cros_ec: Move cros_ec_dev module to drivers/mfd

The cros_ec_dev module is responsible for registering the MFD devices
attached to the ChromeOS EC. This patch moves this module to drivers/mfd
so calls to mfd_add_devices() are not done from outside the MFD subtree
anymore.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

4 files changed, 615 insertions, 0 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 1d20a800e967..538a2ae8bd25 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -222,6 +222,16 @@ config MFD_CROS_EC_SPI
 	  response time cannot be guaranteed, we support ignoring
 	  'pre-amble' bytes before the response actually starts.
 
+config MFD_CROS_EC_CHARDEV
+        tristate "Chrome OS Embedded Controller userspace device interface"
+        depends on MFD_CROS_EC
+        select CROS_EC_CTL
+        ---help---
+          This driver adds support to talk with the ChromeOS EC from userspace.
+
+          If you have a supported Chromebook, choose Y or M here.
+          The module will be called cros_ec_dev.
+
 config MFD_ASIC3
 	bool "Compaq ASIC3"
 	depends on GPIOLIB && ARM
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index d9474ade32e6..fcd8af88110e 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -17,6 +17,7 @@ cros_ec_core-$(CONFIG_ACPI)	+= cros_ec_acpi_gpe.o
 obj-$(CONFIG_MFD_CROS_EC)	+= cros_ec_core.o
 obj-$(CONFIG_MFD_CROS_EC_I2C)	+= cros_ec_i2c.o
 obj-$(CONFIG_MFD_CROS_EC_SPI)	+= cros_ec_spi.o
+obj-$(CONFIG_MFD_CROS_EC_CHARDEV) += cros_ec_dev.o
 obj-$(CONFIG_MFD_EXYNOS_LPASS)	+= exynos-lpass.o
 
 rtsx_pci-objs			:= rtsx_pcr.o rts5209.o rts5229.o rtl8411.o rts5227.o rts5249.o
diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
new file mode 100644
index 000000000000..e4fafdd96e5e
--- /dev/null
+++ b/drivers/mfd/cros_ec_dev.c
@@ -0,0 +1,552 @@
+/*
+ * cros_ec_dev - expose the Chrome OS Embedded Controller to user-space
+ *
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/fs.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#include "cros_ec_dev.h"
+
+#define DRV_NAME "cros-ec-dev"
+
+/* Device variables */
+#define CROS_MAX_DEV 128
+static int ec_major;
+
+static const struct attribute_group *cros_ec_groups[] = {
+	&cros_ec_attr_group,
+	&cros_ec_lightbar_attr_group,
+	&cros_ec_vbc_attr_group,
+	NULL,
+};
+
+static struct class cros_class = {
+	.owner          = THIS_MODULE,
+	.name           = "chromeos",
+	.dev_groups     = cros_ec_groups,
+};
+
+/* Basic communication */
+static int ec_get_version(struct cros_ec_dev *ec, char *str, int maxlen)
+{
+	struct ec_response_get_version *resp;
+	static const char * const current_image_name[] = {
+		"unknown", "read-only", "read-write", "invalid",
+	};
+	struct cros_ec_command *msg;
+	int ret;
+
+	msg = kmalloc(sizeof(*msg) + sizeof(*resp), GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	msg->version = 0;
+	msg->command = EC_CMD_GET_VERSION + ec->cmd_offset;
+	msg->insize = sizeof(*resp);
+	msg->outsize = 0;
+
+	ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
+	if (ret < 0)
+		goto exit;
+
+	if (msg->result != EC_RES_SUCCESS) {
+		snprintf(str, maxlen,
+			 "%s\nUnknown EC version: EC returned %d\n",
+			 CROS_EC_DEV_VERSION, msg->result);
+		ret = -EINVAL;
+		goto exit;
+	}
+
+	resp = (struct ec_response_get_version *)msg->data;
+	if (resp->current_image >= ARRAY_SIZE(current_image_name))
