add attribute (9.4)

4 files changed, 70 insertions, 32 deletions

diff --git a/driver/main.c b/driver/main.c
index 8775727..2676c9a 100644
--- a/driver/main.c
+++ b/driver/main.c
@@ -1,26 +1,11 @@
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/module.h>
-#include <linux/of.h>
 #include <linux/platform_device.h>
 
+#include "main.h"
 #include "platform.h"
 
-static const struct of_device_id lork_ids[] = {
-	{ .compatible = "gpio-extern" },
-	{},
-};
-
-struct platform_driver lork_driver = {
-	.probe = lork_probe,
-	.remove = lork_remove,
-	.driver = {
-		.name = "gpio-extern",
-		.owner = THIS_MODULE,
-		.of_match_table = of_match_ptr(lork_ids),
-	}
-};
-
 struct class* class;
 
 static int mod_init(void) {
@@ -38,17 +23,22 @@ static int mod_init(void) {
 	err = platform_driver_register(&lork_driver);
 	if (err) goto return_err;
 
+	// create attribute under /sys/bus/platform/drivers/gpio-extern
+	err = driver_create_file(&lork_driver.driver, &attr);
+	if (err) goto return_err;
+
 	printk("%s() OK\n", __PRETTY_FUNCTION__);
 	return 0;
 
+return_err:
 free_class:
 	class_destroy(class);
-return_err:
 	printk("%s() -> %d\n", __PRETTY_FUNCTION__, err);
 	return err;
 }
 
 static void mod_exit(void) {
+	driver_remove_file(&lork_driver.driver, &attr);
 	platform_driver_unregister(&lork_driver);
 	class_destroy(class);
 	printk("%s()\n", __PRETTY_FUNCTION__);
diff --git a/driver/main.h b/driver/main.h
new file mode 100644
index 0000000..a0ef924
--- /dev/null
+++ b/driver/main.h
@@ -0,0 +1,22 @@
+#pragma once
+
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+#include "platform.h"
+
+static const struct of_device_id lork_ids[] = {
+	{ .compatible = "gpio-extern" },
+	{},
+};
+
+struct platform_driver lork_driver = {
+	.probe = lork_probe,
+	.remove = lork_remove,
+	.driver = {
+		.name = "gpio-extern",
+		.owner = THIS_MODULE,
+		.of_match_table = of_match_ptr(lork_ids),
+	}
+};
+
diff --git a/driver/platform.c b/driver/platform.c
index da84064..c41d47b 100644
--- a/driver/platform.c
+++ b/driver/platform.c
@@ -2,6 +2,11 @@
 
 #include <linux/types.h>
 #include <linux/of.h>
+#include <linux/of_address.h>
+
+// TODO: shouldn't these be used??
+// #include <linux/pinctrl/pinctrl.h>
+// #include <linux/gpio/driver.h>
 
 #include <dt-bindings/gpio/gpio.h>
 
@@ -19,23 +24,23 @@ int lork_probe(struct platform_device* dev) {
 	printk("lork: configure pin %u w/ mode 0x%02x\n", pin, gpio_mode);
 
 	// find the multiplexer that controls pin
-	size_t len = of_property_count_u32_elems(gpio1, "gpio-ranges");
-	struct device_node* am33xx_pinmux = NULL;
-	for (size_t i = 0; i < len; i += 4) {
-		uint32_t phandle, pin_start, pin_offset, pin_size;
-		of_property_read_u32_index(gpio1, "gpio-ranges", i+0, &phandle);
-		of_property_read_u32_index(gpio1, "gpio-ranges", i+1, &pin_start);
-		of_property_read_u32_index(gpio1, "gpio-ranges", i+2, &pin_offset);
-		of_property_read_u32_index(gpio1, "gpio-ranges", i+3, &pin_size);
+	// size_t len = of_property_count_u32_elems(gpio1, "gpio-ranges");
+	// struct device_node* am33xx_pinmux = NULL;
+	// for (size_t i = 0; i < len; i += 4) {
+	// 	uint32_t phandle, pin_start, pin_offset, pin_size;
+	// 	of_property_read_u32_index(gpio1, "gpio-ranges", i+0, &phandle);
+	// 	of_property_read_u32_index(gpio1, "gpio-ranges", i+1, &pin_start);
+	// 	of_property_read_u32_index(gpio1, "gpio-ranges", i+2, &pin_offset);
+	// 	of_property_read_u32_index(gpio1, "gpio-ranges", i+3, &pin_size);
 
-		// get phandle for multiplexer corresponding to configured pin number
-		if (pin_start > pin || pin >= pin_start + pin_size) continue;
+	// 	// get phandle for multiplexer corresponding to configured pin number
+	// 	if (pin_start > pin || pin >= pin_start + pin_size) continue;
 
-		am33xx_pinmux = of_find_node_by_phandle(phandle);
-		printk("0x%02x, %u -> %u + %u\n", phandle, pin_start, pin_offset, pin_size);
-		break;
-	}
-	if (am33xx_pinmux == NULL) return EINVAL;
+	// 	am33xx_pinmux = of_find_node_by_phandle(phandle);
+	// 	printk("0x%02x, %u -> %u + %u\n", phandle, pin_start, pin_offset, pin_size);
+	// 	break;
+	// }
+	// if (am33xx_pinmux == NULL) return EINVAL;
 
 	// TODO: ???
 
@@ -67,3 +72,12 @@ int lork_remove(struct platform_device* dev) {
 	return 0;
 }
 
+unsigned int val = 0;
+ssize_t attr_show(struct device_driver* drv, char* buf) {
+	return sprintf(buf, "%u\n", val);
+}
+ssize_t attr_store(struct device_driver* drv, const char* buf, size_t count) {
+	sscanf(buf, "%u", &val);
+	return count;
+}
+
diff --git a/driver/platform.h b/driver/platform.h
index 3faaad5..cee82a7 100644
--- a/driver/platform.h
+++ b/driver/platform.h
@@ -3,6 +3,18 @@
 #include <linux/types.h>
 #include <linux/platform_device.h>
 
+ssize_t attr_show(struct device_driver*, char*);
+ssize_t attr_store(struct device_driver*, const char*, size_t);
+
+static struct driver_attribute attr = {
+	.attr = {
+		.name = "attr",
+		.mode = 0644,
+	},
+	.show = attr_show,
+	.store = attr_store,
+};
+
 int lork_probe(struct platform_device*);
 int lork_remove(struct platform_device*);