[PATCH v3 0/8] ARM: sunxi: Add Reduced Serial Bus support

[PATCH v3 0/8] ARM: sunxi: Add Reduced Serial Bus support

[Chen-Yu Tsai]

Hi everyone,

This is my third attempt at adding support for Allwinner's Reduced
Serial Bus (RSB), which is used to communicate with PMICs and other
peripherals on their newer SoCs, such as the A23/A33/A80.

RSB is a simplified two wire interface using push-pull outputs,
supporting multiple slaves, address and data parity checks, and
clock speeds up to 20 MHz. The bus only supports simple register
read/writes, with possible register sizes of 8/16/32 bits. Access
sizes not matching the slave device register sizes result in NACKs
or errors. 32 bit registers in devices have yet to be seen.

Previous attempts to add support through the I2C subsystem have
been rejected, as the bus line protocol is too different to even
consider. In this version, RSB is implemented as a new bus type,
much like SPMI.

Even though there will almost certainly be only one RSB driver,
it's still split into the bus core framework and vendor specific
driver, like other subsystems. Theoretically someone could
implement a bit-banging driver for it.


Patches 1 & 2 add the DT bindings for common RSB properties and
the controller.

Patches 3 & 4 add the RSB framework core and sunxi driver.

Patch 5 (based on regmap/for-next) adds an RSB regmap driver.

Patch 6 adds the RSB nodes for A23/A33 dtsi.

Patch 7 & 8 enable the RSB controller on the boards I have.


Still to come are axp20x driver support for the RSB based AXP223.
The complete series can be found at:

    https://github.com/wens/linux/tree/sunxi-rsb-v3

Since this is a new subsystem, I'm not sure who should pick up
the first 4 patches, or whether they are even in the right place.
Any suggestions?


Regards,
ChenYu


Chen-Yu Tsai (8):
  rsb: Add generic Reduced Serial Bus (RSB) controller binding
    documentation
  rsb: sunxi: Add Allwinner Reduced Serial Bus (RSB) controller bindings
  rsb: Linux driver framework for Reduced Serial Bus (RSB)
  rsb: sunxi: Add driver for Allwinner Reduced Serial Bus controller
  regmap: rsb: Add support for Reduced Serial Bus (RSB) based regmaps
  ARM: dts: sun8i: Add Reduced Serial Bus controller device node to
    A23/A33 dtsi
  ARM: dts: sun8i: ippo-q8h-v5: Enable Reduced Serial Bus controller
  ARM: dts: sun8i: sinlinx-sina33: Enable Reduced Serial Bus controller

 .../devicetree/bindings/rsb/rsb-sunxi.txt          |  34 ++
 Documentation/devicetree/bindings/rsb/rsb.txt      |  50 ++
 arch/arm/boot/dts/sun8i-a23-a33.dtsi               |  21 +
 arch/arm/boot/dts/sun8i-a23-ippo-q8h-v5.dts        |   4 +
 arch/arm/boot/dts/sun8i-a33-sinlinx-sina33.dts     |   4 +
 drivers/Kconfig                                    |   2 +
 drivers/Makefile                                   |   1 +
 drivers/base/regmap/Kconfig                        |   6 +-
 drivers/base/regmap/Makefile                       |   1 +
 drivers/base/regmap/regmap-rsb.c                   | 121 +++++
 drivers/rsb/Kconfig                                |  26 ++
 drivers/rsb/Makefile                               |   6 +
 drivers/rsb/rsb-core.c                             | 511 +++++++++++++++++++++
 drivers/rsb/rsb-sunxi.c                            | 441 ++++++++++++++++++
 include/linux/regmap.h                             |  36 ++
 include/linux/rsb.h                                | 144 ++++++
 16 files changed, 1407 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/rsb/rsb-sunxi.txt
 create mode 100644 Documentation/devicetree/bindings/rsb/rsb.txt
 create mode 100644 drivers/base/regmap/regmap-rsb.c
 create mode 100644 drivers/rsb/Kconfig
 create mode 100644 drivers/rsb/Makefile
 create mode 100644 drivers/rsb/rsb-core.c
 create mode 100644 drivers/rsb/rsb-sunxi.c
 create mode 100644 include/linux/rsb.h

-- 
2.5.0

[PATCH v3 1/8] rsb: Add generic Reduced Serial Bus (RSB) controller binding documentation

[Chen-Yu Tsai]

Reduced Serial Bus is a proprietary 2-line push-pull serial bus
supporting multiple slave devices.

It was developed by Allwinner, Inc. and used by Allwinner and X-Powers,
Inc. for their line of PMICs and other peripheral ICs.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 Documentation/devicetree/bindings/rsb/rsb.txt | 50 +++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rsb/rsb.txt

diff --git a/Documentation/devicetree/bindings/rsb/rsb.txt b/Documentation/devicetree/bindings/rsb/rsb.txt
new file mode 100644
index 000000000000..0b027948ca9c
--- /dev/null
+++ b/Documentation/devicetree/bindings/rsb/rsb.txt
@@ -0,0 +1,50 @@
+Reduced Serial Bus (RSB) Controller
+
+This document defines a generic set of bindings for use by RSB controllers.
+A controller is modelled in device tree as a node with zero or more child
+nodes, each representing a unique slave device on the bus.
+
+Required properties:
+
+ - #address-cells : must be 2
+ - #size-cells : must be 0
+
+Optional properties:
+
+ - clock-frequency : Desired bus clock frequency in Hz. Maximum is 20 MHz.
+
+Child nodes:
+
+An RSB controller node can contain zero or more child nodes representing
+slave devices on the bus.  Child 'reg' properties are specified as a
+runtime address, hardware address pair. The hardware address is hardwired
+in the device, which can normally be found in the datasheet. The runtime
+address is set by software. No 2 devices on the same bus shall have the
+same runtime address.
+
+Valid runtime addresses - There are only 15 valid runtime addresses:
+
+    0x17, 0x2d, 0x3a, 0x4e, 0x59, 0x63, 0x74, 0x8b,
+    0x9c, 0xa6, 0xb1, 0xc5, 0xd2, 0xe8, 0xff
+
+It is highly recommended that one choose the same runtime addresses as
+vendor BSPs use so that a) the addresses remain the same across different
+software systems, and b) addresses of supported and listed slave devices
+don't conflict with unsupported or not yet listed devices.
+
+Example:
+
+	rsb@... {
+		compatible = "...";
+		reg = <...>;
+		/* ... */
+		#address-cells = <2>;
+		#size-cells = <0>;
+
+		pmic@2d {
+			compatible = "...";
+			reg = <0x2d 0x3e3>;
+
+			/* ... */
+		};
+	};
-- 
2.5.0

[PATCH v3 2/8] rsb: sunxi: Add Allwinner Reduced Serial Bus (RSB) controller bindings

[Chen-Yu Tsai]

Recent Allwinner SoCs, starting with the A23, have a Reduced Serial Bus
(RSB) controller. This is used to talk to the PMIC, and later with the
A80 and A83 platform, the audio codec IC.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 .../devicetree/bindings/rsb/rsb-sunxi.txt          | 34 ++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rsb/rsb-sunxi.txt

diff --git a/Documentation/devicetree/bindings/rsb/rsb-sunxi.txt b/Documentation/devicetree/bindings/rsb/rsb-sunxi.txt
new file mode 100644
index 000000000000..057d24b84628
--- /dev/null
+++ b/Documentation/devicetree/bindings/rsb/rsb-sunxi.txt
@@ -0,0 +1,34 @@
+
+* Allwinner RSB (Reduced Serial Bus) controller
+
+Required properties :
+
+ - reg             : Offset and length of the register set for the controller.
+ - compatible      : Shall be "allwinner,sun8i-a23-rsb".
+ - interrupts      : The interrupt line associated to the RSB controller.
+ - clocks          : The gate clk associated to the RSB controller.
+ - resets          : The reset line associated to the RSB controller.
+ - #address-cells  : shall be 2
+ - #size-cells     : shall be 0
+
+Optional properties :
+
+ - clock-frequency : Desired RSB bus clock frequency in Hz. Maximum is 20MHz.
+		     If not set the current hardware setting shall be used.
+
+See rsb.txt for the generic RSB bindings for RSB slaves / child nodes.
+
+Example:
+
+	rsb@01f03400 {
+		compatible = "allwinner,sun8i-a23-rsb";
+		reg = <0x01f03400 0x400>;
+		interrupts = <0 39 4>;
+		clocks = <&apb0_gates 3>;
+		clock-frequency = <3000000>;
+		resets = <&apb0_rst 3>;
+		#address-cells = <2>;
+		#size-cells = <0>;
+
+		/* child nodes ... */
+	};
-- 
2.5.0

[PATCH v3 3/8] rsb: Linux driver framework for Reduced Serial Bus (RSB)

[Chen-Yu Tsai]

Reduced Serial Bus (RSB) is an Allwinner proprietery interface
used to communicate with PMICs and other peripheral ICs.

