linux-kernel - [PATCH v1 5/6] platform/chrome: Register USB PD charger device

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Message-Id: <1454679181-8949-6-git-send-email-tomeu.vizoso@collabora.com>
Date:	Fri,  5 Feb 2016 14:33:00 +0100
From:	Tomeu Vizoso <tomeu.vizoso@...labora.com>
To:	linux-kernel@...r.kernel.org
Cc:	Sameer Nanda <snanda@...omium.org>,
	Benson Leung <bleung@...omium.org>,
	Enric Balletbò <enric.balletbo@...labora.co.uk>,
	Vic Yang <victoryang@...omium.org>,
	Vincent Palatin <vpalatin@...omium.org>,
	Randall Spangler <rspangler@...omium.org>,
	Gwendal Grignou <gwendal@...omium.org>,
	Tomeu Vizoso <tomeu.vizoso@...labora.com>,
	Olof Johansson <olof@...om.net>,
	Lee Jones <lee.jones@...aro.org>
Subject: [PATCH v1 5/6] platform/chrome: Register USB PD charger device

Check if a EC considers EC_CMD_USB_PD_PORTS a valid command and register
a USB PD charger device if so. This check is needed for older versions
of the ChromeOS EC firmware that don't support the EC_CMD_GET_FEATURES
command.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@...labora.com>
---

 drivers/mfd/cros_ec.c                 | 15 +++++++++++++++
 drivers/platform/chrome/cros_ec_dev.c | 34 ++++++++++++++++++++++++++++++++++
 include/linux/mfd/cros_ec.h           |  2 ++
 3 files changed, 51 insertions(+)

diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
index fbe78b819fdd..20ca9794d2f3 100644
--- a/drivers/mfd/cros_ec.c
+++ b/drivers/mfd/cros_ec.c
@@ -202,5 +202,20 @@ EXPORT_SYMBOL(cros_ec_resume);
 
 #endif
 
+static const struct mfd_cell cros_usb_pd_charger_devs[] = {
+	{
+		.name = "cros-usb-pd-charger",
+		.id   = -1,
+	},
+};
+
+int cros_ec_usb_pd_charger_register(struct device *dev)
+{
+	return mfd_add_devices(dev, 0, cros_usb_pd_charger_devs,
+			       ARRAY_SIZE(cros_usb_pd_charger_devs),
+			       NULL, 0, NULL);
+}
+EXPORT_SYMBOL(cros_ec_usb_pd_charger_register);
+
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("ChromeOS EC core driver");
diff --git a/drivers/platform/chrome/cros_ec_dev.c b/drivers/platform/chrome/cros_ec_dev.c
index d45cd254ed1c..7a97cd313c68 100644
--- a/drivers/platform/chrome/cros_ec_dev.c
+++ b/drivers/platform/chrome/cros_ec_dev.c
@@ -87,6 +87,29 @@ exit:
 	return ret;
 }
 
+static int cros_ec_has_cmd_usb_pd_ports(struct cros_ec_dev *ec)
+{
+	struct cros_ec_command *msg;
+	int ret;
+
+	msg = kmalloc(sizeof(*msg) + sizeof(struct ec_response_usb_pd_ports),
+		      GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	msg->version = 0;
+	msg->command = EC_CMD_USB_PD_PORTS + ec->cmd_offset;
+	msg->insize = sizeof(struct ec_response_usb_pd_ports);
+	msg->outsize = 0;
+
+	ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
+	ret = ret >= 0 && msg->result == EC_RES_SUCCESS;
+
+	kfree(msg);
+
+	return ret;
+}
+
 /* Device file ops */
 static int ec_device_open(struct inode *inode, struct file *filp)
 {
@@ -269,8 +292,19 @@ static int ec_device_probe(struct platform_device *pdev)
 		goto dev_reg_failed;
 	}
 
+	/* check whether this EC instance has the PD charge manager */
+	if (cros_ec_has_cmd_usb_pd_ports(ec)) {
+		retval = cros_ec_usb_pd_charger_register(dev);
+		if (retval) {
+			dev_err(dev, "failed to add usb-pd-charger device\n");
+			goto pd_reg_failed;
+		}
+	}
+
 	return 0;
 
+pd_reg_failed:
+	put_device(&ec->class_dev);
 dev_reg_failed:
 set_named_failed:
 	dev_set_drvdata(dev, NULL);
diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index c21583411ba0..543191f493a9 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -329,4 +329,6 @@ extern struct attribute_group cros_ec_vbc_attr_group;
  */
 uint32_t cros_ec_get_host_event(struct cros_ec_device *ec_dev);
 
+int cros_ec_usb_pd_charger_register(struct device *dev);
+
 #endif /* __LINUX_MFD_CROS_EC_H */
-- 
2.5.0