linux-kernel - [PATCH 2/2] mux: mmio: add generic regmap bitfield-based multiplexer

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Date:   Tue, 30 Apr 2019 19:52:41 +0000
From:   Peter Rosin <peda@...ntia.se>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Pankaj Bansal <pankaj.bansal@....com>,
        Peter Rosin <peda@...ntia.se>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: [PATCH 2/2] mux: mmio: add generic regmap bitfield-based multiplexer

From: Pankaj Bansal <pankaj.bansal@....com>

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@....com>
Signed-off-by: Peter Rosin <peda@...ntia.se>
---
 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);
-- 
2.11.0