RSB is a two-wire push-pull serial bus that supports 1 master
device and up to 15 active slave devices.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 drivers/Kconfig        |   2 +
 drivers/Makefile       |   1 +
 drivers/rsb/Kconfig    |  11 ++
 drivers/rsb/Makefile   |   4 +
 drivers/rsb/rsb-core.c | 511 +++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/rsb.h    | 144 ++++++++++++++
 6 files changed, 673 insertions(+)
 create mode 100644 drivers/rsb/Kconfig
 create mode 100644 drivers/rsb/Makefile
 create mode 100644 drivers/rsb/rsb-core.c
 create mode 100644 include/linux/rsb.h

diff --git a/drivers/Kconfig b/drivers/Kconfig
index 6e973b8e3a3b..4ada2d3eb832 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -54,6 +54,8 @@ source "drivers/spi/Kconfig"
 
 source "drivers/spmi/Kconfig"
 
+source "drivers/rsb/Kconfig"
+
 source "drivers/hsi/Kconfig"
 
 source "drivers/pps/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index e4b260ecec15..75e0fc8fe28c 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -75,6 +75,7 @@ obj-$(CONFIG_TARGET_CORE)	+= target/
 obj-$(CONFIG_MTD)		+= mtd/
 obj-$(CONFIG_SPI)		+= spi/
 obj-$(CONFIG_SPMI)		+= spmi/
+obj-$(CONFIG_RSB)		+= rsb/
 obj-y				+= hsi/
 obj-y				+= net/
 obj-$(CONFIG_ATM)		+= atm/
diff --git a/drivers/rsb/Kconfig b/drivers/rsb/Kconfig
new file mode 100644
index 000000000000..6642e1db6d98
--- /dev/null
+++ b/drivers/rsb/Kconfig
@@ -0,0 +1,11 @@
+#
+# RSB driver configuration
+#
+menuconfig RSB
+	tristate "RSB support"
+	help
+	  RSB (Reduced Serial Bus) is a two-wire serial interface between
+	  baseband and application processors and Power Management
+	  Integrated Circuits (PMIC) or other peripherals.
+
+	  These are commonly seen on newer Allwinner SoCs and X-Powers ICs.
diff --git a/drivers/rsb/Makefile b/drivers/rsb/Makefile
new file mode 100644
index 000000000000..6fe56526fbf3
--- /dev/null
+++ b/drivers/rsb/Makefile
@@ -0,0 +1,4 @@
+#
+# Makefile for kernel RSB framework.
+#
+obj-$(CONFIG_RSB)	+= rsb-core.o
diff --git a/drivers/rsb/rsb-core.c b/drivers/rsb/rsb-core.c
new file mode 100644
index 000000000000..6682d827aebb
--- /dev/null
+++ b/drivers/rsb/rsb-core.c
@@ -0,0 +1,511 @@
+/*
+ * Copyright (c) 2015, Chen-Yu Tsai
+ *
+ * Chen-Yu Tsai <wens@csie.org>
+ *
+ * Allwinner Reduced Serial Bus (RSB) driver
+ *
+ * based on spmi/spmi.c
+ *
+ * Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk/clk-conf.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/idr.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/rsb.h>
+#include <linux/slab.h>
+
+static DEFINE_IDA(ctrl_ida);
+
+static void rsb_dev_release(struct device *dev)
+{
+	struct rsb_device *rdev = to_rsb_device(dev);
+
+	kfree(rdev);
+}
+
+static const struct device_type rsb_dev_type = {
+	.release	= rsb_dev_release,
+};
+
+static void rsb_ctrl_release(struct device *dev)
+{
+	struct rsb_controller *ctrl = to_rsb_controller(dev);
+
+	ida_simple_remove(&ctrl_ida, ctrl->nr);
+	kfree(ctrl);
+}
+
+static const struct device_type rsb_ctrl_type = {
+	.release	= rsb_ctrl_release,
+};
+
+static int rsb_device_match(struct device *dev, struct device_driver *drv)
+{
+	if (of_driver_match_device(dev, drv))
+		return 1;
+
+	return strcmp(dev_name(dev), drv->name) == 0;
+}
+
+static inline int rsb_init_cmd(struct rsb_controller *ctrl)
+{
+	int ret;
+
+	if (!ctrl || !ctrl->init_cmd || ctrl->dev.type != &rsb_ctrl_type)
+		return -EINVAL;
+
+	mutex_lock(&ctrl->lock);
+	ret = ctrl->init_cmd(ctrl);
+	mutex_unlock(&ctrl->lock);
+
+	return ret;
+}
+
+static inline int rsb_rtsaddr_cmd(struct rsb_controller *ctrl, u16 hwaddr,
+				  u8 rtaddr)
+{
+	int ret;
+
+	if (!ctrl || !ctrl->rtsaddr_cmd || ctrl->dev.type != &rsb_ctrl_type)
+		return -EINVAL;
+
+	mutex_lock(&ctrl->lock);
+	ret = ctrl->rtsaddr_cmd(ctrl, hwaddr, rtaddr);
+	mutex_unlock(&ctrl->lock);
+
+	return ret;
+}
+
+static inline int rsb_read_cmd(struct rsb_controller *ctrl, u8 rtaddr,
+			       u8 addr, u32 *buf, size_t len)
+{
+	int ret;
+
+	if (!ctrl || !ctrl->read_cmd || ctrl->dev.type != &rsb_ctrl_type)
+		return -EINVAL;
+
+	mutex_lock(&ctrl->lock);
+	ret = ctrl->read_cmd(ctrl, rtaddr, addr, buf, len);
+	mutex_unlock(&ctrl->lock);
+
+	return ret;
+}
+
+static inline int rsb_write_cmd(struct rsb_controller *ctrl, u8 rtaddr,
+				u8 addr, const u32 *buf, size_t len)
+{
+	int ret;
+
+	if (!ctrl || !ctrl->write_cmd || ctrl->dev.type != &rsb_ctrl_type)
+		return -EINVAL;
+
+	mutex_lock(&ctrl->lock);
+	ret = ctrl->write_cmd(ctrl, rtaddr, addr, buf, len);
+	mutex_unlock(&ctrl->lock);
+
+	return ret;
+}
+
+/**
+ * rsb_register_read() - register read
+ * @rdev:	RSB device.
+ * @addr:	slave register address.
+ * @buf:	buffer to be populated with data from the Slave.
+ * @size:	width of the slave register in bytes
+ *
+ * Reads data from a Slave device register.
+ */
+int rsb_register_read(struct rsb_device *rdev, u8 addr, u32 *buf, int size)
+{
+	switch (size) {
+	case 1:
+	case 2:
+	case 4:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return rsb_read_cmd(rdev->ctrl, rdev->rtaddr, addr, buf, size);
+}
+EXPORT_SYMBOL_GPL(rsb_register_read);
+
+/**
+ * rsb_register_write() - register write
+ * @rdev:	RSB device
+ * @addr:	slave register address.
+ * @data:	buffer containing the data to be transferred to the Slave.
+ * @size:	width of the slave register in bytes
+ *
+ * Writes data to a Slave device register.
+ */
+int rsb_register_write(struct rsb_device *rdev, u8 addr, u32 data, int size)
+{
+	switch (size) {
+	case 1:
+	case 2:
+	case 4:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return rsb_write_cmd(rdev->ctrl, rdev->rtaddr, addr, &data, size);
+}
+EXPORT_SYMBOL_GPL(rsb_register_write);
+
+static struct bus_type rsb_bus_type;
+
+static int rsb_device_probe(struct device *dev)
+{
+	const struct rsb_driver *drv = to_rsb_driver(dev->driver);
+	struct rsb_device *rsb = to_rsb_device(dev);
+	int ret;
+
+	if (dev->type != &rsb_dev_type)
+		return 0;
+
+	if (!drv->probe)
+		return -ENODEV;
+
+	if (!rsb->irq) {
+		int irq = -ENOENT;
+
+		if (dev->of_node)
+			irq = of_irq_get(dev->of_node, 0);
+
+		if (irq == -EPROBE_DEFER)
+			return irq;
+		if (irq < 0)
+			irq = 0;
+
+		rsb->irq = irq;
+	}
+
+	ret = of_clk_set_defaults(dev->of_node, false);
+	if (ret < 0)
+		return ret;
+
+	return drv->probe(rsb);
+}
+
+static int rsb_device_remove(struct device *dev)
+{
+	const struct rsb_driver *drv = to_rsb_driver(dev->driver);
+
+	if (dev->type != &rsb_dev_type)
+		return 0;
+
+	return drv->remove(to_rsb_device(dev));
+}
+
+static struct bus_type rsb_bus_type = {
+	.name		= "rsb",
+	.match		= rsb_device_match,
+	.probe		= rsb_device_probe,
+	.remove		= rsb_device_remove,
+};
+
+/**
+ * rsb_device_alloc() - Allocate a new RSB device
+ * @ctrl:	associated controller
+ *
+ * Caller is responsible for either calling rsb_device_add() to add the
+ * newly allocated controller, or calling rsb_device_put() to discard it.
+ */
+static struct rsb_device *rsb_device_alloc(struct rsb_controller *ctrl)
+{
+	struct rsb_device *rdev;
+
+	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
+	if (!rdev)
+		return NULL;
+
+	rdev->ctrl = ctrl;
+	device_initialize(&rdev->dev);
+	rdev->dev.parent = &ctrl->dev;
+	rdev->dev.bus = &rsb_bus_type;
+	rdev->dev.type = &rsb_dev_type;
+	return rdev;
+}
+
+static inline void rsb_device_put(struct rsb_device *rdev)
+{
+	if (rdev)
+		put_device(&rdev->dev);
+}
+
+/* 15 valid runtime addresses for RSB slaves */
+static const u8 rsb_valid_rtaddr[] = {
+	0x17, 0x2d, 0x3a, 0x4e, 0x59, 0x63, 0x74, 0x8b,
+	0x9c, 0xa6, 0xb1, 0xc5, 0xd2, 0xe8, 0xff,
+};
+
+static inline int rsb_check_rt_addr(u8 addr)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(rsb_valid_rtaddr); i++)
+		if (addr == rsb_valid_rtaddr[i])
+			return 0;
+
+	return -EINVAL;
+}
+
+/**
+ * rsb_device_add() - add a device previously constructed via rsb_device_alloc()
+ * @rdev:	rsb_device to be added
+ */
+static int rsb_device_add(struct rsb_device *rdev)
+{
+	struct rsb_controller *ctrl = rdev->ctrl;
+	int err;
+
+	dev_set_name(&rdev->dev, "%d-%02x", ctrl->nr, rdev->rtaddr);
+
+	err = device_add(&rdev->dev);
+	if (err < 0) {
+		dev_err(&rdev->dev, "Can't add %s, status %d\n",
+			dev_name(&rdev->dev), err);
+		goto err_device_add;
+	}
+
+	dev_dbg(&rdev->dev, "device %s registered\n", dev_name(&rdev->dev));
+
+err_device_add:
+	return err;
+}
+
+/**
+ * rsb_device_unregister(): unregister an RSB device
+ * @rdev:	rsb_device to be removed
+ */
+static void rsb_device_unregister(struct rsb_device *rdev)
+{
+	device_unregister(&rdev->dev);
+}
+
+/**
+ * rsb_controller_alloc() - Allocate a new RSB controller
+ * @parent:	parent device
+ * @size:	size of private data
+ *
+ * Caller is responsible for either calling rsb_controller_add() to add the
+ * newly allocated controller, or calling rsb_controller_put() to discard it.
+ * The allocated private data region may be accessed via
+ * rsb_controller_get_drvdata()
+ */
