Merge tag 'w1-drv-6.9' of...

Merge tag 'w1-drv-6.9' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux-w1 into tty-next

Krzysztof writes:

1-Wire bus drivers for v6.9

1. Few cleanups: constifying, convert platform remove callback returning
   void.

2. Add UART 1-Wire bus driver which uses UART interface to create the
   1-Wire timing patterns.

* tag 'w1-drv-6.9' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux-w1:
  w1: w1-gpio: Convert to platform remove callback returning void
  w1: sgi_w1: Convert to platform remove callback returning void
  w1: omap_hdq: Convert to platform remove callback returning void
  w1: mxc_w1: Convert to platform remove callback returning void
  w1: add UART w1 bus driver
  dt-bindings: w1: UART 1-Wire bus
  dt-bindings: serial: allow onewire as child node
  w1: make w1_bus_type const

Documentation/devicetree/bindings/serial/serial.yaml

@@ -88,7 +88,7 @@ properties:
       TX FIFO threshold configuration (in bytes).
 
 patternProperties:
-  "^(bluetooth|bluetooth-gnss|gnss|gps|mcu)$":
+  "^(bluetooth|bluetooth-gnss|gnss|gps|mcu|onewire)$":
     if:
       type: object
     then:

Documentation/devicetree/bindings/w1/w1-uart.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/w1/w1-uart.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: UART 1-Wire Bus
+
+maintainers:
+  - Christoph Winklhofer <cj.winklhofer@gmail.com>
+
+description: |
+  UART 1-wire bus. Utilizes the UART interface via the Serial Device Bus
+  to create the 1-Wire timing patterns.
+
+  The UART peripheral must support full-duplex and operate in open-drain
+  mode. The timing patterns are generated by a specific combination of
+  baud-rate and transmitted byte, which corresponds to a 1-Wire read bit,
+  write bit or reset pulse.
+
+  The default baud-rate for reset and presence detection is 9600 and for
+  a 1-Wire read or write operation 115200. In case the actual baud-rate
+  is different from the requested one, the transmitted byte is adapted
+  to generate the 1-Wire timing patterns.
+
+  https://www.analog.com/en/technical-articles/using-a-uart-to-implement-a-1wire-bus-master.html
+
+properties:
+  compatible:
+    const: w1-uart
+
+  reset-bps:
+    default: 9600
+    description:
+      The baud rate for the 1-Wire reset and presence detect.
+
+  write-0-bps:
+    default: 115200
+    description:
+      The baud rate for the 1-Wire write-0 cycle.
+
+  write-1-bps:
+    default: 115200
+    description:
+      The baud rate for the 1-Wire write-1 and read cycle.
+
+required:
+  - compatible
+
+additionalProperties:
+  type: object
+
+examples:
+  - |
+    serial {
+        onewire {
+            compatible = "w1-uart";
+        };
+    };

Documentation/w1/masters/index.rst

@@ -12,3 +12,4 @@
    mxc-w1
    omap-hdq
    w1-gpio
+   w1-uart

Documentation/w1/masters/w1-uart.rst

+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+=====================
+Kernel driver w1-uart
+=====================
+
+Author: Christoph Winklhofer <cj.winklhofer@gmail.com>
+
+
+Description
+-----------
+
+UART 1-Wire bus driver. The driver utilizes the UART interface via the
+Serial Device Bus to create the 1-Wire timing patterns as described in
+the document `"Using a UART to Implement a 1-Wire Bus Master"`_.
+
+.. _"Using a UART to Implement a 1-Wire Bus Master": https://www.analog.com/en/technical-articles/using-a-uart-to-implement-a-1wire-bus-master.html
+
+In short, the UART peripheral must support full-duplex and operate in
+open-drain mode. The timing patterns are generated by a specific
+combination of baud-rate and transmitted byte, which corresponds to a
+1-Wire read bit, write bit or reset pulse.
+
+For instance the timing pattern for a 1-Wire reset and presence detect uses
+the baud-rate 9600, i.e. 104.2 us per bit. The transmitted byte 0xf0 over
+UART (least significant bit first, start-bit low) sets the reset low time
+for 1-Wire to 521 us. A present 1-Wire device changes the received byte by
+pulling the line low, which is used by the driver to evaluate the result of
+the 1-Wire operation.
+
+Similar for a 1-Wire read bit or write bit, which uses the baud-rate
+115200, i.e. 8.7 us per bit. The transmitted byte 0x80 is used for a
+Write-0 operation (low time 69.6us) and the byte 0xff for Read-0, Read-1
+and Write-1 (low time 8.7us).
+
+The default baud-rate for reset and presence detection is 9600 and for
+a 1-Wire read or write operation 115200. In case the actual baud-rate
+is different from the requested one, the transmitted byte is adapted
+to generate the 1-Wire timing patterns.
+
+
+Usage
+-----
+
+Specify the UART 1-wire bus in the device tree by adding the single child
+onewire to the serial node (e.g. uart0). For example:
+::
+
+  @uart0 {
+    ...
+    onewire {
+      compatible = "w1-uart";
+    };
+  };

drivers/w1/masters/Kconfig

@@ -78,5 +78,15 @@ config W1_MASTER_SGI
 	  This support is also available as a module.  If so, the module
 	  will be called sgi_w1.
 
