soc: qcom: pmic_glink: Introduce base PMIC GLINK driver

The PMIC GLINK service runs on one of the co-processors of some modern
Qualcomm platforms and implements USB-C and battery managements. It uses
a message based protocol over GLINK for communication with the OS, hence
the name.

The driver implemented provides the rpmsg device for communication and
uses auxilirary bus to spawn off individual devices in respsective
subsystem.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/soc/qcom/Kconfig

@@ -91,6 +91,20 @@ config QCOM_PDR_HELPERS
 	tristate
 	select QCOM_QMI_HELPERS
 
+config QCOM_PMIC_GLINK
+	tristate "Qualcomm PMIC GLINK driver"
+	depends on RPMSG
+	depends on TYPEC
+	depends on DRM
+	select QCOM_PDR_HELPERS
+	help
+	  The Qualcomm PMIC GLINK driver provides access, over GLINK, to the
+	  USB and battery firmware running on one of the coprocessors in
+	  several modern Qualcomm platforms.
+
+	  Say yes here to support USB-C and battery status on modern Qualcomm
+	  platforms.
+
 config QCOM_QMI_HELPERS
 	tristate
 	depends on NET

drivers/soc/qcom/Makefile

@@ -8,6 +8,7 @@ obj-$(CONFIG_QCOM_GSBI)	+=	qcom_gsbi.o
 obj-$(CONFIG_QCOM_MDT_LOADER)	+= mdt_loader.o
 obj-$(CONFIG_QCOM_OCMEM)	+= ocmem.o
 obj-$(CONFIG_QCOM_PDR_HELPERS)	+= pdr_interface.o
+obj-$(CONFIG_QCOM_PMIC_GLINK)	+= pmic_glink.o
 obj-$(CONFIG_QCOM_QMI_HELPERS)	+= qmi_helpers.o
 qmi_helpers-y	+= qmi_encdec.o qmi_interface.o
 obj-$(CONFIG_QCOM_RMTFS_MEM)	+= rmtfs_mem.o

