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Subject[PATCH v2 1/2] power: supply: PCHG: Peripheral device charger
Date
This patch adds a driver for PCHG (Peripheral CHarGer). PCHG is a
framework managing power supplies for peripheral devices.

This driver creates a sysfs node for each peripheral charge port:

/sys/class/power_supply/PCHGn

where <n> is the index of a charge port.

For example, when a stylus is connected to a NFC/WLC port, the node
prints:

/sys/class/power_supply/PCHG0/
capacity=50
status=Charging
type=Wireless

Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
---
v1 -> v2
* Separate mfd/cros_ec_dev.c
* Make CONFIG_CHARGER_CROS_PCHG default to CONFIG_MFD_CROS_EC_DEV
---

drivers/power/supply/Kconfig | 10 +
drivers/power/supply/Makefile | 1 +
.../power/supply/cros_peripheral_charger.c | 346 ++++++++++++++++++
.../linux/platform_data/cros_ec_commands.h | 48 +++
4 files changed, 405 insertions(+)
create mode 100644 drivers/power/supply/cros_peripheral_charger.c

diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index eec646c568b7be..407f9fbbc2bb50 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -714,6 +714,16 @@ config CHARGER_CROS_USBPD
what is connected to USB PD ports from the EC and converts
that into power_supply properties.

