mfd: Add Toshiba's TC35892 MFD core

The TC35892 I/O Expander provides 24 GPIOs, a keypad controller, timers,
and a rotator wheel interface.  This patch adds the MFD core.

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

3 files changed, 359 insertions, 0 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 40e0a0a7df5b..614fa7b8a054 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -171,6 +171,17 @@ config TWL4030_CODEC
         select MFD_CORE
         default n
 
+config MFD_TC35892
+        bool "Support Toshiba TC35892"
+        depends on I2C=y && GENERIC_HARDIRQS
+        select MFD_CORE
+        help
+          Support for the Toshiba TC35892 I/O Expander.
+
+          This driver provides common support for accessing the device,
+          additional drivers must be enabled in order to use the
+          functionality of the device.
+
 config MFD_TMIO
         bool
         default n
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index abf6f1766dcd..5eb79794d5a5 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_HTC_I2CPLD)	+= htc-i2cpld.o
 obj-$(CONFIG_MFD_DAVINCI_VOICECODEC)    += davinci_voicecodec.o
 obj-$(CONFIG_MFD_DM355EVM_MSP)  += dm355evm_msp.o
 
+obj-$(CONFIG_MFD_TC35892)       += tc35892.o
 obj-$(CONFIG_MFD_T7L66XB)       += t7l66xb.o tmio_core.o
 obj-$(CONFIG_MFD_TC6387XB)      += tc6387xb.o tmio_core.o
 obj-$(CONFIG_MFD_TC6393XB)      += tc6393xb.o tmio_core.o
diff --git a/drivers/mfd/tc35892.c b/drivers/mfd/tc35892.c
new file mode 100644
index 000000000000..715f095dd7a6
--- /dev/null
+++ b/drivers/mfd/tc35892.c
@@ -0,0 +1,347 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2010
+ *
+ * License Terms: GNU General Public License, version 2
+ * Author: Hanumath Prasad <hanumath.prasad@stericsson.com> for ST-Ericsson
+ * Author: Rabin Vincent <rabin.vincent@stericsson.com> for ST-Ericsson
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/tc35892.h>
+
+/**
+ * tc35892_reg_read() - read a single TC35892 register
+ * @tc35892:    Device to read from
+ * @reg:        Register to read
+ */
+int tc35892_reg_read(struct tc35892 *tc35892, u8 reg)
+{
+        int ret;
+
+        ret = i2c_smbus_read_byte_data(tc35892->i2c, reg);
+        if (ret < 0)
+                dev_err(tc35892->dev, "failed to read reg %#x: %d\n",
+                        reg, ret);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(tc35892_reg_read);
+
+/**
+ * tc35892_reg_read() - write a single TC35892 register
+ * @tc35892:    Device to write to
+ * @reg:        Register to read
+ * @data:       Value to write
+ */
+int tc35892_reg_write(struct tc35892 *tc35892, u8 reg, u8 data)
+{
+        int ret;
+
+        ret = i2c_smbus_write_byte_data(tc35892->i2c, reg, data);
+        if (ret < 0)
+                dev_err(tc35892->dev, "failed to write reg %#x: %d\n",
+                        reg, ret);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(tc35892_reg_write);
+
+/**
+ * tc35892_block_read() - read multiple TC35892 registers
+ * @tc35892:    Device to read from
+ * @reg:        First register
+ * @length:     Number of registers
+ * @values:     Buffer to write to
+ */
+int tc35892_block_read(struct tc35892 *tc35892, u8 reg, u8 length, u8 *values)
+{
+        int ret;
+
+        ret = i2c_smbus_read_i2c_block_data(tc35892->i2c, reg, length, values);
+        if (ret < 0)
+                dev_err(tc35892->dev, "failed to read regs %#x: %d\n",
+                        reg, ret);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(tc35892_block_read);
+
+/**
+ * tc35892_block_write() - write multiple TC35892 registers
