[PATCH v5 0/2] LTC4286 and LTC4287 driver support

[PATCH v5 0/2] LTC4286 and LTC4287 driver support

[Delphine CC Chiu]

v5 - Add LTC4286 and LTC4287 binding document
   - Add LTC4286 and LTC4287 driver

Delphine CC Chiu (2):
  dt-bindings: hwmon: Add lltc ltc4286 driver bindings
  hwmon: pmbus: Add ltc4286 driver

 .../bindings/hwmon/lltc,ltc4286.yaml          |  51 ++++++
 Documentation/hwmon/index.rst                 |   1 +
 Documentation/hwmon/ltc4286.rst               |  95 ++++++++++
 MAINTAINERS                                   |  10 ++
 drivers/hwmon/pmbus/Kconfig                   |  10 ++
 drivers/hwmon/pmbus/Makefile                  |   1 +
 drivers/hwmon/pmbus/ltc4286.c                 | 169 ++++++++++++++++++
 7 files changed, 337 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml
 create mode 100644 Documentation/hwmon/ltc4286.rst
 create mode 100644 drivers/hwmon/pmbus/ltc4286.c

-- 
2.25.1

[PATCH v5 1/2] dt-bindings: hwmon: Add lltc ltc4286 driver bindings

[Delphine CC Chiu]

Add a device tree bindings for ltc4286 device.

Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>

-------------------------------------------------------------
Changelog:
  v5 - Add hyphen under "Changelog" in commit message
  v4 - Revise some inappropriate writing in yaml file
  v3 - Revise adi,vrange-select-25p6 to adi,vrange-low-enable
  v2 - Revise vrange_select_25p6 to adi,vrange-select-25p6
     - Add type for adi,vrange-select-25p6
     - Revise rsense-micro-ohms to shunt-resistor-micro-ohms
---
 .../bindings/hwmon/lltc,ltc4286.yaml          | 51 +++++++++++++++++++
 MAINTAINERS                                   | 10 ++++
 2 files changed, 61 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml

diff --git a/Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml b/Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml
new file mode 100644
index 000000000000..d26f34fb7ea7
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml
@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/lltc,ltc4286.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: LTC4286 power monitors
+
+maintainers:
+  - Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
+
+properties:
+  compatible:
+    enum:
+      - lltc,ltc4286
+      - lltc,ltc4287
+
+  reg:
+    maxItems: 1
+
+  adi,vrange-low-enable:
+    description:
+      This property is a bool parameter to represent the
+      voltage range is 25.6 volts or 102.4 volts for this chip.
+      The default is 102.4 volts.
+    type: boolean
+
+  shunt-resistor-micro-ohms:
+    description:
+      Resistor value micro-ohms.
+
+required:
+  - compatible
+  - reg
+  - shunt-resistor-micro-ohms
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        power-monitor@40 {
+            compatible = "lltc,ltc4286";
+            reg = <0x40>;
+            adi,vrange-low-enable;
+            shunt-resistor-micro-ohms = <300>;
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 5c9f868e13b6..2a73a7c0f160 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12628,6 +12628,16 @@ S:	Maintained
 F:	Documentation/hwmon/ltc4261.rst
 F:	drivers/hwmon/ltc4261.c
 
+LTC4286 HARDWARE MONITOR DRIVER
+M:	Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
+L:	linux-i2c@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml
+F:	Documentation/devicetree/bindings/hwmon/ltc4286.rst
+F:	drivers/hwmon/pmbus/Kconfig
+F:	drivers/hwmon/pmbus/Makefile
+F:	drivers/hwmon/pmbus/ltc4286.c
+
 LTC4306 I2C MULTIPLEXER DRIVER
 M:	Michael Hennerich <michael.hennerich@analog.com>
 L:	linux-i2c@vger.kernel.org
-- 
2.25.1

[PATCH v5 2/2] hwmon: pmbus: Add ltc4286 driver

[Delphine CC Chiu]

