[PATCH v6 2/2] bus: sunxi-rsb: Add driver for Allwinner Reduced Serial Bus
From: Chen-Yu Tsai
Date: Sat Oct 17 2015 - 13:27:50 EST
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@xxxxxxxx>
Reviewed-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
---
drivers/bus/Kconfig | 11 +
drivers/bus/Makefile | 1 +
drivers/bus/sunxi-rsb.c | 783 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/sunxi-rsb.h | 105 +++++++
4 files changed, 900 insertions(+)
create mode 100644 drivers/bus/sunxi-rsb.c
create mode 100644 include/linux/sunxi-rsb.h
diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
index 1a82f3a17681..e921b8c72f8c 100644
--- a/drivers/bus/Kconfig
+++ b/drivers/bus/Kconfig
@@ -121,6 +121,17 @@ config SIMPLE_PM_BUS
Controller (BSC, sometimes called "LBSC within Bus Bridge", or
"External Bus Interface") as found on several Renesas ARM SoCs.
+config SUNXI_RSB
+ bool "Allwinner sunXi Reduced Serial Bus Driver"
+ default MACH_SUN8I || MACH_SUN9I
+ depends on ARCH_SUNXI
+ select REGMAP
+ help
+ Say y here to enable support for Allwinner's Reduced Serial Bus
+ (RSB) support. This controller is responsible for communicating
+ with various RSB based devices, such as AXP223, AXP8XX PMICs,
+ and AC100/AC200 ICs.
+
config VEXPRESS_CONFIG
bool "Versatile Express configuration bus"
default y if ARCH_VEXPRESS
diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
index 790e7b933fb2..fcb9f9794a1f 100644
--- a/drivers/bus/Makefile
+++ b/drivers/bus/Makefile
@@ -15,5 +15,6 @@ obj-$(CONFIG_MVEBU_MBUS) += mvebu-mbus.o
obj-$(CONFIG_OMAP_INTERCONNECT) += omap_l3_smx.o omap_l3_noc.o
obj-$(CONFIG_OMAP_OCP2SCP) += omap-ocp2scp.o
+obj-$(CONFIG_SUNXI_RSB) += sunxi-rsb.o
obj-$(CONFIG_SIMPLE_PM_BUS) += simple-pm-bus.o
obj-$(CONFIG_VEXPRESS_CONFIG) += vexpress-config.o
diff --git a/drivers/bus/sunxi-rsb.c b/drivers/bus/sunxi-rsb.c
new file mode 100644
index 000000000000..846bc29c157d
--- /dev/null
+++ b/drivers/bus/sunxi-rsb.c
@@ -0,0 +1,783 @@
+/*
+ * RSB (Reduced Serial Bus) driver.
+ *
+ * Author: Chen-Yu Tsai <wens@xxxxxxxx>
+ *
+ * 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/clk/clk-conf.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/sunxi-rsb.h>
+#include <linux/types.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 sunxi_rsb_addr_map {
+ u16 hwaddr;
+ u8 rtaddr;
+};
+
+struct sunxi_rsb {
+ struct device *dev;
+ void __iomem *regs;
+ struct clk *clk;
+ struct reset_control *rstc;
+ struct completion complete;
+ struct mutex lock;
+ unsigned int status;
+};
+
+/* bus / slave device related functions */
+static struct bus_type sunxi_rsb_bus;
+
+static int sunxi_rsb_device_match(struct device *dev, struct device_driver *drv)
+{
+ return of_driver_match_device(dev, drv);
+}
+
+static int sunxi_rsb_device_probe(struct device *dev)
+{
+ const struct sunxi_rsb_driver *drv = to_sunxi_rsb_driver(dev->driver);
+ struct sunxi_rsb_device *rdev = to_sunxi_rsb_device(dev);
+ int ret;
+
+ if (!drv->probe)
+ return -ENODEV;
+
+ if (!rdev->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;
+
+ rdev->irq = irq;
+ }
+
+ ret = of_clk_set_defaults(dev->of_node, false);
+ if (ret < 0)
+ return ret;
+