+struct rsb_controller *rsb_controller_alloc(struct device *parent, size_t size)
+{
+	struct rsb_controller *ctrl;
+	int id;
+
+	if (WARN_ON(!parent))
+		return NULL;
+
+	ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
+	if (!ctrl)
+		return NULL;
+
+	device_initialize(&ctrl->dev);
+	mutex_init(&ctrl->lock);
+	ctrl->dev.type = &rsb_ctrl_type;
+	ctrl->dev.bus = &rsb_bus_type;
+	ctrl->dev.parent = parent;
+	ctrl->dev.of_node = parent->of_node;
+	rsb_controller_set_drvdata(ctrl, &ctrl[1]);
+
+	id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
+	if (id < 0) {
+		dev_err(parent,
+			"unable to allocate RSB controller identifier.\n");
+		rsb_controller_put(ctrl);
+		return NULL;
+	}
+
+	ctrl->nr = id;
+	dev_set_name(&ctrl->dev, "rsb-%d", id);
+	dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
+
+	return ctrl;
+}
+EXPORT_SYMBOL_GPL(rsb_controller_alloc);
+
+static void of_rsb_register_devices(struct rsb_controller *ctrl)
+{
+	struct device_node *node;
+	int err;
+	u32 reg[2];
+
+	if (!ctrl->dev.of_node)
+		return;
+
+	/* Runtime addresses for all slaves should be set first */
+	for_each_available_child_of_node(ctrl->dev.of_node, node) {
+		dev_dbg(&ctrl->dev, "setting child %s runtime address\n",
+			node->full_name);
+
+		err = of_property_read_u32_array(node, "reg", reg, 2);
+		if (err) {
+			dev_err(&ctrl->dev,
+				"node %s err (%d) does not have 'reg' property\n",
+				node->full_name, err);
+			continue;
+		}
+
+		if (reg[0] > 0xff || rsb_check_rt_addr(reg[0]) < 0) {
+			dev_err(&ctrl->dev,
+				"invalid runtime address on node %s\n",
+				node->full_name);
+			continue;
+		}
+
+		/* This fails if the slave device was already initialized */
+		err = rsb_rtsaddr_cmd(ctrl, (u16)reg[1], (u8)reg[0]);
+		if (err)
+			dev_info(&ctrl->dev,
+				 "failed to set runtime address: %d\n", err);
+	}
+
+	for_each_available_child_of_node(ctrl->dev.of_node, node) {
+		struct rsb_device *rdev;
+
+		dev_dbg(&ctrl->dev, "adding child %s\n", node->full_name);
+
+		err = of_property_read_u32_array(node, "reg", reg, 2);
+		if (err)
+			continue;
+
+		if (reg[0] > 0xff || rsb_check_rt_addr(reg[0]) < 0)
+			continue;
+
+		rdev = rsb_device_alloc(ctrl);
+		if (!rdev)
+			continue;
+
+		rdev->dev.of_node = node;
+		rdev->rtaddr = (u8)reg[0];
+		rdev->hwaddr = (u16)reg[1];
+
+		err = rsb_device_add(rdev);
+		if (err) {
+			dev_err(&rdev->dev, "failed to add device: %d\n", err);
+			rsb_device_put(rdev);
+		}
+	}
+}
+
+/**
+ * rsb_controller_add() - Add an RSB controller
+ * @ctrl:	controller to be registered.
+ *
+ * Register a controller previously allocated via rsb_controller_alloc() with
+ * the RSB core.
+ */
+int rsb_controller_add(struct rsb_controller *ctrl)
+{
+	int ret;
+
+	/* Can't register until after driver model init */
+	if (WARN_ON(!rsb_bus_type.p))
+		return -EAGAIN;
+
+	ret = device_add(&ctrl->dev);
+	if (ret)
+		return ret;
+
+	/*
+	 * Send RSB init sequence on the bus. This fails if the bus was
+	 * already initialized.
+	 */
+	ret = rsb_init_cmd(ctrl);
+	if (ret)
+		dev_info(&ctrl->dev, "RSB init sequence failed: %d\n", ret);
+
+	if (IS_ENABLED(CONFIG_OF))
+		of_rsb_register_devices(ctrl);
+
+	dev_dbg(&ctrl->dev, "rsb-%d registered: dev:%p\n",
+		ctrl->nr, &ctrl->dev);
+
+	return 0;
+};
+EXPORT_SYMBOL_GPL(rsb_controller_add);
+
+/* Remove a device associated with a controller */
+static int rsb_ctrl_remove_device(struct device *dev, void *data)
+{
+	struct rsb_device *rsb = to_rsb_device(dev);
+
+	if (dev->type == &rsb_dev_type)
+		rsb_device_unregister(rsb);
+	return 0;
+}
+
+/**
+ * rsb_controller_remove(): remove an RSB controller
+ * @ctrl:	controller to remove
+ *
+ * Remove a RSB controller.  Caller is responsible for calling
+ * rsb_controller_put() to discard the allocated controller.
+ */
+void rsb_controller_remove(struct rsb_controller *ctrl)
+{
+	int dummy;
+
+	if (!ctrl)
+		return;
+
+	dummy = device_for_each_child(&ctrl->dev, NULL,
+				      rsb_ctrl_remove_device);
+	mutex_destroy(&ctrl->lock);
+	device_del(&ctrl->dev);
+}
+EXPORT_SYMBOL_GPL(rsb_controller_remove);
+
+/**
+ * rsb_driver_register() - Register device driver with RSB core
+ * @rdrv:	device driver to be associated with slave-device.
+ *
+ * This API will register the client driver with the RSB framework.
+ * It is typically called from the driver's module-init function.
+ */
+int rsb_driver_register(struct rsb_driver *rdrv)
+{
+	rdrv->driver.bus = &rsb_bus_type;
+	return driver_register(&rdrv->driver);
+}
+EXPORT_SYMBOL_GPL(rsb_driver_register);
+
+static void __exit rsb_exit(void)
+{
+	bus_unregister(&rsb_bus_type);
+}
+module_exit(rsb_exit);
+
+static int __init rsb_init(void)
+{
+	return bus_register(&rsb_bus_type);
+}
+postcore_initcall(rsb_init);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Reduce Serial Bus (RSB) core module");
+MODULE_ALIAS("platform:rsb");
diff --git a/include/linux/rsb.h b/include/linux/rsb.h
new file mode 100644
index 000000000000..51a53468f547
--- /dev/null
+++ b/include/linux/rsb.h
@@ -0,0 +1,144 @@
+/* Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#ifndef _LINUX_RSB_H
+#define _LINUX_RSB_H
+
+#include <linux/device.h>
+#include <linux/mod_devicetable.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+
+/**
+ * struct rsb_device - Basic representation of an RSB device
+ * @dev:	Driver model representation of the device.
+ * @ctrl:	RSB controller managing the bus hosting this device.
+ * @rtaddr:	This device's runtime address
+ * @hwaddr:	This device's hardware address
+ */
+struct rsb_device {
+	struct device		dev;
+	struct rsb_controller	*ctrl;
+	int			irq;
+	u8			rtaddr;
+	u16			hwaddr;
+};
+
+static inline struct rsb_device *to_rsb_device(struct device *d)
+{
+	return container_of(d, struct rsb_device, dev);
+}
+
+static inline void *rsb_device_get_drvdata(const struct rsb_device *rdev)
+{
+	return dev_get_drvdata(&rdev->dev);
+}
+
+static inline void rsb_device_set_drvdata(struct rsb_device *rdev, void *data)
+{
+	dev_set_drvdata(&rdev->dev, data);
+}
+
+/**
+ * struct rsb_controller - interface to the RSB master controller
+ * @dev:	Driver model representation of the device.
+ * @nr:		board-specific number identifier for this controller/bus
+ * @init_cmd:	sends a device initialization command sequence on the bus.
+ * @rtsaddr_cmd: sends a "set runtime address" command sequence on the bus.
+ * @read_cmd:	sends a register read command sequence on the RSB bus.
+ * @write_cmd:	sends a register write command sequence on the RSB bus.
+ */
+struct rsb_controller {
+	struct device		dev;
+	unsigned int		nr;
+	struct mutex		lock; /* serialize access to the bus */
+	int	(*init_cmd)(struct rsb_controller *ctrl);
+	int	(*rtsaddr_cmd)(struct rsb_controller *ctrl,
+			       u16 hwaddr, u8 rtaddr);
+	int	(*read_cmd)(struct rsb_controller *ctrl, u8 rtaddr,
+			    u8 addr, u32 *buf, size_t len);
+	int	(*write_cmd)(struct rsb_controller *ctrl, u8 rtaddr,
+			     u8 addr, const u32 *buf, size_t len);
+};
+
+static inline struct rsb_controller *to_rsb_controller(struct device *d)
+{
+	return container_of(d, struct rsb_controller, dev);
+}
+
+static inline
+void *rsb_controller_get_drvdata(const struct rsb_controller *ctrl)
+{
+	return dev_get_drvdata(&ctrl->dev);
+}
+
+static inline void rsb_controller_set_drvdata(struct rsb_controller *ctrl,
+					      void *data)
+{
+	dev_set_drvdata(&ctrl->dev, data);
+}
+
+struct rsb_controller *rsb_controller_alloc(struct device *parent,
+					    size_t size);
+
+/**
+ * rsb_controller_put() - decrement controller refcount
+ * @ctrl	RSB controller.
+ */
+static inline void rsb_controller_put(struct rsb_controller *ctrl)
+{
+	if (ctrl) {
+		mutex_destroy(&ctrl->lock);
+		put_device(&ctrl->dev);
+	}
+}
+
+int rsb_controller_add(struct rsb_controller *ctrl);
+void rsb_controller_remove(struct rsb_controller *ctrl);
+
+/**
+ * struct rsb_driver - RSB slave device driver
+ * @driver:	RSB device drivers should initialize name and owner field of
+ *		this structure.
+ * @probe:	binds this driver to a RSB device.
+ * @remove:	unbinds this driver from the RSB device.
+ */
+struct rsb_driver {
+	struct device_driver driver;
+	int (*probe)(struct rsb_device *rdev);
+	int (*remove)(struct rsb_device *rdev);
+};
+
+static inline struct rsb_driver *to_rsb_driver(struct device_driver *d)
+{
+	return container_of(d, struct rsb_driver, driver);
+}
+
+int rsb_driver_register(struct rsb_driver *rdrv);
+
+/**
+ * rsb_driver_unregister() - unregister an RSB client driver
+ * @rdrv:	the driver to unregister
+ */
+static inline void rsb_driver_unregister(struct rsb_driver *rdrv)
+{
+	if (rdrv)
+		driver_unregister(&rdrv->driver);
+}
+
+#define module_rsb_driver(__rsb_driver) \
+	module_driver(__rsb_driver, rsb_driver_register, \
+			rsb_driver_unregister)
+
+int rsb_register_read(struct rsb_device *rdev, u8 addr, u32 *buf, int size);
+int rsb_register_write(struct rsb_device *rdev, u8 addr, u32 data, int size);
+
+#endif
-- 
2.5.0

