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    SubjectRe: [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@samsung.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@samsung.com>
    > Signed-off-by: Andrzej Hajda <a.hajda@samsung.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@samsung.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@samsung.com>

    --
    Best Regards,
    Chanwoo Choi
    Samsung Electronics

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