mfd: Add initial WM8994 support

The WM8994 is a highly integrated ultra low power audio hub CODEC.
Since it includes on-board regulators and GPIOs it is represented
as a multi-function device, though the overwhelming majority of
the functionality is provided by the ASoC CODEC driver.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

3 files changed, 550 insertions, 0 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index a760dbefd27a..64fbe3334eb3 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -295,6 +295,18 @@ config MFD_WM8350_I2C
           I2C as the control interface.  Additional options must be
           selected to enable support for the functionality of the chip.
 
+config MFD_WM8994
+        tristate "Support Wolfson Microelectronics WM8994"
+        select MFD_CORE
+        depends on I2C
+        help
+          The WM8994 is a highly integrated hi-fi CODEC designed for
+          smartphone applicatiosn.  As well as audio functionality it
+          has on board GPIO and regulator functionality which is
+          supported via the relevant subsystems.  This driver provides
+          core support for the WM8994, in order to use the actual
+          functionaltiy of the device other drivers must be enabled.
+
 config MFD_PCF50633
         tristate "Support for NXP PCF50633"
         depends on I2C
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 142d31202b14..878cac691067 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -25,6 +25,7 @@ wm8350-objs			:= wm8350-core.o wm8350-regmap.o wm8350-gpio.o
 wm8350-objs                     += wm8350-irq.o
 obj-$(CONFIG_MFD_WM8350)        += wm8350.o
 obj-$(CONFIG_MFD_WM8350_I2C)    += wm8350-i2c.o
+obj-$(CONFIG_MFD_WM8994)        += wm8994-core.o
 
 obj-$(CONFIG_TPS65010)          += tps65010.o
 obj-$(CONFIG_MENELAUS)          += menelaus.o
diff --git a/drivers/mfd/wm8994-core.c b/drivers/mfd/wm8994-core.c
new file mode 100644
index 000000000000..299c1af1334e
--- /dev/null
+++ b/drivers/mfd/wm8994-core.c
@@ -0,0 +1,537 @@
+/*
+ * wm8994-core.c  --  Device access for Wolfson WM8994
+ *
+ * Copyright 2009 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/kernel.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <linux/mfd/core.h>
+#include <linux/regulator/consumer.h>
+#include <linux/regulator/machine.h>
+
+#include <linux/mfd/wm8994/core.h>
+#include <linux/mfd/wm8994/pdata.h>
+#include <linux/mfd/wm8994/registers.h>
+
+static int wm8994_read(struct wm8994 *wm8994, unsigned short reg,
+                       int bytes, void *dest)
+{
+        int ret, i;
+        u16 *buf = dest;
+
+        BUG_ON(bytes % 2);
+        BUG_ON(bytes <= 0);
+
+        ret = wm8994->read_dev(wm8994, reg, bytes, dest);
+        if (ret < 0)
+                return ret;
+
+        for (i = 0; i < bytes / 2; i++) {
+                buf[i] = be16_to_cpu(buf[i]);
+
+                dev_vdbg(wm8994->dev, "Read %04x from R%d(0x%x)\n",
+                         buf[i], reg + i, reg + i);
+        }
+
+        return 0;
+}
+
+/**
+ * wm8994_reg_read: Read a single WM8994 register.
+ *
+ * @wm8994: Device to read from.
+ * @reg: Register to read.
+ */
+int wm8994_reg_read(struct wm8994 *wm8994, unsigned short reg)
+{
+        unsigned short val;
+        int ret;
+
+        mutex_lock(&wm8994->io_lock);
+
+        ret = wm8994_read(wm8994, reg, 2, &val);
+
+        mutex_unlock(&wm8994->io_lock);
+
+        if (ret < 0)
+                return ret;
+        else
+                return val;
+}
+EXPORT_SYMBOL_GPL(wm8994_reg_read);
+
+/**
+ * wm8994_bulk_read: Read multiple WM8994 registers
+ *
+ * @wm8994: Device to read from
+ * @reg: First register
+ * @count: Number of registers
+ * @buf: Buffer to fill.
