Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756604Ab2BBUsW (ORCPT ); Thu, 2 Feb 2012 15:48:22 -0500 Received: from comal.ext.ti.com ([198.47.26.152]:39860 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754183Ab2BBUsV (ORCPT ); Thu, 2 Feb 2012 15:48:21 -0500 Message-ID: <4F2AF68D.1000505@ti.com> Date: Thu, 2 Feb 2012 21:48:13 +0100 From: "Cousson, Benoit" Organization: Texas Instruments User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:8.0) Gecko/20111105 Thunderbird/8.0 MIME-Version: 1.0 To: , CC: Grant Likely , Tarun Kanti DebBarma , , , , , Charulatha V Subject: Re: [PATCH v9 01/25] gpio/omap: remove dependency on gpio_bank_count References: <1328203851-20435-1-git-send-email-tarun.kanti@ti.com> <1328203851-20435-2-git-send-email-tarun.kanti@ti.com> <20120202184106.GC29215@legolas.emea.dhcp.ti.com> <20120202191630.GT15343@ponder.secretlab.ca> <20120202194545.GA29351@legolas.emea.dhcp.ti.com> In-Reply-To: <20120202194545.GA29351@legolas.emea.dhcp.ti.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2857 Lines: 87 On 2/2/2012 8:45 PM, Felipe Balbi wrote: > On Thu, Feb 02, 2012 at 12:16:30PM -0700, Grant Likely wrote: >> On Thu, Feb 02, 2012 at 08:41:07PM +0200, Felipe Balbi wrote: >>> Hi, >>> >>> On Thu, Feb 02, 2012 at 11:00:27PM +0530, Tarun Kanti DebBarma wrote: >>>> diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c >>>> index 0b05629..6ea7390 100644 >>>> --- a/drivers/gpio/gpio-omap.c >>>> +++ b/drivers/gpio/gpio-omap.c >>>> @@ -28,7 +28,10 @@ >>>> #include >>>> #include >>>> >>>> +static LIST_HEAD(omap_gpio_list); >>> >>> I guess it's now too late because patch is acked and everything, but I >>> think if you make the driver handle one bank alone and just instantiate >>> it multiple times (omap_gpio.0, omap_gpio.1, omap_gpio.3, etc) driver >>> would be faaaaaar simpler. >> >> Is there any shared state between the banks? On my very cursory glance it >> looked like banks still have some interaction between them. If not, then >> yes I agree that multiple instances would be better. > > A quick glance at the TRM shows that banks have separate address spaces > and IRQ lines. I think it's done this way because we can handoff one (or > more) bank to other cores on the SoC, so they need to be pretty > independent. > > I could be missing something though. In fact the driver already handled the 6 GPIOS banks as individual devices: [ 0.185638] gpiochip_add: registered GPIOs 0 to 31 on device: gpio [ 0.185882] OMAP GPIO hardware version 0.1 [ 0.186767] gpiochip_add: registered GPIOs 32 to 63 on device: gpio [ 0.187744] gpiochip_add: registered GPIOs 64 to 95 on device: gpio [ 0.188751] gpiochip_add: registered GPIOs 96 to 127 on device: gpio [ 0.189819] gpiochip_add: registered GPIOs 128 to 159 on device: gpio [ 0.190917] gpiochip_add: registered GPIOs 160 to 191 on device: gpio That list is only used to iterate over all the instances during CPU idle: void omap2_gpio_prepare_for_idle(int pwr_mode) { struct gpio_bank *bank; list_for_each_entry(bank, &omap_gpio_list, node) { if (!bank->mod_usage || !bank->loses_context) continue; bank->power_mode = pwr_mode; pm_runtime_put_sync_suspend(bank->dev); } } void omap2_gpio_resume_after_idle(void) { struct gpio_bank *bank; list_for_each_entry(bank, &omap_gpio_list, node) { if (!bank->mod_usage || !bank->loses_context) continue; pm_runtime_get_sync(bank->dev); } } I don't know if there is some reason to not use driver_for_each_device. Kevin, Do we have any constraint inside omap_sram_idle to not use the device iterator? Regards, Benoit -- 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/