Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933837AbbDPIMr (ORCPT ); Thu, 16 Apr 2015 04:12:47 -0400 Received: from cantor2.suse.de ([195.135.220.15]:41610 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933628AbbDPIFk (ORCPT ); Thu, 16 Apr 2015 04:05:40 -0400 From: NeilBrown To: Kishon Vijay Abraham I Date: Thu, 16 Apr 2015 18:03:04 +1000 Subject: [PATCH 5/6] phy: twl4030-usb: add support for reading resistor on ID pin. Cc: NeilBrown , linux-kernel@vger.kernel.org, GTA04 owners , Tony Lindgren , Pavel Machek , linux-omap@vger.kernel.org Message-ID: <20150416080304.23307.41913.stgit@notabene.brown> In-Reply-To: <20150416075945.23307.24424.stgit@notabene.brown> References: <20150416075945.23307.24424.stgit@notabene.brown> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4430 Lines: 149 From: NeilBrown The twl4030 phy can measure, with low precision, the resistance-to-ground of the ID pin. Add a function to read the value, and export the result via sysfs. If the read fails, which it does sometimes, try again in 50msec. Acked-by: Pavel Machek Signed-off-by: NeilBrown --- .../ABI/testing/sysfs-platform-twl4030-usb | 22 +++++++ drivers/phy/phy-twl4030-usb.c | 63 ++++++++++++++++++++ 2 files changed, 85 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-platform-twl4030-usb b/Documentation/ABI/testing/sysfs-platform-twl4030-usb index 512c51be64ae..425d23676f8a 100644 --- a/Documentation/ABI/testing/sysfs-platform-twl4030-usb +++ b/Documentation/ABI/testing/sysfs-platform-twl4030-usb @@ -6,3 +6,25 @@ Description: Possible values: "on", "off". Changes are notified via select/poll. + +What: /sys/bus/platform/devices/*twl4030-usb/id +Description: + Read-only report on measurement of USB-OTG ID pin. + + The ID pin may be floating, grounded, or pulled to + ground by a resistor. + + A very course grained reading of the resistance is + available. The numbers given in kilo-ohms are roughly + the center-point of the detected range. + + Possible values are: + ground + 102k + 200k + 440k + floating + unknown + + "unknown" indicates a problem with trying to detect + the resistance. diff --git a/drivers/phy/phy-twl4030-usb.c b/drivers/phy/phy-twl4030-usb.c index 3a707dd14238..1d6f3e70193e 100644 --- a/drivers/phy/phy-twl4030-usb.c +++ b/drivers/phy/phy-twl4030-usb.c @@ -379,6 +379,56 @@ static void twl4030_i2c_access(struct twl4030_usb *twl, int on) } } +enum twl4030_id_status { + TWL4030_GROUND, + TWL4030_102K, + TWL4030_200K, + TWL4030_440K, + TWL4030_FLOATING, + TWL4030_ID_UNKNOWN, +}; +static char *twl4030_id_names[] = { + "ground", + "102k", + "200k", + "440k", + "floating", + "unknown" +}; + +enum twl4030_id_status twl4030_get_id(struct twl4030_usb *twl) +{ + int ret; + + pm_runtime_get_sync(twl->dev); + if (twl->usb_mode == T2_USB_MODE_ULPI) + twl4030_i2c_access(twl, 1); + ret = twl4030_usb_read(twl, ULPI_OTG_CTRL); + if (ret < 0 || !(ret & ULPI_OTG_ID_PULLUP)) { + /* Need pull-up to read ID */ + twl4030_usb_set_bits(twl, ULPI_OTG_CTRL, + ULPI_OTG_ID_PULLUP); + mdelay(50); + } + ret = twl4030_usb_read(twl, ID_STATUS); + if (ret < 0 || (ret & 0x1f) == 0) { + mdelay(50); + ret = twl4030_usb_read(twl, ID_STATUS); + } + + if (twl->usb_mode == T2_USB_MODE_ULPI) + twl4030_i2c_access(twl, 0); + pm_runtime_put_autosuspend(twl->dev); + + if (ret < 0) + return TWL4030_ID_UNKNOWN; + ret = ffs(ret) - 1; + if (ret < TWL4030_GROUND || ret > TWL4030_FLOATING) + return TWL4030_ID_UNKNOWN; + + return ret; +} + static void __twl4030_phy_power(struct twl4030_usb *twl, int on) { u8 pwr = twl4030_usb_read(twl, PHY_PWR_CTRL); @@ -532,6 +582,16 @@ static ssize_t twl4030_usb_vbus_show(struct device *dev, } static DEVICE_ATTR(vbus, 0444, twl4030_usb_vbus_show, NULL); +static ssize_t twl4030_usb_id_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct twl4030_usb *twl = dev_get_drvdata(dev); + return scnprintf(buf, PAGE_SIZE, "%s\n", + twl4030_id_names[twl4030_get_id(twl)]); +} +static DEVICE_ATTR(id, 0444, twl4030_usb_id_show, NULL); + static irqreturn_t twl4030_usb_irq(int irq, void *_twl) { struct twl4030_usb *twl = _twl; @@ -709,6 +769,8 @@ static int twl4030_usb_probe(struct platform_device *pdev) platform_set_drvdata(pdev, twl); if (device_create_file(&pdev->dev, &dev_attr_vbus)) dev_warn(&pdev->dev, "could not create sysfs file\n"); + if (device_create_file(&pdev->dev, &dev_attr_id)) + dev_warn(&pdev->dev, "could not create sysfs file\n"); ATOMIC_INIT_NOTIFIER_HEAD(&twl->phy.notifier); @@ -753,6 +815,7 @@ static int twl4030_usb_remove(struct platform_device *pdev) pm_runtime_get_sync(twl->dev); cancel_delayed_work(&twl->id_workaround_work); device_remove_file(twl->dev, &dev_attr_vbus); + device_remove_file(twl->dev, &dev_attr_id); /* set transceiver mode to power on defaults */ twl4030_usb_set_mode(twl, -1); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/