mfd: Core support for the WM8400 AudioPlus HiFi CODEC and PMU

The WM8400 is a highly integrated audio CODEC and power management unit
optimised for use in mobile multimedia applications.  This patch adds
core support for the WM8400 to the MFD subsystem.

Both I2C and SPI access are supported by the hardware but currently only
I2C access is implemented.  The code is structured to allow SPI support
to be slotted in later.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Samuel Ortiz <sameo@openedhand.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

3 files changed, 465 insertions, 0 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 0dae245c6259..a3ddf6581ea6 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -87,6 +87,14 @@ config MFD_TC6393XB
 	help
 	  Support for Toshiba Mobile IO Controller TC6393XB
 
+config MFD_WM8400
+	tristate "Support Wolfson Microelectronics WM8400"
+	help
+	  Support for the Wolfson Microelecronics WM8400 PMIC and audio
+	  CODEC.  This driver adds provides common support for accessing
+	  the device, additional drivers must be enabled in order to use
+	  the functionality of the device.
+
 endmenu
 
 menu "Multimedia Capabilities Port drivers"
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 6abebe364419..1624c7d87a49 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -12,6 +12,8 @@ obj-$(CONFIG_MFD_T7L66XB)	+= t7l66xb.o
 obj-$(CONFIG_MFD_TC6387XB)	+= tc6387xb.o
 obj-$(CONFIG_MFD_TC6393XB)	+= tc6393xb.o
 
+obj-$(CONFIG_MFD_WM8400)	+= wm8400-core.o
+
 obj-$(CONFIG_MFD_CORE)		+= mfd-core.o
 
 obj-$(CONFIG_MCP)		+= mcp-core.o
diff --git a/drivers/mfd/wm8400-core.c b/drivers/mfd/wm8400-core.c
new file mode 100644
index 000000000000..6a0cedb5bb8a
--- /dev/null
+++ b/drivers/mfd/wm8400-core.c
@@ -0,0 +1,455 @@
+/*
+ * Core driver for WM8400.
+ *
+ * Copyright 2008 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 as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/bug.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/mfd/wm8400-private.h>
+#include <linux/mfd/wm8400-audio.h>
+
+static struct {
+	u16  readable;    /* Mask of readable bits */
+	u16  writable;    /* Mask of writable bits */
+	u16  vol;         /* Mask of volatile bits */
+	int  is_codec;    /* Register controlled by codec reset */
+	u16  default_val; /* Value on reset */
+} reg_data[] = {
+	{ 0xFFFF, 0xFFFF, 0x0000, 0, 0x6172 }, /* R0 */
+	{ 0x7000, 0x0000, 0x8000, 0, 0x0000 }, /* R1 */
+	{ 0xFF17, 0xFF17, 0x0000, 0, 0x0000 }, /* R2 */
+	{ 0xEBF3, 0xEBF3, 0x0000, 1, 0x6000 }, /* R3 */
+	{ 0x3CF3, 0x3CF3, 0x0000, 1, 0x0000 }, /* R4  */
+	{ 0xF1F8, 0xF1F8, 0x0000, 1, 0x4050 }, /* R5  */
+	{ 0xFC1F, 0xFC1F, 0x0000, 1, 0x4000 }, /* R6  */
+	{ 0xDFDE, 0xDFDE, 0x0000, 1, 0x01C8 }, /* R7  */
+	{ 0xFCFC, 0xFCFC, 0x0000, 1, 0x0000 }, /* R8  */
+	{ 0xEFFF, 0xEFFF, 0x0000, 1, 0x0040 }, /* R9  */
+	{ 0xEFFF, 0xEFFF, 0x0000, 1, 0x0040 }, /* R10 */
+	{ 0x27F7, 0x27F7, 0x0000, 1, 0x0004 }, /* R11 */
+	{ 0x01FF, 0x01FF, 0x0000, 1, 0x00C0 }, /* R12 */
+	{ 0x01FF, 0x01FF, 0x0000, 1, 0x00C0 }, /* R13 */
