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AJvYcCUvo8u9oTmPE7Ot3SZ2nNIGuzYonSQLF4x/EZqaB3EvjdnHvI0I3ekJBqijLFSl44HE2T5uGILnD6qsUJO1sVynpS87jwU+sFUMehNHdzfjYcI= X-Gm-Message-State: AOJu0YwWA7rDgjNEbJSrzg/RaCk4IP7qg2xNdfld8I60XfeIx7Yp8IZc nrgbgl4jAyyHdPOhLwXskz8neXp0DSUtqbfEsgP38uJjKqzHT0Pubuosnx+a2nE= X-Google-Smtp-Source: AGHT+IEWYOFclmv+Dob4SK4leA35bYz4CV1ZSG93H0XX8NLBeMikAyl8HGO+4UJqtWZ0FffKI/BoJg== X-Received: by 2002:a05:600c:4b27:b0:423:b5f9:203f with SMTP id 5b1f17b1804b1-42475079466mr46049795e9.5.1718882690982; Thu, 20 Jun 2024 04:24:50 -0700 (PDT) Received: from gpeter-l.lan ([2a0d:3344:2e8:8510::3aa]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3647bf3092csm2025371f8f.97.2024.06.20.04.24.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Jun 2024 04:24:50 -0700 (PDT) From: Peter Griffin To: lee@kernel.org, arnd@arndb.de, krzk@kernel.org, alim.akhtar@samsung.com Cc: linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org, tudor.ambarus@linaro.org, andre.draszik@linaro.org, saravanak@google.com, willmcvicker@google.com, semen.protsenko@linaro.org, kernel-team@android.com, Peter Griffin Subject: [PATCH v2 1/2] mfd: syscon: add of_syscon_register_regmap() API Date: Thu, 20 Jun 2024 12:24:45 +0100 Message-ID: <20240620112446.1286223-2-peter.griffin@linaro.org> X-Mailer: git-send-email 2.45.2.627.g7a2c4fd464-goog In-Reply-To: <20240620112446.1286223-1-peter.griffin@linaro.org> References: <20240620112446.1286223-1-peter.griffin@linaro.org> Precedence: bulk X-Mailing-List: linux-samsung-soc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The of_syscon_register_regmap() API allows an externally created regmap to be registered with syscon. This regmap can then be returned to client drivers using the syscon_regmap_lookup_by_phandle() APIs. The API is used by platforms where mmio access to the syscon registers is not possible, and a underlying soc driver like exynos-pmu provides a SoC specific regmap that can issue a SMC or hypervisor call to write the register. This approach keeps the SoC complexities out of syscon, but allows common drivers such as syscon-poweroff, syscon-reboot and friends that are used by many SoCs already to be re-used. Signed-off-by: Peter Griffin Reviewed-by: Arnd Bergmann Reviewed-by: Sam Protsenko --- Changes in v2: - Keep syscon lock held between checking and adding entry (Krzysztof) - Link to v1 https://lore.kernel.org/linux-arm-kernel/20240614140421.3172674-2-peter.griffin@linaro.org/ --- drivers/mfd/syscon.c | 54 ++++++++++++++++++++++++++++++++++++++ include/linux/mfd/syscon.h | 8 ++++++ 2 files changed, 62 insertions(+) diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c index 7d0e91164cba..75379e089b6b 100644 --- a/drivers/mfd/syscon.c +++ b/drivers/mfd/syscon.c @@ -192,6 +192,60 @@ static struct regmap *device_node_get_regmap(struct device_node *np, return syscon->regmap; } +/** + * of_syscon_register_regmap() - Register regmap for specified device node + * @np: Device tree node + * @regmap: Pointer to regmap object + * + * Register an externally created regmap object with syscon for the specified + * device tree node. This regmap can then be returned to client drivers using + * the syscon_regmap_lookup_by_phandle() API. + * + * Return: 0 on success, negative error code on failure. + */ +int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap) +{ + struct syscon *entry, *syscon = NULL; + int ret; + + if (!np || !regmap) + return -EINVAL; + + /* check if syscon entry already exists */ + spin_lock(&syscon_list_slock); + + list_for_each_entry(entry, &syscon_list, list) + if (entry->np == np) { + syscon = entry; + break; + } + + if (syscon) { + ret = -EEXIST; + goto err_unlock; + } + + syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); + if (!syscon) { + ret = -ENOMEM; + goto err_unlock; + } + + syscon->regmap = regmap; + syscon->np = np; + + /* register the regmap in syscon list */ + list_add_tail(&syscon->list, &syscon_list); + spin_unlock(&syscon_list_slock); + + return 0; + +err_unlock: + spin_unlock(&syscon_list_slock); + return ret; +} +EXPORT_SYMBOL_GPL(of_syscon_register_regmap); + struct regmap *device_node_to_regmap(struct device_node *np) { return device_node_get_regmap(np, false); diff --git a/include/linux/mfd/syscon.h b/include/linux/mfd/syscon.h index c315903f6dab..aad9c6b50463 100644 --- a/include/linux/mfd/syscon.h +++ b/include/linux/mfd/syscon.h @@ -28,6 +28,8 @@ struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np, unsigned int *out_args); struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np, const char *property); +int of_syscon_register_regmap(struct device_node *np, + struct regmap *regmap); #else static inline struct regmap *device_node_to_regmap(struct device_node *np) { @@ -67,6 +69,12 @@ static inline struct regmap *syscon_regmap_lookup_by_phandle_optional( return NULL; } +static inline int of_syscon_register_regmap(struct device_node *np, + struct regmap *regmap) +{ + return -EOPNOTSUPP; +} + #endif #endif /* __LINUX_MFD_SYSCON_H__ */