+		resp->current_image = 3; /* invalid */
+
+	snprintf(str, maxlen, "%s\n%s\n%s\n%s\n", CROS_EC_DEV_VERSION,
+		 resp->version_string_ro, resp->version_string_rw,
+		 current_image_name[resp->current_image]);
+
+	ret = 0;
+exit:
+	kfree(msg);
+	return ret;
+}
+
+static int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
+{
+	struct cros_ec_command *msg;
+	int ret;
+
+	if (ec->features[0] == -1U && ec->features[1] == -1U) {
+		/* features bitmap not read yet */
+
+		msg = kmalloc(sizeof(*msg) + sizeof(ec->features), GFP_KERNEL);
+		if (!msg)
+			return -ENOMEM;
+
+		msg->version = 0;
+		msg->command = EC_CMD_GET_FEATURES + ec->cmd_offset;
+		msg->insize = sizeof(ec->features);
+		msg->outsize = 0;
+
+		ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
+		if (ret < 0 || msg->result != EC_RES_SUCCESS) {
+			dev_warn(ec->dev, "cannot get EC features: %d/%d\n",
+				 ret, msg->result);
+			memset(ec->features, 0, sizeof(ec->features));
+		}
+
+		memcpy(ec->features, msg->data, sizeof(ec->features));
+
+		dev_dbg(ec->dev, "EC features %08x %08x\n",
+			ec->features[0], ec->features[1]);
+
+		kfree(msg);
+	}
+
+	return ec->features[feature / 32] & EC_FEATURE_MASK_0(feature);
+}
+
+/* Device file ops */
+static int ec_device_open(struct inode *inode, struct file *filp)
+{
+	struct cros_ec_dev *ec = container_of(inode->i_cdev,
+					      struct cros_ec_dev, cdev);
+	filp->private_data = ec;
+	nonseekable_open(inode, filp);
+	return 0;
+}
+
+static int ec_device_release(struct inode *inode, struct file *filp)
+{
+	return 0;
+}
+
+static ssize_t ec_device_read(struct file *filp, char __user *buffer,
+			      size_t length, loff_t *offset)
+{
+	struct cros_ec_dev *ec = filp->private_data;
+	char msg[sizeof(struct ec_response_get_version) +
+		 sizeof(CROS_EC_DEV_VERSION)];
+	size_t count;
+	int ret;
+
+	if (*offset != 0)
+		return 0;
+
+	ret = ec_get_version(ec, msg, sizeof(msg));
+	if (ret)
+		return ret;
+
+	count = min(length, strlen(msg));
+
+	if (copy_to_user(buffer, msg, count))
+		return -EFAULT;
+
+	*offset = count;
+	return count;
+}
+
+/* Ioctls */
+static long ec_device_ioctl_xcmd(struct cros_ec_dev *ec, void __user *arg)
+{
+	long ret;
+	struct cros_ec_command u_cmd;
+	struct cros_ec_command *s_cmd;
+
+	if (copy_from_user(&u_cmd, arg, sizeof(u_cmd)))
+		return -EFAULT;
+
+	if ((u_cmd.outsize > EC_MAX_MSG_BYTES) ||
+	    (u_cmd.insize > EC_MAX_MSG_BYTES))
+		return -EINVAL;
+
+	s_cmd = kmalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize),
+			GFP_KERNEL);
+	if (!s_cmd)
+		return -ENOMEM;
+
+	if (copy_from_user(s_cmd, arg, sizeof(*s_cmd) + u_cmd.outsize)) {
+		ret = -EFAULT;
+		goto exit;
+	}
+
+	if (u_cmd.outsize != s_cmd->outsize ||
+	    u_cmd.insize != s_cmd->insize) {
+		ret = -EINVAL;
+		goto exit;
+	}
+
+	s_cmd->command += ec->cmd_offset;
+	ret = cros_ec_cmd_xfer(ec->ec_dev, s_cmd);
+	/* Only copy data to userland if data was received. */
+	if (ret < 0)
+		goto exit;
+
+	if (copy_to_user(arg, s_cmd, sizeof(*s_cmd) + s_cmd->insize))
+		ret = -EFAULT;
+exit:
+	kfree(s_cmd);
+	return ret;
+}
+
+static long ec_device_ioctl_readmem(struct cros_ec_dev *ec, void __user *arg)
+{
+	struct cros_ec_device *ec_dev = ec->ec_dev;
+	struct cros_ec_readmem s_mem = { };
+	long num;
+
+	/* Not every platform supports direct reads */
+	if (!ec_dev->cmd_readmem)
+		return -ENOTTY;
