From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kishon Vijay Abraham I Subject: Re: [PATCH v3 1/5] phy: Add driver for Exynos MIPI CSIS/DSIM DPHYs Date: Mon, 1 Jul 2013 10:54:28 +0530 Message-ID: <51D1128C.90009@ti.com> References: <1372258946-15607-1-git-send-email-s.nawrocki@samsung.com> <1372258946-15607-2-git-send-email-s.nawrocki@samsung.com> <51CD4698.3070409@gmail.com> <51CD6153.5050406@samsung.com> <51CEA197.8070207@ti.com> <51CF36AB.4010300@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <51CF36AB.4010300@gmail.com> Sender: linux-samsung-soc-owner@vger.kernel.org To: Sylwester Nawrocki Cc: Sylwester Nawrocki , linux-fbdev@vger.kernel.org, linux-samsung-soc@vger.kernel.org, t.figa@samsung.com, jg1.han@samsung.com, dh09.lee@samsung.com, balbi@ti.com, inki.dae@samsung.com, kyungmin.park@samsung.com, Hui Wang , kgene.kim@samsung.com, plagnioj@jcrosoft.com, devicetree-discuss@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org List-Id: devicetree@vger.kernel.org Hi, On Sunday 30 June 2013 01:04 AM, Sylwester Nawrocki wrote: > Hi, > > On 06/29/2013 10:57 AM, Kishon Vijay Abraham I wrote: >> On Friday 28 June 2013 03:41 PM, Sylwester Nawrocki wrote: >>> On 06/28/2013 10:17 AM, Hui Wang wrote: >>>> On 06/26/2013 11:02 PM, Sylwester Nawrocki wrote: >>>>> Add a PHY provider driver for the Samsung S5P/Exynos SoC MIPI CSI-2 >>>>> receiver and MIPI DSI transmitter DPHYs. >>>>> >>>>> Signed-off-by: Sylwester Nawrocki >>>>> Signed-off-by: Kyungmin Park >>>>> --- >>>>> Changes since v2: >>>>> - adapted to the generic PHY API v9: use phy_set/get_drvdata(), >>>>> - fixed of_xlate callback to return ERR_PTR() instead of NULL, >>>>> - namespace cleanup, put "GPL v2" as MODULE_LICENSE, removed pr_debug, >>>>> - removed phy id check in __set_phy_state(). >>>>> --- >>>> [...] >>>>> + >>>>> + if (IS_EXYNOS_MIPI_DSIM_PHY_ID(id)) >>>>> + reset = EXYNOS_MIPI_PHY_MRESETN; >>>>> + else >>>>> + reset = EXYNOS_MIPI_PHY_SRESETN; >>>>> + >>>>> + spin_lock_irqsave(&state->slock, flags); >>>> >>>> Sorry for one stupid question here, why do you use spin_lock_irqsave() >>>> rather than spin_lock(), >>>> I don't see the irq handler will use this spinlock anywhere in this c >>>> file. >>> >>> Yes, there is no chance the PHY users could call the phy ops from within >>> an interrupt context. Especially now when there is a per phy object >>> mutex used in the PHY operation helpers. So I'll replace it with plain >>> spin_lock/unlock. Thank you for the review. >> >> Now that PHY ops is already protected, do you really need a spin_lock here? > > It is still needed, to synchronize access to the control register from > two separate PHY objects. The mutex is per PHY object, while the spinlock > is per PHY provider. Ok. Makes sense. Thanks Kishon