Staging: dream: add support for input on GPIO pins

Support for input devices connected to GPIO pins. This adds support
for HTC Dream's keyboard and its trackball. Generic support already
exists for keyboard on GPIO, but this one is more advanced because it
can detect shadow key presses (and actually works with Dream :-).

(It also contains Kconfig/Makefile changes, including some that were
missing from previous commit. Sorry.)

Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 180 insertions, 0 deletions

diff --git a/drivers/staging/dream/gpio_axis.c b/drivers/staging/dream/gpio_axis.c
new file mode 100644
index 000000000000..c801172aa9ee
--- /dev/null
+++ b/drivers/staging/dream/gpio_axis.c
@@ -0,0 +1,180 @@
+/* drivers/input/misc/gpio_axis.c
+ *
+ * Copyright (C) 2007 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/gpio.h>
+#include <linux/gpio_event.h>
+#include <linux/interrupt.h>
+
+struct gpio_axis_state {
+	struct input_dev *input_dev;
+	struct gpio_event_axis_info *info;
+	uint32_t pos;
+};
+
+uint16_t gpio_axis_4bit_gray_map_table[] = {
+	[0x0] = 0x0, [0x1] = 0x1, /* 0000 0001 */
+	[0x3] = 0x2, [0x2] = 0x3, /* 0011 0010 */
+	[0x6] = 0x4, [0x7] = 0x5, /* 0110 0111 */
+	[0x5] = 0x6, [0x4] = 0x7, /* 0101 0100 */
+	[0xc] = 0x8, [0xd] = 0x9, /* 1100 1101 */
+	[0xf] = 0xa, [0xe] = 0xb, /* 1111 1110 */
+	[0xa] = 0xc, [0xb] = 0xd, /* 1010 1011 */
+	[0x9] = 0xe, [0x8] = 0xf, /* 1001 1000 */
+};
+uint16_t gpio_axis_4bit_gray_map(struct gpio_event_axis_info *info, uint16_t in)
+{
+	return gpio_axis_4bit_gray_map_table[in];
+}
+
+uint16_t gpio_axis_5bit_singletrack_map_table[] = {
+	[0x10] = 0x00, [0x14] = 0x01, [0x1c] = 0x02, /*     10000 10100 11100 */
+	[0x1e] = 0x03, [0x1a] = 0x04, [0x18] = 0x05, /*     11110 11010 11000 */
+	[0x08] = 0x06, [0x0a] = 0x07, [0x0e] = 0x08, /*    01000 01010 01110  */
+	[0x0f] = 0x09, [0x0d] = 0x0a, [0x0c] = 0x0b, /*    01111 01101 01100  */
+	[0x04] = 0x0c, [0x05] = 0x0d, [0x07] = 0x0e, /*   00100 00101 00111   */
+	[0x17] = 0x0f, [0x16] = 0x10, [0x06] = 0x11, /*   10111 10110 00110   */
+	[0x02] = 0x12, [0x12] = 0x13, [0x13] = 0x14, /*  00010 10010 10011    */
+	[0x1b] = 0x15, [0x0b] = 0x16, [0x03] = 0x17, /*  11011 01011 00011    */
+	[0x01] = 0x18, [0x09] = 0x19, [0x19] = 0x1a, /* 00001 01001 11001     */
+	[0x1d] = 0x1b, [0x15] = 0x1c, [0x11] = 0x1d, /* 11101 10101 10001     */
+};
+uint16_t gpio_axis_5bit_singletrack_map(
+	struct gpio_event_axis_info *info, uint16_t in)
+{
+	return gpio_axis_5bit_singletrack_map_table[in];
+}
+
+static void gpio_event_update_axis(struct gpio_axis_state *as, int report)
+{
+	struct gpio_event_axis_info *ai = as->info;
+	int i;
+	int change;
+	uint16_t state = 0;
+	uint16_t pos;
+	uint16_t old_pos = as->pos;
+	for (i = ai->count - 1; i >= 0; i--)
+		state = (state << 1) | gpio_get_value(ai->gpio[i]);
+	pos = ai->map(ai, state);
+	if (ai->flags & GPIOEAF_PRINT_RAW)
+		pr_info("axis %d-%d raw %x, pos %d -> %d\n",