+
+	if (copy_from_user(&s_mem, arg, sizeof(s_mem)))
+		return -EFAULT;
+
+	num = ec_dev->cmd_readmem(ec_dev, s_mem.offset, s_mem.bytes,
+				  s_mem.buffer);
+	if (num <= 0)
+		return num;
+
+	if (copy_to_user((void __user *)arg, &s_mem, sizeof(s_mem)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long ec_device_ioctl(struct file *filp, unsigned int cmd,
+			    unsigned long arg)
+{
+	struct cros_ec_dev *ec = filp->private_data;
+
+	if (_IOC_TYPE(cmd) != CROS_EC_DEV_IOC)
+		return -ENOTTY;
+
+	switch (cmd) {
+	case CROS_EC_DEV_IOCXCMD:
+		return ec_device_ioctl_xcmd(ec, (void __user *)arg);
+	case CROS_EC_DEV_IOCRDMEM:
+		return ec_device_ioctl_readmem(ec, (void __user *)arg);
+	}
+
+	return -ENOTTY;
+}
+
+/* Module initialization */
+static const struct file_operations fops = {
+	.open = ec_device_open,
+	.release = ec_device_release,
+	.read = ec_device_read,
+	.unlocked_ioctl = ec_device_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = ec_device_ioctl,
+#endif
+};
+
+static void __remove(struct device *dev)
+{
+	struct cros_ec_dev *ec = container_of(dev, struct cros_ec_dev,
+					      class_dev);
+	kfree(ec);
+}
+
+static void cros_ec_sensors_register(struct cros_ec_dev *ec)
+{
+	/*
+	 * Issue a command to get the number of sensor reported.
+	 * Build an array of sensors driver and register them all.
+	 */
+	int ret, i, id, sensor_num;
+	struct mfd_cell *sensor_cells;
+	struct cros_ec_sensor_platform *sensor_platforms;
+	int sensor_type[MOTIONSENSE_TYPE_MAX];
+	struct ec_params_motion_sense *params;
+	struct ec_response_motion_sense *resp;
+	struct cros_ec_command *msg;
+
+	msg = kzalloc(sizeof(struct cros_ec_command) +
+		      max(sizeof(*params), sizeof(*resp)), GFP_KERNEL);
+	if (msg == NULL)
+		return;
+
+	msg->version = 2;
+	msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
+	msg->outsize = sizeof(*params);
+	msg->insize = sizeof(*resp);
+
+	params = (struct ec_params_motion_sense *)msg->data;
+	params->cmd = MOTIONSENSE_CMD_DUMP;
+
+	ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
+	if (ret < 0 || msg->result != EC_RES_SUCCESS) {
+		dev_warn(ec->dev, "cannot get EC sensor information: %d/%d\n",
+			 ret, msg->result);
+		goto error;
+	}
+
+	resp = (struct ec_response_motion_sense *)msg->data;
+	sensor_num = resp->dump.sensor_count;
+	/* Allocate 2 extra sensors in case lid angle or FIFO are needed */
+	sensor_cells = kzalloc(sizeof(struct mfd_cell) * (sensor_num + 2),
+			       GFP_KERNEL);
+	if (sensor_cells == NULL)
+		goto error;
+
+	sensor_platforms = kzalloc(sizeof(struct cros_ec_sensor_platform) *
+		  (sensor_num + 1), GFP_KERNEL);
+	if (sensor_platforms == NULL)
+		goto error_platforms;
+
+	memset(sensor_type, 0, sizeof(sensor_type));
+	id = 0;
+	for (i = 0; i < sensor_num; i++) {
+		params->cmd = MOTIONSENSE_CMD_INFO;
+		params->info.sensor_num = i;
+		ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
+		if (ret < 0 || msg->result != EC_RES_SUCCESS) {
+			dev_warn(ec->dev, "no info for EC sensor %d : %d/%d\n",
+				 i, ret, msg->result);
+			continue;
+		}
+		switch (resp->info.type) {
+		case MOTIONSENSE_TYPE_ACCEL:
+			sensor_cells[id].name = "cros-ec-accel";
+			break;
+		case MOTIONSENSE_TYPE_BARO:
+			sensor_cells[id].name = "cros-ec-baro";
+			break;
+		case MOTIONSENSE_TYPE_GYRO:
+			sensor_cells[id].name = "cros-ec-gyro";
