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SubjectRe: [PATCH v6 4/8] usb: core: add power sequence handling for USB devices
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On Monday 15 August 2016 02:43 PM, Peter Chen wrote:
> Some hard-wired USB devices need to do power sequence to let the
> device work normally, the typical power sequence like: enable USB
> PHY clock, toggle reset pin, etc. But current Linux USB driver
> lacks of such code to do it, it may cause some hard-wired USB devices
> works abnormal or can't be recognized by controller at all.
>
> In this patch, it calls power sequence library APIs to finish
> the power sequence events. At first, it calls pwrseq_alloc_generic
> to create a generic power sequence instance, then it will do power
> on sequence at hub's probe for all devices under this hub
> (includes root hub).
>
> At hub_disconnect, it will do power off sequence which is at powered
> on list.
>
> Signed-off-by: Peter Chen <peter.chen@nxp.com>
> Tested-by Joshua Clayton <stillcompiling@gmail.com>
> ---
> drivers/usb/core/Makefile | 1 +
> drivers/usb/core/hub.c | 12 ++++--
> drivers/usb/core/hub.h | 12 ++++++
> drivers/usb/core/pwrseq.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 122 insertions(+), 3 deletions(-)
> create mode 100644 drivers/usb/core/pwrseq.c
>
> diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile
> index 9780877..39f2149 100644
> --- a/drivers/usb/core/Makefile
> +++ b/drivers/usb/core/Makefile
> @@ -9,5 +9,6 @@ usbcore-y += port.o of.o
>
> usbcore-$(CONFIG_PCI) += hcd-pci.o
> usbcore-$(CONFIG_ACPI) += usb-acpi.o
> +usbcore-$(CONFIG_PWRSEQ_GENERIC) += pwrseq.o
>
> obj-$(CONFIG_USB) += usbcore.o
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index bee1351..a346a8b 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -1700,6 +1700,7 @@ static void hub_disconnect(struct usb_interface *intf)
> hub->error = 0;
> hub_quiesce(hub, HUB_DISCONNECT);
>
> + hub_pwrseq_off(hub);
> mutex_lock(&usb_port_peer_mutex);
>
> /* Avoid races with recursively_mark_NOTATTACHED() */
> @@ -1733,6 +1734,7 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
> struct usb_endpoint_descriptor *endpoint;
> struct usb_device *hdev;
> struct usb_hub *hub;
> + int ret = -ENODEV;
>
> desc = intf->cur_altsetting;
> hdev = interface_to_usbdev(intf);
> @@ -1839,6 +1841,7 @@ descriptor_error:
> INIT_DELAYED_WORK(&hub->leds, led_work);
> INIT_DELAYED_WORK(&hub->init_work, NULL);
> INIT_WORK(&hub->events, hub_event);
> + INIT_LIST_HEAD(&hub->pwrseq_on_list);
> usb_get_intf(intf);
> usb_get_dev(hdev);
>
> @@ -1852,11 +1855,14 @@ descriptor_error:
> if (id->driver_info & HUB_QUIRK_CHECK_PORT_AUTOSUSPEND)
> hub->quirk_check_port_auto_suspend = 1;
>
> - if (hub_configure(hub, endpoint) >= 0)
> - return 0;
> + if (hub_configure(hub, endpoint) >= 0) {
> + ret = hub_pwrseq_on(hub);
> + if (!ret)
> + return 0;
> + }
>
> hub_disconnect(intf);
> - return -ENODEV;
> + return ret;
> }
>
> static int
> diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
> index 34c1a7e..9473f6f 100644
> --- a/drivers/usb/core/hub.h
> +++ b/drivers/usb/core/hub.h
> @@ -78,6 +78,7 @@ struct usb_hub {
> struct delayed_work init_work;
> struct work_struct events;
> struct usb_port **ports;
> + struct list_head pwrseq_on_list; /* powered pwrseq node list */
> };
>
> /**
> @@ -166,3 +167,14 @@ static inline int hub_port_debounce_be_stable(struct usb_hub *hub,
> {
> return hub_port_debounce(hub, port1, false);
> }
> +
> +#if IS_ENABLED(CONFIG_PWRSEQ_GENERIC)
> +int hub_pwrseq_on(struct usb_hub *hub);
> +void hub_pwrseq_off(struct usb_hub *hub);
> +#else
> +static inline int hub_pwrseq_on(struct usb_hub *hub)
> +{
> + return 0;
> +}
> +static inline void hub_pwrseq_off(struct usb_hub *hub) {}
> +#endif /* CONFIG_PWRSEQ_GENERIC */
> diff --git a/drivers/usb/core/pwrseq.c b/drivers/usb/core/pwrseq.c
> new file mode 100644
> index 0000000..837fe66
> --- /dev/null
> +++ b/drivers/usb/core/pwrseq.c
> @@ -0,0 +1,100 @@
> +/*
> + * pwrseq.c USB device power sequence management
> + *
> + * Copyright (C) 2016 Freescale Semiconductor, Inc.
> + * Author: Peter Chen <peter.chen@nxp.com>
> + *
> + * This program is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 of
> + * the License as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/list.h>
> +#include <linux/of.h>
> +#include <linux/power/pwrseq.h>
> +#include <linux/slab.h>
> +#include <linux/usb.h>
> +#include <linux/usb/hcd.h>
> +
> +#include "hub.h"
> +
> +struct usb_pwrseq_node {
> + struct pwrseq *pwrseq;
> + struct list_head list;
> +};
> +
> +static int hub_of_pwrseq_on(struct device_node *np, struct usb_hub *hub)
> +{
> + struct pwrseq *pwrseq;
> + struct usb_pwrseq_node *pwrseq_node;
> + int ret;
> +
> + pwrseq = pwrseq_alloc_generic();
> + if (IS_ERR(pwrseq))
> + return PTR_ERR(pwrseq);
> +
> + ret = pwrseq_get(np, pwrseq);
> + if (ret)
> + goto pwr_free;
> +
> + ret = pwrseq_on(np, pwrseq);
> + if (ret)
> + goto pwr_put;
> +
> + pwrseq_node = kzalloc(sizeof(*pwrseq_node), GFP_KERNEL);

