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Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ueEw0-00000002sJL-491E; Tue, 22 Jul 2025 15:29:40 +0000 Received: from frasgout.his.huawei.com ([185.176.79.56]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1ueDgf-00000002e6K-1AGf for linux-phy@lists.infradead.org; Tue, 22 Jul 2025 14:09:47 +0000 Received: from mail.maildlp.com (unknown [172.18.186.231]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4bmfHZ0kkCz6H7XD; Tue, 22 Jul 2025 22:08:10 +0800 (CST) Received: from frapeml500008.china.huawei.com (unknown [7.182.85.71]) by mail.maildlp.com (Postfix) with ESMTPS id 17F4B140446; Tue, 22 Jul 2025 22:09:34 +0800 (CST) Received: from localhost (10.203.177.66) by frapeml500008.china.huawei.com (7.182.85.71) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Tue, 22 Jul 2025 16:09:32 +0200 Date: Tue, 22 Jul 2025 15:09:30 +0100 From: Jonathan Cameron To: AngeloGioacchino Del Regno CC: , , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH v2 1/7] spmi: Implement spmi_subdevice_alloc_and_add() and devm variant Message-ID: <20250722150930.00000a2f@huawei.com> In-Reply-To: <20250722101317.76729-2-angelogioacchino.delregno@collabora.com> References: <20250722101317.76729-1-angelogioacchino.delregno@collabora.com> <20250722101317.76729-2-angelogioacchino.delregno@collabora.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) MIME-Version: 1.0 X-Originating-IP: [10.203.177.66] X-ClientProxiedBy: lhrpeml500011.china.huawei.com (7.191.174.215) To frapeml500008.china.huawei.com (7.182.85.71) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250722_070945_612429_B962C7AA X-CRM114-Status: GOOD ( 32.94 ) X-BeenThere: linux-phy@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux Phy Mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-phy" Errors-To: linux-phy-bounces+linux-phy=archiver.kernel.org@lists.infradead.org On Tue, 22 Jul 2025 12:13:11 +0200 AngeloGioacchino Del Regno wrote: > Some devices connected over the SPMI bus may be big, in the sense > that those may be a complex of devices managed by a single chip > over the SPMI bus, reachable through a single SID. > > Add new functions aimed at managing sub-devices of a SPMI device > spmi_subdevice_alloc_and_add() and a spmi_subdevice_put_and_remove() > for adding a new subdevice and removing it respectively, and also > add their devm_* variants. > > The need for such functions comes from the existance of those > complex Power Management ICs (PMICs), which feature one or many > sub-devices, in some cases with these being even addressable on > the chip in form of SPMI register ranges. > > Examples of those devices can be found in both Qualcomm platforms > with their PMICs having PON, RTC, SDAM, GPIO controller, and other > sub-devices, and in newer MediaTek platforms showing similar HW > features and a similar layout with those also having many subdevs. > > Also, instead of generally exporting symbols, export them with a > new "SPMI" namespace: all users will have to import this namespace > to make use of the newly introduced exports. > > Signed-off-by: AngeloGioacchino Del Regno > --- > drivers/spmi/spmi-devres.c | 23 +++++++++++ > drivers/spmi/spmi.c | 83 ++++++++++++++++++++++++++++++++++++++ > include/linux/spmi.h | 16 ++++++++ > 3 files changed, 122 insertions(+) > > diff --git a/drivers/spmi/spmi-devres.c b/drivers/spmi/spmi-devres.c > index 62c4b3f24d06..7e00e38be2ff 100644 > --- a/drivers/spmi/spmi-devres.c > +++ b/drivers/spmi/spmi-devres.c > @@ -60,5 +60,28 @@ int devm_spmi_controller_add(struct device *parent, struct spmi_controller *ctrl > } > EXPORT_SYMBOL_GPL(devm_spmi_controller_add); > > +static void devm_spmi_subdevice_remove(void *res) > +{ > + spmi_subdevice_remove((struct spmi_subdevice *)res); Why the cast? Implicit casts are fine for void * to any other pointer type so spmi_subdevice_remove(res); should be fine. > +} > MODULE_LICENSE("GPL"); > MODULE_DESCRIPTION("SPMI devres helpers"); > diff --git a/drivers/spmi/spmi.c b/drivers/spmi/spmi.c > index 3cf8d9bd4566..62bb782b2bbc 100644 > --- a/drivers/spmi/spmi.c > +++ b/drivers/spmi/spmi.c > @@ -19,6 +19,7 @@ > > static bool is_registered; > static DEFINE_IDA(ctrl_ida); > +static DEFINE_IDA(spmi_subdevice_ida); > > static void spmi_dev_release(struct device *dev) > { > @@ -31,6 +32,18 @@ static const struct device_type spmi_dev_type = { > .release = spmi_dev_release, > }; > > +static void spmi_subdev_release(struct device *dev) > +{ > + struct spmi_device *sdev = to_spmi_device(dev); > + struct spmi_subdevice *sub_sdev = container_of(sdev, struct spmi_subdevice, sdev); > + > + kfree(sub_sdev); > +} > + > +static const struct device_type spmi_subdev_type = { > + .release = spmi_subdev_release, > +}; > + > static void spmi_ctrl_release(struct device *dev) > { > struct spmi_controller *ctrl = to_spmi_controller(dev); > @@ -90,6 +103,19 @@ void spmi_device_remove(struct spmi_device *sdev) > } > EXPORT_SYMBOL_GPL(spmi_device_remove); > > +/** > + * spmi_subdevice_remove() - Remove an SPMI subdevice > + * @sub_sdev: spmi_device to be removed > + */ > +void spmi_subdevice_remove(struct spmi_subdevice *sub_sdev) > +{ > + struct spmi_device *sdev = &sub_sdev->sdev; > + > + device_unregister(&sdev->dev); > + ida_free(&spmi_subdevice_ida, sub_sdev->devid); Why not make the ida free part of the release? If not the device_unregister could (I think) result in a reference count drop and freeing of sub_sdev before you dereference it here. > +} > +EXPORT_SYMBOL_NS_GPL(spmi_subdevice_remove, "SPMI"); > + > static inline int > spmi_cmd(struct spmi_controller *ctrl, u8 opcode, u8 sid) > { > @@ -431,6 +457,63 @@ struct spmi_device *spmi_device_alloc(struct spmi_controller *ctrl) > } > EXPORT_SYMBOL_GPL(spmi_device_alloc); > > +/** > + * spmi_subdevice_alloc_and_add(): Allocate and add a new SPMI sub-device > + * @sparent: SPMI parent device with previously registered SPMI controller > + * > + * Returns: > + * Pointer to newly allocated SPMI sub-device for success or negative ERR_PTR. > + */ > +struct spmi_subdevice *spmi_subdevice_alloc_and_add(struct spmi_device *sparent) > +{ > + struct spmi_subdevice *sub_sdev; > + struct spmi_device *sdev; > + int ret; > + > + if (!sparent) > + return ERR_PTR(-EINVAL); Is this protecting against a real possibility? Feels like something went very wrong if you are allocating a subdevice of 'nothing'. If it's just defensive programming I'd drop it. > + > + sub_sdev = kzalloc(sizeof(*sub_sdev), GFP_KERNEL); > + if (!sub_sdev) > + return ERR_PTR(-ENOMEM); > + > + ret = ida_alloc(&spmi_subdevice_ida, GFP_KERNEL); > + if (ret < 0) > + goto err_ida_alloc; > + > + sdev = &sub_sdev->sdev; > + sdev->ctrl = sparent->ctrl; > + device_initialize(&sdev->dev); Read the device_initialize() documentation for what you need to do if an error occurs after this point. Specifically the last 'NOTE'. > + sdev->dev.parent = &sparent->dev; > + sdev->dev.bus = &spmi_bus_type; > + sdev->dev.type = &spmi_subdev_type; > + > + sub_sdev->devid = ret; > + sdev->usid = sparent->usid; > + > + ret = dev_set_name(&sdev->dev, "%d-%02x.%d.auto", > + sdev->ctrl->nr, sdev->usid, sub_sdev->devid); > + if (ret) > + goto err_set_name; > + > + ret = device_add(&sdev->dev); > + if (ret) { > + dev_err(&sdev->dev, "Can't add %s, status %d\n", > + dev_name(&sdev->dev), ret); > + put_device(&sdev->dev); > + return ERR_PTR(ret); > + } > + > + return sub_sdev; > + > +err_set_name: > + ida_free(&ctrl_ida, sub_sdev->devid); > +err_ida_alloc: > + kfree(sub_sdev); > + return ERR_PTR(ret); > +} > +EXPORT_SYMBOL_NS_GPL(spmi_subdevice_alloc_and_add, "SPMI"); > + > /** > * spmi_controller_alloc() - Allocate a new SPMI controller > * @parent: parent device > diff --git a/include/linux/spmi.h b/include/linux/spmi.h > index 28e8c8bd3944..7cea0a5b034b 100644 > --- a/include/linux/spmi.h > +++ b/include/linux/spmi.h > @@ -69,6 +69,22 @@ int spmi_device_add(struct spmi_device *sdev); > > void spmi_device_remove(struct spmi_device *sdev); > > +/** > + * struct spmi_subdevice - Basic representation of an SPMI sub-device > + * @sdev: Sub-device representation of an SPMI device > + * @devid: Platform Device ID of an SPMI sub-device > + */ > +struct spmi_subdevice { > + struct spmi_device sdev; Having something called a subdevice containing an instance of a device does seem a little odd. Maybe the spmi_device naming is inappropriate after this patch? > + unsigned int devid; > +}; > + > +struct spmi_subdevice *spmi_subdevice_alloc_and_add(struct spmi_device *sparent); > +void spmi_subdevice_remove(struct spmi_subdevice *sdev); > + > +struct spmi_subdevice *devm_spmi_subdevice_alloc_and_add(struct device *dev, > + struct spmi_device *sparent); -- linux-phy mailing list linux-phy@lists.infradead.org https://lists.infradead.org/mailman/listinfo/linux-phy