+			break;
+		case MOTIONSENSE_TYPE_MAG:
+			sensor_cells[id].name = "cros-ec-mag";
+			break;
+		case MOTIONSENSE_TYPE_PROX:
+			sensor_cells[id].name = "cros-ec-prox";
+			break;
+		case MOTIONSENSE_TYPE_LIGHT:
+			sensor_cells[id].name = "cros-ec-light";
+			break;
+		case MOTIONSENSE_TYPE_ACTIVITY:
+			sensor_cells[id].name = "cros-ec-activity";
+			break;
+		default:
+			dev_warn(ec->dev, "unknown type %d\n", resp->info.type);
+			continue;
+		}
+		sensor_platforms[id].sensor_num = i;
+		sensor_cells[id].id = sensor_type[resp->info.type];
+		sensor_cells[id].platform_data = &sensor_platforms[id];
+		sensor_cells[id].pdata_size =
+			sizeof(struct cros_ec_sensor_platform);
+
+		sensor_type[resp->info.type]++;
+		id++;
+	}
+	if (sensor_type[MOTIONSENSE_TYPE_ACCEL] >= 2) {
+		sensor_platforms[id].sensor_num = sensor_num;
+
+		sensor_cells[id].name = "cros-ec-angle";
+		sensor_cells[id].id = 0;
+		sensor_cells[id].platform_data = &sensor_platforms[id];
+		sensor_cells[id].pdata_size =
+			sizeof(struct cros_ec_sensor_platform);
+		id++;
+	}
+	if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO)) {
+		sensor_cells[id].name = "cros-ec-ring";
+		id++;
+	}
+
+	ret = mfd_add_devices(ec->dev, 0, sensor_cells, id,
+			      NULL, 0, NULL);
+	if (ret)
+		dev_err(ec->dev, "failed to add EC sensors\n");
+
+	kfree(sensor_platforms);
+error_platforms:
+	kfree(sensor_cells);
+error:
+	kfree(msg);
+}
+
+static int ec_device_probe(struct platform_device *pdev)
+{
+	int retval = -ENOMEM;
+	struct device *dev = &pdev->dev;
+	struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
+	struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
+
+	if (!ec)
+		return retval;
+
+	dev_set_drvdata(dev, ec);
+	ec->ec_dev = dev_get_drvdata(dev->parent);
+	ec->dev = dev;
+	ec->cmd_offset = ec_platform->cmd_offset;
+	ec->features[0] = -1U; /* Not cached yet */
+	ec->features[1] = -1U; /* Not cached yet */
+	device_initialize(&ec->class_dev);
+	cdev_init(&ec->cdev, &fops);
+
+	/*
+	 * Add the class device
+	 * Link to the character device for creating the /dev entry
+	 * in devtmpfs.
+	 */
+	ec->class_dev.devt = MKDEV(ec_major, pdev->id);
+	ec->class_dev.class = &cros_class;
+	ec->class_dev.parent = dev;
+	ec->class_dev.release = __remove;
+
+	retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name);
+	if (retval) {
+		dev_err(dev, "dev_set_name failed => %d\n", retval);
+		goto failed;
+	}
+
+	retval = cdev_device_add(&ec->cdev, &ec->class_dev);
+	if (retval) {
+		dev_err(dev, "cdev_device_add failed => %d\n", retval);
+		goto failed;
+	}
+
+	if (cros_ec_debugfs_init(ec))
+		dev_warn(dev, "failed to create debugfs directory\n");
+
+	/* check whether this EC is a sensor hub. */
+	if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE))
+		cros_ec_sensors_register(ec);
+
+	/* Take control of the lightbar from the EC. */
+	lb_manual_suspend_ctrl(ec, 1);
+
+	return 0;
+
+failed:
+	put_device(&ec->class_dev);
+	return retval;
+}
+
+static int ec_device_remove(struct platform_device *pdev)
+{
+	struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
+
+	/* Let the EC take over the lightbar again. */
+	lb_manual_suspend_ctrl(ec, 0);
+
+	cros_ec_debugfs_remove(ec);
+
+	cdev_del(&ec->cdev);
+	device_unregister(&ec->class_dev);
+	return 0;
+}
+
+static const struct platform_device_id cros_ec_id[] = {
