH_BYTE_ADDR:
> +	case EMC1812_EXT3_LOW_BYTE_ADDR:
> +	case EMC1812_EXT4_HIGH_BYTE_ADDR:
> +	case EMC1812_EXT4_LOW_BYTE_ADDR:
> +	case EMC1812_HOTTEST_DIODE_HIGH_BYTE_ADDR:
> +	case EMC1812_HOTTEST_DIODE_LOW_BYTE_ADDR:
> +	case EMC1812_HOTTEST_STATUS_ADDR:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static const struct regmap_config emc1812_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.rd_table = &emc1812_regmap_rd_table,
> +	.wr_table = &emc1812_regmap_wr_table,
> +	.volatile_reg = emc1812_is_volatile_reg,
> +	.max_register = EMC1812_REVISION_ADDR,
> +	.cache_type = REGCACHE_MAPLE,
> +};
> +
> +static umode_t emc1812_is_visible(const void *_data, enum hwmon_sensor_types type,
> +				  u32 attr, int channel)
> +{
> +	const struct emc1812_data *data = _data;
> +
> +	switch (type) {
> +	case hwmon_temp:
> +		/* Don't show channels which are not described into the device tree. */
The driver needs to work on systems without devicetree or firmware nodes,
so there will have to be some defaults to handle that.
> +		if (!(data->active_ch_mask & (1 << channel)))
BIT(channel)
> +			return 0;
> +
> +		/* Don't show channels which are not physically connected. */
> +		if (channel >= data->chip->phys_channels)
> +			return 0;
> +
> +		switch (attr) {
> +		case hwmon_temp_input:
> +		case hwmon_temp_min_alarm:
> +		case hwmon_temp_max_alarm:
> +		case hwmon_temp_crit_alarm:
> +		case hwmon_temp_fault:
> +		case hwmon_temp_min_hyst:
> +		case hwmon_temp_max_hyst:
> +		case hwmon_temp_label:
> +			return 0444;
> +		case hwmon_temp_min:
> +		case hwmon_temp_max:
> +		case hwmon_temp_crit:
> +		case hwmon_temp_crit_hyst:
> +			return 0644;
> +		default:
> +			return 0;
> +		}
> +	case hwmon_chip:
> +		switch (attr) {
> +		case hwmon_chip_update_interval:
> +			return 0644;
> +		default:
> +			return 0;
> +		}
> +	default:
> +		return 0;
> +	}
> +};
> +
> +static int emc1812_get_temp(struct emc1812_data *data, int channel, long *val)
> +{
> +	__be16 tmp_be16;
> +	int ret;
> +
> +	ret = regmap_bulk_read(data->regmap, EMC1812_TEMP_CH_ADDR(channel),
> +			       &tmp_be16, sizeof(tmp_be16));
> +	if (ret)
> +		return ret;
> +
> +	/* Range is always -64 to 191.875°C */
> +	*val = ((be16_to_cpu(tmp_be16) >> 5) - 512) * 125;
> +
> +	return 0;
> +}
> +
> +static int emc1812_get_crit_limit_temp(struct emc1812_data *data, int channel, long *val)
> +{
> +	unsigned int tmp;
> +	int ret;
> +
> +	/* Critical register is 8bits long and keeps only integer part of temperature */
> +	ret = regmap_read(data->regmap, emc1812_temp_crit_regs[channel], &tmp);
> +	if (ret)
> +		return ret;
> +
> +	/* Range is always -64 to 191°C */
> +	*val = (tmp - EMC1812_TEMP_OFFSET) * 1000;
> +
> +	return 0;
> +}
> +
> +static int emc1812_get_limit_temp(struct emc1812_data *data, int ch,
> +				  enum emc1812_limit_type type, long *val)
> +{
> +	unsigned int regvalh;
> +	unsigned int regvall = 0;
> +	int ret;
> +
> +	ret = regmap_read(data->regmap, emc1812_limit_regs[ch][type], ®valh);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (ch) {
> +		ret = regmap_read(data->regmap, emc1812_limit_regs_low[ch][type], ®vall);
