linux-kernel - [PATCH v5 5/5] misc serdev: w2sg0004: add debugging code and Kconfig

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Message-Id: <5816bfb9e7cab68591c133e20696d6188ebe70de.1512114577.git.hns@goldelico.com>
Date:   Fri,  1 Dec 2017 08:49:38 +0100
From:   "H. Nikolaus Schaller" <hns@...delico.com>
To:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Benoît Cousson <bcousson@...libre.com>,
        Tony Lindgren <tony@...mide.com>,
        Russell King <linux@...linux.org.uk>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "H. Nikolaus Schaller" <hns@...delico.com>,
        Kevin Hilman <khilman@...libre.com>,
        Andreas Färber <afaerber@...e.de>,
        Thierry Reding <treding@...dia.com>,
        Jonathan Cameron <jic23@...nel.org>
Cc:     devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-omap@...r.kernel.org, letux-kernel@...nphoenux.org,
        kernel@...a-handheld.com, linux-arm-kernel@...ts.infradead.org
Subject: [PATCH v5 5/5] misc serdev: w2sg0004: add debugging code and Kconfig

This allows to set CONFIG_W2SG0004_DEBUG which will
make the driver report more activities and it will turn on the
GPS module during boot while the driver assumes that it
is off. This can be used to debug the correct functioning of
the hardware. Therefore we add it as an option to the driver
because we think it is of general use (and a little tricky to
add by system testers).

Normally it should be off.

Signed-off-by: H. Nikolaus Schaller <hns@...delico.com>
---
 drivers/misc/Kconfig    |  8 ++++++++
 drivers/misc/w2sg0004.c | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index a3b11016ed2b..ad6e60f0cc8c 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -518,4 +518,12 @@ config W2SG0004
 	  is opened/closed.
 	  It also provides a rfkill gps name to control the LNA power.
 
+config W2SG0004_DEBUG
+	bool "W2SG0004 on/off debugging"
+	depends on W2SG0004
+	help
+	  Enable driver debugging mode of W2SG0004 GPS. If you say y here
+	  this will turn on the module and you can check if it is turned
+	  off by the driver.
+
 endmenu
diff --git a/drivers/misc/w2sg0004.c b/drivers/misc/w2sg0004.c
index 6bfd12eb8e02..82c708fce510 100644
--- a/drivers/misc/w2sg0004.c
+++ b/drivers/misc/w2sg0004.c
@@ -26,6 +26,10 @@
  *
  */
 
+#ifdef CONFIG_W2SG0004_DEBUG
+#define DEBUG 1
+#endif
+
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
@@ -256,6 +260,7 @@ static int w2sg_tty_install(struct tty_driver *driver, struct tty_struct *tty)
 	pr_debug("%s() tty = %p\n", __func__, tty);
 
 	data = w2sg_get_by_minor(tty->index);
+	pr_debug("%s() data = %p\n", __func__, data);
 
 	if (!data)
 		return -ENODEV;
@@ -342,6 +347,8 @@ static int w2sg_probe(struct serdev_device *serdev)
 	if (data == NULL)
 		return -ENOMEM;
 
+	pr_debug("w2sg serdev_device_set_drvdata\n");
+
 	serdev_device_set_drvdata(serdev, data);
 
 	data->on_off_gpio = of_get_named_gpio_flags(serdev->dev.of_node,
@@ -375,6 +382,8 @@ static int w2sg_probe(struct serdev_device *serdev)
 
 	INIT_DELAYED_WORK(&data->work, toggle_work);
 
+	pr_debug("w2sg devm_gpio_request\n");
+
 	err = devm_gpio_request(&serdev->dev, data->on_off_gpio,
 				"w2sg0004-on-off");
 	if (err < 0)
@@ -388,6 +397,8 @@ static int w2sg_probe(struct serdev_device *serdev)
 	serdev_device_set_baudrate(data->uart, 9600);
 	serdev_device_set_flow_control(data->uart, false);
 
+	pr_debug("w2sg rfkill_alloc\n");
+
 	rf_kill = rfkill_alloc("GPS", &serdev->dev, RFKILL_TYPE_GPS,
 				&w2sg0004_rfkill_ops, data);
 	if (rf_kill == NULL) {
@@ -395,6 +406,8 @@ static int w2sg_probe(struct serdev_device *serdev)
 		goto err_rfkill;
 	}
 
+	pr_debug("w2sg register rfkill\n");
+
 	err = rfkill_register(rf_kill);
 	if (err) {
 		dev_err(&serdev->dev, "Cannot register rfkill device\n");
@@ -403,6 +416,8 @@ static int w2sg_probe(struct serdev_device *serdev)
 
 	data->rf_kill = rf_kill;
 
+	pr_debug("w2sg alloc_tty_driver\n");
+
 	/* allocate the tty driver */
 	data->tty_drv = alloc_tty_driver(1);
 	if (!data->tty_drv)
@@ -428,6 +443,8 @@ static int w2sg_probe(struct serdev_device *serdev)
 	 */
 	tty_set_operations(data->tty_drv, &w2sg_serial_ops);
 
+	pr_debug("w2sg tty_register_driver\n");
+
 	/* register the tty driver */
 	err = tty_register_driver(data->tty_drv);
 	if (err) {
@@ -443,9 +460,27 @@ static int w2sg_probe(struct serdev_device *serdev)
 	tty_port_init(&data->port);
 	data->port.ops = &w2sg_port_ops;
 
+	pr_debug("w2sg call tty_port_register_device\n");
+
 	data->dev = tty_port_register_device(&data->port,
 			data->tty_drv, minor, &serdev->dev);
 
+	pr_debug("w2sg tty_port_register_device -> %p\n", data->dev);
+	pr_debug("w2sg port.tty = %p\n", data->port.tty);
+
+	pr_debug("w2sg probed\n");
+
+#ifdef CONFIG_W2SG0004_DEBUG
+	pr_debug("w2sg DEBUGGING MODE enabled\n");
+	/* turn on for debugging rx notifications */
+	pr_debug("w2sg power gpio ON\n");
+	gpio_set_value_cansleep(data->on_off_gpio, 1);
+	mdelay(100);
+	pr_debug("w2sg power gpio OFF\n");
+	gpio_set_value_cansleep(data->on_off_gpio, 0);
+	mdelay(300);
+#endif
+
 	/* keep off until user space requests the device */
 	w2sg_set_power(data, false);
 
@@ -455,6 +490,8 @@ static int w2sg_probe(struct serdev_device *serdev)
 	rfkill_destroy(rf_kill);
 	serdev_device_close(data->uart);
 out:
+	pr_debug("w2sg error %d\n", err);
+
 	return err;
 }
 
-- 
2.12.2