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Wed, 29 Apr 2020 07:39:24 -0400 Received: from mail-ot1-x344.google.com (mail-ot1-x344.google.com [IPv6:2607:f8b0:4864:20::344]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 81D72C03C1AE for ; Wed, 29 Apr 2020 04:39:24 -0700 (PDT) Received: by mail-ot1-x344.google.com with SMTP id m13so1379266otf.6 for ; Wed, 29 Apr 2020 04:39:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=o9VrpMFGjOZAS3Z1MSBGkfDTiC/JRHokO7emMoXoeIE=; b=pxa+H+hOMi3z5vWJlv69Dxx4Isvr/SWvy5GTYEsKmySqlgpAvDWT/pCeHv+EPwqCyM ruGoQe8ND8601mqmCQObvux9EZ884oLXSzjlgckjwDhjUjY08IbzoeP41vXhgAwAj/eW tPxsqWfe8wg5llAwmHiUZbdE3rcoueGzCJnSwy0ryepv6QJy1c2lt4VvbGraQqAYKEEp 7YgxIjQ1lVdoW6Jg7nY2Thx2dHW0lvontdVtbRKKGaABSMJvSOj2TyOGA5Sps0EUrQKi wx0IlP/coReesElhwHv0UZ1D/K7TzwiZznSjm2GizSB4PRsh2IZgA9vBpe7KZHk1FJ1E L4/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=o9VrpMFGjOZAS3Z1MSBGkfDTiC/JRHokO7emMoXoeIE=; b=dme3OqO3RIE32TMPlpzSFy1PvsmhQUP1IrcvAhWmVnN6GQikZNJpVJLwqIK+uFVKQa Yp91UC2VUEdbq0g4kD91qlxsT7yamgXIeOAT1kx0Zv1H86TnCDQ8OCb+4aAvxUwZ1UUF HamLSA/6DOWZWU6j/DE4ydw85mLM4b+ZaXIAZ+iGw0S+AG2EHTk/1SgX3S2aDQObtdzf 8hYitz2rCwYd5Pqq5f46euKIddbWFGBHtlMn3SUpAQ+mZSWTDhfab9h3dIxNmn7eS5mF tqrWwp6XusUDlSkGkGnUPGzwss6POIWl65h5a1Syoi7vbxPmIDghExpdNOADoZaTwcGx eH+g== X-Gm-Message-State: AGi0PuYTvCdB6NMrKEyLa0/bDOTNKIvXtcQ53pafoI/ZavwU36/mQEzd mHmBrLnZq79wXRx9PREGSxWMBYKAX1YEWkVzSuqTkw== X-Google-Smtp-Source: APiQypITz23O96j+VAKXsxtYRMC+UiqrZWtT6Qk/x0g9an80p19WixC+bUNecs3lb0W7N89TLaP+nCuleQLr+IvG8ns= X-Received: by 2002:a05:6830:1e4e:: with SMTP id e14mr25681406otj.91.1588160363652; Wed, 29 Apr 2020 04:39:23 -0700 (PDT) MIME-Version: 1.0 References: <20200428180718.1609826-1-robert.foss@linaro.org> <20200428180718.1609826-2-robert.foss@linaro.org> <20200429090012.vhhwatojkncjquwd@gilmour.lan> <20200429111307.GA867@valkosipuli.retiisi.org.uk> In-Reply-To: <20200429111307.GA867@valkosipuli.retiisi.org.uk> From: Robert Foss Date: Wed, 29 Apr 2020 13:39:12 +0200 Message-ID: Subject: Re: [PATCH v5 v5 2/3] media: ov8856: Add devicetree support To: Sakari Ailus Cc: Maxime Ripard , Andy Shevchenko , Marco Felsch , linux-media , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , linux-kernel , "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" , Dongchun Zhu , Fabio Estevam , Tomasz Figa Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 29 Apr 2020 at 13:13, Sakari Ailus wrote: > > Hi Robert, Maxime, > > On Wed, Apr 29, 2020 at 12:19:38PM +0200, Robert Foss wrote: > > On Wed, 29 Apr 2020 at 11:00, Maxime Ripard wrote: > > > > > > Hi, > > > > > > On Tue, Apr 28, 2020 at 08:07:17PM +0200, Robert Foss wrote: > > > > Add match table, enable ov8856_probe() to support > > > > both ACPI and DT modes. > > > > > > > > ACPI and DT modes are primarily distinguished from > > > > each other by relying on devm_XXX_get_optional() > > > > will return NULL instead of a reference for the > > > > desired managed resource. > > > > > > > > Signed-off-by: Robert Foss > > > > --- > > > > > > > > - Changes since v4: > > > > * Maxime & Sakari: Switch to clock-frequency > > > > > > > > - Changes since v3: > > > > * Remove redundant {}-brackets > > > > * Compare xvclk_rate to 5% tolerance > > > > * Andy: Use dev_fwnode() > > > > * Andy: Use %pe instead of %ld + PTR_ERR() > > > > * Andy: Invert