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Message-id: <5A953C21.5020007@samsung.com>
Date: Tue, 27 Feb 2018 20:08:17 +0900
From: Chanwoo Choi <cw00.choi@...sung.com>
To: Andrzej Hajda <a.hajda@...sung.com>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@...r.kernel.org>
Cc: Maciej Purski <m.purski@...sung.com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
Marek Szyprowski <m.szyprowski@...sung.com>,
dri-devel@...ts.freedesktop.org, Inki Dae <inki.dae@...sung.com>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Krzysztof Kozlowski <krzk@...nel.org>,
Archit Taneja <architt@...eaurora.org>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-samsung-soc@...r.kernel.org, linux-usb@...r.kernel.org
Subject: Re: [PATCH v5 6/6] drm/bridge/sii8620: use micro-USB cable
detection logic to detect MHL
Hi,
On 2018년 02월 27일 16:11, Andrzej Hajda wrote:
> From: Maciej Purski <m.purski@...sung.com>
>
> Currently MHL chip must be turned on permanently to detect MHL cable. It
> duplicates micro-USB controller's (MUIC) functionality and consumes
> unnecessary power. Lets use extcon attached to MUIC to enable MHL chip
> only if it detects MHL cable.
>
> Signed-off-by: Maciej Purski <m.purski@...sung.com>
> Signed-off-by: Andrzej Hajda <a.hajda@...sung.com>
> ---
> v5: updated extcon API
>
> This is rework of the patch by Maciej with following changes:
> - use micro-USB port bindings to get extcon, instead of extcon property,
> - fixed remove sequence,
> - fixed extcon get state logic.
>
> Code finding extcon node is hacky IMO, I guess ultimately it should be done
> via some framework (maybe even extcon), or at least via helper, I hope it
> can stay as is until the proper solution will be merged.
>
> Signed-off-by: Andrzej Hajda <a.hajda@...sung.com>
> ---
> drivers/gpu/drm/bridge/sil-sii8620.c | 97 ++++++++++++++++++++++++++++++++++--
> 1 file changed, 94 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c b/drivers/gpu/drm/bridge/sil-sii8620.c
> index 9e785b8e0ea2..62b0adabcac2 100644
> --- a/drivers/gpu/drm/bridge/sil-sii8620.c
> +++ b/drivers/gpu/drm/bridge/sil-sii8620.c
> @@ -17,6 +17,7 @@
>
> #include <linux/clk.h>
> #include <linux/delay.h>
> +#include <linux/extcon.h>
> #include <linux/gpio/consumer.h>
> #include <linux/i2c.h>
> #include <linux/interrupt.h>
> @@ -25,6 +26,7 @@
> #include <linux/list.h>
> #include <linux/module.h>
> #include <linux/mutex.h>
> +#include <linux/of_graph.h>
> #include <linux/regulator/consumer.h>
> #include <linux/slab.h>
>
> @@ -81,6 +83,10 @@ struct sii8620 {
> struct edid *edid;
> unsigned int gen2_write_burst:1;
> enum sii8620_mt_state mt_state;
> + struct extcon_dev *extcon;
> + struct notifier_block extcon_nb;
> + struct work_struct extcon_wq;
> + int cable_state;
> struct list_head mt_queue;
> struct {
> int r_size;
> @@ -2175,6 +2181,77 @@ static void sii8620_init_rcp_input_dev(struct sii8620 *ctx)
> ctx->rc_dev = rc_dev;
> }
>
> +static void sii8620_cable_out(struct sii8620 *ctx)
> +{
> + disable_irq(to_i2c_client(ctx->dev)->irq);
> + sii8620_hw_off(ctx);
> +}
> +
> +static void sii8620_extcon_work(struct work_struct *work)
> +{
> + struct sii8620 *ctx =
> + container_of(work, struct sii8620, 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)
> + sii8620_cable_in(ctx);
> + else
> + sii8620_cable_out(ctx);
> +}
> +
> +static int sii8620_extcon_notifier(struct notifier_block *self,
> + unsigned long event, void *ptr)
> +{
> + struct sii8620 *ctx =
> + container_of(self, struct sii8620, extcon_nb);
> +
> + schedule_work(&ctx->extcon_wq);
> +
> + return NOTIFY_DONE;
> +}
> +
> +static int sii8620_extcon_init(struct sii8620 *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);
> + /* next 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)) {
> + if (PTR_ERR(edev) == -EPROBE_DEFER)
> + return -EPROBE_DEFER;
> + dev_err(ctx->dev, "Invalid or missing extcon\n");
> + return PTR_ERR(edev);
> + }
> +
> + ctx->extcon = edev;
> + ctx->extcon_nb.notifier_call = sii8620_extcon_notifier;
> + INIT_WORK(&ctx->extcon_wq, sii8620_extcon_work);
> + ret = extcon_register_notifier(edev, EXTCON_DISP_MHL, &ctx->extcon_nb);
You better to use devm_extcon_register_notifier().
> + if (ret) {
> + dev_err(ctx->dev, "failed to register notifier for MHL\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> static inline struct sii8620 *bridge_to_sii8620(struct drm_bridge *bridge)
> {
> return container_of(bridge, struct sii8620, bridge);
> @@ -2307,13 +2384,20 @@ static int sii8620_probe(struct i2c_client *client,
> if (ret)
> return ret;
>
> + ret = sii8620_extcon_init(ctx);
> + if (ret < 0) {
> + dev_err(ctx->dev, "failed to initialize EXTCON\n");
> + return ret;
> + }
> +
> i2c_set_clientdata(client, ctx);
>
> ctx->bridge.funcs = &sii8620_bridge_funcs;
> ctx->bridge.of_node = dev->of_node;
> drm_bridge_add(&ctx->bridge);
>
> - sii8620_cable_in(ctx);
> + if (!ctx->extcon)
> + sii8620_cable_in(ctx);
>
> return 0;
> }
> @@ -2322,8 +2406,15 @@ static int sii8620_remove(struct i2c_client *client)
> {
> struct sii8620 *ctx = i2c_get_clientdata(client);
>
> - disable_irq(to_i2c_client(ctx->dev)->irq);
> - sii8620_hw_off(ctx);
> + if (ctx->extcon) {
> + extcon_unregister_notifier(ctx->extcon, EXTCON_DISP_MHL,
> + &ctx->extcon_nb);
Don't need to unregister the notifier if using devm_extcon_register_notifier().
> + flush_work(&ctx->extcon_wq);
> + if (ctx->cable_state > 0)
> + sii8620_cable_out(ctx);
> + } else {
> + sii8620_cable_out(ctx);
> + }
> drm_bridge_remove(&ctx->bridge);
>
> return 0;
>
If you use the resource managed function (devm_extcon_register_notifier), Looks good to me.
Reviewed-by: Chanwoo Choi <cw00.choi@...sung.com>
--
Best Regards,
Chanwoo Choi
Samsung Electronics
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