+	{ 0x1FEF, 0x1FEF, 0x0000, 1, 0x0000 }, /* R14 */
+	{ 0x0163, 0x0163, 0x0000, 1, 0x0100 }, /* R15 */
+	{ 0x01FF, 0x01FF, 0x0000, 1, 0x00C0 }, /* R16 */
+	{ 0x01FF, 0x01FF, 0x0000, 1, 0x00C0 }, /* R17 */
+	{ 0x1FFF, 0x0FFF, 0x0000, 1, 0x0000 }, /* R18 */
+	{ 0xFFFF, 0xFFFF, 0x0000, 1, 0x1000 }, /* R19 */
+	{ 0xFFFF, 0xFFFF, 0x0000, 1, 0x1010 }, /* R20 */
+	{ 0xFFFF, 0xFFFF, 0x0000, 1, 0x1010 }, /* R21 */
+	{ 0x0FDD, 0x0FDD, 0x0000, 1, 0x8000 }, /* R22 */
+	{ 0x1FFF, 0x1FFF, 0x0000, 1, 0x0800 }, /* R23 */
+	{ 0x0000, 0x01DF, 0x0000, 1, 0x008B }, /* R24 */
+	{ 0x0000, 0x01DF, 0x0000, 1, 0x008B }, /* R25 */
+	{ 0x0000, 0x01DF, 0x0000, 1, 0x008B }, /* R26 */
+	{ 0x0000, 0x01DF, 0x0000, 1, 0x008B }, /* R27 */
+	{ 0x0000, 0x01FF, 0x0000, 1, 0x0000 }, /* R28 */
+	{ 0x0000, 0x01FF, 0x0000, 1, 0x0000 }, /* R29 */
+	{ 0x0000, 0x0077, 0x0000, 1, 0x0066 }, /* R30 */
+	{ 0x0000, 0x0033, 0x0000, 1, 0x0022 }, /* R31 */
+	{ 0x0000, 0x01FF, 0x0000, 1, 0x0079 }, /* R32 */
+	{ 0x0000, 0x01FF, 0x0000, 1, 0x0079 }, /* R33 */
+	{ 0x0000, 0x0003, 0x0000, 1, 0x0003 }, /* R34 */
+	{ 0x0000, 0x01FF, 0x0000, 1, 0x0003 }, /* R35 */
+	{ 0x0000, 0x0000, 0x0000, 0, 0x0000 }, /* R36 */
+	{ 0x0000, 0x003F, 0x0000, 1, 0x0100 }, /* R37 */
+	{ 0x0000, 0x0000, 0x0000, 0, 0x0000 }, /* R38 */
+	{ 0x0000, 0x000F, 0x0000, 0, 0x0000 }, /* R39 */
+	{ 0x0000, 0x00FF, 0x0000, 1, 0x0000 }, /* R40 */
+	{ 0x0000, 0x01B7, 0x0000, 1, 0x0000 }, /* R41 */
+	{ 0x0000, 0x01B7, 0x0000, 1, 0x0000 }, /* R42 */
+	{ 0x0000, 0x01FF, 0x0000, 1, 0x0000 }, /* R43 */
+	{ 0x0000, 0x01FF, 0x0000, 1, 0x0000 }, /* R44 */
+	{ 0x0000, 0x00FD, 0x0000, 1, 0x0000 }, /* R45 */
+	{ 0x0000, 0x00FD, 0x0000, 1, 0x0000 }, /* R46 */
+	{ 0x0000, 0x01FF, 0x0000, 1, 0x0000 }, /* R47 */
+	{ 0x0000, 0x01FF, 0x0000, 1, 0x0000 }, /* R48 */
+	{ 0x0000, 0x01FF, 0x0000, 1, 0x0000 }, /* R49 */
+	{ 0x0000, 0x01FF, 0x0000, 1, 0x0000 }, /* R50 */
+	{ 0x0000, 0x01B3, 0x0000, 1, 0x0180 }, /* R51 */
+	{ 0x0000, 0x0077, 0x0000, 1, 0x0000 }, /* R52 */
+	{ 0x0000, 0x0077, 0x0000, 1, 0x0000 }, /* R53 */
+	{ 0x0000, 0x00FF, 0x0000, 1, 0x0000 }, /* R54 */
+	{ 0x0000, 0x0001, 0x0000, 1, 0x0000 }, /* R55 */
+	{ 0x0000, 0x003F, 0x0000, 1, 0x0000 }, /* R56 */
+	{ 0x0000, 0x004F, 0x0000, 1, 0x0000 }, /* R57 */
+	{ 0x0000, 0x00FD, 0x0000, 1, 0x0000 }, /* R58 */
+	{ 0x0000, 0x0000, 0x0000, 0, 0x0000 }, /* R59 */
+	{ 0x1FFF, 0x1FFF, 0x0000, 1, 0x0000 }, /* R60 */
+	{ 0xFFFF, 0xFFFF, 0x0000, 1, 0x0000 }, /* R61 */
+	{ 0x03FF, 0x03FF, 0x0000, 1, 0x0000 }, /* R62 */
+	{ 0x007F, 0x007F, 0x0000, 1, 0x0000 }, /* R63 */
+	{ 0x0000, 0x0000, 0x0000, 0, 0x0000 }, /* R64 */
+	{ 0xDFFF, 0xDFFF, 0x0000, 0, 0x0000 }, /* R65 */
+	{ 0xDFFF, 0xDFFF, 0x0000, 0, 0x0000 }, /* R66 */
+	{ 0xDFFF, 0xDFFF, 0x0000, 0, 0x0000 }, /* R67 */
+	{ 0xDFFF, 0xDFFF, 0x0000, 0, 0x0000 }, /* R68 */
+	{ 0x0000, 0x0000, 0x0000, 0, 0x0000 }, /* R69 */
+	{ 0xFFFF, 0xFFFF, 0x0000, 0, 0x4400 }, /* R70 */
+	{ 0x23FF, 0x23FF, 0x0000, 0, 0x0000 }, /* R71 */
+	{ 0xFFFF, 0xFFFF, 0x0000, 0, 0x4400 }, /* R72 */