reset_gpio logic > > > > * Andy: Remove dev_dbg() from failing reset_gpio setup > > > > * Andy: Use dev_err for logging for failures > > > > * Andy: Remove dev_warn from EDEFER/regulator error path > > > > * Andy & Sakari: Replaced GPIOD_OUT_XXX with 0/1 > > > > * Maxime & Sakari: Verify clock frequency from DT > > > > * Sakari: Verify the 'xvclk_rate' is set correctly for ACPI/DT devices > > > > * Sakari: Remove duplicate ov8856->dev assignment > > > > > > > > - Changes since v2: > > > > * Added "struct device *dev" member to struct ov8856 > > > > * Andy: Switch to optional version of devm_gpiod_get > > > > * Andy: Switch to optional version of devm_clk_get > > > > * Fabio: Add reset sleep period > > > > * Sakari: Unify defines for 19.2Mhz > > > > * Sakari: Remove 24Mhz clock, since it isn't needed for supported modes > > > > * Sakari: Replace dev_info() with dev_dbg() > > > > * Sakari: Switch induction variable type to unsigned > > > > * Sakari: Don't wait for reset_gpio when in ACPI mode > > > > * Sakari: Pull reset GPIO high on power on failure > > > > * Sakari: Add power on/off to resume/suspend > > > > * Sakari: Fix indentation > > > > * Sakari: Power off during ov8856_remove() > > > > * Sakari: Don't sleep during power-on in ACPI mode > > > > * Sakari: Switch to getting xvclk from clk_get_rate > > > > > > > > - Changes since v1: > > > > * Andy & Sakari: Make XVCLK optional since to not break ACPI > > > > * Fabio: Change n_shutdown_gpio name to reset_gpio > > > > * Fabio: Invert reset_gpio due to GPIO_ACTIVE_HIGH -> GPIO_ACTIVE_LOW change > > > > * Fabio: Remove empty line > > > > * Fabio: Remove real error from devm_gpiod_get() failures > > > > * Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES > > > > * Sakari: Use XVCLK rate as provided by DT > > > > > > > > drivers/media/i2c/ov8856.c | 139 +++++++++++++++++++++++++++++++++---- > > > > 1 file changed, 126 insertions(+), 13 deletions(-) > > > > > > > > diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c > > > > index 8655842af275..48b02b8d205f 100644 > > > > --- a/drivers/media/i2c/ov8856.c > > > > +++ b/drivers/media/i2c/ov8856.c > > > > @@ -3,10 +3,13 @@ > > > > > > > > #include > > > > #include > > > > +#include > > > > #include > > > > +#include > > > > #include > > > > #include > > > > #include > > > > +#include > > > > #include > > > > #include > > > > #include > > > > @@ -18,7 +21,7 @@ > > > > #define OV8856_LINK_FREQ_360MHZ 360000000ULL > > > > #define OV8856_LINK_FREQ_180MHZ 180000000ULL > > > > #define OV8856_SCLK 144000000ULL > > > > -#define OV8856_MCLK 19200000 > > > > +#define OV8856_XVCLK_19_2 19200000 > > > > #define OV8856_DATA_LANES 4 > > > > #define OV8856_RGB_DEPTH 10 > > > > > > > > @@ -64,6 +67,12 @@ > > > > > > > > #define to_ov8856(_sd) container_of(_sd, struct ov8856, sd) > > > > > > > > +static const char * const ov8856_supply_names[] = { > > > > + "dovdd", /* Digital I/O power */ > > > > + "avdd", /* Analog power */ > > > > + "dvdd", /* Digital core power */ > > > > +}; > > > > + > > > > enum { > > > > OV8856_LINK_FREQ_720MBPS, > > > > OV8856_LINK_FREQ_360MBPS, > > > > @@ -566,6 +575,11 @@ struct ov8856 { > > > > struct media_pad pad; > > > > struct v4l2_ctrl_handler ctrl_handler; > > > > > > > > + struct device *dev; > > > > + struct clk *xvclk; > > > > + struct