[PATCH net-next v6 4/8] mfd: zl3073x: Add support for devlink device info

[Ivan Vecera <ivecera@redhat.com>]

Use devlink_alloc() to allocate zl3073x_dev structure, register
the device as a devlink device, and add devlink callback to provide
device info.

Signed-off-by: Ivan Vecera <ivecera@redhat.com>
---
v5->v6:
* fixed devlink info firmware version to be running instead of fixed
* added documentation for devlink info versions

v4->v5:
* use new register access helpers

v3->v4:
* pass error code from devm_add_action_or_reset() call

v2->v3:
* merged devlink device allocation, registration and device info
  callback

v1->v2:
* dependency on NET moved to MFD_ZL3073X_CORE in Kconfig
* devlink register managed way
---
 Documentation/networking/devlink/index.rst   |   1 +
 Documentation/networking/devlink/zl3073x.rst |  37 +++++++
 drivers/mfd/Kconfig                          |   2 +
 drivers/mfd/zl3073x-core.c                   | 108 ++++++++++++++++++-
 4 files changed, 146 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/networking/devlink/zl3073x.rst

diff --git a/Documentation/networking/devlink/index.rst b/Documentation/networking/devlink/index.rst
index 8319f43b5933..250ae71f4023 100644
--- a/Documentation/networking/devlink/index.rst
+++ b/Documentation/networking/devlink/index.rst
@@ -98,3 +98,4 @@ parameters, info versions, and other features it supports.
    iosm
    octeontx2
    sfc
+   zl3073x
diff --git a/Documentation/networking/devlink/zl3073x.rst b/Documentation/networking/devlink/zl3073x.rst
new file mode 100644
index 000000000000..9a6744fb2e86
--- /dev/null
+++ b/Documentation/networking/devlink/zl3073x.rst
@@ -0,0 +1,37 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=======================
+zl3073x devlink support
+=======================
+
+This document describes the devlink features implemented by the ``zl3073x``
+device driver.
+
+Info versions
+=============
+
+The ``zl3073x`` driver reports the following versions
+
+.. list-table:: devlink info versions implemented
+    :widths: 5 5 5 90
+
+    * - Name
+      - Type
+      - Example
+      - Description
+    * - ``asic.id``
+      - fixed
+      - 1E94
+      - Chip identification number
+    * - ``asic.rev``
+      - fixed
+      - 300
+      - Chip revision number
+    * - ``fw``
+      - running
+      - 7006
+      - Firmware version number
+    * - ``cfg.custom_ver``
+      - running
+      - 1.3.0.1
+      - Device configuration version customized by OEM
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 7d7902ec1d89..e4eca15af175 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -2424,6 +2424,8 @@ config MFD_UPBOARD_FPGA
 
 config MFD_ZL3073X_CORE
 	tristate
+	depends on NET
+	select NET_DEVLINK
 	select MFD_CORE
 
 config MFD_ZL3073X_I2C
diff --git a/drivers/mfd/zl3073x-core.c b/drivers/mfd/zl3073x-core.c
index c408aafb0f8a..079550682510 100644
--- a/drivers/mfd/zl3073x-core.c
+++ b/drivers/mfd/zl3073x-core.c
@@ -8,8 +8,11 @@
 #include <linux/export.h>
 #include <linux/mfd/zl3073x.h>
 #include <linux/module.h>
+#include <linux/netlink.h>
 #include <linux/regmap.h>
+#include <linux/sprintf.h>
 #include <linux/unaligned.h>
+#include <net/devlink.h>
 #include "zl3073x.h"
 #include "zl3073x-regs.h"
 
@@ -375,6 +378,83 @@ int zl3073x_poll_zero_u8(struct zl3073x_dev *zldev, unsigned int reg, u8 mask)
 }
 EXPORT_SYMBOL_NS_GPL(zl3073x_poll_zero_u8, "ZL3073X");
 