[PATCH v3 4/8] rsb: sunxi: Add driver for Allwinner Reduced Serial Bus controller

[Chen-Yu Tsai]

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 drivers/rsb/Kconfig     |  15 ++
 drivers/rsb/Makefile    |   2 +
 drivers/rsb/rsb-sunxi.c | 441 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 458 insertions(+)
 create mode 100644 drivers/rsb/rsb-sunxi.c

diff --git a/drivers/rsb/Kconfig b/drivers/rsb/Kconfig
index 6642e1db6d98..54a28a39e0e2 100644
--- a/drivers/rsb/Kconfig
+++ b/drivers/rsb/Kconfig
@@ -9,3 +9,18 @@ menuconfig RSB
 	  Integrated Circuits (PMIC) or other peripherals.
 
 	  These are commonly seen on newer Allwinner SoCs and X-Powers ICs.
+
+if RSB
+
+config RSB_SUNXI
+	tristate "Allwinner RSB Controller"
+	depends on ARCH_SUNXI || COMPILE_TEST
+	default MACH_SUN8I || MACH_SUN9I
+	help
+	  If you say yes to this option, support will be included for the
+	  built-in RSB controller on Allwinner sun8i/sun9i family SoCs.
+
+	  This is required for communicating with X-Powers PMICs and other
+	  devices that have the RSB interface.
+
+endif
diff --git a/drivers/rsb/Makefile b/drivers/rsb/Makefile
index 6fe56526fbf3..31cd615f7e58 100644
--- a/drivers/rsb/Makefile
+++ b/drivers/rsb/Makefile
@@ -2,3 +2,5 @@
 # Makefile for kernel RSB framework.
 #
 obj-$(CONFIG_RSB)	+= rsb-core.o
+
+obj-$(CONFIG_RSB_SUNXI)	+= rsb-sunxi.o
diff --git a/drivers/rsb/rsb-sunxi.c b/drivers/rsb/rsb-sunxi.c
new file mode 100644
index 000000000000..07b24291fe4d
--- /dev/null
+++ b/drivers/rsb/rsb-sunxi.c
@@ -0,0 +1,441 @@
+/*
+ * RSB (Reduced Serial Bus) driver.
+ *
+ * Author: Chen-Yu Tsai <wens@csie.org>
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2.  This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ *
+ * The RSB controller looks like an SMBus controller which only supports
+ * byte and word data transfers. But, it differs from standard SMBus
+ * protocol on several aspects:
+ * - it uses addresses set at runtime to address slaves. Runtime addresses
+ *   are sent to slaves using their 12bit hardware addresses. Up to 15
+ *   runtime addresses are available.
+ * - it adds a parity bit every 8bits of data and address for read and
+ *   write accesses; this replaces the ack bit
+ * - only one read access is required to read a byte (instead of a write
+ *   followed by a read access in standard SMBus protocol)
+ * - there's no Ack bit after each read access
+ *
+ * This means this bus cannot be used to interface with standard SMBus
+ * devices. Devices known to support this interface include the AXP223,
+ * AXP809, and AXP806 PMICs, and the AC100 audio codec, all from X-Powers.
+ *
+ * A description of the operation and wire protocol can be found in the
+ * RSB section of Allwinner's A80 user manual, which can be found at
+ *
+ *     https://github.com/allwinner-zh/documents/tree/master/A80
+ *
+ * This document is officially released by Allwinner.
+ *
+ * This driver is based on i2c-sun6i-p2wi.c, the P2WI bus driver.
+ *
+ */
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/rsb.h>
+
+/* RSB registers */
+#define RSB_CTRL	0x0	/* Global control */
+#define RSB_CCR		0x4	/* Clock control */
+#define RSB_INTE	0x8	/* Interrupt controls */
+#define RSB_INTS	0xc	/* Interrupt status */
+#define RSB_ADDR	0x10	/* Address to send with read/write command */
+#define RSB_DATA	0x1c	/* Data to read/write */
+#define RSB_LCR		0x24	/* Line control */
+#define RSB_DMCR	0x28	/* Device mode (init) control */
+#define RSB_CMD		0x2c	/* RSB Command */
+#define RSB_DAR		0x30	/* Device address / runtime address */
+
+/* CTRL fields */
+#define RSB_CTRL_START_TRANS		BIT(7)
+#define RSB_CTRL_ABORT_TRANS		BIT(6)
+#define RSB_CTRL_GLOBAL_INT_ENB		BIT(1)
+#define RSB_CTRL_SOFT_RST		BIT(0)
+
+/* CLK CTRL fields */
+#define RSB_CCR_SDA_OUT_DELAY(v)	(((v) & 0x7) << 8)
+#define RSB_CCR_MAX_CLK_DIV		0xff
+#define RSB_CCR_CLK_DIV(v)		((v) & RSB_CCR_MAX_CLK_DIV)
+
+/* STATUS fields */
+#define RSB_INTS_TRANS_ERR_ACK		BIT(16)
+#define RSB_INTS_TRANS_ERR_DATA_BIT(v)	(((v) >> 8) & 0xf)
+#define RSB_INTS_TRANS_ERR_DATA		GENMASK(11, 8)
+#define RSB_INTS_LOAD_BSY		BIT(2)
+#define RSB_INTS_TRANS_ERR		BIT(1)
+#define RSB_INTS_TRANS_OVER		BIT(0)
+
+/* LINE CTRL fields*/
+#define RSB_LCR_SCL_STATE		BIT(5)
+#define RSB_LCR_SDA_STATE		BIT(4)
+#define RSB_LCR_SCL_CTL			BIT(3)
+#define RSB_LCR_SCL_CTL_EN		BIT(2)
+#define RSB_LCR_SDA_CTL			BIT(1)
+#define RSB_LCR_SDA_CTL_EN		BIT(0)
+
+/* DEVICE MODE CTRL field values */
+#define RSB_DMCR_DEVICE_START		BIT(31)
+#define RSB_DMCR_MODE_DATA		(0x7c << 16)
+#define RSB_DMCR_MODE_REG		(0x3e << 8)
+#define RSB_DMCR_DEV_ADDR		0x00
+
+/* CMD values */
+#define RSB_CMD_RD8			0x8b
+#define RSB_CMD_RD16			0x9c
+#define RSB_CMD_RD32			0xa6
+#define RSB_CMD_WR8			0x4e
+#define RSB_CMD_WR16			0x59
+#define RSB_CMD_WR32			0x63
+#define RSB_CMD_STRA			0xe8
+
+/* DAR fields */
+#define RSB_DAR_RTA(v)			(((v) & 0xff) << 16)
+#define RSB_DAR_DA(v)			((v) & 0xffff)
+
+#define RSB_MAX_FREQ			20000000
+
+#define RSB_CTRL_NAME			"sunxi-rsb"
+
+struct rsb {
+	struct rsb_controller *ctrl;
+	void __iomem *regs;
+	struct clk *clk;
+	struct reset_control *rstc;
+	struct completion complete;
+	unsigned int status;
+};
+
+static irqreturn_t rsb_interrupt(int irq, void *dev_id)
+{
+	struct rsb *rsb = dev_id;
+	u32 status;
+
+	/* Clear interrupts */
+	status = readl(rsb->regs + RSB_INTS);
+	rsb->status = status;
+	writel(status, rsb->regs + RSB_INTS);
+
+	complete(&rsb->complete);
+
+	return IRQ_HANDLED;
+}
+
+/* common code that starts a transfer */
+static int rsb_run_xfer(struct rsb *rsb)
+{
+	if (readl(rsb->regs + RSB_CTRL) & RSB_CTRL_START_TRANS) {
+		dev_dbg(&rsb->ctrl->dev, "RSB transfer still in progress\n");
+		return -EBUSY;
+	}
+
+	reinit_completion(&rsb->complete);
+
+	writel(RSB_INTS_LOAD_BSY | RSB_INTS_TRANS_ERR | RSB_INTS_TRANS_OVER,
+	       rsb->regs + RSB_INTE);
+	writel(RSB_CTRL_START_TRANS | RSB_CTRL_GLOBAL_INT_ENB,
+	       rsb->regs + RSB_CTRL);
+
+	if (!wait_for_completion_io_timeout(&rsb->complete,
+					    msecs_to_jiffies(100))) {
+		dev_dbg(&rsb->ctrl->dev, "RSB timeout\n");
+
+		/* abort the transfer */
+		writel(RSB_CTRL_ABORT_TRANS, rsb->regs + RSB_CTRL);
+
+		/* clear any interrupt flags */
+		writel(readl(rsb->regs + RSB_INTS), rsb->regs + RSB_INTS);
+
+		return -ETIMEDOUT;
+	}
+
+	if (rsb->status & RSB_INTS_LOAD_BSY) {
+		dev_dbg(&rsb->ctrl->dev, "RSB busy\n");
+		return -EBUSY;
+	}
+
+	if (rsb->status & RSB_INTS_TRANS_ERR_ACK) {
+		dev_dbg(&rsb->ctrl->dev, "RSB slave nack\n");
+		return -EINVAL;
+	}
+
+	if (rsb->status & RSB_INTS_TRANS_ERR_DATA) {
+		dev_dbg(&rsb->ctrl->dev, "RSB transfer data error\n");
+		return -EIO;
+	}
+
+	/* This should be covered by the above 2 cases */
+	if (rsb->status & RSB_INTS_TRANS_ERR) {
+		dev_dbg(&rsb->ctrl->dev, "bus transfer error\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int rsb_read_cmd(struct rsb_controller *ctrl, u8 rtaddr,