+ */
+int wm8994_bulk_read(struct wm8994 *wm8994, unsigned short reg,
+                     int count, u16 *buf)
+{
+        int ret;
+
+        mutex_lock(&wm8994->io_lock);
+
+        ret = wm8994_read(wm8994, reg, count * 2, buf);
+
+        mutex_unlock(&wm8994->io_lock);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(wm8994_bulk_read);
+
+static int wm8994_write(struct wm8994 *wm8994, unsigned short reg,
+                        int bytes, void *src)
+{
+        u16 *buf = src;
+        int i;
+
+        BUG_ON(bytes % 2);
+        BUG_ON(bytes <= 0);
+
+        for (i = 0; i < bytes / 2; i++) {
+                dev_vdbg(wm8994->dev, "Write %04x to R%d(0x%x)\n",
+                         buf[i], reg + i, reg + i);
+
+                buf[i] = cpu_to_be16(buf[i]);
+        }
+
+        return wm8994->write_dev(wm8994, reg, bytes, src);
+}
+
+/**
+ * wm8994_reg_write: Write a single WM8994 register.
+ *
+ * @wm8994: Device to write to.
+ * @reg: Register to write to.
+ * @val: Value to write.
+ */
+int wm8994_reg_write(struct wm8994 *wm8994, unsigned short reg,
+                     unsigned short val)
+{
+        int ret;
+
+        mutex_lock(&wm8994->io_lock);
+
+        ret = wm8994_write(wm8994, reg, 2, &val);
+
+        mutex_unlock(&wm8994->io_lock);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(wm8994_reg_write);
+
+/**
+ * wm8994_set_bits: Set the value of a bitfield in a WM8994 register
+ *
+ * @wm8994: Device to write to.
+ * @reg: Register to write to.
+ * @mask: Mask of bits to set.
+ * @val: Value to set (unshifted)
+ */
+int wm8994_set_bits(struct wm8994 *wm8994, unsigned short reg,
+                    unsigned short mask, unsigned short val)
+{
+        int ret;
+        u16 r;
+
+        mutex_lock(&wm8994->io_lock);
+
+        ret = wm8994_read(wm8994, reg, 2, &r);
+        if (ret < 0)
+                goto out;
+
+        r &= ~mask;
+        r |= val;
+
+        ret = wm8994_write(wm8994, reg, 2, &r);
+
+out:
+        mutex_unlock(&wm8994->io_lock);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(wm8994_set_bits);
+
+static struct mfd_cell wm8994_regulator_devs[] = {
+        { .name = "wm8994-ldo", .id = 1 },
+        { .name = "wm8994-ldo", .id = 2 },
+};
+
+static struct mfd_cell wm8994_devs[] = {
+        { .name = "wm8994-codec" },
+        { .name = "wm8994-gpio" },
+};
+
+/*
+ * Supplies for the main bulk of CODEC; the LDO supplies are ignored
+ * and should be handled via the standard regulator API supply
+ * management.
+ */
+static const char *wm8994_main_supplies[] = {
+        "DBVDD",
+        "DCVDD",
+        "AVDD1",
+        "AVDD2",
+        "CPVDD",
+        "SPKVDD1",
+        "SPKVDD2",
+};
+
+#ifdef CONFIG_PM
+static int wm8994_device_suspend(struct device *dev)
+{
+        struct wm8994 *wm8994 = dev_get_drvdata(dev);
+        int ret;
+
+        /* GPIO configuration state is saved here since we may be configuring
+         * the GPIO alternate functions even if we're not using the gpiolib
+         * driver for them.