+config CHARGER_CROS_PCHG
+ tristate "ChromeOS EC based peripheral charger"
+ depends on MFD_CROS_EC_DEV
+ default MFD_CROS_EC_DEV
+ help
+ Say Y here to enable ChromeOS EC based peripheral charge driver.
+ This driver gets various information about the devices connected to
+ the peripheral charge ports from the EC and converts that into
+ power_supply properties.
+
config CHARGER_SC2731
tristate "Spreadtrum SC2731 charger driver"
depends on MFD_SC27XX_PMIC || COMPILE_TEST
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index dd4b86318cd9bd..5263472a64809b 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -91,6 +91,7 @@ obj-$(CONFIG_CHARGER_TPS65217) += tps65217_charger.o
obj-$(CONFIG_AXP288_FUEL_GAUGE) += axp288_fuel_gauge.o
obj-$(CONFIG_AXP288_CHARGER) += axp288_charger.o
obj-$(CONFIG_CHARGER_CROS_USBPD) += cros_usbpd-charger.o
+obj-$(CONFIG_CHARGER_CROS_PCHG) += cros_peripheral_charger.o
obj-$(CONFIG_CHARGER_SC2731) += sc2731_charger.o
obj-$(CONFIG_FUEL_GAUGE_SC27XX) += sc27xx_fuel_gauge.o
obj-$(CONFIG_CHARGER_UCS1002) += ucs1002_power.o
diff --git a/drivers/power/supply/cros_peripheral_charger.c b/drivers/power/supply/cros_peripheral_charger.c
new file mode 100644
index 00000000000000..db68d3b7c80f32
--- /dev/null
+++ b/drivers/power/supply/cros_peripheral_charger.c
@@ -0,0 +1,346 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Power supply driver for ChromeOS EC based Peripheral Device Charger.
+ *
+ * Copyright 2020 Google LLC.
+ */
+
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_data/cros_ec_proto.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/slab.h>
+#include <linux/stringify.h>
+#include <linux/types.h>
+
+#define DRV_NAME "cros-ec-pchg"
+#define PCHG_DIR_NAME "PCHG%d"
+#define PCHG_DIR_NAME_LENGTH sizeof("PCHG" __stringify(EC_PCHG_MAX_PORTS))
+#define PCHG_CACHE_UPDATE_DELAY msecs_to_jiffies(500)
+
+struct port_data {
+ int port_number;
+ char name[PCHG_DIR_NAME_LENGTH];
+ struct power_supply *psy;
+ struct power_supply_desc psy_desc;
+ int psy_status;
+ int battery_percentage;
+ struct charger_data *charger;
+ unsigned long last_update;
+};
+
+struct charger_data {
+ struct device *dev;
+ struct cros_ec_dev *ec_dev;
+ struct cros_ec_device *ec_device;
+ int num_registered_psy;
+ struct port_data *ports[EC_PCHG_MAX_PORTS];
+ struct notifier_block notifier;
+};
+
+static enum power_supply_property cros_pchg_props[] = {
+ POWER_SUPPLY_PROP_STATUS,
+ POWER_SUPPLY_PROP_CAPACITY,
+ /*
+ * todo: Add the following.
+ *
+ * POWER_SUPPLY_PROP_TECHNOLOGY,
+ * POWER_SUPPLY_PROP_ERROR,
+ * POWER_SUPPLY_PROP_SERIAL_NUMBER,
+ *
+ * POWER_SUPPLY_PROP_ONLINE can't be used because it indicates the
+ * system is powered by AC.
+ */
+};
+
+static int cros_pchg_ec_command(const struct charger_data *charger,
+ unsigned int version,
+ unsigned int command,
+ const void *outdata,
+ unsigned int outsize,
+ void *indata,
+ unsigned int insize)
+{
+ struct cros_ec_dev *ec_dev = charger->ec_dev;
+ struct cros_ec_command *msg;
+ int ret;
+
+ msg = kzalloc(sizeof(*msg) + max(outsize, insize), GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ msg->version = version;
+ msg->command = ec_dev->cmd_offset + command;
+ msg->outsize = outsize;
+ msg->insize = insize;
+
+ if (outsize)
+ memcpy(msg->data, outdata, outsize);
+
+ ret = cros_ec_cmd_xfer_status(charger->ec_device, msg);
+ if (ret >= 0 && insize)
+ memcpy(indata, msg->data, insize);
+
+ kfree(msg);
+ return ret;
+}
+
+static int cros_pchg_port_count(const struct charger_data *charger)
+{
+ struct ec_response_pchg_count rsp;
+ int ret;
+
+ ret = cros_pchg_ec_command(charger, 0, EC_CMD_PCHG_COUNT,
+ NULL, 0, &rsp, sizeof(rsp));
+ if (ret < 0) {
+ dev_warn(charger->dev,
+ "Unable to get number or ports (err:%d)\n", ret);
+ return ret;
+ }
+
+ return rsp.port_count;
+}
+
+static int cros_pchg_get_status(struct port_data *port)
+{
+ struct charger_data *charger = port->charger;
+ struct ec_params_pchg req;
+ struct ec_response_pchg rsp;
+ struct device *dev = charger->dev;
+ int ret;
+
+ req.port = port->port_number;
+ ret = cros_pchg_ec_command(charger, 0, EC_CMD_PCHG,
+ &req, sizeof(req), &rsp, sizeof(rsp));
+ if (ret < 0) {
+ dev_err(dev, "Unable to get port.%d status (err:%d)\n",
+ port->port_number, ret);
+ return ret;
+ }
+
+ switch (rsp.state) {
+ case PCHG_STATE_RESET:
+ case PCHG_STATE_INITIALIZED:
+ case PCHG_STATE_ENABLED:
+ default:
+ port->psy_status = POWER_SUPPLY_STATUS_UNKNOWN;
+ port->battery_percentage = 0;
+ break;
+ case PCHG_STATE_DETECTED:
+ port->psy_status = POWER_SUPPLY_STATUS_NOT_CHARGING;
+ port->battery_percentage = rsp.battery_percentage;
+ break;
+ case PCHG_STATE_CHARGING:
+ port->psy_status = POWER_SUPPLY_STATUS_CHARGING;
+ port->battery_percentage = rsp.battery_percentage;
+ break;
+ }
+
+ dev_dbg(dev,
+ "Port %d: state=%d battery=%d%%\n",
+ port->port_number, rsp.state, rsp.battery_percentage);
+
+ return 0;
+}
+
+static int cros_pchg_get_port_status(struct port_data *port, bool ratelimit)
+{
+ int ret;
+
+ if (ratelimit &&
+ time_is_after_jiffies(port->last_update + PCHG_CACHE_UPDATE_DELAY))
