bus: sunxi-rsb: Add driver for Allwinner Reduced Serial Bus (d787dcdb) · Commits · e / devices / android_kernel_fairphone_FP4

drivers/bus/Kconfig

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Original line number	Diff line number	Diff line
		@@ -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
		tristate "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

drivers/bus/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -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

drivers/bus/sunxi-rsb.c

0 → 100644

+783 −0

Original line number	Diff line number	Diff line
		/*
		* 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/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, &regmap_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@csie.org>");
		MODULE_DESCRIPTION("Allwinner sunXi Reduced Serial Bus controller driver");
		MODULE_LICENSE("GPL v2");

include/linux/sunxi-rsb.h

0 → 100644

+105 −0

Original line number	Diff line number	Diff line
		/*
		* Allwinner Reduced Serial Bus Driver
		*
		* Copyright (c) 2015 Chen-Yu Tsai
		*
		* 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.
		*/
		#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 */