+			u8 addr, u32 *buf, size_t len)
+{
+	struct rsb *rsb = rsb_controller_get_drvdata(ctrl);
+	u32 cmd;
+	int ret;
+
+	if (!buf)
+		return -EINVAL;
+
+	switch (len) {
+	case 1:
+		cmd = RSB_CMD_RD8;
+		break;
+	case 2:
+		cmd = RSB_CMD_RD16;
+		break;
+	case 4:
+		cmd = RSB_CMD_RD32;
+		break;
+	default:
+		dev_err(&ctrl->dev, "Invalid access width: %d", len);
+		return -EINVAL;
+	}
+
+	writel(addr, rsb->regs + RSB_ADDR);
+	writel(RSB_DAR_RTA(rtaddr), rsb->regs + RSB_DAR);
+	writel(cmd, rsb->regs + RSB_CMD);
+
+	ret = rsb_run_xfer(rsb);
+	if (ret)
+		return ret;
+
+	*buf = readl(rsb->regs + RSB_DATA);
+
+	return 0;
+}
+
+static int rsb_write_cmd(struct rsb_controller *ctrl, u8 rtaddr,
+			 u8 addr, const u32 *buf, size_t len)
+{
+	struct rsb *rsb = rsb_controller_get_drvdata(ctrl);
+	u32 cmd;
+
+	if (!buf)
+		return -EINVAL;
+
+	switch (len) {
+	case 1:
+		cmd = RSB_CMD_WR8;
+		break;
+	case 2:
+		cmd = RSB_CMD_WR16;
+		break;
+	case 4:
+		cmd = RSB_CMD_WR32;
+		break;
+	default:
+		dev_err(&ctrl->dev, "Invalid access width: %d", len);
+		return -EINVAL;
+	}
+
+	writel(addr, rsb->regs + RSB_ADDR);
+	writel(RSB_DAR_RTA(rtaddr), rsb->regs + RSB_DAR);
+	writel(*buf, rsb->regs + RSB_DATA);
+	writel(cmd, rsb->regs + RSB_CMD);
+
+	return rsb_run_xfer(rsb);
+}
+
+static int rsb_rtsaddr_cmd(struct rsb_controller *ctrl, u16 hwaddr, u8 rtaddr)
+{
+	struct rsb *rsb = rsb_controller_get_drvdata(ctrl);
+
+	/* setup command parameters */
+	writel(RSB_DAR_RTA(rtaddr) | RSB_DAR_DA(hwaddr), rsb->regs + RSB_DAR);
+	writel(RSB_CMD_STRA, rsb->regs + RSB_CMD);
+
+	/* send command */
+	return rsb_run_xfer(rsb);
+}
+
+static int rsb_init_cmd(struct rsb_controller *ctrl)
+{
+	struct rsb *rsb = rsb_controller_get_drvdata(ctrl);
+	int reg;
+
+	/* send init sequence */
+	writel(RSB_DMCR_DEVICE_START | RSB_DMCR_MODE_DATA |
+	       RSB_DMCR_MODE_REG | RSB_DMCR_DEV_ADDR, rsb->regs + RSB_DMCR);
+
+	readl_poll_timeout(rsb->regs + RSB_DMCR, reg,
+			   !(reg & RSB_DMCR_DEVICE_START), 100, 250000);
+	if (reg & RSB_DMCR_DEVICE_START)
+		dev_warn(&ctrl->dev, "send init sequence timeout\n");
+
+	/* clear any interrupt flags */
+	writel(readl(rsb->regs + RSB_INTS), rsb->regs + RSB_INTS);
+
+	return 0;
+}
+
+static const struct of_device_id rsb_of_match_table[] = {
+	{ .compatible = "allwinner,sun8i-a23-rsb" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, rsb_of_match_table);
+
+static int rsb_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct resource *r;
+	struct rsb_controller *ctrl;
+	struct rsb *rsb;
+	unsigned long parent_clk_freq;
+	u32 clk_freq = 100000;
+	int clk_div;
+	int irq;
+	int ret;
+	u32 reg;
+
+	of_property_read_u32(np, "clock-frequency", &clk_freq);
+	if (clk_freq > RSB_MAX_FREQ) {
+		dev_err(dev,
+			"clock-frequency (%u Hz) is too high (max = 20MHz)",
+			clk_freq);
+		return -EINVAL;
+	}
+
+	ctrl = rsb_controller_alloc(dev, sizeof(*rsb));
+	if (!ctrl)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, ctrl);
+
+	/* set callbacks */
+	ctrl->init_cmd = rsb_init_cmd;
+	ctrl->rtsaddr_cmd = rsb_rtsaddr_cmd;
+	ctrl->read_cmd = rsb_read_cmd;
+	ctrl->write_cmd = rsb_write_cmd;
+
+	rsb = rsb_controller_get_drvdata(ctrl);
+	rsb->ctrl = ctrl;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	rsb->regs = devm_ioremap_resource(dev, r);
+	if (IS_ERR(rsb->regs)) {
+		ret = PTR_ERR(rsb->regs);
+		goto err_rsb_controller_put;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(dev, "failed to retrieve irq: %d\n", irq);
+		ret = irq;
+		goto err_rsb_controller_put;
+	}
+
+	rsb->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(rsb->clk)) {
+		ret = PTR_ERR(rsb->clk);
+		dev_err(dev, "failed to retrieve clk: %d\n", ret);
+		goto err_rsb_controller_put;
+	}
+
+	ret = clk_prepare_enable(rsb->clk);
+	if (ret) {
+		dev_err(dev, "failed to enable clk: %d\n", ret);
+		goto err_rsb_controller_put;
+	}
+
+	parent_clk_freq = clk_get_rate(rsb->clk);
+
+	rsb->rstc = devm_reset_control_get(dev, NULL);
+	if (IS_ERR(rsb->rstc)) {
+		ret = PTR_ERR(rsb->rstc);
+		dev_err(dev, "failed to retrieve reset controller: %d\n", ret);
+		goto err_clk_disable;
+	}
+
+	ret = reset_control_deassert(rsb->rstc);
+	if (ret) {
+		dev_err(dev, "failed to deassert reset line: %d\n", ret);
+		goto err_clk_disable;
+	}
+
+	init_completion(&rsb->complete);
+
+	/* reset the controller */
+	writel(RSB_CTRL_SOFT_RST, rsb->regs + RSB_CTRL);
+	readl_poll_timeout(rsb->regs + RSB_CTRL, reg,
+			   !(reg & RSB_CTRL_SOFT_RST), 1000, 100000);
+
+	clk_div = parent_clk_freq / clk_freq;
+	if (!clk_div) {
+		dev_warn(dev,
+			 "clock-frequency is too high, setting it to %lu Hz\n",
+			 parent_clk_freq);
+		clk_div = 1;
+	} else if (clk_div > RSB_CCR_MAX_CLK_DIV + 1) {
+		dev_warn(dev,
+			 "clock-frequency is too low, setting it to %lu Hz\n",
+			 parent_clk_freq / (RSB_CCR_MAX_CLK_DIV + 1));
+		clk_div = RSB_CCR_MAX_CLK_DIV + 1;
+	}
+
+	writel(RSB_CCR_SDA_OUT_DELAY(1) | RSB_CCR_CLK_DIV(clk_div - 1),
+	       rsb->regs + RSB_CCR);
+
+	ret = devm_request_irq(dev, irq, rsb_interrupt, 0, RSB_CTRL_NAME, rsb);
+	if (ret) {
+		dev_err(dev, "can't register interrupt handler irq%d: %d\n",
+			irq, ret);
+		goto err_reset_assert;
+	}
+
+	ret = rsb_controller_add(ctrl);
+	if (!ret)
+		return 0;
+
+err_reset_assert:
+	reset_control_assert(rsb->rstc);
+
+err_clk_disable:
+	clk_disable_unprepare(rsb->clk);
+
+err_rsb_controller_put:
+	rsb_controller_put(ctrl);
+
+	return ret;
+}
+
+static int rsb_remove(struct platform_device *pdev)
+{
+	struct rsb_controller *ctrl = platform_get_drvdata(pdev);
+	struct rsb *rsb = rsb_controller_get_drvdata(ctrl);
+
+	rsb_controller_remove(ctrl);
+	reset_control_assert(rsb->rstc);
+	clk_disable_unprepare(rsb->clk);
+
+	return 0;
+}
+
+static struct platform_driver rsb_driver = {
+	.probe = rsb_probe,
+	.remove	= rsb_remove,
+	.driver	= {
+		.name = "rsb-sunxi",
+		.of_match_table = rsb_of_match_table,
+	},
+};
+module_platform_driver(rsb_driver);
+
+MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>");
+MODULE_DESCRIPTION("Allwinner RSB driver");
+MODULE_LICENSE("GPL v2");
-- 
2.5.0

[PATCH v3 5/8] regmap: rsb: Add support for Reduced Serial Bus (RSB) based regmaps

[Chen-Yu Tsai]

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 drivers/base/regmap/Kconfig      |   6 +-
 drivers/base/regmap/Makefile     |   1 +
 drivers/base/regmap/regmap-rsb.c | 121 +++++++++++++++++++++++++++++++++++++++
 include/linux/regmap.h           |  36 ++++++++++++
 4 files changed, 163 insertions(+), 1 deletion(-)
 create mode 100644 drivers/base/regmap/regmap-rsb.c

diff --git a/drivers/base/regmap/Kconfig b/drivers/base/regmap/Kconfig
index db9d00c36a3e..afb41994c51e 100644
--- a/drivers/base/regmap/Kconfig
+++ b/drivers/base/regmap/Kconfig
@@ -3,7 +3,7 @@
 # subsystems should select the appropriate symbols.
 
