LWIS: Handle shared GPIO device power down

Handover the GPIO handler to the other device that is still enabled.
It'd prevent the error when we disable a shared GPIO device.

Bug: 263340379
Test: GCA
Change-Id: I033b4f29e0f924155ee6d5a336ea80e584da1db7
Signed-off-by: Holmes Chou <holmeschou@google.com>

3 files changed, 56 insertions, 1 deletions

diff --git a/lwis_device.c b/lwis_device.c
index 7e64435..c0f65fb 100644
--- a/lwis_device.c
+++ b/lwis_device.c
@@ -441,6 +441,7 @@ int lwis_dev_process_power_sequence(struct lwis_device *lwis_dev,
 		} else if (strcmp(list->seq_info[i].type, "gpio") == 0) {
 			struct lwis_gpios_info *gpios_info = NULL;
 			int set_value = 0;
+			bool set_state = true;
 
 			gpios_info = lwis_gpios_get_info_by_name(lwis_dev->gpios_list,
 								 list->seq_info[i].name);
@@ -500,6 +501,41 @@ int lwis_dev_process_power_sequence(struct lwis_device *lwis_dev,
 				set_value = 0;
 			}
 
+			if (gpios_info->is_shared && !set_active) {
+				struct lwis_device *lwis_dev_it;
+				struct lwis_gpios_info *gpios_info_it;
+
+				/* Look up if gpio it's already acquired */
+				mutex_lock(&core.lock);
+				list_for_each_entry (lwis_dev_it, &core.lwis_dev_list, dev_list) {
+					if ((lwis_dev->id != lwis_dev_it->id) &&
+					    lwis_dev_it->enabled && lwis_dev_it->gpios_list) {
+						gpios_info_it = lwis_gpios_get_info_by_name(
+							lwis_dev_it->gpios_list,
+							list->seq_info[i].name);
+						if (IS_ERR(gpios_info_it)) {
+							continue;
+						}
+						if (gpios_info_it->id == gpios_info->id &&
+						    gpios_info_it->gpios == NULL) {
+							dev_info(lwis_dev->dev,
+								 "Handover shared GPIO to %s\n",
+								 lwis_dev_it->name);
+							gpios_info_it->gpios = gpios_info->gpios;
+							gpios_info_it->hold_dev =
+								gpios_info->hold_dev;
+							set_state = false;
+							gpios_info->gpios = NULL;
+						}
+						break;
+					}
+				}
+				mutex_unlock(&core.lock);
+			}
+			if (!set_state) {
+				continue;
+			}
+
 			if (gpios_info->is_pulse) {
 				ret = lwis_gpio_list_set_output_value(gpios_info->gpios,
 								      1 - set_value);
@@ -523,7 +559,7 @@ int lwis_dev_process_power_sequence(struct lwis_device *lwis_dev,
 
 			if (!set_active) {
 				/* Release "ownership" of the GPIO pins */
-				lwis_gpio_list_put(gpios_info->gpios, &lwis_dev->plat_dev->dev);
+				lwis_gpio_list_put(gpios_info->gpios, gpios_info->hold_dev);
 				gpios_info->gpios = NULL;
 			}
 		} else if (strcmp(list->seq_info[i].type, "pinctrl") == 0) {
diff --git a/lwis_dt.c b/lwis_dt.c
index 4c263a1..bdfb6ba 100644
--- a/lwis_dt.c
+++ b/lwis_dt.c
@@ -971,6 +971,8 @@ static int parse_power_seqs(struct lwis_device *lwis_dev, const char *seq_name,
 		for (i = 0; i < power_seq_count; ++i) {
 			struct lwis_gpios_info *gpios_info;
 			char *seq_item_name;
+			struct device *dev;
+			struct gpio_descs *descs;
 
 			if (strcmp((*list)->seq_info[i].type, "gpio") != 0) {
 				continue;
@@ -978,6 +980,21 @@ static int parse_power_seqs(struct lwis_device *lwis_dev, const char *seq_name,
 
 			gpios_info = &lwis_dev->gpios_list->gpios_info[type_gpio_count];
 			seq_item_name = (*list)->seq_info[i].name;
+			dev = &lwis_dev->plat_dev->dev;
+			descs = lwis_gpio_list_get(dev, seq_item_name);
+			if (IS_ERR(descs)) {
+				pr_err("Error parsing GPIO list %s (%ld)\n", seq_item_name,
+				       PTR_ERR(descs));
+				ret = PTR_ERR(descs);
+				goto error_parse_power_seqs;
+			}
+			gpios_info->id = desc_to_gpio(descs->desc[0]);
+			gpios_info->hold_dev = dev;
+			/*
+			 * The GPIO pins are valid, release the list as we do not need to hold
+			 * on to the pins yet
+			 */
+			lwis_gpio_list_put(descs, dev);
 
 			gpios_info->gpios = NULL;
 			gpios_info->irq_list = NULL;
diff --git a/lwis_gpio.h b/lwis_gpio.h
index 2dc0ea3..52817e7 100644
--- a/lwis_gpio.h
+++ b/lwis_gpio.h
@@ -20,6 +20,8 @@
  * This structure is to store the gpios information
  */
 struct lwis_gpios_info {
+	int id;
+	struct device *hold_dev;
 	char name[LWIS_MAX_NAME_STRING_LEN];
 	bool is_shared;
 	bool is_pulse;