+	{ 0x23FF, 0x23FF, 0x0000, 0, 0x0000 }, /* R73 */
+	{ 0x0000, 0x0000, 0x0000, 0, 0x0000 }, /* R74 */
+	{ 0x000E, 0x000E, 0x0000, 0, 0x0008 }, /* R75 */
+	{ 0xE00F, 0xE00F, 0x0000, 0, 0x0000 }, /* R76 */
+	{ 0x0000, 0x0000, 0x0000, 0, 0x0000 }, /* R77 */
+	{ 0x03C0, 0x03C0, 0x0000, 0, 0x02C0 }, /* R78 */
+	{ 0xFFFF, 0x0000, 0xffff, 0, 0x0000 }, /* R79 */
+	{ 0xFFFF, 0xFFFF, 0x0000, 0, 0x0000 }, /* R80 */
+	{ 0xFFFF, 0x0000, 0xffff, 0, 0x0000 }, /* R81 */
+	{ 0x2BFF, 0x0000, 0xffff, 0, 0x0000 }, /* R82 */
+	{ 0x0000, 0x0000, 0x0000, 0, 0x0000 }, /* R83 */
+	{ 0x80FF, 0x80FF, 0x0000, 0, 0x00ff }, /* R84 */
+};
+
+static int wm8400_read(struct wm8400 *wm8400, u8 reg, int num_regs, u16 *dest)
+{
+	int i, ret = 0;
+
+	BUG_ON(reg + num_regs - 1 > ARRAY_SIZE(wm8400->reg_cache));
+
+	/* If there are any volatile reads then read back the entire block */
+	for (i = reg; i < reg + num_regs; i++)
+		if (reg_data[i].vol) {
+			ret = wm8400->read_dev(wm8400->io_data, reg,
+					       num_regs, dest);
+			if (ret != 0)
+				return ret;
+			for (i = 0; i < num_regs; i++)
+				dest[i] = be16_to_cpu(dest[i]);
+
+			return 0;
+		}
+
+	/* Otherwise use the cache */
+	memcpy(dest, &wm8400->reg_cache[reg], num_regs * sizeof(u16));
+
+	return 0;
+}
+
+static int wm8400_write(struct wm8400 *wm8400, u8 reg, int num_regs,
+			u16 *src)
+{
+	int ret, i;
+
+	BUG_ON(reg + num_regs - 1 > ARRAY_SIZE(wm8400->reg_cache));
+
+	for (i = 0; i < num_regs; i++) {
+		BUG_ON(!reg_data[reg + i].writable);
+		wm8400->reg_cache[reg + i] = src[i];
+		src[i] = cpu_to_be16(src[i]);
+	}
+
+	/* Do the actual I/O */
+	ret = wm8400->write_dev(wm8400->io_data, reg, num_regs, src);
+	if (ret != 0)
+		return -EIO;
+
+	return 0;
+}
+
+/**
+ * wm8400_reg_read - Single register read
+ *
+ * @wm8400: Pointer to wm8400 control structure
+ * @reg:    Register to read
+ *
+ * @return  Read value
+ */
+u16 wm8400_reg_read(struct wm8400 *wm8400, u8 reg)
+{
+	u16 val;
+
+	mutex_lock(&wm8400->io_lock);
+
+	wm8400_read(wm8400, reg, 1, &val);
+
+	mutex_unlock(&wm8400->io_lock);
+
+	return val;
+}
+EXPORT_SYMBOL_GPL(wm8400_reg_read);
+
+int wm8400_block_read(struct wm8400 *wm8400, u8 reg, int count, u16 *data)
+{
+	int ret;
+
+	mutex_lock(&wm8400->io_lock);
+
+	ret = wm8400_read(wm8400, reg, count, data);
+
+	mutex_unlock(&wm8400->io_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(wm8400_block_read);
+
+/**
+ * wm8400_set_bits - Bitmask write
+ *
+ * @wm8400: Pointer to wm8400 control structure
+ * @reg:    Register to access
+ * @mask:   Mask of bits to change
+ * @val:    Value to set for masked bits
+ */
+int wm8400_set_bits(struct wm8400 *wm8400, u8 reg, u16 mask, u16 val)
+{
+	u16 tmp;
+	int ret;
+
+	mutex_lock(&wm8400->io_lock);
+
+	ret = wm8400_read(wm8400, reg, 1, &tmp);
+	tmp = (tmp & ~mask) | val;
+	if (ret == 0)
+		ret = wm8400_write(wm8400, reg, 1, &tmp);
+
+	mutex_unlock(&wm8400->io_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(wm8400_set_bits);
+
+/**
+ * wm8400_reset_codec_reg_cache - Reset cached codec registers to
+ * their default values.
