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path: root/drivers/input/misc/gpio_axis.c
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Diffstat (limited to 'drivers/input/misc/gpio_axis.c')
-rw-r--r--drivers/input/misc/gpio_axis.c192
1 files changed, 192 insertions, 0 deletions
diff --git a/drivers/input/misc/gpio_axis.c b/drivers/input/misc/gpio_axis.c
new file mode 100644
index 000000000000..0acf4a576f53
--- /dev/null
+++ b/drivers/input/misc/gpio_axis.c
@@ -0,0 +1,192 @@
+/* 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>
+#include <linux/slab.h>
+
+struct gpio_axis_state {
+ struct gpio_event_input_devs *input_devs;
+ 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_devs->dev[ai->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_devs->dev[ai->dev],
+ ai->type, ai->code, pos);
+ }
+ input_sync(as->input_devs->dev[ai->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 gpio_event_input_devs *input_devs,
+ 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_devs = input_devs;
+ as->info = ai;
+ if (ai->dev >= input_devs->count) {
+ pr_err("gpio_event_axis: bad device index %d >= %d "
+ "for %d:%d\n", ai->dev, input_devs->count,
+ ai->type, ai->code);
+ ret = -EINVAL;
+ goto err_bad_device_index;
+ }
+
+ input_set_capability(input_devs->dev[ai->dev],
+ ai->type, ai->code);
+ if (ai->type == EV_ABS) {
+ input_set_abs_params(input_devs->dev[ai->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:
+ ;
+ }
+err_bad_device_index:
+ kfree(as);
+ *data = NULL;
+err_alloc_axis_state_failed:
+ return ret;
+}