+config W1_MASTER_UART
+	tristate "UART 1-wire driver"
+	depends on SERIAL_DEV_BUS
+	help
+	  Say Y here if you want to communicate with your 1-wire devices using
+	  UART interface.
+
+	  This support is also available as a module.  If so, the module
+	  will be called w1-uart.
+
 endmenu
 

drivers/w1/masters/Makefile

@@ -12,3 +12,4 @@ obj-$(CONFIG_W1_MASTER_MXC)		+= mxc_w1.o
 obj-$(CONFIG_W1_MASTER_GPIO)		+= w1-gpio.o
 obj-$(CONFIG_HDQ_MASTER_OMAP)		+= omap_hdq.o
 obj-$(CONFIG_W1_MASTER_SGI)		+= sgi_w1.o
+obj-$(CONFIG_W1_MASTER_UART)		+= w1-uart.o

drivers/w1/masters/mxc_w1.c

@@ -151,15 +151,13 @@ static int mxc_w1_probe(struct platform_device *pdev)
 /*
  * disassociate the w1 device from the driver
  */
-static int mxc_w1_remove(struct platform_device *pdev)
+static void mxc_w1_remove(struct platform_device *pdev)
 {
 	struct mxc_w1_device *mdev = platform_get_drvdata(pdev);
 
 	w1_remove_master_device(&mdev->bus_master);
 
 	clk_disable_unprepare(mdev->clk);
-
-	return 0;
 }
 
 static const struct of_device_id mxc_w1_dt_ids[] = {
@@ -174,7 +172,7 @@ static struct platform_driver mxc_w1_driver = {
 		.of_match_table = mxc_w1_dt_ids,
 	},
 	.probe = mxc_w1_probe,
-	.remove = mxc_w1_remove,
+	.remove_new = mxc_w1_remove,
 };
 module_platform_driver(mxc_w1_driver);
 

drivers/w1/masters/omap_hdq.c

@@ -647,7 +647,7 @@ static int omap_hdq_probe(struct platform_device *pdev)
 	return ret;
 }
 
-static int omap_hdq_remove(struct platform_device *pdev)
+static void omap_hdq_remove(struct platform_device *pdev)
 {
 	int active;
 
@@ -661,8 +661,6 @@ static int omap_hdq_remove(struct platform_device *pdev)
 	if (active >= 0)
 		pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
-
-	return 0;
 }
 
 static const struct of_device_id omap_hdq_dt_ids[] = {
@@ -674,7 +672,7 @@ MODULE_DEVICE_TABLE(of, omap_hdq_dt_ids);
 
 static struct platform_driver omap_hdq_driver = {
 	.probe = omap_hdq_probe,
-	.remove = omap_hdq_remove,
+	.remove_new = omap_hdq_remove,
 	.driver = {
 		.name =	"omap_hdq",
 		.of_match_table = omap_hdq_dt_ids,

drivers/w1/masters/sgi_w1.c

@@ -105,13 +105,11 @@ static int sgi_w1_probe(struct platform_device *pdev)
 /*
  * disassociate the w1 device from the driver
  */
-static int sgi_w1_remove(struct platform_device *pdev)
+static void sgi_w1_remove(struct platform_device *pdev)
 {
 	struct sgi_w1_device *sdev = platform_get_drvdata(pdev);
 
 	w1_remove_master_device(&sdev->bus_master);
-
-	return 0;
 }
 
 static struct platform_driver sgi_w1_driver = {
@@ -119,7 +117,7 @@ static struct platform_driver sgi_w1_driver = {
 		.name = "sgi_w1",
 	},
 	.probe = sgi_w1_probe,
-	.remove = sgi_w1_remove,
+	.remove_new = sgi_w1_remove,
 };
 module_platform_driver(sgi_w1_driver);
 

drivers/w1/masters/w1-gpio.c

@@ -141,7 +141,7 @@ static int w1_gpio_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static int w1_gpio_remove(struct platform_device *pdev)
+static void w1_gpio_remove(struct platform_device *pdev)
 {
 	struct w1_bus_master *master = platform_get_drvdata(pdev);
 	struct w1_gpio_ddata *ddata = master->data;
@@ -150,8 +150,6 @@ static int w1_gpio_remove(struct platform_device *pdev)
 		gpiod_set_value(ddata->pullup_gpiod, 0);
 
 	w1_remove_master_device(master);
-
-	return 0;
 }
 
 static struct platform_driver w1_gpio_driver = {
@@ -160,7 +158,7 @@ static struct platform_driver w1_gpio_driver = {
 		.of_match_table = of_match_ptr(w1_gpio_dt_ids),
 	},
 	.probe = w1_gpio_probe,
-	.remove = w1_gpio_remove,
+	.remove_new = w1_gpio_remove,
 };
 
 module_platform_driver(w1_gpio_driver);

drivers/w1/w1.c

@@ -167,7 +167,7 @@ static struct w1_family w1_default_family = {
 
 static int w1_uevent(const struct device *dev, struct kobj_uevent_env *env);
 
-static struct bus_type w1_bus_type = {
+static const struct bus_type w1_bus_type = {
 	.name = "w1",
 	.uevent = w1_uevent,
 };