You probably want to check the return value here.

I think someone already commented on this, but still for the record
providing it.

Thanks,
Vaibhav
> + pwrseq_node->pwrseq = pwrseq;
> + list_add(&pwrseq_node->list, &hub->pwrseq_on_list);
> +
> + return 0;
> +
> +pwr_put:
> + pwrseq_put(pwrseq);
> +pwr_free:
> + pwrseq_free(pwrseq);
> + return ret;
> +}
> +
> +int hub_pwrseq_on(struct usb_hub *hub)
> +{
> + struct device *parent;
> + struct usb_device *hdev = hub->hdev;
> + struct device_node *np;
> + int ret;
> +
> + if (hdev->parent)
> + parent = &hdev->dev;
> + else
> + parent = bus_to_hcd(hdev->bus)->self.controller;
> +
> + for_each_child_of_node(parent->of_node, np) {
> + ret = hub_of_pwrseq_on(np, hub);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +void hub_pwrseq_off(struct usb_hub *hub)
> +{
> + struct pwrseq *pwrseq;
> + struct usb_pwrseq_node *pwrseq_node, *tmp_node;
> +
> + list_for_each_entry_safe(pwrseq_node, tmp_node,
> + &hub->pwrseq_on_list, list) {
> + pwrseq = pwrseq_node->pwrseq;
> + pwrseq_off(pwrseq);
> + pwrseq_put(pwrseq);
> + pwrseq_free(pwrseq);
> + list_del(&pwrseq_node->list);
> + kfree(pwrseq_node);
> + }
> +}

--
Thanks,
Vaibhav

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