[PATCH v3 1/2] power: supply: PCHG: Peripheral device charger

[PATCH v3 1/2] power: supply: PCHG: Peripheral device charger

[Daisuke Nojiri]

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
		scope=Device
		status=Charging
		type=Battery

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
v2 -> v3
* Return POWER_SUPPLY_SCOPE_DEVICE for POWER_SUPPLY_PROP_SCOPE
* POWER_SUPPLY_TYPE_WIRELESS -> POWER_SUPPLY_TYPE_BATTERY
---
 drivers/power/supply/Kconfig                  |  10 +
 drivers/power/supply/Makefile                 |   1 +
 .../power/supply/cros_peripheral_charger.c    | 350 ++++++++++++++++++
 .../linux/platform_data/cros_ec_commands.h    |  48 +++
 4 files changed, 409 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..a864a33a48033f
--- /dev/null
+++ b/drivers/power/supply/cros_peripheral_charger.c
@@ -0,0 +1,350 @@
+// 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,
+	POWER_SUPPLY_PROP_SCOPE,
+	/*
+	 * 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;
+	case POWER_SUPPLY_PROP_SCOPE:
+		val->intval = POWER_SUPPLY_SCOPE_DEVICE;
+		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_BATTERY;
+		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 5a3ccf8968968e..6a82a9ad99eadf 100644
--- a/include/linux/platform_data/cros_ec_commands.h
+++ b/include/linux/platform_data/cros_ec_commands.h
@@ -4249,6 +4249,7 @@ 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 {
@@ -5480,6 +5481,53 @@ 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
  *
-- 
2.30.0.280.ga3ce27912f-goog

[PATCH v3 2/2] mfd: cros_ec: Add peripheral device charger

[Daisuke Nojiri]

This patch adds a cell entry for PCHG (Peripheral CHarGer). PCHG is a
framework managing power supplies for peripheral devices.

Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>
---
v1->v2
* None
v2->v3
* None
---
 drivers/mfd/cros_ec_dev.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index 6135321592b76c..f3bc1cb6891ba5 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -116,6 +116,7 @@ static const struct mfd_cell cros_ec_platform_cells[] = {
 	{ .name = "cros-ec-pd-sysfs" },
 	{ .name = "cros-ec-sysfs", },
 	{ .name = "cros-ec-pd-update", },
+	{ .name = "cros-ec-pchg", },
 };
 
 static const struct mfd_cell cros_ec_vbc_cells[] = {
-- 
2.30.0.280.ga3ce27912f-goog

Re: [PATCH v3 1/2] power: supply: PCHG: Peripheral device charger

[Doug Anderson]

Hi,

On Fri, Jan 22, 2021 at 2:07 PM Daisuke Nojiri <dnojiri@chromium.org> wrote:
>
> +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;

Drive-by bug report: the above should be NOTIFY_DONE.  By returning
NOTIFY_BAD you're preventing other people on the call chain that come
after you from receiving any events that aren't "host events".
Specifically this includes keyboard events, switch events, etc.

The patch <https://crrev.com/c/2645556> contains the fix.

-Doug