diff options
Diffstat (limited to 'drivers/mfd/syscon.c')
| -rw-r--r-- | drivers/mfd/syscon.c | 196 |
1 files changed, 105 insertions, 91 deletions
diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c index c9550368d9ea..ae71a2710bed 100644 --- a/drivers/mfd/syscon.c +++ b/drivers/mfd/syscon.c @@ -8,25 +8,20 @@ * Author: Dong Aisheng <dong.aisheng@linaro.org> */ +#include <linux/cleanup.h> #include <linux/clk.h> #include <linux/err.h> #include <linux/hwspinlock.h> -#include <linux/io.h> -#include <linux/init.h> #include <linux/list.h> +#include <linux/mutex.h> #include <linux/of.h> #include <linux/of_address.h> -#include <linux/of_platform.h> -#include <linux/platform_data/syscon.h> -#include <linux/platform_device.h> #include <linux/regmap.h> #include <linux/reset.h> #include <linux/mfd/syscon.h> #include <linux/slab.h> -static struct platform_driver syscon_driver; - -static DEFINE_SPINLOCK(syscon_list_slock); +static DEFINE_MUTEX(syscon_list_lock); static LIST_HEAD(syscon_list); struct syscon { @@ -45,7 +40,6 @@ static const struct regmap_config syscon_regmap_config = { static struct syscon *of_syscon_register(struct device_node *np, bool check_res) { struct clk *clk; - struct syscon *syscon; struct regmap *regmap; void __iomem *base; u32 reg_io_width; @@ -53,21 +47,20 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_res) struct regmap_config syscon_config = syscon_regmap_config; struct resource res; struct reset_control *reset; + resource_size_t res_size; - syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); + WARN_ON(!mutex_is_locked(&syscon_list_lock)); + + struct syscon *syscon __free(kfree) = kzalloc(sizeof(*syscon), GFP_KERNEL); if (!syscon) return ERR_PTR(-ENOMEM); - if (of_address_to_resource(np, 0, &res)) { - ret = -ENOMEM; - goto err_map; - } + if (of_address_to_resource(np, 0, &res)) + return ERR_PTR(-ENOMEM); base = of_iomap(np, 0); - if (!base) { - ret = -ENOMEM; - goto err_map; - } + if (!base) + return ERR_PTR(-ENOMEM); /* Parse the device's DT node for an endianness specification */ if (of_property_read_bool(np, "big-endian")) @@ -104,6 +97,12 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_res) } } + res_size = resource_size(&res); + if (res_size < reg_io_width) { + ret = -EFAULT; + goto err_regmap; + } + syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start); if (!syscon_config.name) { ret = -ENOMEM; @@ -111,7 +110,9 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_res) } syscon_config.reg_stride = reg_io_width; syscon_config.val_bits = reg_io_width * 8; - syscon_config.max_register = resource_size(&res) - reg_io_width; + syscon_config.max_register = res_size - reg_io_width; + if (!syscon_config.max_register) + syscon_config.max_register_is_0 = true; regmap = regmap_init_mmio(NULL, base, &syscon_config); kfree(syscon_config.name); @@ -148,11 +149,9 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_res) syscon->regmap = regmap; syscon->np = np; - spin_lock(&syscon_list_slock); list_add_tail(&syscon->list, &syscon_list); - spin_unlock(&syscon_list_slock); - return syscon; + return_ptr(syscon); err_reset: reset_control_put(reset); @@ -163,17 +162,16 @@ err_clk: regmap_exit(regmap); err_regmap: iounmap(base); -err_map: - kfree(syscon); return ERR_PTR(ret); } static struct regmap *device_node_get_regmap(struct device_node *np, + bool create_regmap, bool check_res) { struct syscon *entry, *syscon = NULL; - spin_lock(&syscon_list_slock); + mutex_lock(&syscon_list_lock); list_for_each_entry(entry, &syscon_list, list) if (entry->np == np) { @@ -181,10 +179,13 @@ static struct regmap *device_node_get_regmap(struct device_node *np, break; } - spin_unlock(&syscon_list_slock); - - if (!syscon) - syscon = of_syscon_register(np, check_res); + if (!syscon) { + if (create_regmap) + syscon = of_syscon_register(np, check_res); + else + syscon = ERR_PTR(-EINVAL); + } + mutex_unlock(&syscon_list_lock); if (IS_ERR(syscon)) return