drivers/soc/qcom/pmic_glink.c

@@ -0,0 +1,223 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2019-2020, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2021, Linaro Ltd
+ */
+
+#include <linux/auxiliary_bus.h>
+#include <linux/module.h>
+#include <linux/rpmsg.h>
+#include <linux/slab.h>
+#include <linux/soc/qcom/pdr.h>
+#include <linux/soc/qcom/pmic_glink.h>
+
+struct pmic_glink {
+	struct device *dev;
+	struct pdr_handle *pdr;
+
+	struct rpmsg_endpoint *ept;
+
+	struct auxiliary_device altmode_aux;
+	struct auxiliary_device ps_aux;
+	struct auxiliary_device ucsi_aux;
+
+	struct mutex lock;
+	struct list_head owners;
+};
+
+struct pmic_glink_client {
+	struct list_head node;
+
+	struct pmic_glink *pmic;
+	unsigned int id;
+
+	void (*cb)(const void *, size_t, void *);
+	void *priv;
+};
+
+static void _devm_pmic_glink_release_client(struct device *dev, void *res)
+{
+	struct pmic_glink_client *client = *(struct pmic_glink_client **)res;
+	struct pmic_glink *pg = client->pmic;
+
+	mutex_lock(&pg->lock);
+	list_del(&client->node);
+	mutex_unlock(&pg->lock);
+}
+
+struct pmic_glink_client *devm_pmic_glink_register_client(struct device *dev,
+							  unsigned int id,
+							  void (*cb)(const void *, size_t, void *),
+							  void *priv)
+{
+	struct pmic_glink_client *client;
+	struct pmic_glink *pg = dev_get_drvdata(dev->parent);
+
+	client = devres_alloc(_devm_pmic_glink_release_client, sizeof(*client), GFP_KERNEL);
+	if (!client)
+		return ERR_PTR(-ENOMEM);
+
+	client->pmic = pg;
+	client->id = id;
+	client->cb = cb;
+	client->priv = priv;
+
+	mutex_lock(&pg->lock);
+	list_add(&client->node, &pg->owners);
+	mutex_unlock(&pg->lock);
+
+	devres_add(dev, client);
+
+	return client;
+}
+EXPORT_SYMBOL_GPL(devm_pmic_glink_register_client);
+
+int pmic_glink_send(struct pmic_glink_client *client, void *data, size_t len)
+{
+	struct pmic_glink *pg = client->pmic;
+
+	return rpmsg_send(pg->ept, data, len);
+}
+EXPORT_SYMBOL_GPL(pmic_glink_send);
+
+static int pmic_glink_callback(struct rpmsg_device *rpdev, void *data,
+			       int len, void *priv, u32 addr)
+{
+	struct pmic_glink_client *client;
+	struct pmic_glink_hdr *hdr;
+	struct pmic_glink *pg = dev_get_drvdata(&rpdev->dev);
+
+	if (len < sizeof(*hdr)) {
+		dev_warn(pg->dev, "ignoring truncated message\n");
+		return 0;
+	}
+
+	hdr = data;
+
+	list_for_each_entry(client, &pg->owners, node) {
+		if (client->id == le32_to_cpu(hdr->owner))
+			client->cb(data, len, client->priv);
+	}
+
+	return 0;
+}
+
+static void pmic_glink_aux_release(struct device *dev) {}
+
+static int pmic_glink_add_aux_device(struct pmic_glink *pg,
+				     struct auxiliary_device *aux,
+				     const char *name)
+{
+	struct device *parent = pg->dev;
+	int ret;
+
+	aux->name = name;
+	aux->dev.parent = parent;
+	aux->dev.release = pmic_glink_aux_release;
+	device_set_of_node_from_dev(&aux->dev, parent);
+	ret = auxiliary_device_init(aux);
+	if (ret)
+		return ret;
+
+	ret = auxiliary_device_add(aux);
+	if (ret)
+		auxiliary_device_uninit(aux);
+
+	return ret;
+}
+
+static void pmic_glink_del_aux_device(struct pmic_glink *pg,
+				      struct auxiliary_device *aux)
+{
+	auxiliary_device_delete(aux);
+	auxiliary_device_uninit(aux);
+}
+
+static void pmic_glink_service_up(struct pmic_glink *pg)
+{
+	pmic_glink_add_aux_device(pg, &pg->altmode_aux, "altmode");
+	pmic_glink_add_aux_device(pg, &pg->ps_aux, "power-supply");
+	pmic_glink_add_aux_device(pg, &pg->ucsi_aux, "ucsi");
+}
+
+static void pmic_glink_service_down(struct pmic_glink *pg)
+{
+	pmic_glink_del_aux_device(pg, &pg->altmode_aux);
+	pmic_glink_del_aux_device(pg, &pg->ps_aux);
+	pmic_glink_del_aux_device(pg, &pg->ucsi_aux);
+}
+
+static void pmic_glink_pdr_callback(int state, char *svc_path, void *priv)
+{
+	struct pmic_glink *pg = priv;
+
+	switch (state) {
+	case SERVREG_SERVICE_STATE_UP:
+		pmic_glink_service_up(pg);
+		break;
+	case SERVREG_SERVICE_STATE_DOWN:
+		pmic_glink_service_down(pg);
+		break;
+	}
+}
+
+static int pmic_glink_probe(struct rpmsg_device *rpdev)
+{
+	struct pdr_service *service;
+	struct pmic_glink *pg;
+
+	pg = devm_kzalloc(&rpdev->dev, sizeof(*pg), GFP_KERNEL);
+	if (!pg)
+		return -ENOMEM;
+
+	dev_set_drvdata(&rpdev->dev, pg);
+
+	pg->dev = &rpdev->dev;
+	pg->ept = rpdev->ept;
+
+	INIT_LIST_HEAD(&pg->owners);
+	mutex_init(&pg->lock);
+
+	pg->pdr = pdr_handle_alloc(pmic_glink_pdr_callback, pg);
+	if (IS_ERR(pg->pdr))
+		dev_err_probe(&rpdev->dev, PTR_ERR(pg->pdr), "failed to initalize pdr\n");
+
+	service = pdr_add_lookup(pg->pdr, "tms/servreg", "msm/adsp/charger_pd");
+	if (IS_ERR(service))
+		return dev_err_probe(&rpdev->dev, PTR_ERR(service),
+				     "failed adding pdr lookup for charger_pd\n");
+
+	return 0;
+}
+
+static void pmic_glink_remove(struct rpmsg_device *rpdev)
+{
+	struct pmic_glink *pg = dev_get_drvdata(&rpdev->dev);
+
+	pdr_handle_release(pg->pdr);
+}
+
+static const struct of_device_id pmic_glink_of_match[] = {
+	{ .compatible = "qcom,pmic-glink", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, pmic_glink_of_match);
+
+static const struct rpmsg_device_id pmic_glink_id_match[] = {
+	{ "PMIC_RTR_ADSP_APPS" },
+	{}
+};
+
+static struct rpmsg_driver pmic_glink_driver = {
+	.probe = pmic_glink_probe,
+	.remove = pmic_glink_remove,
+	.callback = pmic_glink_callback,
+	.id_table = pmic_glink_id_match,
+	.drv  = {
+		.name  = "qcom_pmic_glink",
+	},
+};
+module_rpmsg_driver(pmic_glink_driver);
+
+MODULE_DESCRIPTION("Qualcomm PMIC GLINK driver");
+MODULE_LICENSE("GPL v2");

include/linux/soc/qcom/pmic_glink.h

@@ -0,0 +1,28 @@
+#ifndef __PMIC_GLINK_H__
+#define __PMIC_GLINK_H__
+
+struct pmic_glink;
+struct pmic_glink_client;
+
+#define PMIC_GLINK_OWNER_BC		32778
+#define PMIC_GLINK_OWNER_UC		32779
+#define PMIC_GLINK_OWNER_USBC_PAN	32780
+
+#define PMIC_GLINK_REQ_RESP		1
+#define PMIC_GLINK_NOTIFY		2
+
+struct pmic_glink_hdr {
+	__le32 owner;
+	__le32 type;
+	__le32 opcode;
+};
+
+int pmic_glink_send(struct pmic_glink_client *client, void *data, size_t len);
+
+
+struct pmic_glink_client *devm_pmic_glink_register_client(struct device *dev,
+							  unsigned int id,
+							  void (*cb)(const void *, size_t, void *),
+							  void *priv);
+
+#endif