[PATCH v1 2/4] hwmon: (pmbus/crps) Add Intel CRPS185 power supply

[Ninad Palsule <ninad@linux.ibm.com>]

Add the driver to monitor Intel common redundant power supply (crps185)
with hwmon over pmbus.

Signed-off-by: Ninad Palsule <ninad@linux.ibm.com>
---
 Documentation/hwmon/crps.rst |  95 +++++++++++
 MAINTAINERS                  |   7 +
 drivers/hwmon/pmbus/Kconfig  |   9 ++
 drivers/hwmon/pmbus/Makefile |   1 +
 drivers/hwmon/pmbus/crps.c   | 299 +++++++++++++++++++++++++++++++++++
 5 files changed, 411 insertions(+)
 create mode 100644 Documentation/hwmon/crps.rst
 create mode 100644 drivers/hwmon/pmbus/crps.c

diff --git a/Documentation/hwmon/crps.rst b/Documentation/hwmon/crps.rst
new file mode 100644
index 000000000000..81d5dfd68a46
--- /dev/null
+++ b/Documentation/hwmon/crps.rst
@@ -0,0 +1,95 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver crps
+========================
+
+Supported chips:
+
+  * Intel CRPS185
+
+    Prefix: 'crps185'
+
+    Addresses scanned: -
+
+Authors:
+    Ninad Palsule <ninad@linux.ibm.com>
+
+
+Description
+-----------
+
+This driver implements support for Common Redundant Power supply with PMBus
+support.
+
+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.
+
+
+Sysfs entries
+-------------
+
+======================= ======================================================
+curr1_label		"iin"
+curr1_input		Measured input current
+curr1_max		Maximum input current
+curr1_max_alarm         Input maximum current high alarm
+curr1_crit              Critial high input current
+curr1_crit_alarm        Input critical current high alarm
+curr1_rated_max		Maximum rated input current
+
+curr2_label		"iout1"
+curr2_input		Measured output current
+curr2_max		Maximum output current
+curr2_max_alarm         Output maximum current high alarm
+curr2_crit	        Critial high output current
+curr2_crit_alarm        Output critical current high alarm
+curr2_rated_max		Maximum rated output current
+
+in1_label		"vin"
+in1_input		Measured input voltage
+in1_crit                Critical input over voltage
+in1_crit_alarm          Critical input over voltage alarm
+in1_max                 Maximum input over voltage
+in1_max_alarm           Maximum input over voltage alarm
+in1_rated_min		Minimum rated input voltage
+in1_rated_max		Maximum rated input voltage
+
+in2_label		"vout1"
+in2_input		Measured input voltage
+in2_crit                Critical input over voltage
+in2_crit_alarm          Critical input over voltage alarm
+in2_lcrit               Critical input under voltage fault
+in2_lcrit_alarm         Critical input under voltage fault alarm
+in2_max                 Maximum input over voltage
+in2_max_alarm           Maximum input over voltage alarm
+in2_min                 Minimum input under voltage warning
+in2_min_alarm           Minimum input under voltage warning alarm
+in2_rated_min		Minimum rated input voltage
+in2_rated_max		Maximum rated input voltage
+
+power1_label		"pin"
+power1_input		Measured input power
+power1_alarm		Input power high alarm
+power1_max  		Maximum input power
+power1_rated_max        Maximum rated input power
+
+temp[1-2]_input		Measured temperature
+temp[1-2]_crit 		Critical temperature
+temp[1-2]_crit_alarm    Critical temperature alarm
+temp[1-2]_max  		Maximum temperature
+temp[1-2]_max_alarm     Maximum temperature alarm
+temp[1-2]_rated_max     Maximum rated temperature
+
+fan1_alarm		Fan 1 warning.
+fan1_fault		Fan 1 fault.
+fan1_input		Fan 1 speed in RPM.
+fan1_target             Fan 1 target.
+======================= ======================================================
diff --git a/MAINTAINERS b/MAINTAINERS
index 637ddd44245f..6b31d545f0f1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6100,6 +6100,13 @@ L:	linux-input@vger.kernel.org
 S:	Maintained
 F:	drivers/hid/hid-creative-sb0540.c
 
+CRPS COMMON REDUNDANT PSU DRIVER
+M:	Ninad Palsule <ninad@linux.ibm.com>
+L:	linux-hwmon@vger.kernel.org
+S:	Maintained
+F:	Documentation/hwmon/crps.rst
+F:	drivers/hwmon/pmbus/crps.c
+
 CRYPTO API
 M:	Herbert Xu <herbert@gondor.apana.org.au>
 M:	"David S. Miller" <davem@davemloft.net>
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 22418a05ced0..56c4eb4b846e 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -85,6 +85,15 @@ config SENSORS_BPA_RS600
 	  This driver can also be built as a module. If so, the module will
 	  be called bpa-rs600.
 