+         */
+        ret = wm8994_read(wm8994, WM8994_GPIO_1, WM8994_NUM_GPIO_REGS * 2,
+                          &wm8994->gpio_regs);
+        if (ret < 0)
+                dev_err(dev, "Failed to save GPIO registers: %d\n", ret);
+
+        /* For similar reasons we also stash the regulator states */
+        ret = wm8994_read(wm8994, WM8994_LDO_1, WM8994_NUM_LDO_REGS * 2,
+                          &wm8994->ldo_regs);
+        if (ret < 0)
+                dev_err(dev, "Failed to save LDO registers: %d\n", ret);
+
+        ret = regulator_bulk_disable(ARRAY_SIZE(wm8994_main_supplies),
+                                     wm8994->supplies);
+        if (ret != 0) {
+                dev_err(dev, "Failed to disable supplies: %d\n", ret);
+                return ret;
+        }
+
+        return 0;
+}
+
+static int wm8994_device_resume(struct device *dev)
+{
+        struct wm8994 *wm8994 = dev_get_drvdata(dev);
+        int ret;
+
+        ret = regulator_bulk_enable(ARRAY_SIZE(wm8994_main_supplies),
+                                    wm8994->supplies);
+        if (ret != 0) {
+                dev_err(dev, "Failed to enable supplies: %d\n", ret);
+                return ret;
+        }
+
+        ret = wm8994_write(wm8994, WM8994_LDO_1, WM8994_NUM_LDO_REGS * 2,
+                           &wm8994->ldo_regs);
+        if (ret < 0)
+                dev_err(dev, "Failed to restore LDO registers: %d\n", ret);
+
+        ret = wm8994_write(wm8994, WM8994_GPIO_1, WM8994_NUM_GPIO_REGS * 2,
+                           &wm8994->gpio_regs);
+        if (ret < 0)
+                dev_err(dev, "Failed to restore GPIO registers: %d\n", ret);
+
+        return 0;
+}
+#endif
+
+#ifdef CONFIG_REGULATOR
+static int wm8994_ldo_in_use(struct wm8994_pdata *pdata, int ldo)
+{
+        struct wm8994_ldo_pdata *ldo_pdata;
+
+        if (!pdata)
+                return 0;
+
+        ldo_pdata = &pdata->ldo[ldo];
+
+        if (!ldo_pdata->init_data)
+                return 0;
+
+        return ldo_pdata->init_data->num_consumer_supplies != 0;
+}
+#else
+static int wm8994_ldo_in_use(struct wm8994_pdata *pdata, int ldo)
+{
+        return 0;
+}
+#endif
+
+/*
+ * Instantiate the generic non-control parts of the device.
+ */
+static int wm8994_device_init(struct wm8994 *wm8994, unsigned long id, int irq)
+{
+        struct wm8994_pdata *pdata = wm8994->dev->platform_data;
+        int ret, i;
+
+        mutex_init(&wm8994->io_lock);
+        dev_set_drvdata(wm8994->dev, wm8994);
+
+        /* Add the on-chip regulators first for bootstrapping */
+        ret = mfd_add_devices(wm8994->dev, -1,
+                              wm8994_regulator_devs,
+                              ARRAY_SIZE(wm8994_regulator_devs),
+                              NULL, 0);
+        if (ret != 0) {
+                dev_err(wm8994->dev, "Failed to add children: %d\n", ret);
+                goto err;
+        }
+
+        wm8994->supplies = kzalloc(sizeof(struct regulator_bulk_data) *
+                                   ARRAY_SIZE(wm8994_main_supplies),
+                                   GFP_KERNEL);
+        if (!wm8994->supplies)
+                goto err;
+
+        for (i = 0; i < ARRAY_SIZE(wm8994_main_supplies); i++)
+                wm8994->supplies[i].supply = wm8994_main_supplies[i];
+
+        ret = regulator_bulk_get(wm8994->dev, ARRAY_SIZE(wm8994_main_supplies),
+                                 wm8994->supplies);
+        if (ret != 0) {
+                dev_err(wm8994->dev, "Failed to get supplies: %d\n", ret);
+                goto err_get;
+        }
+
+        ret = regulator_bulk_enable(ARRAY_SIZE(wm8994_main_supplies),
+                                    wm8994->supplies);
+        if (ret != 0) {
+                dev_err(wm8994->dev, "Failed to enable supplies: %d\n", ret);
+                goto err_supplies;
+        }
+
+        ret = wm8994_reg_read(wm8994, WM8994_SOFTWARE_RESET);
+        if (ret < 0) {
