[PATCH v4 2/2] drivers: mux: Add Generic regmap bitfield-based multiplexer in mmio-mux

[Pankaj Bansal]

Generic register bitfield-based multiplexer that controls the multiplexer
producer defined under a parent node.
The driver corresponding to parent node provides register read/write
capabilities.

Signed-off-by: Pankaj Bansal <pankaj.bansal@xxxxxxx>
---

Notes:
    V4:
    - As per Peter's suggestion fixup the NULL from dev_get_regmap as early as
      possible using ternary operator.
    V3:
    - Added the patch in series with device tree binding patch
    - Added the NULL return handling for regmap
    V2:
    - removed seperate driver regmap.c and added the regmap function in mmio.c
      based on compatible field, the syscon or regmap function would be called
    - Modified the KConfig as per Peter's comments

 drivers/mux/Kconfig | 12 ++++++------
 drivers/mux/mmio.c  |  6 +++++-
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/mux/Kconfig b/drivers/mux/Kconfig
index 7659d6c5f718..e5c571fd232c 100644
--- a/drivers/mux/Kconfig
+++ b/drivers/mux/Kconfig
@@ -46,14 +46,14 @@ config MUX_GPIO
 	  be called mux-gpio.
 
 config MUX_MMIO
-	tristate "MMIO register bitfield-controlled Multiplexer"
-	depends on (OF && MFD_SYSCON) || COMPILE_TEST
+	tristate "MMIO/Regmap register bitfield-controlled Multiplexer"
+	depends on OF || COMPILE_TEST
 	help
-	  MMIO register bitfield-controlled Multiplexer controller.
+	  MMIO/Regmap register bitfield-controlled Multiplexer controller.
 
-	  The driver builds multiplexer controllers for bitfields in a syscon
-	  register. For N bit wide bitfields, there will be 2^N possible
-	  multiplexer states.
+	  The driver builds multiplexer controllers for bitfields in either
+	  a syscon register or a driver regmap register. For N bit wide
+	  bitfields, there will be 2^N possible multiplexer states.
 
 	  To compile the driver as a module, choose M here: the module will
 	  be called mux-mmio.
diff --git a/drivers/mux/mmio.c b/drivers/mux/mmio.c
index 935ac44aa209..44a7a0e885b8 100644
--- a/drivers/mux/mmio.c
+++ b/drivers/mux/mmio.c
@@ -28,6 +28,7 @@ static const struct mux_control_ops mux_mmio_ops = {
 
 static const struct of_device_id mux_mmio_dt_ids[] = {
 	{ .compatible = "mmio-mux", },
+	{ .compatible = "reg-mux", },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, mux_mmio_dt_ids);
@@ -43,7 +44,10 @@ static int mux_mmio_probe(struct platform_device *pdev)
 	int ret;
 	int i;
 
-	regmap = syscon_node_to_regmap(np->parent);
+	if (of_device_is_compatible(np, "mmio-mux"))
+		regmap = syscon_node_to_regmap(np->parent);
+	else
+		regmap = dev_get_regmap(dev->parent, NULL) ?: ERR_PTR(-ENODEV);
 	if (IS_ERR(regmap)) {
 		ret = PTR_ERR(regmap);
 		dev_err(dev, "failed to get regmap: %d\n", ret);
-- 
2.17.1