gpio: add trace events for setting direction and value

This patch allows to trace gpio operations using ftrace

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

2 files changed, 72 insertions, 2 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index c27e52b56d66..137a8ca67822 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -12,6 +12,8 @@
 #include <linux/idr.h>
 #include <linux/slab.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/gpio.h>
 
 /* Optional implementation infrastructure for GPIO interfaces.
  *
@@ -1405,6 +1407,8 @@ int gpio_direction_input(unsigned gpio)
         status = chip->direction_input(chip, gpio);
         if (status == 0)
                 clear_bit(FLAG_IS_OUT, &desc->flags);
+
+        trace_gpio_direction(chip->base + gpio, 1, status);
 lose:
         return status;
 fail:
@@ -1458,6 +1462,8 @@ int gpio_direction_output(unsigned gpio, int value)
         status = chip->direction_output(chip, gpio, value);
         if (status == 0)
                 set_bit(FLAG_IS_OUT, &desc->flags);
+        trace_gpio_value(chip->base + gpio, 0, value);
+        trace_gpio_direction(chip->base + gpio, 0, status);
 lose:
         return status;
 fail:
@@ -1547,10 +1553,13 @@ EXPORT_SYMBOL_GPL(gpio_set_debounce);
 int __gpio_get_value(unsigned gpio)
 {
         struct gpio_chip        *chip;
+        int value;
 
         chip = gpio_to_chip(gpio);
         WARN_ON(chip->can_sleep);
-        return chip->get ? chip->get(chip, gpio - chip->base) : 0;
+        value = chip->get ? chip->get(chip, gpio - chip->base) : 0;
+        trace_gpio_value(gpio, 1, value);
+        return value;
 }
 EXPORT_SYMBOL_GPL(__gpio_get_value);
 
@@ -1569,6 +1578,7 @@ void __gpio_set_value(unsigned gpio, int value)
 
         chip = gpio_to_chip(gpio);
         WARN_ON(chip->can_sleep);
+        trace_gpio_value(gpio, 0, value);
         chip->set(chip, gpio - chip->base, value);
 }
 EXPORT_SYMBOL_GPL(__gpio_set_value);
@@ -1619,10 +1629,13 @@ EXPORT_SYMBOL_GPL(__gpio_to_irq);
 int gpio_get_value_cansleep(unsigned gpio)
 {
         struct gpio_chip        *chip;
+        int value;
 
         might_sleep_if(extra_checks);
         chip = gpio_to_chip(gpio);
-        return chip->get ? chip->get(chip, gpio - chip->base) : 0;
+        value = chip->get ? chip->get(chip, gpio - chip->base) : 0;
+        trace_gpio_value(gpio, 1, value);
+        return value;
 }
 EXPORT_SYMBOL_GPL(gpio_get_value_cansleep);
 
@@ -1632,6 +1645,7 @@ void gpio_set_value_cansleep(unsigned gpio, int value)
 
         might_sleep_if(extra_checks);
         chip = gpio_to_chip(gpio);
+        trace_gpio_value(gpio, 0, value);
         chip->set(chip, gpio - chip->base, value);
 }
 EXPORT_SYMBOL_GPL(gpio_set_value_cansleep);
diff --git a/include/trace/events/gpio.h b/include/trace/events/gpio.h
new file mode 100644
index 000000000000..927a8ad9e51b
--- /dev/null
+++ b/include/trace/events/gpio.h
@@ -0,0 +1,56 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM gpio
+
+#if !defined(_TRACE_GPIO_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_GPIO_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(gpio_direction,
+
+        TP_PROTO(unsigned gpio, int in, int err),
+
+        TP_ARGS(gpio, in, err),
+
+        TP_STRUCT__entry(
+                __field(unsigned, gpio)
+                __field(int, in)
+                __field(int, err)
+        ),
+
+        TP_fast_assign(
+                __entry->gpio = gpio;
+                __entry->in = in;
+                __entry->err = err;
+        ),
+
+        TP_printk("%u %3s (%d)", __entry->gpio,
+                __entry->in ? "in" : "out", __entry->err)
+);
+
+TRACE_EVENT(gpio_value,
+
+        TP_PROTO(unsigned gpio, int get, int value),
+
+        TP_ARGS(gpio, get, value),
+
+        TP_STRUCT__entry(
+                __field(unsigned, gpio)
+                __field(int, get)
+                __field(int, value)
+        ),
+
+        TP_fast_assign(
+                __entry->gpio = gpio;
+                __entry->get = get;
+                __entry->value = value;
+        ),
+
+        TP_printk("%u %3s %d", __entry->gpio,
+                __entry->get ? "get" : "set", __entry->value)
+);
+
+#endif /* if !defined(_TRACE_GPIO_H) || defined(TRACE_HEADER_MULTI_READ) */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>