+                dev_err(wm8994->dev, "Failed to read ID register\n");
+                goto err_enable;
+        }
+        if (ret != 0x8994) {
+                dev_err(wm8994->dev, "Device is not a WM8994, ID is %x\n",
+                        ret);
+                ret = -EINVAL;
+                goto err_enable;
+        }
+
+        ret = wm8994_reg_read(wm8994, WM8994_CHIP_REVISION);
+        if (ret < 0) {
+                dev_err(wm8994->dev, "Failed to read revision register: %d\n",
+                        ret);
+                goto err_enable;
+        }
+
+        switch (ret) {
+        case 0:
+        case 1:
+                dev_warn(wm8994->dev, "revision %c not fully supported\n",
+                        'A' + ret);
+                break;
+        default:
+                dev_info(wm8994->dev, "revision %c\n", 'A' + ret);
+                break;
+        }
+
+
+        if (pdata) {
+                wm8994->gpio_base = pdata->gpio_base;
+
+                /* GPIO configuration is only applied if it's non-zero */
+                for (i = 0; i < ARRAY_SIZE(pdata->gpio_defaults); i++) {
+                        if (pdata->gpio_defaults[i]) {
+                                wm8994_set_bits(wm8994, WM8994_GPIO_1 + i,
+                                                0xffff,
+                                                pdata->gpio_defaults[i]);
+                        }
+                }
+        }
+
+        /* In some system designs where the regulators are not in use,
+         * we can achieve a small reduction in leakage currents by
+         * floating LDO outputs.  This bit makes no difference if the
+         * LDOs are enabled, it only affects cases where the LDOs were
+         * in operation and are then disabled.
+         */
+        for (i = 0; i < WM8994_NUM_LDO_REGS; i++) {
+                if (wm8994_ldo_in_use(pdata, i))
+                        wm8994_set_bits(wm8994, WM8994_LDO_1 + i,
+                                        WM8994_LDO1_DISCH, WM8994_LDO1_DISCH);
+                else
+                        wm8994_set_bits(wm8994, WM8994_LDO_1 + i,
+                                        WM8994_LDO1_DISCH, 0);
+        }
+
+        ret = mfd_add_devices(wm8994->dev, -1,
+                              wm8994_devs, ARRAY_SIZE(wm8994_devs),
+                              NULL, 0);
+        if (ret != 0) {
+                dev_err(wm8994->dev, "Failed to add children: %d\n", ret);
+                goto err_enable;
+        }
+
+        return 0;
+
+err_enable:
+        regulator_bulk_disable(ARRAY_SIZE(wm8994_main_supplies),
+                               wm8994->supplies);
+err_get:
+        regulator_bulk_free(ARRAY_SIZE(wm8994_main_supplies), wm8994->supplies);
+err_supplies:
+        kfree(wm8994->supplies);
+err:
+        mfd_remove_devices(wm8994->dev);
+        kfree(wm8994);
+        return ret;
+}
+
+static void wm8994_device_exit(struct wm8994 *wm8994)
+{
+        mfd_remove_devices(wm8994->dev);
+        regulator_bulk_disable(ARRAY_SIZE(wm8994_main_supplies),
+                               wm8994->supplies);
+        regulator_bulk_free(ARRAY_SIZE(wm8994_main_supplies), wm8994->supplies);
+        kfree(wm8994->supplies);
+        kfree(wm8994);
+}
+
+static int wm8994_i2c_read_device(struct wm8994 *wm8994, unsigned short reg,
+                                  int bytes, void *dest)
+{
+        struct i2c_client *i2c = wm8994->control_data;
+        int ret;
+        u16 r = cpu_to_be16(reg);
+
+        ret = i2c_master_send(i2c, (unsigned char *)&r, 2);
+        if (ret < 0)
+                return ret;
+        if (ret != 2)
+                return -EIO;
+
+        ret = i2c_master_recv(i2c, dest, bytes);
+        if (ret < 0)
+                return ret;
+        if (ret != bytes)
+                return -EIO;
+        return 0;
+}
+
+/* Currently we allocate the write buffer on the stack; this is OK for
+ * small writes - if we need to do large writes this will need to be
+ * revised.