 config REGMAP
-	default y if (REGMAP_I2C || REGMAP_SPI || REGMAP_SPMI || REGMAP_AC97 || REGMAP_MMIO || REGMAP_IRQ)
+	default y if (REGMAP_I2C || REGMAP_SPI || REGMAP_SPMI || REGMAP_RSB || REGMAP_AC97 || REGMAP_MMIO || REGMAP_IRQ)
 	select LZO_COMPRESS
 	select LZO_DECOMPRESS
 	select IRQ_DOMAIN if REGMAP_IRQ
@@ -24,6 +24,10 @@ config REGMAP_SPMI
 	tristate
 	depends on SPMI
 
+config REGMAP_RSB
+	tristate
+	depends on RSB
+
 config REGMAP_MMIO
 	tristate
 
diff --git a/drivers/base/regmap/Makefile b/drivers/base/regmap/Makefile
index 609e4c84f485..dad32b3903d4 100644
--- a/drivers/base/regmap/Makefile
+++ b/drivers/base/regmap/Makefile
@@ -8,5 +8,6 @@ obj-$(CONFIG_REGMAP_AC97) += regmap-ac97.o
 obj-$(CONFIG_REGMAP_I2C) += regmap-i2c.o
 obj-$(CONFIG_REGMAP_SPI) += regmap-spi.o
 obj-$(CONFIG_REGMAP_SPMI) += regmap-spmi.o
+obj-$(CONFIG_REGMAP_RSB) += regmap-rsb.o
 obj-$(CONFIG_REGMAP_MMIO) += regmap-mmio.o
 obj-$(CONFIG_REGMAP_IRQ) += regmap-irq.o
diff --git a/drivers/base/regmap/regmap-rsb.c b/drivers/base/regmap/regmap-rsb.c
new file mode 100644
index 000000000000..e82aa980abe1
--- /dev/null
+++ b/drivers/base/regmap/regmap-rsb.c
@@ -0,0 +1,121 @@
+/*
+ * Register map access API - RSB support
+ *
+ * Copyright 2015 Chen-Yu Tsai
+ *
+ * Chen-Yu Tsai <wens@csie.org>
+ *
+ * Based on regmap-i2c.c
+ *
+ * Copyright 2011 Wolfson Microelectronics plc
+ *
+ * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/regmap.h>
+#include <linux/rsb.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "internal.h"
+
+struct rsb_context {
+	struct rsb_device *rsb;
+	int size;
+};
+
+static int regmap_rsb_reg_read(void *context, unsigned int reg,
+			       unsigned int *val)
+{
+	struct rsb_context *ctx = context;
+	struct rsb_device *rsb = ctx->rsb;
+
+	if (reg > 0xff)
+		return -EINVAL;
+
+	return rsb_register_read(rsb, reg, val, ctx->size);
+}
+
+static int regmap_rsb_reg_write(void *context, unsigned int reg,
+				unsigned int val)
+{
+	struct rsb_context *ctx = context;
+	struct rsb_device *rsb = ctx->rsb;
+
+	return rsb_register_write(rsb, reg, val, ctx->size);
+}
+
+static void regmap_rsb_free_context(void *context)
+{
+	struct rsb_context *ctx = context;
+
+	kfree(ctx);
+}
+
+static struct regmap_bus regmap_rsb = {
+	.reg_write = regmap_rsb_reg_write,
+	.reg_read = regmap_rsb_reg_read,
+	.free_context = regmap_rsb_free_context,
+	.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
+	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
+};
+
+static struct rsb_context *regmap_rsb_init_context(struct rsb_device *rsb,
+					const struct regmap_config *config)
+{
+	struct rsb_context *ctx;
+
+	switch (config->val_bits) {
+	case 8:
+	case 16:
+	case 32:
+		break;
+	default:
+		return ERR_PTR(-EINVAL);
+	}
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return ERR_PTR(-ENOMEM);
+
+	ctx->rsb = rsb;
+	ctx->size = config->val_bits / 8;
+
+	return ctx;
+}
+
+struct regmap *__regmap_init_rsb(struct rsb_device *rsb,
+				 const struct regmap_config *config,
+				 struct lock_class_key *lock_key,
+				 const char *lock_name)
+{
+	struct rsb_context *ctx = regmap_rsb_init_context(rsb, config);
+
+	if (IS_ERR(ctx))
+		return ERR_CAST(ctx);
+
+	return __regmap_init(&rsb->dev, &regmap_rsb, ctx, config,
+			     lock_key, lock_name);
+}
+EXPORT_SYMBOL_GPL(__regmap_init_rsb);
+
+struct regmap *__devm_regmap_init_rsb(struct rsb_device *rsb,
+				      const struct regmap_config *config,
+				      struct lock_class_key *lock_key,
+				      const char *lock_name)
+{
+	struct rsb_context *ctx = regmap_rsb_init_context(rsb, config);
+
+	if (IS_ERR(ctx))
+		return ERR_CAST(ctx);
+
+	return __devm_regmap_init(&rsb->dev, &regmap_rsb, ctx, config,
+				  lock_key, lock_name);
+}
+EXPORT_SYMBOL_GPL(__devm_regmap_init_rsb);
+
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 17178317bcec..df94574b1d37 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -25,6 +25,7 @@ struct i2c_client;
 struct irq_domain;
 struct spi_device;
 struct spmi_device;
+struct rsb_device;
 struct regmap;
 struct regmap_range_cfg;
 struct regmap_field;
@@ -377,6 +378,10 @@ struct regmap *__regmap_init_ac97(struct snd_ac97 *ac97,
 				  const struct regmap_config *config,
 				  struct lock_class_key *lock_key,
 				  const char *lock_name);
+struct regmap *__regmap_init_rsb(struct rsb_device *rsb,
+				 const struct regmap_config *config,
+				 struct lock_class_key *lock_key,
+				 const char *lock_name);
 
 struct regmap *__devm_regmap_init(struct device *dev,
 				  const struct regmap_bus *bus,
@@ -410,6 +415,10 @@ struct regmap *__devm_regmap_init_ac97(struct snd_ac97 *ac97,
 				       const struct regmap_config *config,
 				       struct lock_class_key *lock_key,
 				       const char *lock_name);
+struct regmap *__devm_regmap_init_rsb(struct rsb_device *rsb,
+				      const struct regmap_config *config,
+				      struct lock_class_key *lock_key,
+				      const char *lock_name);
 
 /*
  * Wrapper for regmap_init macros to include a unique lockdep key and name
@@ -544,6 +553,19 @@ int regmap_attach_dev(struct device *dev, struct regmap *map,
 bool regmap_ac97_default_volatile(struct device *dev, unsigned int reg);
 
 /**
+ * regmap_init_rsb(): Initialise register map
+ *
+ * @rsb: Device that will be interacted with
+ * @config: Configuration for register map
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer to
+ * a struct regmap.
+ */
+#define regmap_init_rsb(rsb, config)					\
+	__regmap_lockdep_wrapper(__regmap_init_rsb, #config,		\
+				rsb, config)
+
+/**
  * devm_regmap_init(): Initialise managed register map
  *
  * @dev: Device that will be interacted with
@@ -658,6 +680,20 @@ bool regmap_ac97_default_volatile(struct device *dev, unsigned int reg);
 	__regmap_lockdep_wrapper(__devm_regmap_init_ac97, #config,	\
 				ac97, config)
 
+/**
+ * devm_regmap_init_rsb(): Initialise managed register map
+ *
+ * @rsb: Device that will be interacted with
+ * @config: Configuration for register map
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer
+ * to a struct regmap.  The regmap will be automatically freed by the
+ * device management code.
+ */
+#define devm_regmap_init_rsb(rsb, config)				\
+	__regmap_lockdep_wrapper(__devm_regmap_init_rsb, #config,	\
+				rsb, config)
+
 void regmap_exit(struct regmap *map);
 int regmap_reinit_cache(struct regmap *map,
 			const struct regmap_config *config);
-- 
2.5.0

[PATCH v3 6/8] ARM: dts: sun8i: Add Reduced Serial Bus controller device node to A23/A33 dtsi

[Chen-Yu Tsai]

This patch adds a device node for the Reduced Serial Bus (RSB)
controller and the defacto pinmux setting to the A23/A33 dtsi.

Since there is only one possible pinmux setting for RSB, just
set it in the dtsi.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 arch/arm/boot/dts/sun8i-a23-a33.dtsi | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/arch/arm/boot/dts/sun8i-a23-a33.dtsi b/arch/arm/boot/dts/sun8i-a23-a33.dtsi
index 27a925ec17d2..db3671382cb2 100644
--- a/arch/arm/boot/dts/sun8i-a23-a33.dtsi
+++ b/arch/arm/boot/dts/sun8i-a23-a33.dtsi
@@ -661,6 +661,13 @@
 			#size-cells = <0>;
 			#gpio-cells = <3>;
 
+			r_rsb_pins: r_rsb {
+				allwinner,pins = "PL0", "PL1";
+				allwinner,function = "s_rsb";
+				allwinner,drive = <SUN4I_PINCTRL_20_MA>;
+				allwinner,pull = <SUN4I_PINCTRL_PULL_UP>;
+			};
+
 			r_uart_pins_a: r_uart@0 {
 				allwinner,pins = "PL2", "PL3";
 				allwinner,function = "s_uart";
@@ -668,5 +675,19 @@
 				allwinner,pull = <SUN4I_PINCTRL_NO_PULL>;
 			};
 		};
+
+		r_rsb: i2c@01f03400 {
+			compatible = "allwinner,sun8i-a23-rsb";
+			reg = <0x01f03400 0x400>;
+			interrupts = <GIC_SPI 39 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&apb0_gates 3>;
+			clock-frequency = <3000000>;
+			resets = <&apb0_rst 3>;
+			pinctrl-names = "default";
+			pinctrl-0 = <&r_rsb_pins>;
+			status = "disabled";
+			#address-cells = <2>;
+			#size-cells = <0>;
+		};
 	};
 };
-- 
2.5.0

[PATCH v3 7/8] ARM: dts: sun8i: ippo-q8h-v5: Enable Reduced Serial Bus controller

[Chen-Yu Tsai]

The Reduced Serial Bus controller is used to talk to the onboard PMIC.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 arch/arm/boot/dts/sun8i-a23-ippo-q8h-v5.dts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/boot/dts/sun8i-a23-ippo-q8h-v5.dts b/arch/arm/boot/dts/sun8i-a23-ippo-q8h-v5.dts
index 8d9da6886a4c..2e45a82c8981 100644
--- a/arch/arm/boot/dts/sun8i-a23-ippo-q8h-v5.dts
+++ b/arch/arm/boot/dts/sun8i-a23-ippo-q8h-v5.dts
@@ -120,6 +120,10 @@
 	};
 };
 
