From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aaro Koskinen Subject: Re: [PATCH v3 4/4] USB: OMAP1: Tahvo USB transceiver driver Date: Mon, 8 Jul 2013 22:44:02 +0300 Message-ID: <20130708194402.GA8516@blackmetal.musicnaut.iki.fi> References: <1371575221-360-1-git-send-email-aaro.koskinen@iki.fi> <1371575221-360-5-git-send-email-aaro.koskinen@iki.fi> <20130708072109.GA16635@arwen.pp.htv.fi> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20130708072109.GA16635-S8G//mZuvNWo5Im9Ml3/Zg@public.gmane.org> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Felipe Balbi Cc: linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-omap@vger.kernel.org Hi, On Mon, Jul 08, 2013 at 10:21:09AM +0300, Felipe Balbi wrote: > On Tue, Jun 18, 2013 at 08:07:01PM +0300, Aaro Koskinen wrote: > > +static ssize_t vbus_state_show(struct device *device, > > + struct device_attribute *attr, char *buf) > > +{ > > + struct tahvo_usb *tu = dev_get_drvdata(device); > > + return sprintf(buf, "%d\n", tu->vbus_state); > > +} > > +static DEVICE_ATTR(vbus_state, 0444, vbus_state_show, NULL); > > VBUS status sounds generic enough, also, you should be printing on/off > here instead of tahvo-specific values. Some users might not have access > to the docs, or even the kernel sources, to understand what that integer > means. Ok, I'll fix. > > +static void tahvo_usb_become_host(struct tahvo_usb *tu) > > +{ > > + struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent); > > + > > + extcon_set_cable_state(&tu->extcon, "USB-HOST", true); > > + > > + /* Power up the transceiver in USB host mode */ > > + retu_write(rdev, TAHVO_REG_USBR, USBR_REGOUT | USBR_NSUSPEND | > > + USBR_MASTER_SW2 | USBR_MASTER_SW1); > > + tu->phy.state = OTG_STATE_A_IDLE; > > + > > + check_vbus_state(tu); > > +} > > + > > +static void tahvo_usb_stop_host(struct tahvo_usb *tu) > > +{ > > + tu->phy.state = OTG_STATE_A_IDLE; > > shouldn't you undo tahvo_usb_become_host() here ? I mean, set the > transceiver to SLAVE ? tahvo_usb_become_peripheral() (or power_off) is always called after this function. Actually, these stop functions can be eliminated altogether as they are only called from a single place... > > +static int tahvo_usb_set_host(struct usb_otg *otg, struct usb_bus *host) > > +{ > > + struct tahvo_usb *tu = container_of(otg->phy, struct tahvo_usb, phy); > > + > > + dev_dbg(&tu->pt_dev->dev, "%s %p\n", __func__, host); > > + > > + if (otg == NULL) > > + return -ENODEV; > > + > > + mutex_lock(&tu->serialize); > > + > > + if (host == NULL) { > > + if (tu->tahvo_mode == TAHVO_MODE_HOST) > > + tahvo_usb_power_off(tu); > > + otg->host = NULL; > > + mutex_unlock(&tu->serialize); > > + return 0; > > + } > > + > > + if (tu->tahvo_mode == TAHVO_MODE_HOST) { > > + otg->host = NULL; > > + tahvo_usb_become_host(tu); > > + } > > + > > + otg->host = host; > > + > > + mutex_unlock(&tu->serialize); > > + > > + return 0; > > +} > > + > > +static int tahvo_usb_set_peripheral(struct usb_otg *otg, > > + struct usb_gadget *gadget) > > I want to get rid of the extra 'gadget' and 'host' parameters on > ->set_host() and ->set_peripheral(). Nobody really uses them other than: > > my_phy->phy.otg->{gadget,host} = {gadget,host}; > > For that, I need all other PHYs to stop relying on those parameters and > I'll cook patches for that for v3.12 merge window. How will the PHY know if there is a host/gadget driver present? I guess I will need to wait for those patches... > > +static ssize_t otg_mode_store(struct device *device, > > + struct device_attribute *attr, > > + const char *buf, size_t count) > > +{ > > + struct tahvo_usb *tu = dev_get_drvdata(device); > > + int r; > > + > > + mutex_lock(&tu->serialize); > > + if (count >= 4 && strncmp(buf, "host", 4) == 0) { > > + if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL) > > + tahvo_usb_stop_peripheral(tu); > > + tu->tahvo_mode = TAHVO_MODE_HOST; > > + if (tu->phy.otg->host) { > > + dev_info(device, "HOST mode: host controller present\n"); > > + tahvo_usb_become_host(tu); > > + } else { > > + dev_info(device, "HOST mode: no host controller, powering off\n"); > > + tahvo_usb_power_off(tu); > > + } > > + r = strlen(buf); > > + } else if (count >= 10 && strncmp(buf, "peripheral", 10) == 0) { > > + if (tu->tahvo_mode == TAHVO_MODE_HOST) > > + tahvo_usb_stop_host(tu); > > + tu->tahvo_mode = TAHVO_MODE_PERIPHERAL; > > + if (tu->phy.otg->gadget) { > > + dev_info(device, "PERIPHERAL mode: gadget driver present\n"); > > + tahvo_usb_become_peripheral(tu); > > + } else { > > + dev_info(device, "PERIPHERAL mode: no gadget driver, powering off\n"); > > + tahvo_usb_power_off(tu); > > + } > > + r = strlen(buf); > > + } else { > > + r = -EINVAL; > > + } > > + mutex_unlock(&tu->serialize); > > + > > + return r; > > +} > > + > > +static DEVICE_ATTR(otg_mode, 0644, otg_mode_show, otg_mode_store); > > this looks like something which would be very nice if implemented > generically. Since you, anyway miss the documentation in > Documentation/ABI/ and need to respin the patch, how about making this > generic ? Ok, I'll try to come up with something... > > +static int tahvo_usb_probe(struct platform_device *pdev) > > +{ > > + struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent); > > + struct tahvo_usb *tu; > > + int ret; > > + > > + tu = devm_kzalloc(&pdev->dev, sizeof(*tu), GFP_KERNEL); > > + if (!tu) > > + return -ENOMEM; > > + > > + tu->phy.otg = devm_kzalloc(&pdev->dev, sizeof(*tu->phy.otg), > > + GFP_KERNEL); > > + if (!tu->phy.otg) > > + return -ENOMEM; > > + > > + tu->pt_dev = pdev; > > + > > + /* Default mode */ > > +#ifdef CONFIG_TAHVO_USB_HOST_BY_DEFAULT > > + tu->tahvo_mode = TAHVO_MODE_HOST; > > +#else > > + tu->tahvo_mode = TAHVO_MODE_PERIPHERAL; > > +#endif > > should you call become_host()/become_peripheral() here ? Not needed. Once the PHY is registered, the framework will call set_host / set_peripheral and the HW gets set to correct state. > > + mutex_init(&tu->serialize); > > + > > + tu->ick = devm_clk_get(&pdev->dev, "usb_l4_ick"); > > + if (!IS_ERR(tu->ick)) > > + clk_enable(tu->ick); > > + > > + /* > > + * Set initial state, so that we generate kevents only on state changes. > > + */ > > + tu->vbus_state = retu_read(rdev, TAHVO_REG_IDSR) & TAHVO_STAT_VBUS; > > + > > + tu->extcon.name = DRIVER_NAME; > > + tu->extcon.supported_cable = tahvo_cable; > > + ret = extcon_dev_register(&tu->extcon, &pdev->dev); > > + if (ret) { > > + dev_err(&pdev->dev, "could not register extcon device: %d\n", > > + ret); > > + return ret; > > + } > > + > > + /* Set the initial cable state. */ > > + extcon_set_cable_state(&tu->extcon, "USB-HOST", > > + tu->tahvo_mode == TAHVO_MODE_HOST); > > + extcon_set_cable_state(&tu->extcon, "USB", tu->vbus_state); > > + > > + tu->irq = platform_get_irq(pdev, 0); > > + ret = request_threaded_irq(tu->irq, NULL, tahvo_usb_vbus_interrupt, 0, > > + "tahvo-vbus", tu); > > since your hardirq handler is NULL, you *must* pass IRQF_ONESHOT. Ok. > /Could also use devm_request_threaded_irq() Does not really help much, since the IRQ has to be freed manually anyway (to ensure it's disabled before usb_remove_phy(); also looks like it's currently enabled too early...). > > + if (ret) { > > + dev_err(&pdev->dev, "could not register tahvo-vbus irq: %d\n", > > + ret); > > + goto err_disable_clk; > > + } > > + > > + /* Attributes */ > > + ret = device_create_file(&pdev->dev, &dev_attr_vbus_state); > > + ret |= device_create_file(&pdev->dev, &dev_attr_otg_mode); > > heh, Greg wrote a very interesting article recently (look at his blog) > discussing kernel/userland races wrt creation of sysfs files. [...] > what if someone accesses the sysfs file you've already created before > you call dev_set_drvdata? (not sure if it's possible). Yes, that's a bug, will fix. Thanks for comments, A. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html