Fixed MTP to work with TWRP

drivers/input/serio/ams_delta_serio.c

@@ -0,0 +1,191 @@
+/*
+ *  Amstrad E3 (Delta) keyboard port driver
+ *
+ *  Copyright (c) 2006 Matt Callow
+ *  Copyright (c) 2010 Janusz Krzysztofik
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * Thanks to Cliff Lawson for his help
+ *
+ * The Amstrad Delta keyboard (aka mailboard) uses normal PC-AT style serial
+ * transmission.  The keyboard port is formed of two GPIO lines, for clock
+ * and data.  Due to strict timing requirements of the interface,
+ * the serial data stream is read and processed by a FIQ handler.
+ * The resulting words are fetched by this driver from a circular buffer.
+ *
+ * Standard AT keyboard driver (atkbd) is used for handling the keyboard data.
+ * However, when used with the E3 mailboard that producecs non-standard
+ * scancodes, a custom key table must be prepared and loaded from userspace.
+ */
+#include <linux/gpio.h>
+#include <linux/irq.h>
+#include <linux/serio.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+
+#include <asm/mach-types.h>
+#include <mach/board-ams-delta.h>
+
+#include <mach/ams-delta-fiq.h>
+
+MODULE_AUTHOR("Matt Callow");
+MODULE_DESCRIPTION("AMS Delta (E3) keyboard port driver");
+MODULE_LICENSE("GPL");
+
+static struct serio *ams_delta_serio;
+
+static int check_data(int data)
+{
+	int i, parity = 0;
+
+	/* check valid stop bit */
+	if (!(data & 0x400)) {
+		dev_warn(&ams_delta_serio->dev,
+				"invalid stop bit, data=0x%X\n",
+				data);
+		return SERIO_FRAME;
+	}
+	/* calculate the parity */
+	for (i = 1; i < 10; i++) {
+		if (data & (1 << i))
+			parity++;
+	}
+	/* it should be odd */
+	if (!(parity & 0x01)) {
+		dev_warn(&ams_delta_serio->dev,
+				"paritiy check failed, data=0x%X parity=0x%X\n",
+				data, parity);
+		return SERIO_PARITY;
+	}
+	return 0;
+}
+
+static irqreturn_t ams_delta_serio_interrupt(int irq, void *dev_id)
+{
+	int *circ_buff = &fiq_buffer[FIQ_CIRC_BUFF];
+	int data, dfl;
+	u8 scancode;
+
+	fiq_buffer[FIQ_IRQ_PEND] = 0;
+
+	/*
+	 * Read data from the circular buffer, check it
+	 * and then pass it on the serio
+	 */
+	while (fiq_buffer[FIQ_KEYS_CNT] > 0) {
+
+		data = circ_buff[fiq_buffer[FIQ_HEAD_OFFSET]++];
+		fiq_buffer[FIQ_KEYS_CNT]--;
+		if (fiq_buffer[FIQ_HEAD_OFFSET] == fiq_buffer[FIQ_BUF_LEN])
+			fiq_buffer[FIQ_HEAD_OFFSET] = 0;
+
+		dfl = check_data(data);
+		scancode = (u8) (data >> 1) & 0xFF;
+		serio_interrupt(ams_delta_serio, scancode, dfl);
+	}
+	return IRQ_HANDLED;
+}
+
+static int ams_delta_serio_open(struct serio *serio)
+{
+	/* enable keyboard */
+	gpio_set_value(AMS_DELTA_GPIO_PIN_KEYBRD_PWR, 1);
+
+	return 0;
+}
+
+static void ams_delta_serio_close(struct serio *serio)
+{
+	/* disable keyboard */
+	gpio_set_value(AMS_DELTA_GPIO_PIN_KEYBRD_PWR, 0);
+}
+
+static const struct gpio ams_delta_gpios[] __initconst_or_module = {
+	{
+		.gpio	= AMS_DELTA_GPIO_PIN_KEYBRD_DATA,
+		.flags	= GPIOF_DIR_IN,
+		.label	= "serio-data",
+	},
+	{
+		.gpio	= AMS_DELTA_GPIO_PIN_KEYBRD_CLK,
+		.flags	= GPIOF_DIR_IN,
+		.label	= "serio-clock",
+	},
+	{
+		.gpio	= AMS_DELTA_GPIO_PIN_KEYBRD_PWR,
+		.flags	= GPIOF_OUT_INIT_LOW,
+		.label	= "serio-power",
+	},
+	{
+		.gpio	= AMS_DELTA_GPIO_PIN_KEYBRD_DATAOUT,
+		.flags	= GPIOF_OUT_INIT_LOW,
+		.label	= "serio-dataout",
+	},
+};
+
+static int __init ams_delta_serio_init(void)
+{
+	int err;
+
+	if (!machine_is_ams_delta())
+		return -ENODEV;
+
+	ams_delta_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
+	if (!ams_delta_serio)
+		return -ENOMEM;
+
+	ams_delta_serio->id.type = SERIO_8042;
+	ams_delta_serio->open = ams_delta_serio_open;
+	ams_delta_serio->close = ams_delta_serio_close;
+	strlcpy(ams_delta_serio->name, "AMS DELTA keyboard adapter",
+			sizeof(ams_delta_serio->name));
+	strlcpy(ams_delta_serio->phys, "GPIO/serio0",
+			sizeof(ams_delta_serio->phys));
+
+	err = gpio_request_array(ams_delta_gpios,
+				ARRAY_SIZE(ams_delta_gpios));
+	if (err) {
+		pr_err("ams_delta_serio: Couldn't request gpio pins\n");
+		goto serio;
+	}
+
+	err = request_irq(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK),
+			ams_delta_serio_interrupt, IRQ_TYPE_EDGE_RISING,
+			"ams-delta-serio", 0);
+	if (err < 0) {
+		pr_err("ams_delta_serio: couldn't request gpio interrupt %d\n",
+				gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK));
+		goto gpio;
+	}
+	/*
+	 * Since GPIO register handling for keyboard clock pin is performed
+	 * at FIQ level, switch back from edge to simple interrupt handler
+	 * to avoid bad interaction.
+	 */
+	irq_set_handler(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK),
+			handle_simple_irq);
+
+	serio_register_port(ams_delta_serio);
+	dev_info(&ams_delta_serio->dev, "%s\n", ams_delta_serio->name);
+
+	return 0;
+gpio:
+	gpio_free_array(ams_delta_gpios,
+			ARRAY_SIZE(ams_delta_gpios));
+serio:
+	kfree(ams_delta_serio);
+	return err;
+}
+module_init(ams_delta_serio_init);
+
+static void __exit ams_delta_serio_exit(void)
+{
+	serio_unregister_port(ams_delta_serio);
+	free_irq(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK), 0);
+	gpio_free_array(ams_delta_gpios,
+			ARRAY_SIZE(ams_delta_gpios));
+}
+module_exit(ams_delta_serio_exit);