+config SENSORS_CRPS
+	tristate "Common Redundant Power Supply"
+	help
+	  If you say yes here you get hardware monitoring support for the Common
+	  Redundant Power Supply.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called crps.
+
 config SENSORS_DELTA_AHE50DC_FAN
 	tristate "Delta AHE-50DC fan control module"
 	help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 3d3183f8d2a7..c7eb7739b7f8 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -62,3 +62,4 @@ obj-$(CONFIG_SENSORS_XDPE122)	+= xdpe12284.o
 obj-$(CONFIG_SENSORS_XDPE152)	+= xdpe152c4.o
 obj-$(CONFIG_SENSORS_ZL6100)	+= zl6100.o
 obj-$(CONFIG_SENSORS_PIM4328)	+= pim4328.o
+obj-$(CONFIG_SENSORS_CRPS)	+= crps.o
diff --git a/drivers/hwmon/pmbus/crps.c b/drivers/hwmon/pmbus/crps.c
new file mode 100644
index 000000000000..44d309f81803
--- /dev/null
+++ b/drivers/hwmon/pmbus/crps.c
@@ -0,0 +1,299 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2024 IBM Corp.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/i2c.h>
+#include <linux/of.h>
+#include <linux/pmbus.h>
+
+#include "pmbus.h"
+
+/* Intel crps185 specific commands. */
+#define CRPS185_MFR_IOUT_MAX		0xA6
+#define CRPS185_MFR_POUT_MAX		0xA7
+
+enum {
+	CRPS_DEBUGFS_PMBUS_REVISION = 0,
+	CRPS_DEBUGFS_MAX_POWER_OUT,
+	CRPS_DEBUGFS_MAX_CURRENT_OUT,
+	CRPS_DEBUGFS_NUM_ENTRIES
+};
+
+enum models { crps185 = 1, crps_unknown };
+
+struct crps {
+	enum models version;
+	struct i2c_client *client;
+
+	int debugfs_entries[CRPS_DEBUGFS_NUM_ENTRIES];
+};
+
+#define to_psu(x, y) container_of((x), struct crps, debugfs_entries[(y)])
+
+static struct pmbus_platform_data crps_pdata = {
+	.flags = PMBUS_SKIP_STATUS_CHECK,
+};
+
+static const struct i2c_device_id crps_id[] = {
+	{ "intel_crps185", crps185 },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, crps_id);
+
+/*
+ * Convert linear format word to machine format. 11 LSB side bits are two's
+ * complement integer mantissa and 5 MSB side bits are two's complement
+ * exponent
+ */
+static int crps_convert_linear(int rc)
+{
+	s16 exponent;
+	s32 mantissa;
+	s64 val;
+
+	exponent = ((s16)rc) >> 11;
+	mantissa = ((s16)((rc & 0x7ff) << 5)) >> 5;
+
+	val = mantissa;
+	if (exponent >= 0)
+		val <<= exponent;
+	else
+		val >>= -exponent;
+
+	return (int)val;
+}
+
+static ssize_t crps_debugfs_read(struct file *file, char __user *buf,
+				 size_t count, loff_t *ppos)
+{
+	int rc;
+	int *idxp = file->private_data;
+	int idx = *idxp;
+	struct crps *psu = to_psu(idxp, idx);
+	char data[2 * I2C_SMBUS_BLOCK_MAX] = { 0 };
+
+	rc = pmbus_lock_interruptible(psu->client);
+	if (rc)
+		return rc;
+
+	rc = pmbus_set_page(psu->client, 0, 0xff);
+	if (rc)
+		goto unlock;
+
+	switch (idx) {
+	case CRPS_DEBUGFS_PMBUS_REVISION:
+		rc = i2c_smbus_read_byte_data(psu->client, PMBUS_REVISION);
+		if (rc >= 0) {
+			if (psu->version == crps185) {
+				if (rc == 0)
+					rc = sprintf(data, "%s", "1.0");
+				else if (rc == 0x11)
+					rc = sprintf(data, "%s", "1.1");
+				else if (rc == 0x22)
+					rc = sprintf(data, "%s", "1.2");
+				else
+					rc = snprintf(data, 3, "0x%02x", rc);
+			} else {
+				rc = snprintf(data, 3, "%02x", rc);
+			}
+		}
+		break;
+	case CRPS_DEBUGFS_MAX_POWER_OUT:
+		rc = i2c_smbus_read_word_data(psu->client, PMBUS_MFR_POUT_MAX);
+		if (rc >= 0) {
+			rc = crps_convert_linear(rc);
+			rc = snprintf(data, I2C_SMBUS_BLOCK_MAX, "%d", rc);
+		}
+		break;
+	case CRPS_DEBUGFS_MAX_CURRENT_OUT:
+		rc = i2c_smbus_read_word_data(psu->client, PMBUS_MFR_IOUT_MAX);
+		if (rc >= 0) {
+			rc = crps_convert_linear(rc);
+			rc = snprintf(data, I2C_SMBUS_BLOCK_MAX, "%d", rc);
+		}
+		break;
+	default:
+		rc = -EINVAL;
+		break;
+	}
+
+unlock:
+	pmbus_unlock(psu->client);
+	if (rc < 0)
+		return rc;
+
+	data[rc] = '\n';
+	rc += 2;
+
+	return simple_read_from_buffer(buf, count, ppos, data, rc);
+}
+
+static const struct file_operations crps_debugfs_fops = {
+	.llseek = noop_llseek,
