From nobody Thu Oct 9 10:58:55 2025 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D78762DE208 for ; Wed, 18 Jun 2025 12:03:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750248193; cv=none; b=klvciJYf8vHsTDL99vGFE/44vD5kq71AV7QQkdP+XZNhrMqY486nzKQEFr2OQ2UBkSEWKnX9aMAmvnff7wH5fVt3nNrm+PVznWbeoqXcVBmbR7evx4Hy+LQRPOhaioHyuxoTpKvcThrIZ33Pdo/BwtchcSV5DK5jvav6Z2fxSlo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750248193; c=relaxed/simple; bh=XGojHH9F0Yv1Zaj14e+r4bcattMMcYs/2iz2DruAfIQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=CTeCKL08WD71F3ZOqhnfC3R//Z2AiXE2+L1twubTEHHStfyXq+BV7YlOCGYK4GvJ6L7nty9thDSOxxmD1kHIOXrU7C5nGwPr47d/xAWKIcYCBorNShDxPWUSpGKA1gBzSi3ifOyr9YpB2kBZgUcMAmYNU+/AltNlyDtt7ZVFlhA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1uRrVJ-0007EY-Fn; Wed, 18 Jun 2025 14:02:57 +0200 Received: from dude04.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::ac]) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1uRrVI-0048CO-1g; Wed, 18 Jun 2025 14:02:56 +0200 Received: from ore by dude04.red.stw.pengutronix.de with local (Exim 4.96) (envelope-from ) id 1uRrVI-00DBMX-1J; Wed, 18 Jun 2025 14:02:56 +0200 From: Oleksij Rempel To: Sebastian Reichel , Srinivas Kandagatla , Benson Leung , Tzung-Bi Shih , Daniel Lezcano Cc: Oleksij Rempel , kernel@pengutronix.de, linux-kernel@vger.kernel.org, Liam Girdwood , Mark Brown , "Rafael J. Wysocki" , Zhang Rui , Lukasz Luba , linux-pm@vger.kernel.org, =?UTF-8?q?S=C3=B8ren=20Andersen?= , Guenter Roeck , Matti Vaittinen , Ahmad Fatoum , Andrew Morton , chrome-platform@lists.linux.dev Subject: [PATCH v11 5/7] nvmem: add support for device and sysfs-based cell lookups Date: Wed, 18 Jun 2025 14:02:53 +0200 Message-Id: <20250618120255.3141862-6-o.rempel@pengutronix.de> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250618120255.3141862-1-o.rempel@pengutronix.de> References: <20250618120255.3141862-1-o.rempel@pengutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Introduce new API functions to allow looking up NVMEM devices and cells by name, enhancing flexibility in cases where devicetree-based lookup is not available. Key changes: - Added `nvmem_device_get_by_name()`: Enables retrieving an NVMEM device by its name for systems where direct device reference is needed. - Added `nvmem_cell_get_by_sysfs_name()`: Allows retrieving an NVMEM cell based on its sysfs-style name (e.g., "cell@offset,bits"), making it possible to identify cells dynamically. - Introduced `nvmem_find_cell_entry_by_sysfs_name()`: A helper function that constructs sysfs-like names and searches for matching cell entries. Signed-off-by: Oleksij Rempel --- changes v5: - fix build we NVMEM=3Dn --- drivers/nvmem/core.c | 105 +++++++++++++++++++++++++++++++++ include/linux/nvmem-consumer.h | 18 ++++++ 2 files changed, 123 insertions(+) diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index 59c295a11d86..d310fd8ca9c0 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -1177,6 +1177,23 @@ struct nvmem_device *of_nvmem_device_get(struct devi= ce_node *np, const char *id) EXPORT_SYMBOL_GPL(of_nvmem_device_get); #endif =20 +/** + * nvmem_device_get_by_name - Look up an NVMEM device by its device name + * @name: String matching device name in the provider + * + * Return: A valid pointer to struct nvmem_device on success, + * or ERR_PTR(...) on failure. The caller must later call nvmem_device_put= () to + * release the reference. + */ +struct nvmem_device *nvmem_device_get_by_name(const char *name) +{ + if (!name) + return ERR_PTR(-EINVAL); + + return __nvmem_device_get((void *)name, device_match_name); +} +EXPORT_SYMBOL_GPL(nvmem_device_get_by_name); + /** * nvmem_device_get() - Get nvmem device from a given id * @@ -1490,6 +1507,94 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_n= ode *np, const char *id) EXPORT_SYMBOL_GPL(of_nvmem_cell_get); #endif =20 +/** + * nvmem_find_cell_entry_by_sysfs_name - Find an NVMEM cell entry by its s= ysfs + * name. + * @nvmem: The nvmem_device pointer where the cell is located. + * @sysfs_name: The full sysfs cell name, e.g. "mycell@0x100,8". + * + * This function constructs the sysfs-like name for each cell and compares= it + * to @sysfs_name. If a match is found, the matching nvmem_cell_entry poin= ter + * is returned. This is analogous to nvmem_find_cell_entry_by_name(), exce= pt + * it matches on the sysfs naming convention used in the device's attribut= es. + * + * Return: Pointer to the matching nvmem_cell_entry on success, or NULL if= no + * match is found. + */ +static struct nvmem_cell_entry * +nvmem_find_cell_entry_by_sysfs_name(struct nvmem_device *nvmem, + const char *sysfs_name) +{ + struct nvmem_cell_entry *entry; + char tmp[NVMEM_CELL_NAME_MAX]; + + mutex_lock(&nvmem_mutex); + list_for_each_entry(entry, &nvmem->cells, node) { + int len =3D snprintf(tmp, NVMEM_CELL_NAME_MAX, "%s@%x,%u", + entry->name, entry->offset, + entry->bit_offset); + + if (len >=3D NVMEM_CELL_NAME_MAX) { + pr_warn("nvmem: cell name too long (max %zu bytes): %s\n", + NVMEM_CELL_NAME_MAX, sysfs_name); + continue; + } + + if (len < 0) { + pr_warn("nvmem: error formatting cell name\n"); + continue; + } + + if (!strcmp(tmp, sysfs_name)) { + mutex_unlock(&nvmem_mutex); + return entry; + } + } + + mutex_unlock(&nvmem_mutex); + return NULL; +} + +/** + * nvmem_cell_get_by_sysfs_name - Retrieve an NVMEM cell using a sysfs-sty= le + * name. + * @nvmem: Pointer to the `struct nvmem_device` containing the cell. + * @sysfs_name: The sysfs-style cell name, formatted as + * "@,". + * + * This function enables dynamic lookup of NVMEM cells via sysfs-style + * identifiers. It is useful when devicetree-based lookup is unavailable o= r when + * cells are managed dynamically. + * + * Example Usage: + * nvmem_cell_get_by_sysfs_name(nvmem, "mycell@0x100,8"); + * + * Return: Pointer to `struct nvmem_cell` on success. On error, an ERR_PTR= () is + * returned with the appropriate error code. + */ +struct nvmem_cell *nvmem_cell_get_by_sysfs_name(struct nvmem_device *nvmem, + const char *sysfs_name) +{ + struct nvmem_cell_entry *entry; + struct nvmem_cell *cell; + + entry =3D nvmem_find_cell_entry_by_sysfs_name(nvmem, sysfs_name); + if (!entry) + return ERR_PTR(-ENOENT); + + if (!try_module_get(nvmem->owner)) + return ERR_PTR(-EINVAL); + + kref_get(&nvmem->refcnt); + + cell =3D nvmem_create_cell(entry, entry->name, 0); + if (IS_ERR(cell)) + __nvmem_device_put(nvmem); + + return cell; +} +EXPORT_SYMBOL_GPL(nvmem_cell_get_by_sysfs_name); + /** * nvmem_cell_get() - Get nvmem cell of device form a given cell name * diff --git a/include/linux/nvmem-consumer.h b/include/linux/nvmem-consumer.h index bcb0e17e415d..2b5e06f457b0 100644 --- a/include/linux/nvmem-consumer.h +++ b/include/linux/nvmem-consumer.h @@ -20,6 +20,10 @@ struct nvmem_cell; struct nvmem_device; struct nvmem_cell_info; =20 +#define NVMEM_CELL_NAME_MAX \ + (sizeof("very_long_cell_name_with_some_extra_chars_12345678@0x12345678,12= 8")) + + /** * struct nvmem_cell_lookup - cell lookup entry * @@ -52,6 +56,8 @@ enum { /* Cell based interface */ struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *id); struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id); +struct nvmem_cell *nvmem_cell_get_by_sysfs_name(struct nvmem_device *nvmem, + const char *cell_name); void nvmem_cell_put(struct nvmem_cell *cell); void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell); void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len); @@ -70,6 +76,7 @@ int nvmem_cell_read_variable_le_u64(struct device *dev, c= onst char *cell_id, struct nvmem_device *nvmem_device_get(struct device *dev, const char *name= ); struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *name); +struct nvmem_device *nvmem_device_get_by_name(const char *name); void nvmem_device_put(struct nvmem_device *nvmem); void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem); int nvmem_device_read(struct nvmem_device *nvmem, unsigned int offset, @@ -109,6 +116,12 @@ static inline struct nvmem_cell *devm_nvmem_cell_get(s= truct device *dev, return ERR_PTR(-EOPNOTSUPP); } =20 +static inline struct nvmem_cell * +nvmem_cell_get_by_sysfs_name(struct nvmem_device *nvmem, const char *cell_= name) +{ + return ERR_PTR(-EOPNOTSUPP); +} + static inline void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell) { @@ -185,6 +198,11 @@ static inline struct nvmem_device *devm_nvmem_device_g= et(struct device *dev, return ERR_PTR(-EOPNOTSUPP); } =20 +static inline struct nvmem_device *nvmem_device_get_by_name(const char *na= me) +{ + return ERR_PTR(-EOPNOTSUPP); +} + static inline void nvmem_device_put(struct nvmem_device *nvmem) { } --=20 2.39.5