Add a driver to support ltc4286 chip

Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>

-------------------------------------------------------------
Changelog:
  v5 - Check the overflow when reading rsense
     - Set default rsense value
  v4 - Add empty line before "config SENSORS_LTC4286" in Kconfig
     - Add ltc4286 to Documentation/hwmon/index.rst
     - Revise comment typo
     - Use devm_kmemdup instead of memcpy
     - Check MBR value before writting into
  v3 - Use dev_err_probe() instead of dev_err()
     - The VRANGE_SELECT bit only be written if it actually changed
     - Avoid the info pointer being overwritten
     - Check the MBR value range to avoid overflow
     - Revise ltc4286.rst to corrcet description
  v2 - Revise Linear Technologies LTC4286 to
       Analog Devices LTC4286 in Kconfig
     - Add more description for this driver in Kconfig
     - Add some comments for MBR setting in ltc4286.c
     - Add ltc4286.rst
---
 Documentation/hwmon/index.rst   |   1 +
 Documentation/hwmon/ltc4286.rst |  95 ++++++++++++++++++
 drivers/hwmon/pmbus/Kconfig     |  10 ++
 drivers/hwmon/pmbus/Makefile    |   1 +
 drivers/hwmon/pmbus/ltc4286.c   | 169 ++++++++++++++++++++++++++++++++
 5 files changed, 276 insertions(+)
 create mode 100644 Documentation/hwmon/ltc4286.rst
 create mode 100644 drivers/hwmon/pmbus/ltc4286.c

diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 72f4e6065bae..080827cc4c34 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -128,6 +128,7 @@ Hardware Monitoring Kernel Drivers
    ltc4245
    ltc4260
    ltc4261
+   ltc4286
    max127
    max15301
    max16064
diff --git a/Documentation/hwmon/ltc4286.rst b/Documentation/hwmon/ltc4286.rst
new file mode 100644
index 000000000000..2cd149676d86
--- /dev/null
+++ b/Documentation/hwmon/ltc4286.rst
@@ -0,0 +1,95 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver ltc4286
+=====================
+
+Supported chips:
+
+  * Analog Devices LTC4286
+
+    Prefix: 'ltc4286'
+
+    Addresses scanned: -
+
+    Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4286.pdf
+
+  * Analog Devices LTC4287
+
+    Prefix: 'ltc4287'
+
+    Addresses scanned: -
+
+    Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4287.pdf
+
+Author: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
+
+
+Description
+-----------
+
+This driver supports hardware monitoring for Analog Devices LTC4286
+and LTC4287 Hot-Swap Controller and Digital Power Monitors.
+
+LTC4286 and LTC4287 are hot-swap controllers that allow a circuit board
+to be removed from or inserted into a live backplane. They also feature
+current and voltage readback via an integrated 12 bit analog-to-digital
+converter (ADC), accessed using a PMBus interface.
+
+The driver is a client driver to the core PMBus driver. Please see
+Documentation/hwmon/pmbus.rst for details on PMBus client drivers.
+
+
+Usage Notes
+-----------
+
+This driver does not auto-detect devices. You will have to instantiate the
+devices explicitly. Please see Documentation/i2c/instantiating-devices.rst for
+details.
+
+The shunt value in micro-ohms can be set via device tree at compile-time. Please
+refer to the Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml for bindings
+if the device tree is used.
+
+
+Platform data support
+---------------------
+
+The driver supports standard PMBus driver platform data. Please see
+Documentation/hwmon/pmbus.rst for details.
+
+
+Sysfs entries
+-------------
+
+The following attributes are supported. Limits are read-write, history reset
+attributes are write-only, all other attributes are read-only.
+
+======================= =======================================================
+in1_label		"vin"
+in1_input		Measured voltage.
+in1_alarm		Input voltage alarm.
+in1_min 		Minimum input voltage.
+in1_max 		Maximum input voltage.
+
+in2_label		"vout1"
+in2_input		Measured voltage.
+in2_alarm		Output voltage alarm.
+in2_min 		Minimum output voltage.
+in2_max 		Maximum output voltage.
+
+curr1_label		"iout1"
+curr1_input		Measured current.
+curr1_alarm		Output current alarm.
+curr1_max		Maximum current.
+
+power1_label		"pin"
+power1_input		Input power.
+power1_alarm		Input power alarm.
+power1_max		Maximum poewr.
+
+temp1_input		Chip temperature.
+temp1_min		Minimum chip temperature.
+temp1_max		Maximum chip temperature.
+temp1_crit		Critical chip temperature.
+temp1_alarm		Chip temperature alarm.
+======================= =======================================================
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index b4e93bd5835e..2d4f972e5a65 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -227,6 +227,16 @@ config SENSORS_LTC3815
 	  This driver can also be built as a module. If so, the module will
 	  be called ltc3815.
 