+	.read = crps_debugfs_read,
+	.open = simple_open,
+};
+
+static int crps_read_word_data(struct i2c_client *client, int page,
+				int phase, int reg)
+{
+	int rc;
+
+	switch (reg) {
+	case PMBUS_STATUS_WORD:
+		rc = pmbus_read_word_data(client, page, phase, reg);
+		if (rc < 0)
+			return rc;
+		break;
+	case PMBUS_OT_WARN_LIMIT:
+		rc = pmbus_read_word_data(client, page, phase,
+					  PMBUS_MFR_MAX_TEMP_1);
+		if (rc < 0)
+			return rc;
+		break;
+	case PMBUS_IOUT_OC_WARN_LIMIT:
+		rc = pmbus_read_word_data(client, page, phase,
+					  CRPS185_MFR_IOUT_MAX);
+		if (rc < 0)
+			return rc;
+		break;
+	case PMBUS_POUT_OP_WARN_LIMIT:
+		rc = pmbus_read_word_data(client, page, phase,
+					  CRPS185_MFR_POUT_MAX);
+		if (rc < 0)
+			return rc;
+		break;
+	default:
+		rc = -ENODATA;
+		break;
+	}
+
+	return rc;
+}
+
+static struct pmbus_driver_info crps_info[] = {
+	[crps185] = {
+		.pages = 1,
+		/* PSU uses default linear data format. */
+		.func[0] = PMBUS_HAVE_PIN | PMBUS_HAVE_IOUT |
+			PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_IIN |
+			PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT |
+			PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
+			PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 |
+			PMBUS_HAVE_STATUS_TEMP |
+			PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12,
+		.read_word_data = crps_read_word_data,
+	},
+};
+
+#define to_psu(x, y) container_of((x), struct crps, debugfs_entries[(y)])
+
+static void crps_init_debugfs(struct crps *psu)
+{
+	struct i2c_client *client = psu->client;
+	struct dentry *debugfs;
+	int i;
+
+	/* Don't fail the probe if we can't create debugfs */
+	debugfs = pmbus_get_debugfs_dir(client);
+	if (!debugfs)
+		return;
+
+	for (i = 0; i < CRPS_DEBUGFS_NUM_ENTRIES; ++i)
+		psu->debugfs_entries[i] = i;
+
+	debugfs_create_file("pmbus_revision", 0444, debugfs,
+			    &psu->debugfs_entries[CRPS_DEBUGFS_PMBUS_REVISION],
+			    &crps_debugfs_fops);
+	debugfs_create_file("max_power_out", 0444, debugfs,
+			    &psu->debugfs_entries[CRPS_DEBUGFS_MAX_POWER_OUT],
+			    &crps_debugfs_fops);
+	debugfs_create_file("max_current_out", 0444, debugfs,
+			    &psu->debugfs_entries[CRPS_DEBUGFS_MAX_CURRENT_OUT],
+			    &crps_debugfs_fops);
+}
+
+static int crps_probe(struct i2c_client *client)
+{
+	int rc;
+	struct device *dev = &client->dev;
+	enum models vs = crps_unknown;
+	struct crps *psu;
+	const void *md = of_device_get_match_data(&client->dev);
+	const struct i2c_device_id *id = NULL;
+	char buf[I2C_SMBUS_BLOCK_MAX + 2] = { 0 };
+
+	if (md) {
+		vs = (uintptr_t)md;
+	} else {
+		id = i2c_match_id(crps_id, client);
+		if (id)
+			vs = (enum models)id->driver_data;
+	}
+
+	if (!vs || vs >= crps_unknown) {
+		dev_err(dev, "Version %d not supported\n", vs);
+		return -EINVAL;
+	}
+
+	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, "03NK260", 7)) {
+		buf[rc] = '\0';
+		dev_err(dev, "Model '%s' not supported\n", buf);
+		return -ENODEV;
+	}
+
+	client->dev.platform_data = &crps_pdata;
+	rc = pmbus_do_probe(client, &crps_info[vs]);
+	if (rc) {
+		dev_err(dev, "Failed to probe %d\n", 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) {
+		dev_warn(dev, "Failed to allocate memory. debugfs are not supported.\n");
+		return 0;
+	}
+
+	psu->version = vs;
+	psu->client = client;
+
+	crps_init_debugfs(psu);
+
+	return 0;
+}
+
+static const struct of_device_id crps_of_match[] = {
+	{
+		.compatible = "intel,crps185",
+		.data = (void *)crps185
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(of, crps_of_match);
+
+static struct i2c_driver crps_driver = {
+	.driver = {
+		.name = "crps",
+		.of_match_table = crps_of_match,
+	},
+	.probe = crps_probe,
+	.id_table = crps_id,
+};
+
+module_i2c_driver(crps_driver);
+
+MODULE_AUTHOR("Ninad Palsule");
+MODULE_DESCRIPTION("PMBus driver for Common Redundant power supplies");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PMBUS");
-- 
2.43.0