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 code to perform the deassertion/assertion on
probe/remove.
Signed-off-by: Jeremy Kerr <[email protected]>
---
v2:
* do reset control in the early of_syscon_register() path, rather than
the platform device init, which isn't used.
---
drivers/mfd/syscon.c | 27 +++++++++++++++++++++------
1 file changed, 21 insertions(+), 6 deletions(-)
diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index bdb2ce7ff03b..6b99488d05a6 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -20,6 +20,7 @@
#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>
@@ -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);
@@ -124,7 +127,17 @@ 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;
+ } else if (reset) {
+ ret = regmap_mmio_attach_reset(regmap, reset);
+ if (ret)
+ goto err_attach_reset;
}
}
@@ -137,7 +150,9 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
return syscon;
-err_attach:
+err_attach_reset:
+ reset_control_put(reset);
+err_attach_clk:
if (!IS_ERR(clk))
clk_put(clk);
err_clk:
@@ -150,7 +165,7 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
}
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);
--
2.35.1