+ return 0;
+
+ ret = cros_pchg_get_status(port);
+ if (ret < 0)
+ return ret;
+
+ port->last_update = jiffies;
+
+ return ret;
+}
+
+static int cros_pchg_get_prop(struct power_supply *psy,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ struct port_data *port = power_supply_get_drvdata(psy);
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_STATUS:
+ case POWER_SUPPLY_PROP_CAPACITY:
+ cros_pchg_get_port_status(port, true);
+ break;
+ default:
+ break;
+ }
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_STATUS:
+ val->intval = port->psy_status;
+ break;
+ case POWER_SUPPLY_PROP_CAPACITY:
+ val->intval = port->battery_percentage;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int cros_pchg_event(const struct charger_data *charger,
+ unsigned long host_event)
+{
+ int i;
+
+ for (i = 0; i < charger->num_registered_psy; i++)
+ cros_pchg_get_port_status(charger->ports[i], false);
+
+ return NOTIFY_OK;
+}
+
+static u32 cros_get_device_event(const struct charger_data *charger)
+{
+ struct ec_params_device_event req;
+ struct ec_response_device_event rsp;
+ struct device *dev = charger->dev;
+ int ret;
+
+ req.param = EC_DEVICE_EVENT_PARAM_GET_CURRENT_EVENTS;
+ ret = cros_pchg_ec_command(charger, 0, EC_CMD_DEVICE_EVENT,
+ &req, sizeof(req), &rsp, sizeof(rsp));
+ if (ret < 0) {
+ dev_warn(dev, "Unable to get device events (err:%d)\n", ret);
+ return 0;
+ }
+
+ return rsp.event_mask;
+}
+
+static int cros_ec_notify(struct notifier_block *nb,
+ unsigned long queued_during_suspend,
+ void *data)
+{
+ struct cros_ec_device *ec_dev = (struct cros_ec_device *)data;
+ u32 host_event = cros_ec_get_host_event(ec_dev);
+ struct charger_data *charger =
+ container_of(nb, struct charger_data, notifier);
+ u32 device_event_mask;
+
+ if (!host_event)
+ return NOTIFY_BAD;
+
+ if (!(host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_DEVICE)))
+ return NOTIFY_DONE;
+
+ /*
+ * todo: Retrieve device event mask in common place
+ * (e.g. cros_ec_proto.c).
+ */
+ device_event_mask = cros_get_device_event(charger);
+ if (!(device_event_mask & EC_DEVICE_EVENT_MASK(EC_DEVICE_EVENT_WLC)))
+ return NOTIFY_DONE;
+
+ return cros_pchg_event(charger, host_event);
+}
+
+static int cros_pchg_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
+ struct cros_ec_device *ec_device = ec_dev->ec_dev;
+ struct power_supply_desc *psy_desc;
+ struct charger_data *charger;
+ struct power_supply *psy;
+ struct port_data *port;
+ struct notifier_block *nb;
+ int num_ports;
+ int ret;
+ int i;
+
+ charger = devm_kzalloc(dev, sizeof(*charger), GFP_KERNEL);
+ if (!charger)
+ return -ENOMEM;
+
+ charger->dev = dev;
+ charger->ec_dev = ec_dev;
+ charger->ec_device = ec_device;
+
+ ret = cros_pchg_port_count(charger);
+ if (ret <= 0) {
+ /*
+ * This feature is enabled by the EC and the kernel driver is
+ * included by default for CrOS devices. Don't need to be loud
+ * since this error can be normal.
+ */
+ dev_info(dev, "No peripheral charge ports (err:%d)\n", ret);
+ return -ENODEV;
+ }
+
+ num_ports = ret;
+ if (num_ports > EC_PCHG_MAX_PORTS) {
+ dev_err(dev, "Too many peripheral charge ports (%d)\n",
+ num_ports);
+ return -ENOBUFS;
+ }
+
+ dev_info(dev, "%d peripheral charge ports found\n", num_ports);
+
+ for (i = 0; i < num_ports; i++) {
+ struct power_supply_config psy_cfg = {};
+
+ port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
+ if (!port)
+ return -ENOMEM;
+
+ port->charger = charger;
+ port->port_number = i;
+ snprintf(port->name, sizeof(port->name), PCHG_DIR_NAME, i);
+
+ psy_desc = &port->psy_desc;
+ psy_desc->name = port->name;
+ psy_desc->type = POWER_SUPPLY_TYPE_WIRELESS;
+ psy_desc->get_property = cros_pchg_get_prop;
+ psy_desc->external_power_changed = NULL;
+ psy_desc->properties = cros_pchg_props;
+ psy_desc->num_properties = ARRAY_SIZE(cros_pchg_props);
+ psy_cfg.drv_data = port;
+
+ psy = devm_power_supply_register_no_ws(dev, psy_desc, &psy_cfg);
+ if (IS_ERR(psy)) {
+ dev_err(dev, "Failed to register power supply\n");
+ continue;
+ }
+ port->psy = psy;
+
+ charger->ports[charger->num_registered_psy++] = port;
+ }
+
+ if (!charger->num_registered_psy)
+ return -ENODEV;
+
+ nb = &charger->notifier;
+ nb->notifier_call = cros_ec_notify;
+ ret = blocking_notifier_chain_register(&ec_dev->ec_dev->event_notifier,
+ nb);
+ if (ret < 0)
+ dev_err(dev, "Failed to register notifier (err:%d)\n", ret);
+
+ return 0;
+}
+
+static struct platform_driver cros_pchg_driver = {
+ .driver = {
+ .name = DRV_NAME,
+ },
+ .probe = cros_pchg_probe
+};
+
+module_platform_driver(cros_pchg_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("ChromeOS EC peripheral device charger");
+MODULE_ALIAS("platform:" DRV_NAME);
diff --git a/include/linux/platform_data/cros_ec_commands.h b/include/linux/platform_data/cros_ec_commands.h
index 58495127dfa656..c0f0a032c8beb6 100644
--- a/include/linux/platform_data/cros_ec_commands.h
+++ b/include/linux/platform_data/cros_ec_commands.h
@@ -4225,6 +4225,7 @@ enum ec_device_event {
EC_DEVICE_EVENT_TRACKPAD,
EC_DEVICE_EVENT_DSP,
EC_DEVICE_EVENT_WIFI,
+ EC_DEVICE_EVENT_WLC,
};