ERR_CAST(syscon); @@ -192,18 +193,85 @@ 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 will 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; + + syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); + if (!syscon) + return -ENOMEM; + + /* check if syscon entry already exists */ + mutex_lock(&syscon_list_lock); + + list_for_each_entry(entry, &syscon_list, list) + if (entry->np == np) { + ret = -EEXIST; + goto err_unlock; + } + + syscon->regmap = regmap; + syscon->np = np; + + /* register the regmap in syscon list */ + list_add_tail(&syscon->list, &syscon_list); + mutex_unlock(&syscon_list_lock); + + return 0; + +err_unlock: + mutex_unlock(&syscon_list_lock); + kfree(syscon); + return ret; +} +EXPORT_SYMBOL_GPL(of_syscon_register_regmap); + +/** + * device_node_to_regmap() - Get or create a regmap for specified device node + * @np: Device tree node + * + * Get a regmap for the specified device node. If there's not an existing + * regmap, then one is instantiated. This function should not be used if the + * device node has a custom regmap driver or has resources (clocks, resets) to + * be managed. Use syscon_node_to_regmap() instead for those cases. + * + * Return: regmap ptr on success, negative error code on failure. + */ struct regmap *device_node_to_regmap(struct device_node *np) { - return device_node_get_regmap(np, false); + return device_node_get_regmap(np, true, false); } EXPORT_SYMBOL_GPL(device_node_to_regmap); +/** + * syscon_node_to_regmap() - Get or create a regmap for specified syscon device node + * @np: Device tree node + * + * Get a regmap for the specified device node. If there's not an existing + * regmap, then one is instantiated if the node is a generic "syscon". This + * function is safe to use for a syscon registered with + * of_syscon_register_regmap(). + * + * Return: regmap ptr on success, negative error code on failure. + */ struct regmap *syscon_node_to_regmap(struct device_node *np) { - if (!of_device_is_compatible(np, "syscon")) - return ERR_PTR(-EINVAL); - - return device_node_get_regmap(np, true); + return device_node_get_regmap(np, of_device_is_compatible(np, "syscon"), true); } EXPORT_SYMBOL_GPL(syscon_node_to_regmap); @@ -238,7 +306,9 @@ struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, return ERR_PTR(-ENODEV); regmap = syscon_node_to_regmap(syscon_np); - of_node_put(syscon_np); + + if (property) + of_node_put(syscon_np); return regmap; } @@ -290,59 +360,3 @@ struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np, return regmap; } EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional); - -static int syscon_probe(struct platform_device *pdev) -{ - struct device *dev = &pdev->dev; - struct syscon_platform_data *pdata = dev_get_platdata(dev); - struct syscon *syscon; - struct regmap_config syscon_config = syscon_regmap_config; - struct resource *res; - void __iomem *base; - - syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); - if (!syscon) - return -ENOMEM; - - res = platform_get_resource(pdev, IORESOURCE_MEM, 0); - if (!res) - return -ENOENT; - - base = devm_ioremap(dev, res->start, resource_size(res)); - if (!base) - return -ENOMEM; - - syscon_config.max_register = resource_size(res) - 4; - if (pdata) - syscon_config.name = pdata->label; - syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config); - if (IS_ERR(syscon->regmap)) { - dev_err(dev, "regmap init failed\n"); - return PTR_ERR(syscon->regmap); - } - - platform_set_drvdata(pdev, syscon); - - dev_dbg(dev, "regmap %pR registered\n", res); - - return 0; -} - -static const struct platform_device_id syscon_ids[] = { - { "syscon", }, - { } -}; - -static struct platform_driver syscon_driver = { - .driver = { - .name = "syscon", - }, - .probe = syscon_probe, - .id_table = syscon_ids, -}; - -static int __init syscon_init(void) -{ - return platform_driver_register(&syscon_driver); -} -postcore_initcall(syscon_init); |