+&r_rsb {
+	status = "okay";
+};
+
 &r_uart {
 	pinctrl-names = "default";
 	pinctrl-0 = <&r_uart_pins_a>;
-- 
2.5.0

[PATCH v3 8/8] ARM: dts: sun8i: sinlinx-sina33: Enable Reduced Serial Bus controller

[Chen-Yu Tsai]

The Reduced Serial Bus controller is used to talk to the onboard PMIC.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 arch/arm/boot/dts/sun8i-a33-sinlinx-sina33.dts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/boot/dts/sun8i-a33-sinlinx-sina33.dts b/arch/arm/boot/dts/sun8i-a33-sinlinx-sina33.dts
index 1d5390d4e03a..13ce68f06dd6 100644
--- a/arch/arm/boot/dts/sun8i-a33-sinlinx-sina33.dts
+++ b/arch/arm/boot/dts/sun8i-a33-sinlinx-sina33.dts
@@ -130,6 +130,10 @@
 	};
 };
 
+&r_rsb {
+	status = "okay";
+};
+
 &uart0 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&uart0_pins_b>;
-- 
2.5.0

Re: [PATCH v3 0/8] ARM: sunxi: Add Reduced Serial Bus support

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 565 bytes --]

On Wed, Aug 19, 2015 at 12:20:01PM +0800, Chen-Yu Tsai wrote:
> Hi everyone,
> 
> This is my third attempt at adding support for Allwinner's Reduced
> Serial Bus (RSB), which is used to communicate with PMICs and other
> peripherals on their newer SoCs, such as the A23/A33/A80.

This is flagged as something that is specific to the Allwinner SoCs.
Why add generic regmap support rather than just implement the regmap
reg_read() and reg_write() in a regmap in the controller driver?  Are
there expected to be other controller drivers from other vendors?

[-- Attachment #2: Digital signature --]
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Re: [PATCH v3 0/8] ARM: sunxi: Add Reduced Serial Bus support

[Chen-Yu Tsai]

On Thu, Aug 20, 2015 at 12:32 AM, Mark Brown <broonie@kernel.org> wrote:
> On Wed, Aug 19, 2015 at 12:20:01PM +0800, Chen-Yu Tsai wrote:
>> Hi everyone,
>>
>> This is my third attempt at adding support for Allwinner's Reduced
>> Serial Bus (RSB), which is used to communicate with PMICs and other
>> peripherals on their newer SoCs, such as the A23/A33/A80.
>
> This is flagged as something that is specific to the Allwinner SoCs.
> Why add generic regmap support rather than just implement the regmap
> reg_read() and reg_write() in a regmap in the controller driver?  Are
> there expected to be other controller drivers from other vendors?

I don't expect there to be any other controller drivers. And it seems
at least some of the devices are dual interface (I2C/RSB). Though I
don't see how its connected to the generic regmap support. Regmap
is for device drivers connected to the RSB bus, not the bus controller
itself.

That said, there are a few RSB mfd slave devices that need support,
those being the later AXP series PMICs, and AC100/AC200 audio-codec/RTC
chips. The current axp20x driver already uses i2c regmaps.

I could throw all the RSB-related stuff together, presumably under
drivers/soc/sunxi/rsb, though that doesn't help the fact that common
regmap code would be  better than scattering regmap_* in various mfd
drivers.


Regards
ChenYu

Re: [PATCH v3 1/8] rsb: Add generic Reduced Serial Bus (RSB) controller binding documentation

[Maxime Ripard]

[-- Attachment #1: Type: text/plain, Size: 2814 bytes --]

Hi,

Thanks a lot for working on this.

On Wed, Aug 19, 2015 at 12:20:02PM +0800, Chen-Yu Tsai wrote:
> Reduced Serial Bus is a proprietary 2-line push-pull serial bus
> supporting multiple slave devices.
> 
> It was developed by Allwinner, Inc. and used by Allwinner and X-Powers,
> Inc. for their line of PMICs and other peripheral ICs.
> 
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> ---
>  Documentation/devicetree/bindings/rsb/rsb.txt | 50 +++++++++++++++++++++++++++
>  1 file changed, 50 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/rsb/rsb.txt
> 
> diff --git a/Documentation/devicetree/bindings/rsb/rsb.txt b/Documentation/devicetree/bindings/rsb/rsb.txt
> new file mode 100644
> index 000000000000..0b027948ca9c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/rsb/rsb.txt
> @@ -0,0 +1,50 @@
> +Reduced Serial Bus (RSB) Controller
> +
> +This document defines a generic set of bindings for use by RSB controllers.
> +A controller is modelled in device tree as a node with zero or more child
> +nodes, each representing a unique slave device on the bus.
> +
> +Required properties:
> +
> + - #address-cells : must be 2
> + - #size-cells : must be 0
> +
> +Optional properties:
> +
> + - clock-frequency : Desired bus clock frequency in Hz. Maximum is 20 MHz.

What is the default if not set?

> +
> +Child nodes:
> +
> +An RSB controller node can contain zero or more child nodes representing
> +slave devices on the bus.  Child 'reg' properties are specified as a
> +runtime address, hardware address pair. The hardware address is hardwired
> +in the device, which can normally be found in the datasheet. The runtime
> +address is set by software. No 2 devices on the same bus shall have the
> +same runtime address.
> +
> +Valid runtime addresses - There are only 15 valid runtime addresses:
> +
> +    0x17, 0x2d, 0x3a, 0x4e, 0x59, 0x63, 0x74, 0x8b,
> +    0x9c, 0xa6, 0xb1, 0xc5, 0xd2, 0xe8, 0xff
> +
> +It is highly recommended that one choose the same runtime addresses as
> +vendor BSPs use so that a) the addresses remain the same across different
> +software systems, and b) addresses of supported and listed slave devices
> +don't conflict with unsupported or not yet listed devices.

I'd expect to have the hardware address first, but maybe it's just me
:)


> +Example:
> +
> +	rsb@... {
> +		compatible = "...";
> +		reg = <...>;
> +		/* ... */
> +		#address-cells = <2>;
> +		#size-cells = <0>;
> +
> +		pmic@2d {

The unit-address should be 2d,3e3.

> +			compatible = "...";
> +			reg = <0x2d 0x3e3>;
> +
> +			/* ... */
> +		};
> +	};
> -- 
> 2.5.0
> 

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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Re: [PATCH v3 1/8] rsb: Add generic Reduced Serial Bus (RSB) controller binding documentation

[Chen-Yu Tsai]

On Thu, Aug 20, 2015 at 11:08 PM, Maxime Ripard
<maxime.ripard@free-electrons.com> wrote:
> Hi,
>
> Thanks a lot for working on this.
>
> On Wed, Aug 19, 2015 at 12:20:02PM +0800, Chen-Yu Tsai wrote:
>> Reduced Serial Bus is a proprietary 2-line push-pull serial bus
>> supporting multiple slave devices.
>>
>> It was developed by Allwinner, Inc. and used by Allwinner and X-Powers,
>> Inc. for their line of PMICs and other peripheral ICs.
>>
>> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
>> ---
>>  Documentation/devicetree/bindings/rsb/rsb.txt | 50 +++++++++++++++++++++++++++
>>  1 file changed, 50 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/rsb/rsb.txt
>>
>> diff --git a/Documentation/devicetree/bindings/rsb/rsb.txt b/Documentation/devicetree/bindings/rsb/rsb.txt
>> new file mode 100644
>> index 000000000000..0b027948ca9c
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/rsb/rsb.txt
>> @@ -0,0 +1,50 @@
>> +Reduced Serial Bus (RSB) Controller
>> +
>> +This document defines a generic set of bindings for use by RSB controllers.
>> +A controller is modelled in device tree as a node with zero or more child
>> +nodes, each representing a unique slave device on the bus.
>> +
>> +Required properties:
>> +
>> + - #address-cells : must be 2
>> + - #size-cells : must be 0
>> +
>> +Optional properties:
>> +
>> + - clock-frequency : Desired bus clock frequency in Hz. Maximum is 20 MHz.
>
> What is the default if not set?

Presently the driver would have it default to 1 MHz, Which doesn't match
the driver binding. Will fix this.

>> +
>> +Child nodes:
>> +
>> +An RSB controller node can contain zero or more child nodes representing
>> +slave devices on the bus.  Child 'reg' properties are specified as a
>> +runtime address, hardware address pair. The hardware address is hardwired
>> +in the device, which can normally be found in the datasheet. The runtime
>> +address is set by software. No 2 devices on the same bus shall have the
>> +same runtime address.
>> +
>> +Valid runtime addresses - There are only 15 valid runtime addresses:
>> +
>> +    0x17, 0x2d, 0x3a, 0x4e, 0x59, 0x63, 0x74, 0x8b,
>> +    0x9c, 0xa6, 0xb1, 0xc5, 0xd2, 0xe8, 0xff
>> +
>> +It is highly recommended that one choose the same runtime addresses as
>> +vendor BSPs use so that a) the addresses remain the same across different
>> +software systems, and b) addresses of supported and listed slave devices
>> +don't conflict with unsupported or not yet listed devices.
>
> I'd expect to have the hardware address first, but maybe it's just me
> :)

I don't know. It's only used at init time.

And in my latest experience, once the runtime address is set by the
bootloader, it can't be changed. My earlier experience was the opposite,
though I haven't figured out why.

>
>> +Example:
>> +
>> +     rsb@... {
>> +             compatible = "...";
>> +             reg = <...>;
>> +             /* ... */
>> +             #address-cells = <2>;
>> +             #size-cells = <0>;
>> +
>> +             pmic@2d {
>
> The unit-address should be 2d,3e3.

Hmm... I didn't know this was legal.