enum ec_device_event_param {
@@ -5456,6 +5457,53 @@ struct ec_response_rollback_info {
/* Issue AP reset */
#define EC_CMD_AP_RESET 0x0125

+/**
+ * Get the number of peripheral charge ports
+ */
+#define EC_CMD_PCHG_COUNT 0x0134
+
+#define EC_PCHG_MAX_PORTS 8
+
+struct ec_response_pchg_count {
+ uint8_t port_count;
+} __ec_align1;
+
+/**
+ * Get the status of a peripheral charge port
+ */
+#define EC_CMD_PCHG 0x0135
+
+struct ec_params_pchg {
+ uint8_t port;
+} __ec_align1;
+
+struct ec_response_pchg {
+ uint32_t error; /* enum pchg_error */
+ uint8_t state; /* enum pchg_state state */
+ uint8_t battery_percentage;
+} __ec_align2;
+
+enum pchg_state {
+ /* Charger is reset and not initialized. */
+ PCHG_STATE_RESET = 0,
+ /* Charger is initialized or disabled. */
+ PCHG_STATE_INITIALIZED,
+ /* Charger is enabled and ready to detect a device. */
+ PCHG_STATE_ENABLED,
+ /* Device is detected in proximity. */
+ PCHG_STATE_DETECTED,
+ /* Device is being charged. */
+ PCHG_STATE_CHARGING,
+};
+
+#define EC_PCHG_STATE_TEXT { \
+ [PCHG_STATE_RESET] = "RESET", \
+ [PCHG_STATE_INITIALIZED] = "INITIALIZED", \
+ [PCHG_STATE_ENABLED] = "ENABLED", \
+ [PCHG_STATE_DETECTED] = "DETECTED", \
+ [PCHG_STATE_CHARGING] = "CHARGING", \
+ }
+
/*****************************************************************************/
/* Locate peripheral chips
*
--
2.29.2.684.gfbc64c5ab5-goog
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