+ return drv->probe(rdev);
+}
+
+static int sunxi_rsb_device_remove(struct device *dev)
+{
+ const struct sunxi_rsb_driver *drv = to_sunxi_rsb_driver(dev->driver);
+
+ return drv->remove(to_sunxi_rsb_device(dev));
+}
+
+static struct bus_type sunxi_rsb_bus = {
+ .name = RSB_CTRL_NAME,
+ .match = sunxi_rsb_device_match,
+ .probe = sunxi_rsb_device_probe,
+ .remove = sunxi_rsb_device_remove,
+};
+
+static void sunxi_rsb_dev_release(struct device *dev)
+{
+ struct sunxi_rsb_device *rdev = to_sunxi_rsb_device(dev);
+
+ kfree(rdev);
+}
+
+/**
+ * sunxi_rsb_device_create() - allocate and add an RSB device
+ * @rsb: RSB controller
+ * @node: RSB slave device node
+ * @hwaddr: RSB slave hardware address
+ * @rtaddr: RSB slave runtime address
+ */
+static struct sunxi_rsb_device *sunxi_rsb_device_create(struct sunxi_rsb *rsb,
+ struct device_node *node, u16 hwaddr, u8 rtaddr)
+{
+ int err;
+ struct sunxi_rsb_device *rdev;
+
+ rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
+ if (!rdev)
+ return ERR_PTR(-ENOMEM);
+
+ rdev->rsb = rsb;
+ rdev->hwaddr = hwaddr;
+ rdev->rtaddr = rtaddr;
+ rdev->dev.bus = &sunxi_rsb_bus;
+ rdev->dev.parent = rsb->dev;
+ rdev->dev.of_node = node;
+ rdev->dev.release = sunxi_rsb_dev_release;
+
+ dev_set_name(&rdev->dev, "%s-%x", RSB_CTRL_NAME, hwaddr);
+
+ err = device_register(&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:
+ put_device(&rdev->dev);
+
+ return ERR_PTR(err);
+}
+
+/**
+ * sunxi_rsb_device_unregister(): unregister an RSB device
+ * @rdev: rsb_device to be removed
+ */
+static void sunxi_rsb_device_unregister(struct sunxi_rsb_device *rdev)
+{
+ device_unregister(&rdev->dev);
+}
+
+static int sunxi_rsb_remove_devices(struct device *dev, void *data)
+{
+ struct sunxi_rsb_device *rdev = to_sunxi_rsb_device(dev);
+
+ if (dev->bus == &sunxi_rsb_bus)
+ sunxi_rsb_device_unregister(rdev);
+
+ return 0;
+}
+
+/**
+ * sunxi_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 sunxi_rsb_driver_register(struct sunxi_rsb_driver *rdrv)
+{
+ rdrv->driver.bus = &sunxi_rsb_bus;
+ return driver_register(&rdrv->driver);
+}
+EXPORT_SYMBOL_GPL(sunxi_rsb_driver_register);
+
+/* common code that starts a transfer */
+static int _sunxi_rsb_run_xfer(struct sunxi_rsb *rsb)
+{
+ if (readl(rsb->regs + RSB_CTRL) & RSB_CTRL_START_TRANS) {
+ dev_dbg(rsb->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->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->dev, "RSB busy\n");
+ return -EBUSY;
+ }
+
+ if (rsb->status & RSB_INTS_TRANS_ERR) {
+ if (rsb->status & RSB_INTS_TRANS_ERR_ACK) {
+ dev_dbg(rsb->dev, "RSB slave nack\n");
+ return -EINVAL;
+ }
+
+ if (rsb->status & RSB_INTS_TRANS_ERR_DATA) {
+ dev_dbg(rsb->dev, "RSB transfer data error\n");
+ return -EIO;
+ }
+ }
+
+ return 0;
+}
+
+static int sunxi_rsb_read(struct sunxi_rsb *rsb, u8 rtaddr, u8 addr,
+ u32 *buf, size_t len)
+{
+ 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(rsb->dev, "Invalid access width: %d\n", len);
+ return -EINVAL;
+ }
+
+ mutex_lock(&rsb->lock);
+
+ writel(addr, rsb->regs + RSB_ADDR);
+ writel(RSB_DAR_RTA(rtaddr), rsb->regs + RSB_DAR);
+ writel(cmd, rsb->regs + RSB_CMD);
+
+ ret = _sunxi_rsb_run_xfer(rsb);
+ if (ret)