> +		if (ret < 0)
> +			return ret;
> +	}
> +	/* Range is always -64 to 191.875°C */
> +	*val = (((regvalh - EMC1812_TEMP_OFFSET) << 3) | (regvall >> 5)) * 125;
> +
> +	return 0;
> +}
> +
> +static int emc1812_read_reg(struct device *dev, struct emc1812_data *data, u32 attr,
> +			    int channel, long *val)
> +{
> +	unsigned int mask;
> +	int hyst, ret;
> +
> +	switch (attr) {
> +	case hwmon_temp_min:
> +		return emc1812_get_limit_temp(data, channel, temp_min, val);
> +	case hwmon_temp_max:
> +		return emc1812_get_limit_temp(data, channel, temp_max, val);
> +	case hwmon_temp_crit:
> +		return emc1812_get_crit_limit_temp(data, channel, val);
> +	case hwmon_temp_input:
> +		return emc1812_get_temp(data, channel, val);
> +	case hwmon_temp_min_hyst:
> +		ret = emc1812_get_limit_temp(data, channel, temp_min, val);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = regmap_read(data->regmap, EMC1812_THRM_HYS_ADDR, &hyst);
> +		if (ret < 0)
> +			return ret;
> +
> +		*val = *val + hyst * 1000;
> +
> +		return 0;
> +
> +	case hwmon_temp_max_hyst:
> +		ret = emc1812_get_limit_temp(data, channel, temp_max, val);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = regmap_read(data->regmap, EMC1812_THRM_HYS_ADDR, &hyst);
> +		if (ret < 0)
> +			return ret;
> +
> +		*val = *val - hyst * 1000;
> +
> +		return 0;
> +	case hwmon_temp_crit_hyst:
> +		ret = emc1812_get_crit_limit_temp(data, channel, val);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = regmap_read(data->regmap, EMC1812_THRM_HYS_ADDR, &hyst);
> +		if (ret < 0)
> +			return ret;
> +
> +		*val = *val - hyst * 1000;
> +		return 0;
> +	case hwmon_temp_min_alarm:
> +		mask = 1 << channel;
> +		*val = regmap_test_bits(data->regmap, EMC1812_LOW_LIMIT_STATUS_ADDR, mask);
> +		if (*val < 0)
> +			return *val;
> +		return 0;
> +	case hwmon_temp_max_alarm:
> +		mask = 1 << channel;
> +		*val = regmap_test_bits(data->regmap, EMC1812_HIGH_LIMIT_STATUS_ADDR, mask);
> +		if (*val < 0)
> +			return *val;
> +		return 0;
> +	case hwmon_temp_crit_alarm:
> +		mask = 1 << channel;
> +		*val = regmap_test_bits(data->regmap, EMC1812_THERM_LIMIT_STATUS_ADDR, mask);
> +		if (*val < 0)
> +			return *val;
> +		return 0;
> +	case hwmon_temp_fault:
> +		mask = 1 << channel;
> +		*val = regmap_test_bits(data->regmap, EMC1812_EXT_DIODE_FAULT_STATUS_ADDR, mask);
> +		if (*val < 0)
> +			return *val;
> +		return 0;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +static int emc1812_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
> +			int channel, long *val)
> +{
> +	struct emc1812_data *data = dev_get_drvdata(dev);
> +	unsigned int convrate;
> +	int ret;
> +
> +	switch (type) {
> +	case hwmon_temp:
> +		return emc1812_read_reg(dev, data, attr, channel, val);
> +	case hwmon_chip:
> +		switch (attr) {
> +		case hwmon_chip_update_interval:
> +			ret = regmap_read(data->regmap, EMC1812_CONV_ADDR, &convrate);
> +			if (ret < 0)
> +				return ret;
> +
> +			if (convrate > 10)
> +				convrate = 4;
> +
> +			*val = 16000 >> convrate;
> +			return 0;
> +		default:
> +			return -EOPNOTSUPP;
> +		}
