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Message-Id: <20250721-exynos4-sii9234-driver-v1-3-2e47ed02f677@grimler.se>
Date: Mon, 21 Jul 2025 11:43:19 +0200
From: Henrik Grimler <henrik@...mler.se>
To: Andrzej Hajda <andrzej.hajda@...el.com>,
Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
Maciej Purski <m.purski@...sung.com>
Cc: dri-devel@...ts.freedesktop.org, linux-samsung-soc@...r.kernel.org,
~postmarketos/upstreaming@...ts.sr.ht, replicant@...osl.org,
linux-kernel@...r.kernel.org, Henrik Grimler <henrik@...mler.se>
Subject: [PATCH 3/3] drm/bridge: sii9234: use extcon cable detection logic
to detect MHL
To use MHL we currently need the MHL chip to be permanently on, which
consumes unnecessary power. Let's use extcon attached to MUIC to enable
the MHL chip only if it detects an MHL cable.
Signed-off-by: Henrik Grimler <henrik@...mler.se>
---
drivers/gpu/drm/bridge/sii9234.c | 89 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 86 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/bridge/sii9234.c b/drivers/gpu/drm/bridge/sii9234.c
index 0e0bb1bf71fdcef788715cfd6fa158a6992def33..4d84ba01ea76816bebdbc29d48a041c9c6cd508e 100644
--- a/drivers/gpu/drm/bridge/sii9234.c
+++ b/drivers/gpu/drm/bridge/sii9234.c
@@ -19,6 +19,7 @@
#include <linux/delay.h>
#include <linux/err.h>
+#include <linux/extcon.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
@@ -26,6 +27,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
+#include <linux/of_graph.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
@@ -170,8 +172,12 @@ struct sii9234 {
struct drm_bridge bridge;
struct device *dev;
struct gpio_desc *gpio_reset;
- int i2c_error;
struct regulator_bulk_data supplies[4];
+ struct extcon_dev *extcon;
+ struct notifier_block extcon_nb;
+ struct work_struct extcon_wq;
+ int cable_state;
+ int i2c_error;
struct mutex lock; /* Protects fields below and device registers */
enum sii9234_state state;
@@ -864,6 +870,70 @@ static int sii9234_init_resources(struct sii9234 *ctx,
return 0;
}
+static void sii9234_extcon_work(struct work_struct *work)
+{
+ struct sii9234 *ctx =
+ container_of(work, struct sii9234, extcon_wq);
+ int state = extcon_get_state(ctx->extcon, EXTCON_DISP_MHL);
+
+ if (state == ctx->cable_state)
+ return;
+
+ ctx->cable_state = state;
+
+ if (state > 0)
+ sii9234_cable_in(ctx);
+ else
+ sii9234_cable_out(ctx);
+}
+
+static int sii9234_extcon_notifier(struct notifier_block *self,
+ unsigned long event, void *ptr)
+{
+ struct sii9234 *ctx =
+ container_of(self, struct sii9234, extcon_nb);
+
+ schedule_work(&ctx->extcon_wq);
+
+ return NOTIFY_DONE;
+}
+
+static int sii9234_extcon_init(struct sii9234 *ctx)
+{
+ struct extcon_dev *edev;
+ struct device_node *musb, *muic;
+ int ret;
+
+ /* Get micro-USB connector node */
+ musb = of_graph_get_remote_node(ctx->dev->of_node, 1, -1);
+ /* Then get micro-USB Interface Controller node */
+ muic = of_get_next_parent(musb);
+
+ if (!muic) {
+ dev_info(ctx->dev,
+ "no extcon found, switching to 'always on' mode\n");
+ return 0;
+ }
+
+ edev = extcon_find_edev_by_node(muic);
+ of_node_put(muic);
+ if (IS_ERR(edev)) {
+ dev_err_probe(ctx->dev, PTR_ERR(edev),
+ "invalid or missing extcon\n");
+ }
+
+ ctx->extcon = edev;
+ ctx->extcon_nb.notifier_call = sii9234_extcon_notifier;
+ INIT_WORK(&ctx->extcon_wq, sii9234_extcon_work);
+ ret = extcon_register_notifier(edev, EXTCON_DISP_MHL, &ctx->extcon_nb);
+ if (ret) {
+ dev_err(ctx->dev, "failed to register notifier for MHL\n");
+ return ret;
+ }
+
+ return 0;
+}
+
static enum drm_mode_status sii9234_mode_valid(struct drm_bridge *bridge,
const struct drm_display_info *info,
const struct drm_display_mode *mode)
@@ -916,12 +986,17 @@ static int sii9234_probe(struct i2c_client *client)
if (ret < 0)
return ret;
+ ret = sii9234_extcon_init(ctx);
+ if (ret < 0)
+ return ret;
+
i2c_set_clientdata(client, ctx);
ctx->bridge.of_node = dev->of_node;
drm_bridge_add(&ctx->bridge);
- sii9234_cable_in(ctx);
+ if (!ctx->extcon)
+ sii9234_cable_in(ctx);
return 0;
}
@@ -930,7 +1005,15 @@ static void sii9234_remove(struct i2c_client *client)
{
struct sii9234 *ctx = i2c_get_clientdata(client);
- sii9234_cable_out(ctx);
+ if (ctx->extcon) {
+ extcon_unregister_notifier(ctx->extcon, EXTCON_DISP_MHL,
+ &ctx->extcon_nb);
+ flush_work(&ctx->extcon_wq);
+ if (ctx->cable_state > 0)
+ sii9234_cable_out(ctx);
+ } else {
+ sii9234_cable_out(ctx);
+ }
drm_bridge_remove(&ctx->bridge);
}
--
2.50.1
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