+ */
+static int wm8994_i2c_write_device(struct wm8994 *wm8994, unsigned short reg,
+                                   int bytes, void *src)
+{
+        struct i2c_client *i2c = wm8994->control_data;
+        unsigned char msg[bytes + 2];
+        int ret;
+
+        reg = cpu_to_be16(reg);
+        memcpy(&msg[0], &reg, 2);
+        memcpy(&msg[2], src, bytes);
+
+        ret = i2c_master_send(i2c, msg, bytes + 2);
+        if (ret < 0)
+                return ret;
+        if (ret < bytes + 2)
+                return -EIO;
+
+        return 0;
+}
+
+static int wm8994_i2c_probe(struct i2c_client *i2c,
+                            const struct i2c_device_id *id)
+{
+        struct wm8994 *wm8994;
+
+        wm8994 = kzalloc(sizeof(struct wm8994), GFP_KERNEL);
+        if (wm8994 == NULL) {
+                kfree(i2c);
+                return -ENOMEM;
+        }
+
+        i2c_set_clientdata(i2c, wm8994);
+        wm8994->dev = &i2c->dev;
+        wm8994->control_data = i2c;
+        wm8994->read_dev = wm8994_i2c_read_device;
+        wm8994->write_dev = wm8994_i2c_write_device;
+
+        return wm8994_device_init(wm8994, id->driver_data, i2c->irq);
+}
+
+static int wm8994_i2c_remove(struct i2c_client *i2c)
+{
+        struct wm8994 *wm8994 = i2c_get_clientdata(i2c);
+
+        wm8994_device_exit(wm8994);
+
+        return 0;
+}
+
+#ifdef CONFIG_PM
+static int wm8994_i2c_suspend(struct i2c_client *i2c, pm_message_t state)
+{
+        return wm8994_device_suspend(&i2c->dev);
+}
+
+static int wm8994_i2c_resume(struct i2c_client *i2c)
+{
+        return wm8994_device_resume(&i2c->dev);
+}
+#else
+#define wm8994_i2c_suspend NULL
+#define wm8994_i2c_resume NULL
+#endif
+
+static const struct i2c_device_id wm8994_i2c_id[] = {
+        { "wm8994", 0 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, wm8994_i2c_id);
+
+static struct i2c_driver wm8994_i2c_driver = {
+        .driver = {
+                   .name = "wm8994",
+                   .owner = THIS_MODULE,
+        },
+        .probe = wm8994_i2c_probe,
+        .remove = wm8994_i2c_remove,
+        .suspend = wm8994_i2c_suspend,
+        .resume = wm8994_i2c_resume,
+        .id_table = wm8994_i2c_id,
+};
+
+static int __init wm8994_i2c_init(void)
+{
+        int ret;
+
+        ret = i2c_add_driver(&wm8994_i2c_driver);
+        if (ret != 0)
+                pr_err("Failed to register wm8994 I2C driver: %d\n", ret);
+
+        return ret;
+}
+module_init(wm8994_i2c_init);
+
+static void __exit wm8994_i2c_exit(void)
+{
+        i2c_del_driver(&wm8994_i2c_driver);
+}
+module_exit(wm8994_i2c_exit);
+
+MODULE_DESCRIPTION("Core support for the WM8994 audio CODEC");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");