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +static int emc1812_read_string(struct device *dev, enum hwmon_sensor_types type,
> +			       u32 attr, int channel, const char **str)
> +{
> +	struct emc1812_data *data = dev_get_drvdata(dev);
> +
> +	if (channel >= data->chip->phys_channels)
> +		return 0;
> +
> +	switch (type) {
> +	case hwmon_temp:
> +		switch (attr) {
> +		case hwmon_temp_label:
> +			*str = data->labels[channel];
> +			return 0;
> +		default:
> +			return -EOPNOTSUPP;
> +		}
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +static int emc1812_set_hyst(struct emc1812_data *data, int channel, long val)
> +{
> +	int hyst, ret;
> +	int limit;
> +
> +	/* Critical register is 8bits long and keeps only integer part of temperature */
> +	ret = regmap_read(data->regmap, emc1812_temp_crit_regs[channel], &limit);
> +	if (ret)
> +		return ret;
> +
> +	hyst = clamp_val(limit - val, 0, 256);
> +
> +	ret = regmap_write(data->regmap, EMC1812_THRM_HYS_ADDR, hyst);
> +
> +	return ret;
> +}
> +
> +static int emc1812_set_temp(struct emc1812_data *data, int channel,
> +			    enum emc1812_limit_type map, long val)
> +{
> +	int ret;
> +	u8 regh, regl;
> +
> +	regh = emc1812_limit_regs[channel][map];
> +	regl = emc1812_limit_regs_low[channel][map];
> +
> +	ret = regmap_write(data->regmap, regh, (val >> 3) & 0xff);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (channel)
> +		ret = regmap_write(data->regmap, regl, (val & 0x07) << 5);
> +
> +	return ret;
> +}
> +
> +static int emc1812_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
> +			 int channel, long val)
> +{
> +	struct emc1812_data *data = dev_get_drvdata(dev);
> +	unsigned int interval;
> +	int convrate;
> +
> +	switch (type) {
> +	case hwmon_temp:
> +		/* Range is always -64 to 191.875°C */
> +		val = clamp_val(val, -64000, 191875);
> +		val = val + (EMC1812_TEMP_OFFSET * 1000);
> +		val = DIV_ROUND_CLOSEST(val, 125);
> +
> +		switch (attr) {
> +		case hwmon_temp_min:
> +		case hwmon_temp_max:
> +			return emc1812_set_temp(data, channel, emc1812_temp_map[attr], val);
> +		case hwmon_temp_crit:
> +			val = (val >> 3) & 0xff;
> +			return regmap_write(data->regmap, emc1812_temp_crit_regs[channel], val);
> +		case hwmon_temp_crit_hyst:
> +			val = (val >> 3) & 0xff;
> +			return emc1812_set_hyst(data, channel, val);
> +		default:
> +			return -EOPNOTSUPP;
> +		}
> +	case hwmon_chip:
> +		switch (attr) {
> +		case hwmon_chip_update_interval:
> +			interval = clamp_val(val, 0, 16000);
> +			convrate = find_closest_descending(interval, emc1812_conv_time,
> +							   ARRAY_SIZE(emc1812_conv_time));
> +			return regmap_write(data->regmap, EMC1812_CONV_ADDR, convrate);
> +		default:
> +			return -EOPNOTSUPP;
> +		}
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +static int emc1812_init(struct emc1812_data *priv)
> +{
> +	int ret;
> +	u8 val;
> +
> +	/*
> +	 * Set default values in registers. APDD, RECD12 and RECD34 are active
> +	 * on 0.
> +	 * Set the device to be in Run (Active) state and converting on all
> +	 * channels.
> +	 * The temperature measurement range is -64°C to +191.875°C.
> +	 */
> +	val = FIELD_PREP(EMC1812_CFG_MSKAL, 1) |
> +	      FIELD_PREP(EMC1812_CFG_RS, 0) |
> +	      FIELD_PREP(EMC1812_CFG_ATTHM, 1) |
> +	      FIELD_PREP(EMC1812_CFG_RECD12, !priv->recd12_en) |
> +	      FIELD_PREP(EMC1812_CFG_RECD34, !priv->recd34_en) |
> +	      FIELD_PREP(EMC1812_CFG_RANGE, 1) |
> +	      FIELD_PREP(EMC1812_CFG_DA_ENA, 0) |
> +	      FIELD_PREP(EMC1812_CFG_APDD, !priv->apdd_en);
> +
> +	ret = regmap_write(priv->regmap, EMC1812_CFG_ADDR, val);
> +	if (ret)
> +		return ret;
> +
> +	/* Default is 4 conversions/seconds */
> +	ret = regmap_write(priv->regmap, EMC1812_CONV_ADDR, 6);
> +	if (ret)
> +		return ret;
> +	priv->freq_idx = 6;
> +
> +	ret = regmap_write(priv->regmap, EMC1812_THRM_HYS_ADDR, 0x0A);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_write(priv->regmap, EMC1812_CONSEC_ALERT_ADDR, 0x70);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_write(priv->regmap, EMC1812_FILTER_SEL_ADDR, 0);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_write(priv->regmap, EMC1812_HOTTEST_CFG_ADDR, 0);
> +	if (ret)
> +		return ret;
> +
> +	/* Enables the beta compensation factor auto-detection function for beta1 and beta2 */
> +	ret = regmap_write(priv->regmap, EMC1812_EXT1_BETA_CONFIG_ADDR,
> +			   EMC1812_BETA_LOCK_VAL);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_write(priv->regmap, EMC1812_EXT2_BETA_CONFIG_ADDR,
> +			   EMC1812_BETA_LOCK_VAL);
> +	if (ret)
> +		return ret;
> +
> +	/* Set ideality factor for all external channels */
> +	ret = regmap_write(priv->regmap, EMC1812_EXT1_IDEALITY_FACTOR_ADDR,
> +			   EMC1812_DEFAULT_IDEALITY_FACTOR);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_write(priv->regmap, EMC1812_EXT2_IDEALITY_FACTOR_ADDR,
> +			   EMC1812_DEFAULT_IDEALITY_FACTOR);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_write(priv->regmap, EMC1812_EXT3_IDEALITY_FACTOR_ADDR,
> +			   EMC1812_DEFAULT_IDEALITY_FACTOR);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_write(priv->regmap, EMC1812_EXT4_IDEALITY_FACTOR_ADDR,
> +			   EMC1812_DEFAULT_IDEALITY_FACTOR);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int emc1812_parse_fw_config(struct emc1812_data *data, struct device *dev)
> +{
> +	unsigned int reg_nr = 0;
> +	int ret;
> +
> +	data->apdd_en = device_property_read_bool(dev, "microchip,enable-anti-parallel");
> +	data->recd12_en = device_property_read_bool(dev, "microchip,parasitic-res-on-channel1-2");
> +	data->recd34_en = device_property_read_bool(dev, "microchip,parasitic-res-on-channel3-4");
> +
> +	data->num_channels = device_get_child_node_count(dev) + 1;
> +
> +	if (data->num_channels > data->chip->phys_channels)
> +		return dev_err_probe(dev, -E2BIG, "More channels than the chip supports\n");
> +
> +	/* internal temperature channel as always active */
s/as/is/ ?
> +	data->labels[reg_nr] = "internal_diode";
> +	set_bit(reg_nr, &data->active_ch_mask);
> +
> +	device_for_each_child_node_scoped(dev, child) {
> +		ret = fwnode_property_read_u32(child, "reg", ®_nr);
> +		if (ret || reg_nr >= data->chip->phys_channels)
> +			return dev_err_probe(dev, -EINVAL,
> +				     "The index of the channels does not match the chip\n");
> +		/* mark external channel as active */
> +		set_bit(reg_nr, &data->active_ch_mask);
> +
> +		fwnode_property_read_string(child, "label", &data->labels[reg_nr]);
> +	}
> +
> +	return 0;
> +}
> +
> +static int emc1812_chip_identify(struct emc1812_data *data, struct i2c_client *client)
> +{
> +	int ret, tmp;
> +
> +	ret = regmap_read(data->regmap, EMC1812_PRODUCT_ID_ADDR, &tmp);
> +	if (ret)
> +		return ret;
> +
> +	switch (tmp) {
> +	case EMC1812_PID:
> +		data->chip = &emc1812_chip_config;
> +		break;
> +	case EMC1813_PID:
> +		data->chip = &emc1813_chip_config;
> +		break;
> +	case EMC1814_PID:
> +		data->chip = &emc1814_chip_config;
> +		break;
> +	case EMC1815_PID:
> +		data->chip = &emc1815_chip_config;
> +		break;
> +	case EMC1833_PID:
> +		data->chip = &emc1833_chip_config;
> +		break;
> +	default:
> +		/*
> +		 * If failed to identify the hardware based on internal registers,
> +		 * try using fallback compatible in device tree to deal with some
> +		 * newer part number.
