hwmon: (pmbus) Add support for ADM1266

Add pmbus probing driver for the adm1266 Cascadable
Super Sequencer with Margin Control and Fault Recording.
Driver is using the pmbus_core, creating sysfs files
under hwmon for inputs: vh1->vh4 and vp1->vp13.

Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
Link: https://lore.kernel.org/r/20200812142055.9213-2-alexandru.tachici@analog.com
[groeck: Use .probe_new function, adjust for changed pmbus_do_probe API]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/adm1266.rst

@@ -0,0 +1,37 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver adm1266
+=====================
+
+Supported chips:
+  * Analog Devices ADM1266
+    Prefix: 'adm1266'
+    Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ADM1266.pdf
+
+Author: Alexandru Tachici <alexandru.tachici@analog.com>
+
+
+Description
+-----------
+
+This driver supports hardware monitoring for Analog Devices ADM1266 sequencer.
+
+ADM1266 is a sequencer that features voltage readback from 17 channels via an
+integrated 12 bit SAR ADC, accessed using a PMBus interface.
+
+The driver is a client driver to the core PMBus driver. Please see
+Documentation/hwmon/pmbus for details on PMBus client drivers.
+
+
+Sysfs entries
+-------------
+
+The following attributes are supported. Limits are read-write, history reset
+attributes are write-only, all other attributes are read-only.
+
+inX_label		"voutx"
+inX_input		Measured voltage.
+inX_min			Minimum Voltage.
+inX_max			Maximum voltage.
+inX_min_alarm		Voltage low alarm.
+inX_max_alarm		Voltage high alarm.

Documentation/hwmon/index.rst

@@ -30,6 +30,7 @@ Hardware Monitoring Kernel Drivers
    adm1026
    adm1031
    adm1177
+   adm1266
    adm1275
    adm9240
    ads7828

drivers/hwmon/pmbus/Kconfig

@@ -26,6 +26,15 @@ config SENSORS_PMBUS
 	  This driver can also be built as a module. If so, the module will
 	  be called pmbus.
 
+config SENSORS_ADM1266
+	tristate "Analog Devices ADM1266 Sequencer"
+	help
+	  If you say yes here you get hardware monitoring support for Analog
+	  Devices ADM1266 Cascadable Super Sequencer.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called adm1266.
+
 config SENSORS_ADM1275
 	tristate "Analog Devices ADM1275 and compatibles"
 	help

drivers/hwmon/pmbus/Makefile

@@ -5,6 +5,7 @@
 
 obj-$(CONFIG_PMBUS)		+= pmbus_core.o
 obj-$(CONFIG_SENSORS_PMBUS)	+= pmbus.o
+obj-$(CONFIG_SENSORS_ADM1266)	+= adm1266.o
 obj-$(CONFIG_SENSORS_ADM1275)	+= adm1275.o
 obj-$(CONFIG_SENSORS_BEL_PFE)	+= bel-pfe.o
 obj-$(CONFIG_SENSORS_IBM_CFFPS)	+= ibm-cffps.o

drivers/hwmon/pmbus/adm1266.c

@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ADM1266 - Cascadable Super Sequencer with Margin
+ * Control and Fault Recording
+ *
+ * Copyright 2020 Analog Devices Inc.
+ */
+
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include "pmbus.h"
+#include <linux/slab.h>
+
+struct adm1266_data {
+	struct pmbus_driver_info info;
+	struct i2c_client *client;
+};
+
+static int adm1266_probe(struct i2c_client *client)
+{
+	struct adm1266_data *data;
+	int i;
+
+	data = devm_kzalloc(&client->dev, sizeof(struct adm1266_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	data->info.pages = 17;
+	data->info.format[PSC_VOLTAGE_OUT] = linear;
+	for (i = 0; i < data->info.pages; i++)
+		data->info.func[i] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT;
+
+	return pmbus_do_probe(client, &data->info);
+}
+
+static const struct of_device_id adm1266_of_match[] = {
+	{ .compatible = "adi,adm1266" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, adm1266_of_match);
+
+static const struct i2c_device_id adm1266_id[] = {
+	{ "adm1266", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, adm1266_id);
+
+static struct i2c_driver adm1266_driver = {
+	.driver = {
+		   .name = "adm1266",
+		   .of_match_table = adm1266_of_match,
+		  },
+	.probe_new = adm1266_probe,
+	.remove = pmbus_do_remove,
+	.id_table = adm1266_id,
+};
+
+module_i2c_driver(adm1266_driver);
+
+MODULE_AUTHOR("Alexandru Tachici <alexandru.tachici@analog.com>");
+MODULE_DESCRIPTION("PMBus driver for Analog Devices ADM1266");
+MODULE_LICENSE("GPL v2");