linux-kernel - [PATCH v5] platform/chrome: wilco_ec: Add debugfs test

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Message-Id: <20190924203716.209420-1-campello@chromium.org>
Date:   Tue, 24 Sep 2019 14:37:16 -0600
From:   Daniel Campello <campello@...omium.org>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Daniel Campello <campello@...omium.org>,
        Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        Benson Leung <bleung@...omium.org>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Duncan Laurie <dlaurie@...gle.com>,
        Nick Crews <ncrews@...omium.org>
Subject: [PATCH v5] platform/chrome: wilco_ec: Add debugfs test_event file

This change introduces a new debugfs file 'test_event' that when written
to causes the EC to generate a test event.
This adds a second sub cmd for the test event, and pulls out send_ec_cmd
to be a common helper between h1_gpio_get and test_event_set.

Signed-off-by: Daniel Campello <campello@...omium.org>
---
Changes for v2:
  - Cleaned up and added comments.
  - Renamed and updated function signature from write_to_mailbox to
    send_ec_cmd.
Changes for v3:
  - Switched NULL format string to empty format string
  - Renamed val parameter on send_ec_cmd to out_val
Changes for v4:
  - Provided a format string to avoid -Wformat-zero-length warning
Changes for v5:
  - Updated commit message to include more implementation details
  - Restored removed empty line between functions

 drivers/platform/chrome/wilco_ec/debugfs.c | 47 +++++++++++++++++-----
 1 file changed, 37 insertions(+), 10 deletions(-)

diff --git a/drivers/platform/chrome/wilco_ec/debugfs.c b/drivers/platform/chrome/wilco_ec/debugfs.c
index 8d65a1e2f1a3..df5a5f6c3ec6 100644
--- a/drivers/platform/chrome/wilco_ec/debugfs.c
+++ b/drivers/platform/chrome/wilco_ec/debugfs.c
@@ -160,29 +160,29 @@ static const struct file_operations fops_raw = {

 #define CMD_KB_CHROME		0x88
 #define SUB_CMD_H1_GPIO		0x0A
+#define SUB_CMD_TEST_EVENT	0x0B

-struct h1_gpio_status_request {
+struct ec_request {
 	u8 cmd;		/* Always CMD_KB_CHROME */
 	u8 reserved;
-	u8 sub_cmd;	/* Always SUB_CMD_H1_GPIO */
+	u8 sub_cmd;
 } __packed;

-struct hi_gpio_status_response {
+struct ec_response {
 	u8 status;	/* 0 if allowed */
-	u8 val;		/* BIT(0)=ENTRY_TO_FACT_MODE, BIT(1)=SPI_CHROME_SEL */
+	u8 val;
 } __packed;

-static int h1_gpio_get(void *arg, u64 *val)
+static int send_ec_cmd(struct wilco_ec_device *ec, u8 sub_cmd, u8 *out_val)
 {
-	struct wilco_ec_device *ec = arg;
-	struct h1_gpio_status_request rq;
-	struct hi_gpio_status_response rs;
+	struct ec_request rq;
+	struct ec_response rs;
 	struct wilco_ec_message msg;
 	int ret;

 	memset(&rq, 0, sizeof(rq));
 	rq.cmd = CMD_KB_CHROME;
-	rq.sub_cmd = SUB_CMD_H1_GPIO;
+	rq.sub_cmd = sub_cmd;

 	memset(&msg, 0, sizeof(msg));
 	msg.type = WILCO_EC_MSG_LEGACY;
@@ -196,13 +196,38 @@ static int h1_gpio_get(void *arg, u64 *val)
 	if (rs.status)
 		return -EIO;

-	*val = rs.val;
+	*out_val = rs.val;

 	return 0;
 }

+/**
+ * h1_gpio_get() - Gets h1 gpio status.
+ * @arg: The wilco EC device.
+ * @val: BIT(0)=ENTRY_TO_FACT_MODE, BIT(1)=SPI_CHROME_SEL
+ */
+static int h1_gpio_get(void *arg, u64 *val)
+{
+	return send_ec_cmd(arg, SUB_CMD_H1_GPIO, (u8 *)val);
+}
+
 DEFINE_DEBUGFS_ATTRIBUTE(fops_h1_gpio, h1_gpio_get, NULL, "0x%02llx\n");

+/**
+ * test_event_set() - Sends command to EC to cause an EC test event.
+ * @arg: The wilco EC device.
+ * @val: unused.
+ */
+static int test_event_set(void *arg, u64 val)
+{
+	u8 ret;
+
+	return send_ec_cmd(arg, SUB_CMD_TEST_EVENT, &ret);
+}
+
+/* Format is unused since it is only required for get method which is NULL */
+DEFINE_DEBUGFS_ATTRIBUTE(fops_test_event, NULL, test_event_set, "%llu\n");
+
 /**
  * wilco_ec_debugfs_probe() - Create the debugfs node
  * @pdev: The platform device, probably created in core.c
@@ -226,6 +251,8 @@ static int wilco_ec_debugfs_probe(struct platform_device *pdev)
 	debugfs_create_file("raw", 0644, debug_info->dir, NULL, &fops_raw);
 	debugfs_create_file("h1_gpio", 0444, debug_info->dir, ec,
 			    &fops_h1_gpio);
+	debugfs_create_file("test_event", 0200, debug_info->dir, ec,
+			    &fops_test_event);

 	return 0;
 }
--
2.23.0.351.gc4317032e6-goog