>> +                     compatible = "...";
>> +                     reg = <0x2d 0x3e3>;
>> +
>> +                     /* ... */
>> +             };
>> +     };
>> --
>> 2.5.0
>>
>
> --
> Maxime Ripard, Free Electrons
> Embedded Linux, Kernel and Android engineering
> http://free-electrons.com

Re: [PATCH v3 0/8] ARM: sunxi: Add Reduced Serial Bus support

[Mark Brown]

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On Thu, Aug 20, 2015 at 09:59:27AM +0800, Chen-Yu Tsai wrote:
> On Thu, Aug 20, 2015 at 12:32 AM, Mark Brown <broonie@kernel.org> wrote:

> > This is flagged as something that is specific to the Allwinner SoCs.
> > Why add generic regmap support rather than just implement the regmap
> > reg_read() and reg_write() in a regmap in the controller driver?  Are
> > there expected to be other controller drivers from other vendors?

> I don't expect there to be any other controller drivers. And it seems
> at least some of the devices are dual interface (I2C/RSB). Though I
> don't see how its connected to the generic regmap support. Regmap
> is for device drivers connected to the RSB bus, not the bus controller
> itself.

The point here is that you can use regmap for a custom controller
without having to implement a bus, to repeat what I said:

| > Why add generic regmap support rather than just implement the regmap
| > reg_read() and reg_write() in a regmap in the controller driver?  Are

> I could throw all the RSB-related stuff together, presumably under
> drivers/soc/sunxi/rsb, though that doesn't help the fact that common
> regmap code would be  better than scattering regmap_* in various mfd
> drivers.

If there is only one controller driver you just have a single call into
that driver in the client device which gives you the same level of
shared code, having a wrapper layer in regmap that puts regmap_
functions around the equivalent controller specific functions isn't
really adding a huge amount.

It's a similar thing to the way we just reuse the platform bus for basic
buses rather than copying it to make new bus types, we don't need to
create lots of new boilerplate regmap types that are just really basic
wrappers.  There are a lot of these custom buses that people have.

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Re: [PATCH v3 3/8] rsb: Linux driver framework for Reduced Serial Bus (RSB)

[Mark Brown]

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On Wed, Aug 19, 2015 at 12:20:04PM +0800, Chen-Yu Tsai wrote:

> Reduced Serial Bus (RSB) is an Allwinner proprietery interface
> used to communicate with PMICs and other peripheral ICs.

>  drivers/rsb/Kconfig    |  11 ++
>  drivers/rsb/Makefile   |   4 +
>  drivers/rsb/rsb-core.c | 511 +++++++++++++++++++++++++++++++++++++++++++++++++

Based on the changelog and what you were saying in your other mail about
this being very Allwinner specific I think the current trend would be to
put this into drivers/soc rather than making a new top level directory
in drivers.

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Re: [PATCH v3 1/8] rsb: Add generic Reduced Serial Bus (RSB) controller binding documentation

[Maxime Ripard]

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On Thu, Aug 20, 2015 at 11:58:39PM +0800, Chen-Yu Tsai wrote:
> >> +Child nodes:
> >> +
> >> +An RSB controller node can contain zero or more child nodes representing
> >> +slave devices on the bus.  Child 'reg' properties are specified as a
> >> +runtime address, hardware address pair. The hardware address is hardwired
> >> +in the device, which can normally be found in the datasheet. The runtime
> >> +address is set by software. No 2 devices on the same bus shall have the
> >> +same runtime address.
> >> +
> >> +Valid runtime addresses - There are only 15 valid runtime addresses:
> >> +
> >> +    0x17, 0x2d, 0x3a, 0x4e, 0x59, 0x63, 0x74, 0x8b,
> >> +    0x9c, 0xa6, 0xb1, 0xc5, 0xd2, 0xe8, 0xff
> >> +
> >> +It is highly recommended that one choose the same runtime addresses as
> >> +vendor BSPs use so that a) the addresses remain the same across different
> >> +software systems, and b) addresses of supported and listed slave devices
> >> +don't conflict with unsupported or not yet listed devices.
> >
> > I'd expect to have the hardware address first, but maybe it's just me
> > :)
> 
> I don't know. It's only used at init time.
> 
> And in my latest experience, once the runtime address is set by the
> bootloader, it can't be changed. My earlier experience was the opposite,
> though I haven't figured out why.

Note that I'm only talking about the order of runtime and hardware
addresses in the reg property, having both is fine.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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Re: [PATCH v3 1/8] rsb: Add generic Reduced Serial Bus (RSB) controller binding documentation

[Rob Herring]

On Tue, Aug 18, 2015 at 11:20 PM, Chen-Yu Tsai <wens@csie.org> wrote:
> Reduced Serial Bus is a proprietary 2-line push-pull serial bus
> supporting multiple slave devices.
>
> It was developed by Allwinner, Inc. and used by Allwinner and X-Powers,
> Inc. for their line of PMICs and other peripheral ICs.
>
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> ---
>  Documentation/devicetree/bindings/rsb/rsb.txt | 50 +++++++++++++++++++++++++++
>  1 file changed, 50 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/rsb/rsb.txt
>
> diff --git a/Documentation/devicetree/bindings/rsb/rsb.txt b/Documentation/devicetree/bindings/rsb/rsb.txt
> new file mode 100644
> index 000000000000..0b027948ca9c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/rsb/rsb.txt
> @@ -0,0 +1,50 @@
> +Reduced Serial Bus (RSB) Controller
> +
> +This document defines a generic set of bindings for use by RSB controllers.
> +A controller is modelled in device tree as a node with zero or more child
> +nodes, each representing a unique slave device on the bus.
> +
> +Required properties:
> +
> + - #address-cells : must be 2
> + - #size-cells : must be 0
> +
> +Optional properties:
> +
> + - clock-frequency : Desired bus clock frequency in Hz. Maximum is 20 MHz.
> +
> +Child nodes:
> +
> +An RSB controller node can contain zero or more child nodes representing
> +slave devices on the bus.  Child 'reg' properties are specified as a
> +runtime address, hardware address pair. The hardware address is hardwired
> +in the device, which can normally be found in the datasheet. The runtime
> +address is set by software. No 2 devices on the same bus shall have the
> +same runtime address.
> +
> +Valid runtime addresses - There are only 15 valid runtime addresses:
> +
> +    0x17, 0x2d, 0x3a, 0x4e, 0x59, 0x63, 0x74, 0x8b,
> +    0x9c, 0xa6, 0xb1, 0xc5, 0xd2, 0xe8, 0xff
> +
> +It is highly recommended that one choose the same runtime addresses as
> +vendor BSPs use so that a) the addresses remain the same across different
> +software systems, and b) addresses of supported and listed slave devices
> +don't conflict with unsupported or not yet listed devices.

I fail to understand why the run-time address belongs in DT or why
alignment to vendor BSP matters? I can see the desire to align DTs if
the vendor OS was dependent on having this information. Having to
access the vendor OS to determine what address to pick does not seem
like the right way to write a DTS. It seems to me that the RSB bus
driver should allocate run-time addresses dynamically.

Rob

Re: [PATCH v3 1/8] rsb: Add generic Reduced Serial Bus (RSB) controller binding documentation

[Chen-Yu Tsai]

On Mon, Aug 24, 2015 at 6:43 AM, Rob Herring <robherring2@gmail.com> wrote:
> On Tue, Aug 18, 2015 at 11:20 PM, Chen-Yu Tsai <wens@csie.org> wrote:
>> Reduced Serial Bus is a proprietary 2-line push-pull serial bus
>> supporting multiple slave devices.
>>
>> It was developed by Allwinner, Inc. and used by Allwinner and X-Powers,
>> Inc. for their line of PMICs and other peripheral ICs.
>>
>> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
>> ---
>>  Documentation/devicetree/bindings/rsb/rsb.txt | 50 +++++++++++++++++++++++++++
>>  1 file changed, 50 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/rsb/rsb.txt
>>
>> diff --git a/Documentation/devicetree/bindings/rsb/rsb.txt b/Documentation/devicetree/bindings/rsb/rsb.txt
>> new file mode 100644
>> index 000000000000..0b027948ca9c
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/rsb/rsb.txt
>> @@ -0,0 +1,50 @@
>> +Reduced Serial Bus (RSB) Controller
>> +
>> +This document defines a generic set of bindings for use by RSB controllers.
>> +A controller is modelled in device tree as a node with zero or more child
>> +nodes, each representing a unique slave device on the bus.
>> +
>> +Required properties:
>> +
>> + - #address-cells : must be 2
>> + - #size-cells : must be 0
>> +
>> +Optional properties:
>> +
>> + - clock-frequency : Desired bus clock frequency in Hz. Maximum is 20 MHz.
>> +
>> +Child nodes:
>> +
>> +An RSB controller node can contain zero or more child nodes representing
>> +slave devices on the bus.  Child 'reg' properties are specified as a
>> +runtime address, hardware address pair. The hardware address is hardwired
>> +in the device, which can normally be found in the datasheet. The runtime
>> +address is set by software. No 2 devices on the same bus shall have the
>> +same runtime address.
>> +
>> +Valid runtime addresses - There are only 15 valid runtime addresses:
>> +
>> +    0x17, 0x2d, 0x3a, 0x4e, 0x59, 0x63, 0x74, 0x8b,
>> +    0x9c, 0xa6, 0xb1, 0xc5, 0xd2, 0xe8, 0xff
>> +
>> +It is highly recommended that one choose the same runtime addresses as
>> +vendor BSPs use so that a) the addresses remain the same across different
>> +software systems, and b) addresses of supported and listed slave devices
>> +don't conflict with unsupported or not yet listed devices.
>
> I fail to understand why the run-time address belongs in DT or why
> alignment to vendor BSP matters? I can see the desire to align DTs if
> the vendor OS was dependent on having this information. Having to
> access the vendor OS to determine what address to pick does not seem
> like the right way to write a DTS. It seems to me that the RSB bus
> driver should allocate run-time addresses dynamically.

I agree it seems better that the driver should allocate them dynamically.
However my attempts to reset the runtime addresses all fail, with the
device in question rejecting the request.

I'll run some more tests. Another way would be for the driver to test
if the device was already allocated an address, and just use that. If
not, then just allocate one to it. The implementation is a bit more
complicated, as there's no lookup function.

But if we cannot reliably reset the runtime addresses, I don't see
any alternative to putting the address in the DT. Most of the use cases
we want to support are PMICs, which are initialized by the boot loader.


Regards
ChenYu