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SubjectRe: [PATCH v5 6/6] drm/bridge/sii8620: use micro-USB cable detection logic to detect MHL
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On 27.02.2018 12:08, Chanwoo Choi wrote:
> 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().

With devm version I risk that in case of device unbind notification will
be called after .remove callback, it seems to me quite dangerous. Or am
I missing something?

Regards
Andrzej

>
>> + 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>
>

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