gpio_desc *reset_gpio; > > > > + struct regulator_bulk_data supplies[ARRAY_SIZE(ov8856_supply_names)]; > > > > + > > > > /* V4L2 Controls */ > > > > struct v4l2_ctrl *link_freq; > > > > struct v4l2_ctrl *pixel_rate; > > > > @@ -908,6 +922,52 @@ static int ov8856_set_stream(struct v4l2_subdev *sd, int enable) > > > > return ret; > > > > } > > > > > > > > +static int __ov8856_power_on(struct ov8856 *ov8856) > > > > +{ > > > > + struct i2c_client *client = v4l2_get_subdevdata(&ov8856->sd); > > > > + int ret; > > > > + > > > > + ret = clk_prepare_enable(ov8856->xvclk); > > > > + if (ret < 0) { > > > > + dev_err(&client->dev, "failed to enable xvclk\n"); > > > > + return ret; > > > > + } > > > > + > > > > + if (is_acpi_node(dev_fwnode(ov8856->dev))) > > > > + return 0; > > > > + > > > > + if (ov8856->reset_gpio) { > > > > + gpiod_set_value_cansleep(ov8856->reset_gpio, 1); > > > > + usleep_range(1000, 2000); > > > > + } > > > > + > > > > + ret = regulator_bulk_enable(ARRAY_SIZE(ov8856_supply_names), > > > > + ov8856->supplies); > > > > + if (ret < 0) { > > > > + dev_err(&client->dev, "failed to enable regulators\n"); > > > > + goto disable_clk; > > > > + } > > > > + > > > > + gpiod_set_value_cansleep(ov8856->reset_gpio, 0); > > > > + usleep_range(1500, 1800); > > > > + > > > > + return 0; > > > > + > > > > +disable_clk: > > > > + gpiod_set_value_cansleep(ov8856->reset_gpio, 1); > > > > + clk_disable_unprepare(ov8856->xvclk); > > > > + > > > > + return ret; > > > > +} > > > > + > > > > +static void __ov8856_power_off(struct ov8856 *ov8856) > > > > +{ > > > > + gpiod_set_value_cansleep(ov8856->reset_gpio, 1); > > > > + regulator_bulk_disable(ARRAY_SIZE(ov8856_supply_names), > > > > + ov8856->supplies); > > > > + clk_disable_unprepare(ov8856->xvclk); > > > > +} > > > > + > > > > static int __maybe_unused ov8856_suspend(struct device *dev) > > > > { > > > > struct i2c_client *client = to_i2c_client(dev); > > > > @@ -918,6 +978,7 @@ static int __maybe_unused ov8856_suspend(struct device *dev) > > > > if (ov8856->streaming) > > > > ov8856_stop_streaming(ov8856); > > > > > > > > + __ov8856_power_off(ov8856); > > > > mutex_unlock(&ov8856->mutex); > > > > > > > > return 0; > > > > @@ -931,6 +992,8 @@ static int __maybe_unused ov8856_resume(struct device *dev) > > > > int ret; > > > > > > > > mutex_lock(&ov8856->mutex); > > > > + > > > > + __ov8856_power_on(ov8856); > > > > if (ov8856->streaming) { > > > > ret = ov8856_start_streaming(ov8856); > > > > if (ret) { > > > > @@ -1092,29 +1155,58 @@ static int ov8856_identify_module(struct ov8856 *ov8856) > > > > return 0; > > > > } > > > > > > > > -static int ov8856_check_hwcfg(struct device *dev) > > > > +static int ov8856_get_hwcfg(struct ov8856 *ov8856) > > > > { > > > > + struct device *dev = ov8856->dev; > > > > struct fwnode_handle *ep; > > > > struct fwnode_handle *fwnode = dev_fwnode(dev); > > > > struct v4l2_fwnode_endpoint bus_cfg = { > > > > .bus_type = V4L2_MBUS_CSI2_DPHY > > > > }; > > > > - u32 mclk; > > > > + u32 xvclk_rate; > > > > int ret; > > > > unsigned int i, j; > > > > > > > > if (!fwnode) > > > > return -ENXIO; > > > > > > > > - ret = fwnode_property_read_u32(fwnode, "clock-frequency", &mclk); > > > > + ret = fwnode_property_read_u32(fwnode, "clock-frequency", > > > > + &xvclk_rate); > > > > if (ret) > > > > return