+			ai->type, ai->code, state, old_pos, pos);
+	if (report && pos != old_pos) {
+		if (ai->type == EV_REL) {
+			change = (ai->decoded_size + pos - old_pos) %
+				  ai->decoded_size;
+			if (change > ai->decoded_size / 2)
+				change -= ai->decoded_size;
+			if (change == ai->decoded_size / 2) {
+				if (ai->flags & GPIOEAF_PRINT_EVENT)
+					pr_info("axis %d-%d unknown direction, "
+						"pos %d -> %d\n", ai->type,
+						ai->code, old_pos, pos);
+				change = 0; /* no closest direction */
+			}
+			if (ai->flags & GPIOEAF_PRINT_EVENT)
+				pr_info("axis %d-%d change %d\n",
+					ai->type, ai->code, change);
+			input_report_rel(as->input_dev, ai->code, change);
+		} else {
+			if (ai->flags & GPIOEAF_PRINT_EVENT)
+				pr_info("axis %d-%d now %d\n",
+					ai->type, ai->code, pos);
+			input_event(as->input_dev, ai->type, ai->code, pos);
+		}
+		input_sync(as->input_dev);
+	}
+	as->pos = pos;
+}
+
+static irqreturn_t gpio_axis_irq_handler(int irq, void *dev_id)
+{
+	struct gpio_axis_state *as = dev_id;
+	gpio_event_update_axis(as, 1);
+	return IRQ_HANDLED;
+}
+
+int gpio_event_axis_func(struct input_dev *input_dev,
+			 struct gpio_event_info *info, void **data, int func)
+{
+	int ret;
+	int i;
+	int irq;
+	struct gpio_event_axis_info *ai;
+	struct gpio_axis_state *as;
+
+	ai = container_of(info, struct gpio_event_axis_info, info);
+	if (func == GPIO_EVENT_FUNC_SUSPEND) {
+		for (i = 0; i < ai->count; i++)
+			disable_irq(gpio_to_irq(ai->gpio[i]));
+		return 0;
+	}
+	if (func == GPIO_EVENT_FUNC_RESUME) {
+		for (i = 0; i < ai->count; i++)
+			enable_irq(gpio_to_irq(ai->gpio[i]));
+		return 0;
+	}
+
+	if (func == GPIO_EVENT_FUNC_INIT) {
+		*data = as = kmalloc(sizeof(*as), GFP_KERNEL);
+		if (as == NULL) {
+			ret = -ENOMEM;
+			goto err_alloc_axis_state_failed;
+		}
+		as->input_dev = input_dev;
+		as->info = ai;
+
+		input_set_capability(input_dev, ai->type, ai->code);
+		if (ai->type == EV_ABS) {
+			input_set_abs_params(input_dev, ai->code, 0,
+					     ai->decoded_size - 1, 0, 0);
+		}
+		for (i = 0; i < ai->count; i++) {
+			ret = gpio_request(ai->gpio[i], "gpio_event_axis");
+			if (ret < 0)
+				goto err_request_gpio_failed;
+			ret = gpio_direction_input(ai->gpio[i]);
+			if (ret < 0)
+				goto err_gpio_direction_input_failed;
+			ret = irq = gpio_to_irq(ai->gpio[i]);
+			if (ret < 0)
+				goto err_get_irq_num_failed;
+			ret = request_irq(irq, gpio_axis_irq_handler,
+					  IRQF_TRIGGER_RISING |
+					  IRQF_TRIGGER_FALLING,
+					  "gpio_event_axis", as);
+			if (ret < 0)
+				goto err_request_irq_failed;
+		}
+		gpio_event_update_axis(as, 0);
+		return 0;
+	}
+
+	ret = 0;
+	as = *data;
+	for (i = ai->count - 1; i >= 0; i--) {
+		free_irq(gpio_to_irq(ai->gpio[i]), as);
+err_request_irq_failed:
+err_get_irq_num_failed:
+err_gpio_direction_input_failed:
+		gpio_free(ai->gpio[i]);
+err_request_gpio_failed:
+		;
+	}
+	kfree(as);
+	*data = NULL;
+err_alloc_axis_state_failed:
+	return ret;
+}