+config SENSORS_LTC4286
+	bool "Analog Devices LTC4286"
+	help
+	  LTC4286 is an integrated solution for hot swap applications that
+	  allows a board to be safely inserted and removed from a live
+	  backplane.
+	  This chip could be used to monitor voltage, current, ...etc.
+	  If you say yes here you get hardware monitoring support for Analog
+	  Devices LTC4286.
+
 config SENSORS_MAX15301
 	tristate "Maxim MAX15301"
 	help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 84ee960a6c2d..94e28f6d6a61 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_SENSORS_LM25066)	+= lm25066.o
 obj-$(CONFIG_SENSORS_LT7182S)	+= lt7182s.o
 obj-$(CONFIG_SENSORS_LTC2978)	+= ltc2978.o
 obj-$(CONFIG_SENSORS_LTC3815)	+= ltc3815.o
+obj-$(CONFIG_SENSORS_LTC4286)	+= ltc4286.o
 obj-$(CONFIG_SENSORS_MAX15301)	+= max15301.o
 obj-$(CONFIG_SENSORS_MAX16064)	+= max16064.o
 obj-$(CONFIG_SENSORS_MAX16601)	+= max16601.o
diff --git a/drivers/hwmon/pmbus/ltc4286.c b/drivers/hwmon/pmbus/ltc4286.c
new file mode 100644
index 000000000000..32cf3946388e
--- /dev/null
+++ b/drivers/hwmon/pmbus/ltc4286.c
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pmbus.h>
+#include "pmbus.h"
+
+/* LTC4286 register */
+#define LTC4286_MFR_CONFIG1	0xF2
+
+/* LTC4286 configuration */
+#define VRANGE_SELECT_BIT	BIT(1)
+
+#define LTC4286_MFR_ID_SIZE	3
+#define VRANGE_25P6		0
+
+/*
+ * Initialize the MBR as default settings which is referred to LTC4286 datasheet
+ * (March 22, 2022 version) table 3 page 16
+ */
+static struct pmbus_driver_info ltc4286_info = {
+	.pages = 1,
+	.format[PSC_VOLTAGE_IN] = direct,
+	.format[PSC_VOLTAGE_OUT] = direct,
+	.format[PSC_CURRENT_OUT] = direct,
+	.format[PSC_POWER] = direct,
+	.format[PSC_TEMPERATURE] = direct,
+	.m[PSC_VOLTAGE_IN] = 32,
+	.b[PSC_VOLTAGE_IN] = 0,
+	.R[PSC_VOLTAGE_IN] = 1,
+	.m[PSC_VOLTAGE_OUT] = 32,
+	.b[PSC_VOLTAGE_OUT] = 0,
+	.R[PSC_VOLTAGE_OUT] = 1,
+	.m[PSC_CURRENT_OUT] = 1024,
+	.b[PSC_CURRENT_OUT] = 0,
+	/*
+	 * The rsense value used in MBR formula in LTC4286 datasheet should be ohm unit.
+	 * However, the rsense value that user input is micro ohm.
+	 * Thus, the MBR setting which involves rsense should be shifted by 6 digits.
+	 */
+	.R[PSC_CURRENT_OUT] = 3 - 6,
+	.m[PSC_POWER] = 1,
+	.b[PSC_POWER] = 0,
+	/*
+	 * The rsense value used in MBR formula in LTC4286 datasheet should be ohm unit.
+	 * However, the rsense value that user input is micro ohm.
+	 * Thus, the MBR setting which involves rsense should be shifted by 6 digits.
+	 */
+	.R[PSC_POWER] = 4 - 6,
+	.m[PSC_TEMPERATURE] = 1,
+	.b[PSC_TEMPERATURE] = 273,
+	.R[PSC_TEMPERATURE] = 0,
+	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
+		   PMBUS_HAVE_PIN | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_VOUT |
+		   PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_TEMP,
+};
+
+static const struct i2c_device_id ltc4286_id[] = {
+	{ "ltc4286", 0 },
+	{ "ltc4287", 1 },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, ltc4286_id);
+
+static int ltc4286_probe(struct i2c_client *client)
+{
+	int ret;
+	const struct i2c_device_id *mid;
+	u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1];
+	struct pmbus_driver_info *info;
+	u32 rsense;
+
+	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, block_buffer);
+	if (ret < 0) {
+		return dev_err_probe(&client->dev, ret,
+				     "Failed to read manufacturer id\n");
+	}
+
+	/*
+	 * Refer to ltc4286 datasheet page 20
+	 * the manufacturer id is LTC
+	 */
+	if (ret != LTC4286_MFR_ID_SIZE ||
+	    strncmp(block_buffer, "LTC", LTC4286_MFR_ID_SIZE)) {
+		return dev_err_probe(&client->dev, ret,
+				     "Manufacturer id mismatch\n");
+	}
+
+	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, block_buffer);
+	if (ret < 0) {
+		return dev_err_probe(&client->dev, ret,
+				     "Failed to read manufacturer model\n");
+	}
+
+	for (mid = ltc4286_id; mid->name[0]; mid++) {
+		if (!strncasecmp(mid->name, block_buffer, strlen(mid->name)))
+			break;
+	}
+	if (!mid->name[0])
+		return dev_err_probe(&client->dev, -ENODEV,
+				     "Unsupported device\n");
+
+	if (of_property_read_u32(client->dev.of_node,
+				 "shunt-resistor-micro-ohms", &rsense))
+		rsense = 300; /* 0.3 mOhm if not set via DT */
+
+	if (rsense == 0)
+		return -EINVAL;
+
+	/* Check for the latter MBR value won't overflow */
+	if (rsense > (INT_MAX / 1024))
+		return -EINVAL;
+
+	info = devm_kmemdup(&client->dev, &ltc4286_info, sizeof(*info),
+			    GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	/* Default of VRANGE_SELECT = 1, 102.4V */
+	if (device_property_read_bool(&client->dev, "adi,vrange-low-enable")) {
+		/* Setup MFR1 CONFIG register bit 1 VRANGE_SELECT */
+		ret = i2c_smbus_read_word_data(client, LTC4286_MFR_CONFIG1);
+		if (ret < 0)
+			return dev_err_probe(
+				&client->dev, ret,
+				"Failed to read manufacturer configuration one\n");
+
+		ret &= ~VRANGE_SELECT_BIT; /* VRANGE_SELECT = 0, 25.6V */
+		ret = i2c_smbus_write_word_data(client, LTC4286_MFR_CONFIG1,
+						ret);
+		if (ret < 0)
+			return dev_err_probe(&client->dev, ret,
+					     "Failed to set vrange\n");
+
+		info->m[PSC_VOLTAGE_IN] = 128;
+		info->m[PSC_VOLTAGE_OUT] = 128;
+		info->m[PSC_POWER] = 4 * rsense;
+	} else {
+		info->m[PSC_POWER] = rsense;
+	}
+
+	info->m[PSC_CURRENT_OUT] = 1024 * rsense;
+
+	return pmbus_do_probe(client, info);
+}
+
+static const struct of_device_id ltc4286_of_match[] = {
+	{ .compatible = "lltc,ltc4286" },
+	{ .compatible = "lltc,ltc4287" },
+	{}
+};
+
+static struct i2c_driver ltc4286_driver = {
+	.driver = {
+		.name = "ltc4286",
+		.of_match_table = ltc4286_of_match,
+	},
+	.probe = ltc4286_probe,
+	.id_table = ltc4286_id,
+};
+
+module_i2c_driver(ltc4286_driver);
+
+MODULE_AUTHOR("Delphine CC Chiu <Delphine_CC_Chiu@wiwynn.com>");
+MODULE_DESCRIPTION("PMBUS driver for LTC4286 and compatibles");
+MODULE_LICENSE("GPL");
-- 
2.25.1

Re: [PATCH v5 1/2] dt-bindings: hwmon: Add lltc ltc4286 driver bindings

[Krzysztof Kozlowski]

On 16/11/2023 03:30, Delphine CC Chiu wrote:
> Add a device tree bindings for ltc4286 device.
> 
> Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
> 
> -------------------------------------------------------------
> Changelog:
>   v5 - Add hyphen under "Changelog" in commit message

Apply your patch from the list and check the result... You can easily
see it's broken. We asked about ---. Please read the message carefully.

Best regards,
Krzysztof

Re: [PATCH v5 1/2] dt-bindings: hwmon: Add lltc ltc4286 driver bindings

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 690 bytes --]

On Thu, Nov 16, 2023 at 01:13:58PM +0100, Krzysztof Kozlowski wrote:
> On 16/11/2023 03:30, Delphine CC Chiu wrote:
> > Add a device tree bindings for ltc4286 device.
> > 
> > Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
> > 
> > -------------------------------------------------------------
> > Changelog:
> >   v5 - Add hyphen under "Changelog" in commit message
> 
> Apply your patch from the list and check the result... You can easily
> see it's broken. We asked about ---. Please read the message carefully.

My reviewed-by was also omitted again, but I suppose that is a good
thing since I conditionally gave that based on the changelog being
fixed!

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

Re: [PATCH v5 2/2] hwmon: pmbus: Add ltc4286 driver

[Guenter Roeck]

On 11/15/23 18:30, Delphine CC Chiu wrote:
> Add a driver to support ltc4286 chip
> 
> Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
> 
> -------------------------------------------------------------
[ ... ]

> +	/* Default of VRANGE_SELECT = 1, 102.4V */
> +	if (device_property_read_bool(&client->dev, "adi,vrange-low-enable")) {
> +		/* Setup MFR1 CONFIG register bit 1 VRANGE_SELECT */
> +		ret = i2c_smbus_read_word_data(client, LTC4286_MFR_CONFIG1);
> +		if (ret < 0)
> +			return dev_err_probe(
> +				&client->dev, ret,
> +				"Failed to read manufacturer configuration one\n");
> +
> +		ret &= ~VRANGE_SELECT_BIT; /* VRANGE_SELECT = 0, 25.6V */
> +		ret = i2c_smbus_write_word_data(client, LTC4286_MFR_CONFIG1,
> +						ret);
> +		if (ret < 0)
> +			return dev_err_probe(&client->dev, ret,
> +					     "Failed to set vrange\n");
> +
> +		info->m[PSC_VOLTAGE_IN] = 128;
> +		info->m[PSC_VOLTAGE_OUT] = 128;
> +		info->m[PSC_POWER] = 4 * rsense;
> +	} else {
> +		info->m[PSC_POWER] = rsense;
> +	}

My feedback has not been addressed.

Guenter

RE: [PATCH v5 1/2] dt-bindings: hwmon: Add lltc ltc4286 driver bindings

[Delphine_CC_Chiu/WYHQ/Wiwynn]

> -----Original Message-----
> From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> Sent: Thursday, November 16, 2023 8:14 PM
> To: Delphine_CC_Chiu/WYHQ/Wiwynn <Delphine_CC_Chiu@wiwynn.com>;
> patrick@stwcx.xyz; Jean Delvare <jdelvare@suse.com>; Guenter Roeck
> <linux@roeck-us.net>; Rob Herring <robh+dt@kernel.org>; Krzysztof Kozlowski
> <krzysztof.kozlowski+dt@linaro.org>; Conor Dooley <conor+dt@kernel.org>
> Cc: Jonathan Corbet <corbet@lwn.net>; linux-i2c@vger.kernel.org;
> linux-hwmon@vger.kernel.org; devicetree@vger.kernel.org;
> linux-kernel@vger.kernel.org; linux-doc@vger.kernel.org
> Subject: Re: [PATCH v5 1/2] dt-bindings: hwmon: Add lltc ltc4286 driver
> bindings
> 
>   Security Reminder: Please be aware that this email is sent by an external
> sender.
> 
> On 16/11/2023 03:30, Delphine CC Chiu wrote:
> > Add a device tree bindings for ltc4286 device.
> >
> > Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
> >
> > -------------------------------------------------------------
> > Changelog:
> >   v5 - Add hyphen under "Changelog" in commit message
> 
> Apply your patch from the list and check the result... You can easily see it's
> broken. We asked about ---. Please read the message carefully.

We will add ---
Thanks.

> 
> Best regards,
> Krzysztof