ret; > > > > > > > > - if (mclk != OV8856_MCLK) { > > > > - dev_err(dev, "external clock %d is not supported", mclk); > > > > + if (!is_acpi_node(fwnode)) { > > > > + ov8856->xvclk = devm_clk_get(dev, "xvclk"); > > > > + if (IS_ERR(ov8856->xvclk)) { > > > > + dev_err(dev, "could not get xvclk clock (%pe)\n", > > > > + ov8856->xvclk); > > > > + return PTR_ERR(ov8856->xvclk); > > > > + } > > > > + > > > > + clk_set_rate(ov8856->xvclk, xvclk_rate); > > > > + xvclk_rate = clk_get_rate(ov8856->xvclk); > > > > + } > > > > + > > > > + /* external clock must be 19.2MHz, allow 5% tolerance */ > > > > > > Where is that 5% tolerance coming from? Experimentations, datasheets, something > > > that looks good enough? Either way, this should be in the comment. > > > > I don't have access to the full datasheet unfortunately. A 24Mhz rate > > is as far as I understand it supported and required for higher > > bandwidth count modes. > > It was suggested to me that adding a tolerance is the best practice, > > the ov5645 driver uses a 1% tolerance, which may be more appropriate. > > The frequency should really be exact. Sometimes what happens is, however, > that a register list based driver does not have the register lists for a > frequency that is available on a given system. That's why some drivers have > allowed some difference to the intended frequency. > > That 5 % seems like a random value, just like any other number that differs > from the exact frequency would be. > > I'd issue a warning if the frequency differs from what was intended, but > still proceed with probe. This way we can make sure the difference is noted > while boards that cannot provide the exact frequency supported by the > driver can still function. Issuing a warning sounds like a good solution to me. What do you think Maxime? > > -- > Regards, > > Sakari Ailus From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0988FC8300A for ; Wed, 29 Apr 2020 11:39:32 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B30902082E for ; Wed, 29 Apr 2020 11:39:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="dkfWLf8L"; 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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=o9VrpMFGjOZAS3Z1MSBGkfDTiC/JRHokO7emMoXoeIE=; b=IN5KvHEcsr0wyyZtQEkfqybP514UQre1jHc9R6eteOnLCrclzygy33O2KLB3eukX/R yJRaiZVqmXD9K4Q3jzrdM1VBsq/r08j8/6UOuUh3gADjgI8EDT9edzotZZxSp58NqxWk 9f9WDRAG5pxMWwN6xpPgeXuqVNRep+eSl2H4EZmgctRV8Bdkj3Qs6cBnbUjToaCfLiQZ qjZyXqqQfPM2pA/EnI0qqsFHdeKpxAvbRpguehiFztv0BOVML91YFIhl7HrbD9/gaAyA NbAYFdMW9IPPtospDjynNdd448R7DEKDmySUGDxW6VEfvANQkEepXOk/wRLgsB1Z7Igt uHyg== X-Gm-Message-State: AGi0PubP5a5Trhc8GaX8PK7wDvn5+0RwHdd1pj9T4Uucu1YVAmdVQtZP lPjvOBhFCg7CVNwBK4OBhcWDLJHnD2AC1a8/sn8ffg== X-Google-Smtp-Source: APiQypITz23O96j+VAKXsxtYRMC+UiqrZWtT6Qk/x0g9an80p19WixC+bUNecs3lb0W7N89TLaP+nCuleQLr+IvG8ns= X-Received: by 2002:a05:6830:1e4e:: with SMTP id e14mr25681406otj.91.1588160363652; Wed, 29 Apr 2020 04:39:23 -0700 (PDT) MIME-Version: 1.0 References: <20200428180718.1609826-1-robert.foss@linaro.org> <20200428180718.1609826-2-robert.foss@linaro.org> <20200429090012.vhhwatojkncjquwd@gilmour.lan> <20200429111307.GA867@valkosipuli.retiisi.org.uk> In-Reply-To: <20200429111307.GA867@valkosipuli.retiisi.org.uk> From: Robert Foss Date: Wed, 29 Apr 2020 13:39:12 +0200 Message-ID: Subject: Re: [PATCH v5 v5 2/3] media: ov8856: Add devicetree support To: Sakari Ailus X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200429_043925_239994_379C599A X-CRM114-Status: GOOD ( 32.29 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Tomasz Figa , Dongchun Zhu , linux-kernel , Marco Felsch , Maxime Ripard , Andy Shevchenko , Fabio Estevam , "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" , linux-media Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 29 Apr 2020 at 13:13, Sakari Ailus wrote: > > Hi Robert, Maxime, > > On Wed, Apr 29, 2020 at 12:19:38PM +0200, Robert Foss wrote: > > On Wed, 29 Apr 2020 at 11:00, Maxime Ripard wrote: > > > > > > Hi, > > > > > > On Tue, Apr 28, 2020 at 08:07:17PM +0200, Robert Foss wrote: > > > > Add match table, enable ov8856_probe() to support > > > > both ACPI and DT modes. > > > > > > > > ACPI and DT modes are primarily distinguished from > > > > each other by relying on devm_XXX_get_optional() > > > > will return NULL instead of a reference for the > > > > desired managed resource. > > > > > > > > Signed-off-by: Robert Foss > > > > --- > > > > > > > > - Changes since v4: > > > > * Maxime & Sakari: Switch to clock-frequency > > > > > > > > - Changes since v3: > > > > * Remove redundant {}-brackets > > > > * Compare xvclk_rate to 5% tolerance > > > > * Andy: Use dev_fwnode() > > > > * Andy: Use %pe instead of %ld + PTR_ERR() > > > > * Andy: Invert reset_gpio logic > > > > * Andy: Remove dev_dbg() from failing reset_gpio setup > > > > * Andy: Use dev_err for logging for failures > > > > * Andy: Remove dev_warn from EDEFER/regulator error path > > > > * Andy & Sakari: Replaced GPIOD_OUT_XXX with 0/1 > > > > * Maxime & Sakari: Verify clock frequency from DT > > > > * Sakari: Verify the 'xvclk_rate' is set correctly for ACPI/DT devices > > > > * Sakari: Remove duplicate ov8856->dev assignment > > > > > > > > - Changes since v2: > > > > * Added "struct device *dev" member to struct ov8856 > > > > * Andy: Switch to optional version of devm_gpiod_get > > > > * Andy: Switch to optional version of devm_clk_get > > > > * Fabio: Add reset sleep period > > > > * Sakari: Unify defines for 19.2Mhz > > > > * Sakari: Remove 24Mhz clock, since it isn't needed for supported modes > > > > * Sakari: Replace dev_info() with dev_dbg() > > > > * Sakari: Switch induction variable type to unsigned > > > > * Sakari: Don't wait for reset_gpio when in ACPI mode > > > > * Sakari: Pull reset GPIO high on power on failure > > > > * Sakari: Add power on/off to resume/suspend > > > > * Sakari: Fix indentation > > > > * Sakari: Power off during ov8856_remove() > > > > * Sakari: Don't sleep during power-on in ACPI mode > > > > * Sakari: Switch to getting xvclk from clk_get_rate > > > > > > > > - Changes since v1: > > > > * Andy & Sakari: Make XVCLK optional since to not break ACPI > > > > * Fabio: Change n_shutdown_gpio name to reset_gpio > > > > * Fabio: Invert reset_gpio due to GPIO_ACTIVE_HIGH -> GPIO_ACTIVE_LOW change > > > > * Fabio: Remove empty line > > > > * Fabio: Remove real error from devm_gpiod_get() failures > > > > * Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES > > > > * Sakari: Use XVCLK rate as provided by DT > > > > > > > > drivers/media/i2c/ov8856.c | 139 +++++++++++++++++++++++++++++++++---- > > > > 1 file changed, 