+ goto out;
+
+ *buf = readl(rsb->regs + RSB_DATA);
+
+ mutex_unlock(&rsb->lock);
+
+out:
+ return ret;
+}
+
+static int sunxi_rsb_write(struct sunxi_rsb *rsb, u8 rtaddr, u8 addr,
+ const u32 *buf, size_t len)
+{
+ u32 cmd;
+ int ret;
+
+ 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(rsb->dev, "Invalid access width: %d\n", len);
+ return -EINVAL;
+ }
+
+ mutex_lock(&rsb->lock);
+
+ 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);
+ ret = _sunxi_rsb_run_xfer(rsb);
+
+ mutex_unlock(&rsb->lock);
+
+ return ret;
+}
+
+/* RSB regmap functions */
+struct sunxi_rsb_ctx {
+ struct sunxi_rsb_device *rdev;
+ int size;
+};
+
+static int regmap_sunxi_rsb_reg_read(void *context, unsigned int reg,
+ unsigned int *val)
+{
+ struct sunxi_rsb_ctx *ctx = context;
+ struct sunxi_rsb_device *rdev = ctx->rdev;
+
+ if (reg > 0xff)
+ return -EINVAL;
+
+ return sunxi_rsb_read(rdev->rsb, rdev->rtaddr, reg, val, ctx->size);
+}
+
+static int regmap_sunxi_rsb_reg_write(void *context, unsigned int reg,
+ unsigned int val)
+{
+ struct sunxi_rsb_ctx *ctx = context;
+ struct sunxi_rsb_device *rdev = ctx->rdev;
+
+ return sunxi_rsb_write(rdev->rsb, rdev->rtaddr, reg, &val, ctx->size);
+}
+
+static void regmap_sunxi_rsb_free_ctx(void *context)
+{
+ struct sunxi_rsb_ctx *ctx = context;
+
+ kfree(ctx);
+}
+
+static struct regmap_bus regmap_sunxi_rsb = {
+ .reg_write = regmap_sunxi_rsb_reg_write,
+ .reg_read = regmap_sunxi_rsb_reg_read,
+ .free_context = regmap_sunxi_rsb_free_ctx,
+ .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
+ .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
+};
+
+static struct sunxi_rsb_ctx *regmap_sunxi_rsb_init_ctx(struct sunxi_rsb_device *rdev,
+ const struct regmap_config *config)
+{
+ struct sunxi_rsb_ctx *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->rdev = rdev;
+ ctx->size = config->val_bits / 8;
+
+ return ctx;
+}
+
+struct regmap *__devm_regmap_init_sunxi_rsb(struct sunxi_rsb_device *rdev,
+ const struct regmap_config *config,
+ struct lock_class_key *lock_key,
+ const char *lock_name)
+{
+ struct sunxi_rsb_ctx *ctx = regmap_sunxi_rsb_init_ctx(rdev, config);
+
+ if (IS_ERR(ctx))
+ return ERR_CAST(ctx);
+
+ return __devm_regmap_init(&rdev->dev, ®map_sunxi_rsb, ctx, config,
+ lock_key, lock_name);
+}
+EXPORT_SYMBOL_GPL(__devm_regmap_init_sunxi_rsb);
+
+/* RSB controller driver functions */
+static irqreturn_t sunxi_rsb_irq(int irq, void *dev_id)
+{
+ struct sunxi_rsb *rsb = dev_id;
+ u32 status;
+
+ status = readl(rsb->regs + RSB_INTS);
+ rsb->status = status;
+
+ /* Clear interrupts */
+ status &= (RSB_INTS_LOAD_BSY | RSB_INTS_TRANS_ERR |
+ RSB_INTS_TRANS_OVER);
+ writel(status, rsb->regs + RSB_INTS);
+
+ complete(&rsb->complete);
+
+ return IRQ_HANDLED;
+}
+
+static int sunxi_rsb_init_device_mode(struct sunxi_rsb *rsb)
+{
+ int ret = 0;
+ u32 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)
+ ret = -ETIMEDOUT;
+
+ /* clear interrupt status bits */
+ writel(readl(rsb->regs + RSB_INTS), rsb->regs + RSB_INTS);
+
+ return ret;
+}
+
+/*
+ * There are 15 valid runtime addresses, though Allwinner typically
+ * skips the first, for unknown reasons, and uses the following three.
+ *
+ * 0x17, 0x2d, 0x3a, 0x4e, 0x59, 0x63, 0x74, 0x8b,
+ * 0x9c, 0xa6, 0xb1, 0xc5, 0xd2, 0xe8, 0xff
+ *
+ * No designs with 2 RSB slave devices sharing identical hardware
+ * addresses on the same bus have been seen in the wild. All designs
+ * use 0x2d for the primary PMIC, 0x3a for the secondary PMIC if
+ * there is one, and 0x45 for peripheral ICs.
+ *
+ * The hardware does not seem to support re-setting runtime addresses.
+ * Attempts to do so result in the slave devices returning a NACK.
+ * Hence we just hardcode the mapping here, like Allwinner does.
+ */
+
+static const struct sunxi_rsb_addr_map sunxi_rsb_addr_maps[] = {
+ { 0x3e3, 0x2d }, /* Primary PMIC: AXP223, AXP809, AXP81X, ... */
+ { 0x745, 0x3a }, /* Secondary PMIC: AXP806, ... */
+ { 0xe89, 0x45 }, /* Peripheral IC: AC100, ... */
+};
+
+static u8 sunxi_rsb_get_rtaddr(u16 hwaddr)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(sunxi_rsb_addr_maps); i++)
+ if (hwaddr == sunxi_rsb_addr_maps[i].hwaddr)
+ return sunxi_rsb_addr_maps[i].rtaddr;
+
+ return 0; /* 0 is an invalid runtime address */
+}
+
+static int of_rsb_register_devices(struct sunxi_rsb *rsb)
+{
+ struct device *dev = rsb->dev;
+ struct device_node *child, *np = dev->of_node;
+ u32 hwaddr;
+ u8 rtaddr;
+ int ret;
+
+ if (!np)
+ return -EINVAL;
+
+ /* Runtime addresses for all slaves should be set first */
+ for_each_available_child_of_node(np, child) {
+ dev_dbg(dev, "setting child %s runtime address\n",
+ child->full_name);
+
+ ret = of_property_read_u32(child, "reg", &hwaddr);
+ if (ret) {
+ dev_err(dev, "%s: invalid 'reg' property: %d\n",
+ child->full_name, ret);
+ continue;
+ }
+
+ rtaddr = sunxi_rsb_get_rtaddr(hwaddr);
+ if (!rtaddr) {
+ dev_err(dev, "%s: unknown hardware device address\n",
+ child->full_name);
+ continue;
+ }
+
+ /*
+ * Since no devices have been registered yet, we are the
+ * only ones using the bus, we can skip locking the bus.
+ */
+
+ /* setup command parameters */
+ writel(RSB_CMD_STRA, rsb->regs + RSB_CMD);
+ writel(RSB_DAR_RTA(rtaddr) | RSB_DAR_DA(hwaddr),
+ rsb->regs + RSB_DAR);
+
+ /* send command */
+ ret = _sunxi_rsb_run_xfer(rsb);
+ if (ret)
+ dev_warn(dev, "%s: set runtime address failed: %d\n",
+ child->full_name, ret);
+ }
+
+ /* Then we start adding devices and probing them */
+ for_each_available_child_of_node(np, child) {
+ struct sunxi_rsb_device *rdev;
+
+ dev_dbg(dev, "adding child %s\n", child->full_name);
+
+ ret = of_property_read_u32(child, "reg", &hwaddr);
+ if (ret)
+ continue;
+
+ rtaddr = sunxi_rsb_get_rtaddr(hwaddr);
+ if (!rtaddr)
+ continue;
+
+ rdev = sunxi_rsb_device_create(rsb, child, hwaddr, rtaddr);
+ if (IS_ERR(rdev))
+ dev_err(dev, "failed to add child device %s: %ld\n",
+ child->full_name, PTR_ERR(rdev));
+ }
+
+ return 0;
+}
+
+static const struct of_device_id sunxi_rsb_of_match_table[] = {
+ { .compatible = "allwinner,sun8i-a23-rsb" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, sunxi_rsb_of_match_table);
+
+static int sunxi_rsb_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct resource *r;
+ struct sunxi_rsb *rsb;
+ unsigned long p_clk_freq;
+ u32 clk_delay, clk_freq = 3000000;
+ int clk_div, irq, 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)\n",
+ clk_freq);
+ return -EINVAL;
+ }
+
+ rsb = devm_kzalloc(dev, sizeof(*rsb), GFP_KERNEL);
+ if (!rsb)
+ return -ENOMEM;
+
+ rsb->dev = dev;
+ platform_set_drvdata(pdev, rsb);
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ rsb->regs = devm_ioremap_resource(dev, r);
+ if (IS_ERR(rsb->regs))
+ return PTR_ERR(rsb->regs);
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(dev, "failed to retrieve irq: %d\n", irq);
+ return irq;
+ }
+
+ 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);
+ return ret;
+ }
+
+ ret = clk_prepare_enable(rsb->clk);
+ if (ret) {
+ dev_err(dev, "failed to enable clk: %d\n", ret);
+ return ret;
+ }
+
+ p_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);
+ mutex_init(&rsb->lock);
+
+ /* 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);
+
+ /*
+ * Clock frequency and delay calculation code is from
+ * Allwinner U-boot sources.
+ *
+ * From A83 user manual:
+ * bus clock frequency = parent clock frequency / (2 * (divider + 1))
+ */
+ clk_div = p_clk_freq / clk_freq / 2;
+ if (!clk_div)
+ clk_div = 1;
+ else if (clk_div > RSB_CCR_MAX_CLK_DIV + 1)
+ clk_div = RSB_CCR_MAX_CLK_DIV + 1;
+
+ clk_delay = clk_div >> 1;
+ if (!clk_delay)
+ clk_delay = 1;
+
+ dev_info(dev, "RSB running at %lu Hz\n", p_clk_freq / clk_div / 2);
+ writel(RSB_CCR_SDA_OUT_DELAY(clk_delay) | RSB_CCR_CLK_DIV(clk_div - 1),
+ rsb->regs + RSB_CCR);
+
+ ret = devm_request_irq(dev, irq, sunxi_rsb_irq, 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;
+ }
+
+ /* initialize all devices on the bus into RSB mode */
+ ret = sunxi_rsb_init_device_mode(rsb);
+ if (ret)
+ dev_warn(dev, "Initialize device mode failed: %d\n", ret);
+
+ of_rsb_register_devices(rsb);
+
+ return 0;
+
+err_reset_assert:
+ reset_control_assert(rsb->rstc);
+
+err_clk_disable:
+ clk_disable_unprepare(rsb->clk);
+
+ return ret;
+}
+
+static int sunxi_rsb_remove(struct platform_device *pdev)
+{
+ struct sunxi_rsb *rsb = platform_get_drvdata(pdev);
+
+ device_for_each_child(rsb->dev, NULL, sunxi_rsb_remove_devices);
+ reset_control_assert(rsb->rstc);
+ clk_disable_unprepare(rsb->clk);
+
+ return 0;
+}
+
+static struct platform_driver sunxi_rsb_driver = {
+ .probe = sunxi_rsb_probe,
+ .remove = sunxi_rsb_remove,
+ .driver = {
+ .name = RSB_CTRL_NAME,
+ .of_match_table = sunxi_rsb_of_match_table,
+ },
+};
+
+static int __init sunxi_rsb_init(void)
+{
+ int ret;
+
+ ret = bus_register(&sunxi_rsb_bus);
+ if (ret) {
+ pr_err("failed to register sunxi sunxi_rsb bus: %d\n", ret);
+ return ret;
+ }
+
+ return platform_driver_register(&sunxi_rsb_driver);
+}
+module_init(sunxi_rsb_init);
+
+static void __exit sunxi_rsb_exit(void)
+{
+ platform_driver_unregister(&sunxi_rsb_driver);
+ bus_unregister(&sunxi_rsb_bus);
+}
+module_exit(sunxi_rsb_exit);
+
+MODULE_AUTHOR("Chen-Yu Tsai <wens@xxxxxxxx>");
+MODULE_DESCRIPTION("Allwinner sunXi Reduced Serial Bus controller driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/sunxi-rsb.h b/include/linux/sunxi-rsb.h
new file mode 100644
index 000000000000..7e75bb0346d0
--- /dev/null
+++ b/include/linux/sunxi-rsb.h
@@ -0,0 +1,105 @@
+/*
+ * Allwinner Reduced Serial Bus Driver
+ *
+ * Copyright (c) 2015 Chen-Yu Tsai
+ *
+ * Author: Chen-Yu Tsai <wens@xxxxxxxx>
+ *
+ * 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.
+ */
+#ifndef _SUNXI_RSB_H
+#define _SUNXI_RSB_H
+
+#include <linux/device.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+struct sunxi_rsb;
+
+/**
+ * struct sunxi_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 sunxi_rsb_device {
+ struct device dev;
+ struct sunxi_rsb *rsb;
+ int irq;
+ u8 rtaddr;
+ u16 hwaddr;
+};
+
+static inline struct sunxi_rsb_device *to_sunxi_rsb_device(struct device *d)
+{
+ return container_of(d, struct sunxi_rsb_device, dev);
+}
+
+static inline void *sunxi_rsb_device_get_drvdata(const struct sunxi_rsb_device *rdev)
+{
+ return dev_get_drvdata(&rdev->dev);
+}
+
+static inline void sunxi_rsb_device_set_drvdata(struct sunxi_rsb_device *rdev,
+ void *data)
+{
+ dev_set_drvdata(&rdev->dev, data);
+}
+
+/**
+ * struct sunxi_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 sunxi_rsb_driver {
+ struct device_driver driver;
+ int (*probe)(struct sunxi_rsb_device *rdev);
+ int (*remove)(struct sunxi_rsb_device *rdev);
+};
+
+static inline struct sunxi_rsb_driver *to_sunxi_rsb_driver(struct device_driver *d)
+{
+ return container_of(d, struct sunxi_rsb_driver, driver);
+}
+
+int sunxi_rsb_driver_register(struct sunxi_rsb_driver *rdrv);
+
+/**
+ * sunxi_rsb_driver_unregister() - unregister an RSB client driver
+ * @rdrv: the driver to unregister
+ */
+static inline void sunxi_rsb_driver_unregister(struct sunxi_rsb_driver *rdrv)
+{
+ if (rdrv)
+ driver_unregister(&rdrv->driver);
+}
+
+#define module_sunxi_rsb_driver(__sunxi_rsb_driver) \
+ module_driver(__sunxi_rsb_driver, sunxi_rsb_driver_register, \
+ sunxi_rsb_driver_unregister)
+
+struct regmap *__devm_regmap_init_sunxi_rsb(struct sunxi_rsb_device *rdev,
+ const struct regmap_config *config,
+ struct lock_class_key *lock_key,
+ const char *lock_name);
+
+/**
+ * devm_regmap_init_sunxi_rsb(): Initialise managed register map
+ *
+ * @rdev: 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_sunxi_rsb(rdev, config) \
+ __regmap_lockdep_wrapper(__devm_regmap_init_sunxi_rsb, #config, \
+ rdev, config)
+
+#endif /* _SUNXI_RSB_H */
--
2.6.1
--
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