+ */
+void wm8400_reset_codec_reg_cache(struct wm8400 *wm8400)
+{
+	int i;
+
+	mutex_lock(&wm8400->io_lock);
+
+	/* Reset all codec registers to their initial value */
+	for (i = 0; i < ARRAY_SIZE(wm8400->reg_cache); i++)
+		if (reg_data[i].is_codec)
+			wm8400->reg_cache[i] = reg_data[i].default_val;
+
+	mutex_unlock(&wm8400->io_lock);
+}
+EXPORT_SYMBOL_GPL(wm8400_reset_codec_reg_cache);
+
+/*
+ * wm8400_init - Generic initialisation
+ *
+ * The WM8400 can be configured as either an I2C or SPI device.  Probe
+ * functions for each bus set up the accessors then call into this to
+ * set up the device itself.
+ */
+static int wm8400_init(struct wm8400 *wm8400,
+		       struct wm8400_platform_data *pdata)
+{
+	u16 reg;
+	int ret, i;
+
+	mutex_init(&wm8400->io_lock);
+
+	wm8400->dev->driver_data = wm8400;
+
+	/* Check that this is actually a WM8400 */
+	ret = wm8400->read_dev(wm8400->io_data, WM8400_RESET_ID, 1, &reg);
+	if (ret != 0) {
+		dev_err(wm8400->dev, "Chip ID register read failed\n");
+		return -EIO;
+	}
+	if (be16_to_cpu(reg) != reg_data[WM8400_RESET_ID].default_val) {
+		dev_err(wm8400->dev, "Device is not a WM8400, ID is %x\n",
+			be16_to_cpu(reg));
+		return -ENODEV;
+	}
+
+	/* We don't know what state the hardware is in and since this
+	 * is a PMIC we can't reset it safely so initialise the register
+	 * cache from the hardware.
+	 */
+	ret = wm8400->read_dev(wm8400->io_data, 0,
+			       ARRAY_SIZE(wm8400->reg_cache),
+			       wm8400->reg_cache);
+	if (ret != 0) {
+		dev_err(wm8400->dev, "Register cache read failed\n");
+		return -EIO;
+	}
+	for (i = 0; i < ARRAY_SIZE(wm8400->reg_cache); i++)
+		wm8400->reg_cache[i] = be16_to_cpu(wm8400->reg_cache[i]);
+
+	/* If the codec is in reset use hard coded values */
+	if (!(wm8400->reg_cache[WM8400_POWER_MANAGEMENT_1] & WM8400_CODEC_ENA))
+		for (i = 0; i < ARRAY_SIZE(wm8400->reg_cache); i++)
+			if (reg_data[i].is_codec)
+				wm8400->reg_cache[i] = reg_data[i].default_val;
+
+	ret = wm8400_read(wm8400, WM8400_ID, 1, &reg);
+	if (ret != 0) {
+		dev_err(wm8400->dev, "ID register read failed: %d\n", ret);
+		return ret;
+	}
+	reg = (reg & WM8400_CHIP_REV_MASK) >> WM8400_CHIP_REV_SHIFT;
+	dev_info(wm8400->dev, "WM8400 revision %x\n", reg);
+
+	if (pdata && pdata->platform_init) {
+		ret = pdata->platform_init(wm8400->dev);
+		if (ret != 0)
+			dev_err(wm8400->dev, "Platform init failed: %d\n",
+				ret);
+	} else
+		dev_warn(wm8400->dev, "No platform initialisation supplied\n");
+
+	return ret;
+}
+
+static void wm8400_release(struct wm8400 *wm8400)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(wm8400->regulators); i++)
+		if (wm8400->regulators[i].name)
+			platform_device_unregister(&wm8400->regulators[i]);
+}
+
+#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
+static int wm8400_i2c_read(void *io_data, char reg, int count, u16 *dest)
+{
+	struct i2c_client *i2c = io_data;
+	struct i2c_msg xfer[2];
+	int ret;
+
+	/* Write register */
+	xfer[0].addr = i2c->addr;
+	xfer[0].flags = 0;
+	xfer[0].len = 1;
+	xfer[0].buf = &reg;
+
+	/* Read data */
+	xfer[1].addr = i2c->addr;
+	xfer[1].flags = I2C_M_RD;
+	xfer[1].len = count * sizeof(u16);
+	xfer[1].buf = (u8 *)dest;
+
+	ret = i2c_transfer(i2c->adapter, xfer, 2);
+	if (ret == 2)
+		ret = 0;
+	else if (ret >= 0)
+		ret = -EIO;
+
+	return ret;
+}
+
+static int wm8400_i2c_write(void *io_data, char reg, int count, const u16 *src)
+{
+	struct i2c_client *i2c = io_data;
+	u8 *msg;
+	int ret;
+
+	/* We add 1 byte for device register - ideally I2C would gather. */
+	msg = kmalloc((count * sizeof(u16)) + 1, GFP_KERNEL);
+	if (msg == NULL)
+		return -ENOMEM;
+
+	msg[0] = reg;
+	memcpy(&msg[1], src, count * sizeof(u16));
+
+	ret = i2c_master_send(i2c, msg, (count * sizeof(u16)) + 1);
+
+	if (ret == (count * 2) + 1)
+		ret = 0;
+	else if (ret >= 0)
+		ret = -EIO;
+
+	kfree(msg);
+
+	return ret;
+}
+
+static int wm8400_i2c_probe(struct i2c_client *i2c,
+			    const struct i2c_device_id *id)
+{
+	struct wm8400 *wm8400;
+	int ret;
+
+	wm8400 = kzalloc(sizeof(struct wm8400), GFP_KERNEL);
+	if (wm8400 == NULL) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	wm8400->io_data = i2c;
+	wm8400->read_dev = wm8400_i2c_read;
+	wm8400->write_dev = wm8400_i2c_write;
+	wm8400->dev = &i2c->dev;
+	i2c_set_clientdata(i2c, wm8400);
+
+	ret = wm8400_init(wm8400, i2c->dev.platform_data);
+	if (ret != 0)
+		goto struct_err;
+
+	return 0;
+
+struct_err:
+	i2c_set_clientdata(i2c, NULL);
+	kfree(wm8400);
+err:
+	return ret;
+}
+
+static int wm8400_i2c_remove(struct i2c_client *i2c)
+{
+	struct wm8400 *wm8400 = i2c_get_clientdata(i2c);
+
+	wm8400_release(wm8400);
+	i2c_set_clientdata(i2c, NULL);
+	kfree(wm8400);
+
+	return 0;
+}
+
+static const struct i2c_device_id wm8400_i2c_id[] = {
+       { "wm8400", 0 },
+       { }
+};
+MODULE_DEVICE_TABLE(i2c, wm8400_i2c_id);
+
+static struct i2c_driver wm8400_i2c_driver = {
+	.driver = {
+		.name = "WM8400",
+		.owner = THIS_MODULE,
+	},
+	.probe    = wm8400_i2c_probe,
+	.remove   = wm8400_i2c_remove,
+	.id_table = wm8400_i2c_id,
+};
+#endif
+
+static int __init wm8400_module_init(void)
+{
+	int ret = -ENODEV;
+
+#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
+	ret = i2c_add_driver(&wm8400_i2c_driver);
+	if (ret != 0)
+		pr_err("Failed to register I2C driver: %d\n", ret);
+#endif
+
+	return ret;
+}
+module_init(wm8400_module_init);
+
+static void __exit wm8400_module_exit(void)
+{
+#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
+	i2c_del_driver(&wm8400_i2c_driver);
+#endif
+}
+module_exit(wm8400_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");