126 insertions(+), 13 deletions(-) > > > > > > > > diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c > > > > index 8655842af275..48b02b8d205f 100644 > > > > --- a/drivers/media/i2c/ov8856.c > > > > +++ b/drivers/media/i2c/ov8856.c > > > > @@ -3,10 +3,13 @@ > > > > > > > > #include > > > > #include > > > > +#include > > > > #include > > > > +#include > > > > #include > > > > #include > > > > #include > > > > +#include > > > > #include > > > > #include > > > > #include > > > > @@ -18,7 +21,7 @@ > > > > #define OV8856_LINK_FREQ_360MHZ 360000000ULL > > > > #define OV8856_LINK_FREQ_180MHZ 180000000ULL > > > > #define OV8856_SCLK 144000000ULL > > > > -#define OV8856_MCLK 19200000 > > > > +#define OV8856_XVCLK_19_2 19200000 > > > > #define OV8856_DATA_LANES 4 > > > > #define OV8856_RGB_DEPTH 10 > > > > > > > > @@ -64,6 +67,12 @@ > > > > > > > > #define to_ov8856(_sd) container_of(_sd, struct ov8856, sd) > > > > > > > > +static const char * const ov8856_supply_names[] = { > > > > + "dovdd", /* Digital I/O power */ > > > > + "avdd", /* Analog power */ > > > > + "dvdd", /* Digital core power */ > > > > +}; > > > > + > > > > enum { > > > > OV8856_LINK_FREQ_720MBPS, > > > > OV8856_LINK_FREQ_360MBPS, > > > > @@ -566,6 +575,11 @@ struct ov8856 { > > > > struct media_pad pad; > > > > struct v4l2_ctrl_handler ctrl_handler; > > > > > > > > + struct device *dev; > > > > + struct clk *xvclk; > > > > + struct gpio_desc *reset_gpio; > > > > + struct regulator_bulk_data supplies[ARRAY_SIZE(ov8856_supply_names)]; > > > > + > > > > /* V4L2 Controls */ > > > > struct v4l2_ctrl *link_freq; > > > > struct v4l2_ctrl *pixel_rate; > > > > @@ -908,6 +922,52 @@ static int ov8856_set_stream(struct v4l2_subdev *sd, int enable) > > > > return ret; > > > > } > > > > > > > > +static int __ov8856_power_on(struct ov8856 *ov8856) > > > > +{ > > > > + struct i2c_client *client = v4l2_get_subdevdata(&ov8856->sd); > > > > + int ret; > > > > + > > > > + ret = clk_prepare_enable(ov8856->xvclk); > > > > + if (ret < 0) { > > > > + dev_err(&client->dev, "failed to enable xvclk\n"); > > > > + return ret; > > > > + } > > > > + > > > > + if (is_acpi_node(dev_fwnode(ov8856->dev))) > > > > + return 0; > > > > + > > > > + if (ov8856->reset_gpio) { > > > > + gpiod_set_value_cansleep(ov8856->reset_gpio, 1); > > > > + usleep_range(1000, 2000); > > > > + } > > > > + > > > > + ret = regulator_bulk_enable(ARRAY_SIZE(ov8856_supply_names), > > > > + ov8856->supplies); > > > > + if (ret < 0) { > > > > + dev_err(&client->dev, "failed to enable regulators\n"); > > > > + goto disable_clk; > > > > + } > > > > + > > > > + gpiod_set_value_cansleep(ov8856->reset_gpio, 0); > > > > + usleep_range(1500, 1800); > > > > + > > > > + return 0; > > > > + > > > > +disable_clk: > > > > + gpiod_set_value_cansleep(ov8856->reset_gpio, 1); > > > > + clk_disable_unprepare(ov8856->xvclk); > > > > + > > > > + return ret; > > > > +} > > > > + > > > > +static void __ov8856_power_off(struct ov8856 *ov8856) > > > > +{ > > > > + gpiod_set_value_cansleep(ov8856->reset_gpio, 1); > > > > + regulator_bulk_disable(ARRAY_SIZE(ov8856_supply_names), > > > > + ov8856->supplies); > > > > + clk_disable_unprepare(ov8856->xvclk); > > > > +} > > > > + > > > > static int __maybe_unused ov8856_suspend(struct device *dev) > > > > { > > > > struct i2c_client *client = to_i2c_client(dev); > > > > @@ -918,6 +978,7 @@ static int __maybe_unused ov8856_suspend(struct device *dev) > > > > if (ov8856->streaming) > > > > ov8856_stop_streaming(ov8856); > > > > > > > > + __ov8856_power_off(ov8856); > > > > mutex_unlock(&ov8856->mutex); > > > > > > > > return 0; > > > > @@ -931,6 +992,8 @@ static int __maybe_unused ov8856_resume(struct device *dev) > > > > int ret; > > > > > > > > mutex_lock(&ov8856->mutex); > > > > + > > > > + __ov8856_power_on(ov8856); > > > > if (ov8856->streaming) { > > > > ret = ov8856_start_streaming(ov8856); > > > > if (ret) { > > > > @@ -1092,29 +1155,58 @@ static int ov8856_identify_module(struct ov8856 *ov8856) > > > > return 0; > > > > } > > > > > > > > -static int ov8856_check_hwcfg(struct device *dev) > > > > +static int ov8856_get_hwcfg(struct ov8856 *ov8856) > > > > { > > > > + struct device *dev = ov8856->dev; > > > > struct fwnode_handle *ep; > > > > struct fwnode_handle *fwnode = dev_fwnode(dev); > > > > struct v4l2_fwnode_endpoint bus_cfg = { > > > > .bus_type = V4L2_MBUS_CSI2_DPHY > > > > }; > > > > - u32 mclk; > > > > + u32 xvclk_rate; > > > > int ret; > > > > unsigned int i, j; > > > > > > > > if (!fwnode) > > > > return -ENXIO; > > > > > > > > - ret = fwnode_property_read_u32(fwnode, "clock-frequency", &mclk); > > > > + ret = fwnode_property_read_u32(fwnode, "clock-frequency", > > > > + &xvclk_rate); > > > > if (ret) > > > > return ret; > > > > > > > > - if (mclk != OV8856_MCLK) { > > > > - dev_err(dev, "external clock %d is not supported", mclk); > > > > + if (!is_acpi_node(fwnode)) { > > > > + ov8856->xvclk = devm_clk_get(dev, "xvclk"); > > > > + if (IS_ERR(ov8856->xvclk)) { > > > > + dev_err(dev, "could not get xvclk clock (%pe)\n", > > > > + ov8856->xvclk); > > > > + return PTR_ERR(ov8856->xvclk); > > > > + } > > > > + > > > > + clk_set_rate(ov8856->xvclk, xvclk_rate); > > > > + xvclk_rate = clk_get_rate(ov8856->xvclk); > > > > + } > > > > + > > > > + /* external clock must be 19.2MHz, allow 5% tolerance */ > > > > > > Where is that 5% tolerance coming from? Experimentations, datasheets, something > > > that looks good enough? Either way, this should be in the comment. > > > > I don't have access to the full datasheet unfortunately. A 24Mhz rate > > is as far as I understand it supported and required for higher > > bandwidth count modes. > > It was suggested to me that adding a tolerance is the best practice, > > the ov5645 driver uses a 1% tolerance, which may be more appropriate. > > The frequency should really be exact. Sometimes what happens is, however, > that a register list based driver does not have the register lists for a > frequency that is available on a given system. That's why some drivers have > allowed some difference to the intended frequency. > > That 5 % seems like a random value, just like any other number that differs > from the exact frequency would be. > > I'd issue a warning if the frequency differs from what was intended, but > still proceed with probe. This way we can make sure the difference is noted > while boards that cannot provide the exact frequency supported by the > driver can still function. Issuing a warning sounds like a good solution to me. What do you think Maxime? > > -- > Regards, > > Sakari Ailus _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel