Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752758Ab2KILBq (ORCPT ); Fri, 9 Nov 2012 06:01:46 -0500 Received: from bear.ext.ti.com ([192.94.94.41]:51324 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752199Ab2KILA7 convert rfc822-to-8bit (ORCPT ); Fri, 9 Nov 2012 06:00:59 -0500 From: "Philip, Avinash" To: Thierry Reding CC: "paul@pwsan.com" , "tony@atomide.com" , "linux@arm.linux.org.uk" , "Cousson, Benoit" , "Hiremath, Vaibhav" , "AnilKumar, Chimata" , "linux-kernel@vger.kernel.org" , "devicetree-discuss@lists.ozlabs.org" , "linux-doc@vger.kernel.org" , "linux-omap@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "Nori, Sekhar" , "Hebbar, Gururaja" , "Bedia, Vaibhav" Subject: RE: [PATCH v2 01/10] PWMSS: Add PWM Subsystem driver for parent<->child relationship Thread-Topic: [PATCH v2 01/10] PWMSS: Add PWM Subsystem driver for parent<->child relationship Thread-Index: AQHNvYZaLj+J99sDHUCOiHqMkaBmqZfgwMmAgACHQxA= Date: Fri, 9 Nov 2012 10:59:29 +0000 Deferred-Delivery: Fri, 9 Nov 2012 10:58:00 +0000 Message-ID: <518397C60809E147AF5323E0420B992E3E9E44F3@DBDE01.ent.ti.com> References: <1352361197-27442-1-git-send-email-avinashphilip@ti.com> <1352361197-27442-2-git-send-email-avinashphilip@ti.com> <20121109072957.GA21991@avionic-0098.mockup.avionic-design.de> In-Reply-To: <20121109072957.GA21991@avionic-0098.mockup.avionic-design.de> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [172.24.162.24] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10921 Lines: 389 On Fri, Nov 09, 2012 at 12:59:57, Thierry Reding wrote: > On Thu, Nov 08, 2012 at 01:23:08PM +0530, Philip, Avinash wrote: > > diff --git a/Documentation/devicetree/bindings/pwm/tipwmss.txt b/Documentation/devicetree/bindings/pwm/tipwmss.txt > > new file mode 100644 > > index 0000000..b6c2814 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/pwm/tipwmss.txt > > @@ -0,0 +1,30 @@ > [...] > > +Also child nodes should also populated under PWMSS DT node. > > +Example: > > Maybe put an blank line between these two lines for readability? Ok I will add. > > > +pwmss0: pwmss@48300000 { > > + compatible = "ti,am33xx-pwmss"; > > + reg = <0x48300000 0x10 > > + 0x48300100 0x80 > > + 0x48300180 0x80 > > + 0x48300200 0x80>; > > I don't think you should list the register spaces of the children here. > From what I understand, all regions listed in the reg property are > supposed to be requested by the corresponding driver and therefore > cannot be used by any other device. I will check & correct it. > > > + ti,hwmods = "epwmss0"; > > + #address-cells = <1>; > > + #size-cells = <1>; > > + status = "disabled"; > > + ranges; > > I think to represent which memory regions go to the children, you should > put them in this ranges property, which would then look like this: > > ranges = <0x48300100 0x48300100 0x80 /* ECAP */ > 0x48300180 0x48300180 0x80 /* EQEP */ > 0x48300200 0x48300200 0x80>; /* EHRPWM */ I will correct it. > > > + > > + /* child nodes go here */ > > +}; > > Maybe you should actually list a full set of children here? Ok. > > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > > index 6e556c7..384a346 100644 > > --- a/drivers/pwm/Kconfig > > +++ b/drivers/pwm/Kconfig > > @@ -136,6 +136,7 @@ config PWM_TEGRA > > config PWM_TIECAP > > tristate "ECAP PWM support" > > depends on SOC_AM33XX > > + select PWM_TIPWMSS > > help > > PWM driver support for the ECAP APWM controller found on AM33XX > > TI SOC > > @@ -146,6 +147,7 @@ config PWM_TIECAP > > config PWM_TIEHRPWM > > tristate "EHRPWM PWM support" > > depends on SOC_AM33XX > > + select PWM_TIPWMSS > > help > > PWM driver support for the EHRPWM controller found on AM33XX > > TI SOC > > @@ -153,6 +155,15 @@ config PWM_TIEHRPWM > > To compile this driver as a module, choose M here: the module > > will be called pwm-tiehrpwm. > > > > +config PWM_TIPWMSS > > + tristate "TI PWM Subsytem parent support" > > + depends on SOC_AM33XX && (PWM_TIEHRPWM || PWM_TIECAP) > > Since you select the symbol from the PWM_TIECAP and PWM_TIEHRPWM symbols > there is no need to depend on them, right? Oh, but maybe that's to make > sure the symbol is deselected automatically if neither user is selected. I want to make sure that, symbol selected only if either are selected. > > Perhaps this should actually be a hidden symbol (i.e. leave away the > prompt string in the tristate option) since it's purely a dependency and > not useful of its own. Ok I will take care. > > > + help > > + PWM Subsystem driver support for AM33xx SOC. > > + > > + PWM submodules require PWM config space access from submodule > > + drivers and require common parent driver support. > > + > > config PWM_TWL6030 > > tristate "TWL6030 PWM support" > > depends on TWL4030_CORE > > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile > > index 3b3f4c9..55f6fb2 100644 > > --- a/drivers/pwm/Makefile > > +++ b/drivers/pwm/Makefile > > @@ -12,5 +12,6 @@ obj-$(CONFIG_PWM_SPEAR) += pwm-spear.o > > obj-$(CONFIG_PWM_TEGRA) += pwm-tegra.o > > obj-$(CONFIG_PWM_TIECAP) += pwm-tiecap.o > > obj-$(CONFIG_PWM_TIEHRPWM) += pwm-tiehrpwm.o > > +obj-$(CONFIG_PWM_TIPWMSS) += tipwmss.o > > This should have a pwm- prefix as well. Ok I will add. > > > obj-$(CONFIG_PWM_TWL6030) += pwm-twl6030.o > > obj-$(CONFIG_PWM_VT8500) += pwm-vt8500.o > > diff --git a/drivers/pwm/tipwmss.c b/drivers/pwm/tipwmss.c > > new file mode 100644 > > index 0000000..c188348 > > --- /dev/null > > +++ b/drivers/pwm/tipwmss.c > > @@ -0,0 +1,142 @@ > [...] > > +#include "tipwmss.h" > > + > > +#define PWMSS_CLKCONFIG 0x8 /* Clock gaitng reg, for PWM submodules */ > > "gating" Ok > > > +#define PWMSS_CLKSTATUS 0xc /* Clock gating status reg */ > > + > > +struct pwmss_info { > > + void __iomem *mmio_base; > > + struct mutex pwmss_lock; > > + u16 pwmss_clkconfig; > > The indentation looks weird on this last field. Ok I will correct it. > > > +}; > > + > > +u16 pwmss_submodule_state_change(struct device *dev, int set) > > +{ > > + struct pwmss_info *info = dev_get_drvdata(dev); > > + u16 val; > > + > > + val = readw(info->mmio_base + PWMSS_CLKCONFIG); > > + val |= set; > > + mutex_lock(&info->pwmss_lock); > > + writew(val , info->mmio_base + PWMSS_CLKCONFIG); > > + mutex_unlock(&info->pwmss_lock); > > The mutex needs to span the whole read-modify-write sequence, not just > the write. I missed. I will correct it. > > Also, how do you clear this state? Here is the hardware trick comes. For enabling should write enable bit. For disabling stop_req bit should set & it will clear enable bit also. > > > + return readw(info->mmio_base + PWMSS_CLKSTATUS); > > +} > > +EXPORT_SYMBOL(pwmss_submodule_state_change); > > + > > +static const struct of_device_id pwmss_of_match[] = { > > + { > > + .compatible = "ti,am33xx-pwmss", > > + }, > > + {}, > > +}; > > +MODULE_DEVICE_TABLE(of, pwmss_of_match); > > + > > +static int __devinit pwmss_probe(struct platform_device *pdev) > > __dev* annotation usage is deprecated, you should drop it. Ok > > > +{ > > + int ret; > > + struct resource *r; > > + struct pwmss_info *info; > > + struct device_node *node = pdev->dev.of_node; > > + > > + info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL); > > + if (!info) { > > + dev_err(&pdev->dev, "failed to allocate memory\n"); > > + return -ENOMEM; > > + } > > + > > + mutex_init(&info->pwmss_lock); > > + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > Blank line between those two lines? Ok > > > + if (!r) { > > + dev_err(&pdev->dev, "no memory resource defined\n"); > > + return -ENODEV; > > + } > > + > > + info->mmio_base = devm_request_and_ioremap(&pdev->dev, r); > > + if (!info->mmio_base) > > + return -EADDRNOTAVAIL; > > + > > + pm_runtime_enable(&pdev->dev); > > + pm_runtime_get_sync(&pdev->dev); > > + platform_set_drvdata(pdev, info); > > + > > + /* Populate all the child nodes here... */ > > + ret = of_platform_populate(node, NULL, NULL, &pdev->dev); > > + if (ret) > > + dev_warn(&pdev->dev, "Doesn't have any child node\n"); > > This reads oddly compared to the other error messages, maybe something > like "no children found" or similar would be more consistent. Ok > > > + > > + return ret; > > Then again, since you return of_platform_populate()'s error code here, > you may just want to skip the above warning since the driver probe won't > succeed anyway. Or if you really want to give a hint as to why loading > failed, maybe it would be better to make it an error message instead. Ok I will change to error message. > > There is one little problem with registering the children here, which is > that if you build the drivers as modules, because once the pwm-tipwmss > module is unloaded, reloading it will fail since it will try to create > the children again. > > AFAICT there are two solutions to this: a) do not allow the pwm-tipwmss > code to be built as a module and b) have of_platform_populate() called > by the architecture initialization code. Both are relatively easy to > implement. a) can be done by making the PWM_TIPWMSS symbol bool instead > of tristate, and b) can be done by adding "simple-bus" to the end of the > compatible list in the DT. Ok I will go for option a. > > > +} > > + > > +static int __devexit pwmss_remove(struct platform_device *pdev) > > Again, no need for __devexit anymore. I will remove > ... > > + > > +static const struct dev_pm_ops pwmss_pm_ops = { > > + .suspend = pwmss_suspend, > > + .resume = pwmss_resume, > > +}; > > Shouldn't these functions be conditionalized on CONFIG_PM_SLEEP? And > maybe you want to use the SIMPLE_DEV_PM_OPS macro here. I will check and correct it. > > > + > > +static struct platform_driver pwmss_driver = { > > + .driver = { > > + .name = "pwmss", > > + .owner = THIS_MODULE, > > + .pm = &pwmss_pm_ops, > > + .of_match_table = of_match_ptr(pwmss_of_match), > > You already define the pwmss_of_match table unconditionally, so you > don't need the of_match_ptr() either. Will remove > > > + }, > > + .probe = pwmss_probe, > > + .remove = __devexit_p(pwmss_remove), > > __devexit_p() can go away. Will remove > > > +}; > > + > > +module_platform_driver(pwmss_driver); > > + > > +MODULE_DESCRIPTION("pwmss driver"); > > This description could be better. Will add. > > > +MODULE_AUTHOR("Texas Instruments"); > > +MODULE_LICENSE("GPL"); > > diff --git a/drivers/pwm/tipwmss.h b/drivers/pwm/tipwmss.h > > new file mode 100644 > > index 0000000..f9cb2e2 > > --- /dev/null > > +++ b/drivers/pwm/tipwmss.h > > I think this should also get the pwm- prefix for consistency with the > source file. Will add the prefix. > > > @@ -0,0 +1,30 @@ > > +/* > > + * TI PWM Subsystem driver > > + * > > + * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/ > > + * > > + * This program is free software; you can redistribute it and/or modify > > + * it under the terms of the GNU General Public License as published by > > + * the Free Software Foundation; either version 2 of the License, or > > + * (at your option) any later version. > > + * > > + * 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. > > + * > > + */ > > + > > +#ifndef __TIPWMSS_H > > +#define __TIPWMSS_H > > + > > +#ifdef CONFIG_PWM_TIPWMSS > > +extern u16 pwmss_submodule_state_change(struct device *dev, int set); > > +#else > > +static inline u16 pwmss_submodule_state_change(struct device *dev, int set) > > +{ > > + /* return success status value */ > > + return 0xFFFF; > > +} > > +#endif > > +#endif /* __TIPWMSS_H */ > > Is it really necessary to provide a !PWM_TIPWMSS version of this > function? All users that want to use it can select it and get the > correct version, right? Added the !PWM_TIPWMSS part to support platforms that didn't have PWM Subsytem support. I will send next version on nov 19th as I was on leave on next week. Thanks Avinash > > Thierry > -- 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/