From 7d1e3bd94828ad9fc86f55253cd6fec8edd65394 Mon Sep 17 00:00:00 2001 From: Jeremy Kerr Date: Thu, 5 Jan 2023 08:50:10 +0800 Subject: mfd: syscon: Allow reset control for syscon devices Simple syscon devices may require deassertion of a reset signal in order to access their register set. Rather than requiring a custom driver to implement this, we can use the generic "resets" specifiers to link a reset line to the syscon. This change adds an optional reset line to the syscon device description, and deasserts the reset if detected. Signed-off-by: Jeremy Kerr Reviewed-by: Arnd Bergmann Signed-off-by: Lee Jones Link: https://lore.kernel.org/r/20230105005010.124948-3-jk@codeconstruct.com.au --- drivers/mfd/syscon.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) (limited to 'drivers/mfd') diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c index bdb2ce7ff03b..57b29c325131 100644 --- a/drivers/mfd/syscon.c +++ b/drivers/mfd/syscon.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include @@ -31,6 +32,7 @@ static LIST_HEAD(syscon_list); struct syscon { struct device_node *np; struct regmap *regmap; + struct reset_control *reset; struct list_head list; }; @@ -40,7 +42,7 @@ static const struct regmap_config syscon_regmap_config = { .reg_stride = 4, }; -static struct syscon *of_syscon_register(struct device_node *np, bool check_clk) +static struct syscon *of_syscon_register(struct device_node *np, bool check_res) { struct clk *clk; struct syscon *syscon; @@ -50,6 +52,7 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk) int ret; struct regmap_config syscon_config = syscon_regmap_config; struct resource res; + struct reset_control *reset; syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); if (!syscon) @@ -114,7 +117,7 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk) goto err_regmap; } - if (check_clk) { + if (check_res) { clk = of_clk_get(np, 0); if (IS_ERR(clk)) { ret = PTR_ERR(clk); @@ -124,8 +127,18 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk) } else { ret = regmap_mmio_attach_clk(regmap, clk); if (ret) - goto err_attach; + goto err_attach_clk; } + + reset = of_reset_control_get_optional_exclusive(np, NULL); + if (IS_ERR(reset)) { + ret = PTR_ERR(reset); + goto err_attach_clk; + } + + ret = reset_control_deassert(reset); + if (ret) + goto err_reset; } syscon->regmap = regmap; @@ -137,7 +150,9 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk) return syscon; -err_attach: +err_reset: + reset_control_put(reset); +err_attach_clk: if (!IS_ERR(clk)) clk_put(clk); err_clk: @@ -150,7 +165,7 @@ err_map: } static struct regmap *device_node_get_regmap(struct device_node *np, - bool check_clk) + bool check_res) { struct syscon *entry, *syscon = NULL; @@ -165,7 +180,7 @@ static struct regmap *device_node_get_regmap(struct device_node *np, spin_unlock(&syscon_list_slock); if (!syscon) - syscon = of_syscon_register(np, check_clk); + syscon = of_syscon_register(np, check_res); if (IS_ERR(syscon)) return ERR_CAST(syscon); -- cgit v1.2.3