> +		 */
> +		data->chip = device_get_match_data(&client->dev);
> +		if (!data->chip)
> +			return -EINVAL;
> +		break;
Interesting approach. It might be useful though to compare
devicetree data with the actual chip just in case the devicetree data
refers to the wrong chip, and display a warning in that case.
Either case, I would suggest to display a message in the default:
case to inform the user that the referenced chip is unknown.
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct hwmon_ops emc1812_ops = {
> +	.is_visible = emc1812_is_visible,
> +	.read = emc1812_read,
> +	.read_string = emc1812_read_string,
> +	.write = emc1812_write,
> +};
> +
> +static const struct hwmon_chip_info emc1812_chip_info = {
> +	.ops = &emc1812_ops,
> +	.info = emc1812_info,
> +};
> +
> +static int emc1812_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct emc1812_data *data;
> +	int ret;
> +
> +	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	i2c_set_clientdata(client, data);
> +	data->client = client;
> +
> +	data->regmap = devm_regmap_init_i2c(client, &emc1812_regmap_config);
> +	if (IS_ERR(data->regmap))
> +		return dev_err_probe(dev, PTR_ERR(data->regmap),
> +				     "Cannot initialize register map\n");
> +
> +	ret = devm_mutex_init(dev, &data->lock);
> +	if (ret)
> +		return ret;
> +
> +	ret = emc1812_chip_identify(data, client);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Chip identification fails\n");
> +
> +	dev_info(dev, "Device name: %s\n", data->chip->name);
> +
> +	ret = emc1812_parse_fw_config(data, dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = emc1812_init(data);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Cannot initialize device\n");
> +
> +	data->hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
> +							       &emc1812_chip_info, NULL);
> +	if (IS_ERR(data->hwmon_dev))
> +		return PTR_ERR(data->hwmon_dev);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id emc1812_id[] = {
> +	{ .name = "emc1812", .driver_data = (kernel_ulong_t)&emc1812_chip_config },
> +	{ .name = "emc1813", .driver_data = (kernel_ulong_t)&emc1813_chip_config },
> +	{ .name = "emc1814", .driver_data = (kernel_ulong_t)&emc1814_chip_config },
> +	{ .name = "emc1815", .driver_data = (kernel_ulong_t)&emc1815_chip_config },
> +	{ .name = "emc1833", .driver_data = (kernel_ulong_t)&emc1833_chip_config },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, emc1812_id);
> +
> +static const struct of_device_id emc1812_of_match[] = {
> +	{
> +		.compatible = "microchip,emc1812",
> +		.data = &emc1812_chip_config
> +	},
> +	{
> +		.compatible = "microchip,emc1813",
> +		.data = &emc1813_chip_config
> +	},
> +	{
> +		.compatible = "microchip,emc1814",
> +		.data = &emc1814_chip_config
> +	},
> +	{
> +		.compatible = "microchip,emc1815",
> +		.data = &emc1815_chip_config
> +	},
> +	{
> +		.compatible = "microchip,emc1833",
> +		.data = &emc1833_chip_config
> +	},
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, emc1812_of_match);
> +
> +static struct i2c_driver emc1812_driver = {
> +	.driver	 = {
> +		.name = "emc1812",
> +		.of_match_table = emc1812_of_match,
> +	},
> +	.probe = emc1812_probe,
> +	.id_table = emc1812_id,
> +};
> +module_i2c_driver(emc1812_driver);
> +
> +MODULE_AUTHOR("Marius Cristea <marius.cristea@...rochip.com>");
> +MODULE_DESCRIPTION("EMC1812/13/14/15/33 high-accuracy remote diode temperature monitor Driver");
> +MODULE_LICENSE("GPL");
> 
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