[PATCH 1/2] mfd: syscon: Support physical regmap bus

From: Baolin Wang
Date: Thu Apr 16 2020 - 22:14:38 EST


Some platforms such as Spreadtrum platform, define a special method to
update bits of the registers instead of reading and writing, which means
we should use a physical regmap bus to define the reg_update_bits()
operation instead of the MMIO regmap bus.

Thus add a new helper for the syscon driver to allow to register a physical
regmap bus to support this new requirement.

Signed-off-by: Baolin Wang <baolin.wang7@xxxxxxxxx>
---
drivers/mfd/syscon.c | 23 +++++++++++++++++++++--
include/linux/mfd/syscon.h | 7 +++++++
2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index 3a97816d0cba..92bfe87038ca 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -24,6 +24,7 @@
#include <linux/slab.h>

static struct platform_driver syscon_driver;
+static struct regmap_bus *syscon_phy_regmap_bus;

static DEFINE_SPINLOCK(syscon_list_slock);
static LIST_HEAD(syscon_list);
@@ -106,14 +107,25 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
syscon_config.val_bits = reg_io_width * 8;
syscon_config.max_register = resource_size(&res) - reg_io_width;

- regmap = regmap_init_mmio(NULL, base, &syscon_config);
+ /*
+ * The Spreadtrum syscon need register a real physical regmap bus
+ * with new atomic bits updating operation instead of using
+ * read-modify-write.
+ */
+ if (IS_ENABLED(CONFIG_ARCH_SPRD) &&
+ of_device_is_compatible(np, "sprd,atomic-syscon") &&
+ syscon_phy_regmap_bus)
+ regmap = regmap_init(NULL, syscon_phy_regmap_bus, base,
+ &syscon_config);
+ else
+ regmap = regmap_init_mmio(NULL, base, &syscon_config);
if (IS_ERR(regmap)) {
pr_err("regmap init failed\n");
ret = PTR_ERR(regmap);
goto err_regmap;
}

- if (check_clk) {
+ if (check_clk && !syscon_phy_regmap_bus) {
clk = of_clk_get(np, 0);
if (IS_ERR(clk)) {
ret = PTR_ERR(clk);
@@ -172,6 +184,13 @@ static struct regmap *device_node_get_regmap(struct device_node *np,
return syscon->regmap;
}

+void syscon_register_phys_regmap_bus(struct regmap_bus *phy_regmap_bus)
+{
+ if (phy_regmap_bus)
+ syscon_phy_regmap_bus = phy_regmap_bus;
+}
+EXPORT_SYMBOL_GPL(syscon_register_phys_regmap_bus);
+
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 7f20e9b502a5..fbc2a2f0f414 100644
--- a/include/linux/mfd/syscon.h
+++ b/include/linux/mfd/syscon.h
@@ -13,6 +13,7 @@

#include <linux/err.h>
#include <linux/errno.h>
+#include <linux/regmap.h>

struct device_node;

@@ -28,6 +29,7 @@ extern struct regmap *syscon_regmap_lookup_by_phandle_args(
const char *property,
int arg_count,
unsigned int *out_args);
+extern void syscon_register_phys_regmap_bus(struct regmap_bus *phy_regmap_bus);
#else
static inline struct regmap *device_node_to_regmap(struct device_node *np)
{
@@ -59,6 +61,11 @@ static inline struct regmap *syscon_regmap_lookup_by_phandle_args(
{
return ERR_PTR(-ENOTSUPP);
}
+
+static inline void
+syscon_register_phys_regmap_bus(struct regmap_bus *phy_regmap_bus)
+{
+}
#endif

#endif /* __LINUX_MFD_SYSCON_H__ */
--
2.17.1