+/**
+ * zl3073x_devlink_info_get - Devlink device info callback
+ * @devlink: devlink structure pointer
+ * @req: devlink request pointer to store information
+ * @extack: netlink extack pointer to report errors
+ *
+ * Return: 0 on success, <0 on error
+ */
+static int zl3073x_devlink_info_get(struct devlink *devlink,
+				    struct devlink_info_req *req,
+				    struct netlink_ext_ack *extack)
+{
+	struct zl3073x_dev *zldev = devlink_priv(devlink);
+	u16 id, revision, fw_ver;
+	char buf[16];
+	u32 cfg_ver;
+	int rc;
+
+	rc = zl3073x_read_u16(zldev, ZL_REG_ID, &id);
+	if (rc)
+		return rc;
+
+	snprintf(buf, sizeof(buf), "%X", id);
+	rc = devlink_info_version_fixed_put(req,
+					    DEVLINK_INFO_VERSION_GENERIC_ASIC_ID,
+					    buf);
+	if (rc)
+		return rc;
+
+	rc = zl3073x_read_u16(zldev, ZL_REG_REVISION, &revision);
+	if (rc)
+		return rc;
+
+	snprintf(buf, sizeof(buf), "%X", revision);
+	rc = devlink_info_version_fixed_put(req,
+					    DEVLINK_INFO_VERSION_GENERIC_ASIC_REV,
+					    buf);
+	if (rc)
+		return rc;
+
+	rc = zl3073x_read_u16(zldev, ZL_REG_FW_VER, &fw_ver);
+	if (rc)
+		return rc;
+
+	snprintf(buf, sizeof(buf), "%u", fw_ver);
+	rc = devlink_info_version_running_put(req,
+					      DEVLINK_INFO_VERSION_GENERIC_FW,
+					      buf);
+	if (rc)
+		return rc;
+
+	rc = zl3073x_read_u32(zldev, ZL_REG_CUSTOM_CONFIG_VER, &cfg_ver);
+	if (rc)
+		return rc;
+
+	/* No custom config version */
+	if (cfg_ver == U32_MAX)
+		return 0;
+
+	snprintf(buf, sizeof(buf), "%lu.%lu.%lu.%lu",
+		 FIELD_GET(GENMASK(31, 24), cfg_ver),
+		 FIELD_GET(GENMASK(23, 16), cfg_ver),
+		 FIELD_GET(GENMASK(15, 8), cfg_ver),
+		 FIELD_GET(GENMASK(7, 0), cfg_ver));
+
+	return devlink_info_version_running_put(req, "cfg.custom_ver", buf);
+}
+
+static const struct devlink_ops zl3073x_devlink_ops = {
+	.info_get = zl3073x_devlink_info_get,
+};
+
+static void zl3073x_devlink_free(void *ptr)
+{
+	devlink_free(ptr);
+}
+
 /**
  * zl3073x_devm_alloc - allocates zl3073x device structure
  * @dev: pointer to device structure
@@ -386,11 +466,19 @@ EXPORT_SYMBOL_NS_GPL(zl3073x_poll_zero_u8, "ZL3073X");
 struct zl3073x_dev *zl3073x_devm_alloc(struct device *dev)
 {
 	struct zl3073x_dev *zldev;
+	struct devlink *devlink;
+	int rc;
 
-	zldev = devm_kzalloc(dev, sizeof(*zldev), GFP_KERNEL);
-	if (!zldev)
+	devlink = devlink_alloc(&zl3073x_devlink_ops, sizeof(*zldev), dev);
+	if (!devlink)
 		return ERR_PTR(-ENOMEM);
 
+	/* Add devres action to free devlink device */
+	rc = devm_add_action_or_reset(dev, zl3073x_devlink_free, devlink);
+	if (rc)
+		return ERR_PTR(rc);
+
+	zldev = devlink_priv(devlink);
 	zldev->dev = dev;
 	dev_set_drvdata(zldev->dev, zldev);
 
@@ -410,6 +498,11 @@ void zl3073x_dev_init_regmap_config(struct regmap_config *regmap_cfg)
 }
 EXPORT_SYMBOL_NS_GPL(zl3073x_dev_init_regmap_config, "ZL3073X");
 
+static void zl3073x_devlink_unregister(void *ptr)
+{
+	devlink_unregister(ptr);
+}
+
 /**
  * zl3073x_dev_probe - initialize zl3073x device
  * @zldev: pointer to zl3073x device
@@ -423,6 +516,7 @@ int zl3073x_dev_probe(struct zl3073x_dev *zldev,
 		      const struct zl3073x_chip_info *chip_info)
 {
 	u16 id, revision, fw_ver;
+	struct devlink *devlink;
 	unsigned int i;
 	u32 cfg_ver;
 	int rc;
@@ -463,6 +557,16 @@ int zl3073x_dev_probe(struct zl3073x_dev *zldev,
 		FIELD_GET(GENMASK(15, 8), cfg_ver),
 		FIELD_GET(GENMASK(7, 0), cfg_ver));
 
+	/* Register the device as devlink device */
+	devlink = priv_to_devlink(zldev);
+	devlink_register(devlink);
+
+	/* Add devres action to unregister devlink device */
+	rc = devm_add_action_or_reset(zldev->dev, zl3073x_devlink_unregister,
+				      devlink);
+	if (rc)
+		return rc;
+
 	return 0;
 }
 EXPORT_SYMBOL_NS_GPL(zl3073x_dev_probe, "ZL3073X");
-- 
2.49.0