1 files changed, 94 insertions, 0 deletions
diff --git a/drivers/input/misc/rb532_button.c b/drivers/input/misc/rb532_button.c
new file mode 100644
index 0000000000..190a80e1e2
--- /dev/null
+++ b/drivers/input/misc/rb532_button.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Support for the S1 button on Routerboard 532
+ *
+ * Copyright (C) 2009  Phil Sutter <n0-1@freewrt.org>
+ */
+
+#include <linux/input.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+
+#include <asm/mach-rc32434/gpio.h>
+#include <asm/mach-rc32434/rb.h>
+
+#define DRV_NAME "rb532-button"
+
+#define RB532_BTN_RATE 100 /* msec */
+#define RB532_BTN_KSYM BTN_0
+
+/* The S1 button state is provided by GPIO pin 1. But as this
+ * pin is also used for uart input as alternate function, the
+ * operational modes must be switched first:
+ * 1) disable uart using set_latch_u5()
+ * 2) turn off alternate function implicitly through
+ *    gpio_direction_input()
+ * 3) read the GPIO's current value
+ * 4) undo step 2 by enabling alternate function (in this
+ *    mode the GPIO direction is fixed, so no change needed)
+ * 5) turn on uart again
+ * The GPIO value occurs to be inverted, so pin high means
+ * button is not pressed.
+ */
+static bool rb532_button_pressed(void)
+{
+	int val;
+
+	set_latch_u5(0, LO_FOFF);
+	gpio_direction_input(GPIO_BTN_S1);
+
+	val = gpio_get_value(GPIO_BTN_S1);
+
+	rb532_gpio_set_func(GPIO_BTN_S1);
+	set_latch_u5(LO_FOFF, 0);
+
+	return !val;
+}
+
+static void rb532_button_poll(struct input_dev *input)
+{
+	input_report_key(input, RB532_BTN_KSYM, rb532_button_pressed());
+	input_sync(input);
+}
+
+static int rb532_button_probe(struct platform_device *pdev)
+{
+	struct input_dev *input;
+	int error;
+
+	input = devm_input_allocate_device(&pdev->dev);
+	if (!input)
+		return -ENOMEM;
+
+	input->name = "rb532 button";
+	input->phys = "rb532/button0";
+	input->id.bustype = BUS_HOST;
+
+	input_set_capability(input, EV_KEY, RB532_BTN_KSYM);
+
+	error = input_setup_polling(input, rb532_button_poll);
+	if (error)
+		return error;
+
+	input_set_poll_interval(input, RB532_BTN_RATE);
+
+	error = input_register_device(input);
+	if (error)
+		return error;
+
+	return 0;
+}
+
+static struct platform_driver rb532_button_driver = {
+	.probe = rb532_button_probe,
+	.driver = {
+		.name = DRV_NAME,
+	},
+};
+module_platform_driver(rb532_button_driver);
+
+MODULE_AUTHOR("Phil Sutter <n0-1@freewrt.org>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Support for S1 button on Routerboard 532");
+MODULE_ALIAS("platform:" DRV_NAME);