+	{ DRV_NAME, 0 },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(platform, cros_ec_id);
+
+static __maybe_unused int ec_device_suspend(struct device *dev)
+{
+	struct cros_ec_dev *ec = dev_get_drvdata(dev);
+
+	lb_suspend(ec);
+
+	return 0;
+}
+
+static __maybe_unused int ec_device_resume(struct device *dev)
+{
+	struct cros_ec_dev *ec = dev_get_drvdata(dev);
+
+	lb_resume(ec);
+
+	return 0;
+}
+
+static const struct dev_pm_ops cros_ec_dev_pm_ops = {
+#ifdef CONFIG_PM_SLEEP
+	.suspend = ec_device_suspend,
+	.resume = ec_device_resume,
+#endif
+};
+
+static struct platform_driver cros_ec_dev_driver = {
+	.driver = {
+		.name = DRV_NAME,
+		.pm = &cros_ec_dev_pm_ops,
+	},
+	.probe = ec_device_probe,
+	.remove = ec_device_remove,
+};
+
+static int __init cros_ec_dev_init(void)
+{
+	int ret;
+	dev_t dev = 0;
+
+	ret  = class_register(&cros_class);
+	if (ret) {
+		pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
+		return ret;
+	}
+
+	/* Get a range of minor numbers (starting with 0) to work with */
+	ret = alloc_chrdev_region(&dev, 0, CROS_MAX_DEV, CROS_EC_DEV_NAME);
+	if (ret < 0) {
+		pr_err(CROS_EC_DEV_NAME ": alloc_chrdev_region() failed\n");
+		goto failed_chrdevreg;
+	}
+	ec_major = MAJOR(dev);
+
+	/* Register the driver */
+	ret = platform_driver_register(&cros_ec_dev_driver);
+	if (ret < 0) {
+		pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret);
+		goto failed_devreg;
+	}
+	return 0;
+
+failed_devreg:
+	unregister_chrdev_region(MKDEV(ec_major, 0), CROS_MAX_DEV);
+failed_chrdevreg:
+	class_unregister(&cros_class);
+	return ret;
+}
+
+static void __exit cros_ec_dev_exit(void)
+{
+	platform_driver_unregister(&cros_ec_dev_driver);
+	unregister_chrdev(ec_major, CROS_EC_DEV_NAME);
+	class_unregister(&cros_class);
+}
+
+module_init(cros_ec_dev_init);
+module_exit(cros_ec_dev_exit);
+
+MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>");
+MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
+MODULE_VERSION("1.0");
+MODULE_LICENSE("GPL");
diff --git a/drivers/mfd/cros_ec_dev.h b/drivers/mfd/cros_ec_dev.h
new file mode 100644
index 000000000000..45e9453608c5
--- /dev/null
+++ b/drivers/mfd/cros_ec_dev.h
@@ -0,0 +1,52 @@
+/*
+ * cros_ec_dev - expose the Chrome OS Embedded Controller to userspace
+ *
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _CROS_EC_DEV_H_
+#define _CROS_EC_DEV_H_
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+#include <linux/mfd/cros_ec.h>
+
+#define CROS_EC_DEV_VERSION "1.0.0"
+
+/*
+ * @offset: within EC_LPC_ADDR_MEMMAP region
+ * @bytes: number of bytes to read. zero means "read a string" (including '\0')
+ *         (at most only EC_MEMMAP_SIZE bytes can be read)
+ * @buffer: where to store the result
+ * ioctl returns the number of bytes read, negative on error
+ */
+struct cros_ec_readmem {
+	uint32_t offset;
+	uint32_t bytes;
+	uint8_t buffer[EC_MEMMAP_SIZE];
+};
+
+#define CROS_EC_DEV_IOC       0xEC
+#define CROS_EC_DEV_IOCXCMD   _IOWR(CROS_EC_DEV_IOC, 0, struct cros_ec_command)
+#define CROS_EC_DEV_IOCRDMEM  _IOWR(CROS_EC_DEV_IOC, 1, struct cros_ec_readmem)
+
+/* Lightbar utilities */
+extern bool ec_has_lightbar(struct cros_ec_dev *ec);
+extern int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable);
+extern int lb_suspend(struct cros_ec_dev *ec);
+extern int lb_resume(struct cros_ec_dev *ec);
+
+#endif /* _CROS_EC_DEV_H_ */