[RFC PATCH 03/10] CHROMIUM: wilco_ec: Add sysfs attributes

From: Nick Crews
Date: Fri Dec 14 2018 - 19:19:49 EST

From: Duncan Laurie <dlaurie@xxxxxxxxxx>

Add some sample sysfs attributes for the Wilco EC that show how
the mailbox interface works.

> cat /sys/bus/platform/devices/GOOG000C\:00/version
Label : 99.99.99
SVN Revision : 738ed.99
Model Number : 08;8
Build Date : 08/30/18

Signed-off-by: Duncan Laurie <dlaurie@xxxxxxxxxx>
Signed-off-by: Nick Crews <ncrews@xxxxxxxxxx>
---

drivers/platform/chrome/Makefile | 3 +-
drivers/platform/chrome/wilco_ec.h | 14 +++
drivers/platform/chrome/wilco_ec_mailbox.c | 12 ++
drivers/platform/chrome/wilco_ec_sysfs.c | 121 +++++++++++++++++++++
4 files changed, 148 insertions(+), 2 deletions(-)
create mode 100644 drivers/platform/chrome/wilco_ec_sysfs.c

diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index b132ba5b3e3d..e8603bc5b095 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -13,6 +13,5 @@ cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC) += cros_ec_lpc_mec.o
obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpcs.o
obj-$(CONFIG_CROS_EC_PROTO) += cros_ec_proto.o

-obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT) += cros_kbd_led_backlight.o
-wilco_ec-objs := wilco_ec_mailbox.o
+wilco_ec-objs := wilco_ec_mailbox.o wilco_ec_sysfs.o
obj-$(CONFIG_WILCO_EC) += wilco_ec.o
diff --git a/drivers/platform/chrome/wilco_ec.h b/drivers/platform/chrome/wilco_ec.h
index ba16fcff87c4..699f4cf744dc 100644
--- a/drivers/platform/chrome/wilco_ec.h
+++ b/drivers/platform/chrome/wilco_ec.h
@@ -94,4 +94,18 @@ struct wilco_ec_message {
*/
int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg);

+/**
+ * wilco_ec_sysfs_init() - Create sysfs attributes.
+ * @ec: EC device.
+ *
+ * Return: 0 for success or negative error code on failure.
+ */
+int wilco_ec_sysfs_init(struct wilco_ec_device *ec);
+
+/**
+ * wilco_ec_sysfs_remove() - Remove sysfs attributes.
+ * @ec: EC device.
+ */
+void wilco_ec_sysfs_remove(struct wilco_ec_device *ec);
+
#endif /* WILCO_EC_H */
diff --git a/drivers/platform/chrome/wilco_ec_mailbox.c b/drivers/platform/chrome/wilco_ec_mailbox.c
index 6613c18c2a82..414ea0a8ad03 100644
--- a/drivers/platform/chrome/wilco_ec_mailbox.c
+++ b/drivers/platform/chrome/wilco_ec_mailbox.c
@@ -361,11 +361,23 @@ static int wilco_ec_probe(struct platform_device *pdev)
cros_ec_lpc_mec_init(ec->io_packet->start,
ec->io_packet->start + EC_MAILBOX_DATA_SIZE);

+ /* Create sysfs attributes for userspace interaction */
+ if (wilco_ec_sysfs_init(ec) < 0) {
+ dev_err(dev, "Failed to create sysfs attributes\n");
+ cros_ec_lpc_mec_destroy();
+ return -ENODEV;
+ }
+
return 0;
}

static int wilco_ec_remove(struct platform_device *pdev)
{
+ struct wilco_ec_device *ec = platform_get_drvdata(pdev);
+
+ /* Remove sysfs attributes */
+ wilco_ec_sysfs_remove(ec);
+
/* Teardown cros_ec interface */
cros_ec_lpc_mec_destroy();

diff --git a/drivers/platform/chrome/wilco_ec_sysfs.c b/drivers/platform/chrome/wilco_ec_sysfs.c
new file mode 100644
index 000000000000..f9ae6cef6169
--- /dev/null
+++ b/drivers/platform/chrome/wilco_ec_sysfs.c
@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * wilco_ec_sysfs - Sysfs attributes for Wilco Embedded Controller
+ *
+ * Copyright 2018 Google LLC
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+
+#include <linux/ctype.h>
+#include <linux/platform_device.h>
+#include <linux/sysfs.h>
+#include "wilco_ec.h"
+
+#define EC_COMMAND_EC_INFO 0x38
+#define EC_INFO_SIZE 9
+#define EC_COMMAND_STEALTH_MODE 0xfc
+
+struct ec_info {
+ u8 index;
+ const char *label;
+};
+
+static ssize_t wilco_ec_show_info(struct wilco_ec_device *ec, char *buf,
+ ssize_t count, struct ec_info *info)
+{
+ char result[EC_INFO_SIZE];
+ struct wilco_ec_message msg = {
+ .type = WILCO_EC_MSG_LEGACY,
+ .command = EC_COMMAND_EC_INFO,
+ .request_data = &info->index,
+ .request_size = sizeof(info->index),
+ .response_data = result,
+ .response_size = EC_INFO_SIZE,
+ };
+ int ret;
+
+ ret = wilco_ec_mailbox(ec, &msg);
+ if (ret != EC_INFO_SIZE)
+ return scnprintf(buf + count, PAGE_SIZE - count,
+ "%-12s : ERROR %d\n", info->label, ret);
+
+ return scnprintf(buf + count, PAGE_SIZE - count,
+ "%-12s : %s\n", info->label, result);
+}
+
+static ssize_t version_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct wilco_ec_device *ec = dev_get_drvdata(dev);
+ struct ec_info wilco_ec_info[] = {
+ { 0, "Label" },
+ { 1, "SVN Revision" },
+ { 2, "Model Number" },
+ { 3, "Build Date" },
+ { 0xff, NULL },
+ };
+ struct ec_info *info = wilco_ec_info;
+ ssize_t c = 0;
+
+ for (info = wilco_ec_info; info->label; info++)
+ c += wilco_ec_show_info(ec, buf, c, info);
+
+ return c;
+}
+
+static ssize_t stealth_mode_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct wilco_ec_device *ec = dev_get_drvdata(dev);
+ u8 param;
+ struct wilco_ec_message msg = {
+ .type = WILCO_EC_MSG_LEGACY,
+ .command = EC_COMMAND_STEALTH_MODE,
+ .request_data = &param,
+ .request_size = sizeof(param),
+ };
+ int ret;
+ bool enable;
+
+ ret = kstrtobool(buf, &enable);
+ if (ret)
+ return ret;
+
+ /* Invert input parameter, EC expects 0=on and 1=off */
+ param = enable ? 0 : 1;
+
+ ret = wilco_ec_mailbox(ec, &msg);
+ if (ret < 0)
+ return ret;
+
+ return count;
+}
+
+static DEVICE_ATTR_RO(version);
+static DEVICE_ATTR_WO(stealth_mode);
+
+static struct attribute *wilco_ec_attrs[] = {
+ &dev_attr_version.attr,
+ &dev_attr_stealth_mode.attr,
+ NULL
+};
+ATTRIBUTE_GROUPS(wilco_ec);
+
+int wilco_ec_sysfs_init(struct wilco_ec_device *ec)
+{
+ return sysfs_create_groups(&ec->dev->kobj, wilco_ec_groups);
+}
+
+void wilco_ec_sysfs_remove(struct wilco_ec_device *ec)
+{
+ sysfs_remove_groups(&ec->dev->kobj, wilco_ec_groups);
+}
--
2.20.0.405.gbc1bbc6f85-goog