From patchwork Fri Jan 23 11:21:22 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Heikki Krogerus X-Patchwork-Id: 432149 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 0C8401401F0 for ; Fri, 23 Jan 2015 22:23:37 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752595AbbAWLXg (ORCPT ); Fri, 23 Jan 2015 06:23:36 -0500 Received: from mga02.intel.com ([134.134.136.20]:34799 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752810AbbAWLXe (ORCPT ); Fri, 23 Jan 2015 06:23:34 -0500 Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga101.jf.intel.com with ESMTP; 23 Jan 2015 03:23:34 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.09,453,1418112000"; d="scan'208,223";a="641540103" Received: from kuha.fi.intel.com ([10.237.72.108]) by orsmga001.jf.intel.com with SMTP; 23 Jan 2015 03:23:30 -0800 Received: by kuha.fi.intel.com (sSMTP sendmail emulation); Fri, 23 Jan 2015 13:21:22 +0200 Date: Fri, 23 Jan 2015 13:21:22 +0200 From: Heikki Krogerus To: "Rafael J. Wysocki" , Alexandre Courbot , Linus Walleij Cc: "Rafael J. Wysocki" , Darren Hart , Arnd Bergmann , Andy Shevchenko , Mika Westerberg , "linux-gpio@vger.kernel.org" , "linux-kernel@vger.kernel.org" , ACPI Devel Maling List Subject: Re: [RFC PATCH] gpio: support for GPIO forwarding Message-ID: <20150123112122.GD30522@kuha.fi.intel.com> References: <1418890998-23811-1-git-send-email-heikki.krogerus@linux.intel.com> <4078818.ecVtLF3hjd@vostro.rjw.lan> <1564228.rcRekIyDUd@vostro.rjw.lan> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1564228.rcRekIyDUd@vostro.rjw.lan> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org Hi guys, On Thu, Jan 22, 2015 at 05:14:22PM +0100, Rafael J. Wysocki wrote: > On Thursday, January 22, 2015 11:57:55 AM Alexandre Courbot wrote: > > If we decide to go ahead with the solution proposed by this patch for > > practical reasons (which are good reasons indeed), I still have one > > problem with its current form. > > > > As the discussion highlighted, this is an ACPI problem, so I'd very > > much like it to be confined to the ACPI GPIO code, to be enabled only > > when ACPI is, and to use function names that start with acpi_gpio. > > I can agree with that. > > > The current implementation leverages platform lookup, making said lookup > > less efficient in the process and bringing confusion about its > > purpose. Although the two processes are indeed similar, they are > > separate things: one is a legitimate way to map GPIOs, the other is a > > fixup for broken firmware. > > > > I suppose we all agree this is a hackish fix, so let's confine it as > > much as we can. > > OK > > Heikki, any comments? I'm fine with that. That actually makes me think that we could then drop the lookup tables completely and use device properties instead with the help of "generic property" (attached): We would just need to agree on the format how to describe a gpio property, document it and of course convert the current users as usual. The format could be something like this as an example (I'm writing this out of my head so don't shoot me if you can see it would not work. Just an example): static const u32 example_gpio[] = { , , }; static struct dev_gen_prop example_prop[] = { .type = DEV_PROP_U32, .name = "gpio,", .nval = 2, .num = &example_gpio, }, { }, }; static struct platform_device example_pdev = { ... .dev = { .gen_prop = &example_prop, }, } In gpiolib.c we would then, instead of going through the lookups, simply ask for that property: ... sprintf(propname, "gpio,%s", con_id); device_property_read_u32_array(dev, propname, &val, 2); ... desc = gpio_to_desc(val[0]); flags = val[1]; ... So this is just and idea. I think it would be relatively easy to implement. What do you guys think? Cheers, diff --git a/drivers/base/property.c b/drivers/base/property.c index c458458..4ea6d27 100644 --- a/drivers/base/property.c +++ b/drivers/base/property.c @@ -15,6 +15,108 @@ #include #include +static struct dev_gen_prop *dev_prop_get(struct device *dev, const char *name) +{ + struct dev_gen_prop *prop; + + if (!dev->gen_prop) + return NULL; + + for (prop = dev->gen_prop; prop->name; prop++) + if (!strcmp(name, prop->name)) + return prop; + return NULL; +} + +static int dev_prop_copy_array_u8(u8 *src, u8 *val, size_t nval) +{ + int i; + + for (i = 0; i < nval; i++) + val[i] = src[i]; + return 0; +} + +static int dev_prop_copy_array_u16(u16 *src, u16 *val, size_t nval) +{ + int i; + + for (i = 0; i < nval; i++) + val[i] = src[i]; + return 0; +} + +static int dev_prop_copy_array_u32(u32 *src, u32 *val, size_t nval) +{ + int i; + + for (i = 0; i < nval; i++) + val[i] = src[i]; + return 0; +} + +static int dev_prop_copy_array_u64(u64 *src, u64 *val, size_t nval) +{ + int i; + + for (i = 0; i < nval; i++) + val[i] = src[i]; + return 0; +} + +static int dev_prop_copy_array_string(const char **src, const char **val, + size_t nval) +{ + int i; + + for (i = 0; i < nval; i++) + val[i] = src[i]; + return 0; +} + +static int dev_prop_read_array(struct device *dev, const char *name, + enum dev_prop_type type, void *val, size_t nval) +{ + struct dev_gen_prop *prop; + int ret = 0; + + prop = dev_prop_get(dev, name); + if (!prop) + return -ENODATA; + + if (prop->type != type) + return -EPROTO; + + if (prop->nval < nval) + return -EOVERFLOW; + + switch (prop->type) { + case DEV_PROP_U8: + ret = dev_prop_copy_array_u8((u8 *)prop->num, (u8 *)val, + nval); + break; + case DEV_PROP_U16: + ret = dev_prop_copy_array_u16((u16 *)prop->num, (u16 *)val, + nval); + break; + case DEV_PROP_U32: + ret = dev_prop_copy_array_u32((u32 *)prop->num, (u32 *)val, + nval); + break; + case DEV_PROP_U64: + ret = dev_prop_copy_array_u64(prop->num, (u64 *)val, nval); + break; + case DEV_PROP_STRING: + ret = dev_prop_copy_array_string(prop->str, + (const char **)val, nval); + break; + default: + ret = -EINVAL; + break; + } + return ret; +} + /** * device_property_present - check if a property of a device is present * @dev: Device whose property is being checked @@ -26,8 +128,9 @@ bool device_property_present(struct device *dev, const char *propname) { if (IS_ENABLED(CONFIG_OF) && dev->of_node) return of_property_read_bool(dev->of_node, propname); - - return !acpi_dev_prop_get(ACPI_COMPANION(dev), propname, NULL); + if (ACPI_HANDLE(dev)) + return !acpi_dev_prop_get(ACPI_COMPANION(dev), propname, NULL); + return !!dev_prop_get(dev, propname); } EXPORT_SYMBOL_GPL(device_property_present); @@ -55,8 +158,11 @@ EXPORT_SYMBOL_GPL(fwnode_property_present); IS_ENABLED(CONFIG_OF) && _dev_->of_node ? \ (OF_DEV_PROP_READ_ARRAY(_dev_->of_node, _propname_, _type_, \ _val_, _nval_)) : \ - acpi_dev_prop_read(ACPI_COMPANION(_dev_), _propname_, \ - _proptype_, _val_, _nval_) + ACPI_HANDLE(_dev_) ? \ + acpi_dev_prop_read(ACPI_COMPANION(_dev_), _propname_, \ + _proptype_, _val_, _nval_) : \ + dev_prop_read_array(_dev_, _propname_, _proptype_, \ + _val_, _nval_) /** * device_property_read_u8_array - return a u8 array property of a device @@ -169,10 +275,13 @@ EXPORT_SYMBOL_GPL(device_property_read_u64_array); int device_property_read_string_array(struct device *dev, const char *propname, const char **val, size_t nval) { - return IS_ENABLED(CONFIG_OF) && dev->of_node ? - of_property_read_string_array(dev->of_node, propname, val, nval) : - acpi_dev_prop_read(ACPI_COMPANION(dev), propname, - DEV_PROP_STRING, val, nval); + if (IS_ENABLED(CONFIG_OF) && dev->of_node) + return of_property_read_string_array(dev->of_node, propname, + val, nval); + if (ACPI_HANDLE(dev)) + return acpi_dev_prop_read(ACPI_COMPANION(dev), propname, + DEV_PROP_STRING, val, nval); + return dev_prop_read_array(dev, propname, DEV_PROP_STRING, val, nval); } EXPORT_SYMBOL_GPL(device_property_read_string_array); @@ -193,10 +302,12 @@ EXPORT_SYMBOL_GPL(device_property_read_string_array); int device_property_read_string(struct device *dev, const char *propname, const char **val) { - return IS_ENABLED(CONFIG_OF) && dev->of_node ? - of_property_read_string(dev->of_node, propname, val) : - acpi_dev_prop_read(ACPI_COMPANION(dev), propname, - DEV_PROP_STRING, val, 1); + if (IS_ENABLED(CONFIG_OF) && dev->of_node) + return of_property_read_string(dev->of_node, propname, val); + if (ACPI_HANDLE(dev)) + return acpi_dev_prop_read(ACPI_COMPANION(dev), propname, + DEV_PROP_STRING, val, 1); + return dev_prop_read_array(dev, propname, DEV_PROP_STRING, val, 1); } EXPORT_SYMBOL_GPL(device_property_read_string); diff --git a/include/linux/device.h b/include/linux/device.h index fb50673..738dc25 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -27,6 +27,7 @@ #include #include #include +#include #include struct device; @@ -704,6 +705,7 @@ struct acpi_dev_node { * @archdata: For arch-specific additions. * @of_node: Associated device tree node. * @acpi_node: Associated ACPI device node. + * @gen_prop: Generic device property * @devt: For creating the sysfs "dev". * @id: device instance * @devres_lock: Spinlock to protect the resource of the device. @@ -780,6 +782,7 @@ struct device { struct device_node *of_node; /* associated device tree node */ struct acpi_dev_node acpi_node; /* associated ACPI device node */ + struct dev_gen_prop *gen_prop; /* generic device property */ dev_t devt; /* dev_t, creates the sysfs "dev" */ u32 id; /* device instance */ diff --git a/include/linux/property.h b/include/linux/property.h index a6a3d98..44e875f 100644 --- a/include/linux/property.h +++ b/include/linux/property.h @@ -26,6 +26,23 @@ enum dev_prop_type { DEV_PROP_MAX, }; +/** + * struct dev_gen_prop - Generic Device Property + * @name: property name + * @nval: number of elements in the array + * @str: value array of strings + * @num: value array of numbers + * + * Used when of_node and acpi_node are missing. + */ +struct dev_gen_prop { + enum dev_prop_type type; + const char *name; + size_t nval; + const char **str; + u64 *num; +}; + bool device_property_present(struct device *dev, const char *propname); int device_property_read_u8_array(struct device *dev, const char *propname, u8 *val, size_t nval);