From 22f0d90a34827812413bb3fbeda6a2a79bb58423 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Sat, 21 Jan 2012 12:01:14 +0000 Subject: regmap: Support register patch sets Device manufacturers frequently provide register sequences, usually not fully documented, to be run at startup in order to provide better defaults for devices (for example, improving performance in the light of silicon evaluation). Support such updates by allowing drivers to register update sets with the core. These updates will be written to the device immediately and will also be rewritten when the cache is synced. The assumption is that the reason for resyncing the cache will always be that the device has been powered off. If this turns out to not be the case then a separate operation can be provided. Currently the implementation only allows a single set of updates to be specified for a device, this could be extended in future. Signed-off-by: Mark Brown --- drivers/base/regmap/regmap.c | 58 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) (limited to 'drivers/base/regmap/regmap.c') diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index be10a4f..28e89fd7 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -669,6 +669,64 @@ int regmap_update_bits_check(struct regmap *map, unsigned int reg, } EXPORT_SYMBOL_GPL(regmap_update_bits_check); +/** + * regmap_register_patch: Register and apply register updates to be applied + * on device initialistion + * + * @map: Register map to apply updates to. + * @regs: Values to update. + * @num_regs: Number of entries in regs. + * + * Register a set of register updates to be applied to the device + * whenever the device registers are synchronised with the cache and + * apply them immediately. Typically this is used to apply + * corrections to be applied to the device defaults on startup, such + * as the updates some vendors provide to undocumented registers. + */ +int regmap_register_patch(struct regmap *map, const struct reg_default *regs, + int num_regs) +{ + int i, ret; + bool bypass; + + /* If needed the implementation can be extended to support this */ + if (map->patch) + return -EBUSY; + + mutex_lock(&map->lock); + + bypass = map->cache_bypass; + + map->cache_bypass = true; + + /* Write out first; it's useful to apply even if we fail later. */ + for (i = 0; i < num_regs; i++) { + ret = _regmap_write(map, regs[i].reg, regs[i].def); + if (ret != 0) { + dev_err(map->dev, "Failed to write %x = %x: %d\n", + regs[i].reg, regs[i].def, ret); + goto out; + } + } + + map->patch = kcalloc(sizeof(struct reg_default), num_regs, GFP_KERNEL); + if (map->patch != NULL) { + memcpy(map->patch, regs, + num_regs * sizeof(struct reg_default)); + map->patch_regs = num_regs; + } else { + ret = -ENOMEM; + } + +out: + map->cache_bypass = bypass; + + mutex_unlock(&map->lock); + + return ret; +} +EXPORT_SYMBOL_GPL(regmap_register_patch); + static int __init regmap_initcall(void) { regmap_debugfs_initcall(); -- cgit v1.1