[PATCH v2 3/5] hwmon: (pmbus/acbel-crps) Add Acbel CRPS power supply driver

[Lakshmi Yadlapati <lakshmiy@us.ibm.com>]

Add the driver to support Acbel CRPS power supply.

Signed-off-by: Lakshmi Yadlapati <lakshmiy@us.ibm.com>
---
Changes since V1
- Removed debugfs stuff.
- Removed acbel_crps_read_word_data and acbel_crps_read_byte_data.
- Removed PMBUS_MFR_IIN_MAX.
- Added validation for the supported power supply.
- Fix the formatting.

 drivers/hwmon/pmbus/Kconfig      |  10 +++
 drivers/hwmon/pmbus/Makefile     |   1 +
 drivers/hwmon/pmbus/acbel-crps.c | 102 +++++++++++++++++++++++++++++++
 3 files changed, 113 insertions(+)
 create mode 100644 drivers/hwmon/pmbus/acbel-crps.c

diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 59d9a7430499..0215709c3dd2 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -27,6 +27,16 @@ config SENSORS_PMBUS
 	  This driver can also be built as a module. If so, the module will
 	  be called pmbus.
 
+config SENSORS_ACBEL_CRPS
+	tristate "ACBEL CRPS Power Supply"
+	help
+	  If you say yes here you get hardware monitoring support for the ACBEL
+	  Common Redundant Power Supply.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called acbel-crps.
+	  Supported models: FSG032-00xG
+
 config SENSORS_ADM1266
 	tristate "Analog Devices ADM1266 Sequencer"
 	select CRC8
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 3ae019916267..39aef0cb9934 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -5,6 +5,7 @@
 
 obj-$(CONFIG_PMBUS)		+= pmbus_core.o
 obj-$(CONFIG_SENSORS_PMBUS)	+= pmbus.o
+obj-$(CONFIG_SENSORS_ACBEL_CRPS) += acbel-crps.o
 obj-$(CONFIG_SENSORS_ADM1266)	+= adm1266.o
 obj-$(CONFIG_SENSORS_ADM1275)	+= adm1275.o
 obj-$(CONFIG_SENSORS_BEL_PFE)	+= bel-pfe.o
diff --git a/drivers/hwmon/pmbus/acbel-crps.c b/drivers/hwmon/pmbus/acbel-crps.c
new file mode 100644
index 000000000000..ac281699709f
--- /dev/null
+++ b/drivers/hwmon/pmbus/acbel-crps.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2023 IBM Corp.
+ */
+
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/pmbus.h>
+#include <linux/hwmon-sysfs.h>
+#include "pmbus.h"
+
+struct acbel_crps {
+	struct i2c_client *client;
+};
+
+static const struct i2c_device_id acbel_crps_id[] = {
+	{ "acbel_crps" },
+	{}
+};
+#define to_psu(x, y) container_of((x), struct acbel_crps, debugfs_entries[(y)])
+
+static const struct file_operations acbel_crps_fops = {
+	.llseek = noop_llseek,
+	.open = simple_open,
+};
+
+static struct pmbus_driver_info acbel_crps_info = {
+	.pages = 1,
+	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN | PMBUS_HAVE_PIN |
+		   PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT | PMBUS_HAVE_POUT |
+		   PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_TEMP3 |
+		   PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_VOUT |
+		   PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_TEMP |
+		   PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_STATUS_FAN12,
+};
+
+static int acbel_crps_probe(struct i2c_client *client)
+{
+	struct acbel_crps *psu;
+	u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
+	struct device *dev = &client->dev;
+	int rc;
+
+	rc = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, buf);
+	if (rc < 0) {
+		dev_err(dev, "Failed to read PMBUS_MFR_ID\n");
+		return rc;
+	}
+	if (strncmp(buf, "ACBEL", 5)) {
+		buf[rc] = '\0';
+		dev_err(dev, "Manufacturer '%s' not supported\n", buf);
+		return -ENODEV;
+	}
+
+	rc = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
+	if (rc < 0) {
+		dev_err(dev, "Failed to read PMBUS_MFR_MODEL\n");
+		return rc;
+	}
+
+	if (strncmp(buf, "FSG032", 6)) {
+		buf[rc] = '\0';
+		dev_err(dev, "Model '%s' not supported\n", buf);
+		return -ENODEV;
+	}
+
+	rc = pmbus_do_probe(client, &acbel_crps_info);
+	if (rc)
+		return rc;
+	/*
+         * Don't fail the probe if there isn't enough memory for debugfs.
+         */
+	psu = devm_kzalloc(&client->dev, sizeof(*psu), GFP_KERNEL);
+	if (!psu)
+		return 0;
+
+	return 0;
+}
+
+static const struct of_device_id acbel_crps_of_match[] = {
+	{ .compatible = "acbel,crps" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, acbel_crps_of_match);
+
+static struct i2c_driver acbel_crps_driver = {
+	.driver = {
+		.name = "acbel-crps",
+		.of_match_table = acbel_crps_of_match,
+	},
+	.probe_new = acbel_crps_probe,
+	.id_table = acbel_crps_id,
+};
+
+module_i2c_driver(acbel_crps_driver);
+
+MODULE_AUTHOR("Lakshmi Yadlapati");
+MODULE_DESCRIPTION("PMBus driver for AcBel Power System power supplies");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(PMBUS);
-- 
2.37.2