+ * @tc35892:    Device to write to
+ * @reg:        First register
+ * @length:     Number of registers
+ * @values:     Values to write
+ */
+int tc35892_block_write(struct tc35892 *tc35892, u8 reg, u8 length,
+                        const u8 *values)
+{
+        int ret;
+
+        ret = i2c_smbus_write_i2c_block_data(tc35892->i2c, reg, length,
+                                             values);
+        if (ret < 0)
+                dev_err(tc35892->dev, "failed to write regs %#x: %d\n",
+                        reg, ret);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(tc35892_block_write);
+
+/**
+ * tc35892_set_bits() - set the value of a bitfield in a TC35892 register
+ * @tc35892:    Device to write to
+ * @reg:        Register to write
+ * @mask:       Mask of bits to set
+ * @values:     Value to set
+ */
+int tc35892_set_bits(struct tc35892 *tc35892, u8 reg, u8 mask, u8 val)
+{
+        int ret;
+
+        mutex_lock(&tc35892->lock);
+
+        ret = tc35892_reg_read(tc35892, reg);
+        if (ret < 0)
+                goto out;
+
+        ret &= ~mask;
+        ret |= val;
+
+        ret = tc35892_reg_write(tc35892, reg, ret);
+
+out:
+        mutex_unlock(&tc35892->lock);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(tc35892_set_bits);
+
+static struct resource gpio_resources[] = {
+        {
+                .start  = TC35892_INT_GPIIRQ,
+                .end    = TC35892_INT_GPIIRQ,
+                .flags  = IORESOURCE_IRQ,
+        },
+};
+
+static struct mfd_cell tc35892_devs[] = {
+        {
+                .name           = "tc35892-gpio",
+                .num_resources  = ARRAY_SIZE(gpio_resources),
+                .resources      = &gpio_resources[0],
+        },
+};
+
+static irqreturn_t tc35892_irq(int irq, void *data)
+{
+        struct tc35892 *tc35892 = data;
+        int status;
+
+        status = tc35892_reg_read(tc35892, TC35892_IRQST);
+        if (status < 0)
+                return IRQ_NONE;
+
+        while (status) {
+                int bit = __ffs(status);
+
+                handle_nested_irq(tc35892->irq_base + bit);
+                status &= ~(1 << bit);
+        }
+
+        /*
+         * A dummy read or write (to any register) appears to be necessary to
+         * have the last interrupt clear (for example, GPIO IC write) take
+         * effect.
+         */
+        tc35892_reg_read(tc35892, TC35892_IRQST);
+
+        return IRQ_HANDLED;
+}
+
+static void tc35892_irq_dummy(unsigned int irq)
+{
+        /* No mask/unmask at this level */
+}
+
+static struct irq_chip tc35892_irq_chip = {
+        .name   = "tc35892",
+        .mask   = tc35892_irq_dummy,
+        .unmask = tc35892_irq_dummy,
+};
+
+static int tc35892_irq_init(struct tc35892 *tc35892)
+{
+        int base = tc35892->irq_base;
+        int irq;
+
+        for (irq = base; irq < base + TC35892_NR_INTERNAL_IRQS; irq++) {
+                set_irq_chip_data(irq, tc35892);
+                set_irq_chip_and_handler(irq, &tc35892_irq_chip,
+                                         handle_edge_irq);
+                set_irq_nested_thread(irq, 1);
+#ifdef CONFIG_ARM
+                set_irq_flags(irq, IRQF_VALID);
+#else
+                set_irq_noprobe(irq);
+#endif
+        }
+
+        return 0;
+}
+
+static void tc35892_irq_remove(struct tc35892 *tc35892)
+{
+        int base = tc35892->irq_base;
+        int irq;
+
+        for (irq = base; irq < base + TC35892_NR_INTERNAL_IRQS; irq++) {
+#ifdef CONFIG_ARM
+                set_irq_flags(irq, 0);
+#endif
+                set_irq_chip_and_handler(irq, NULL, NULL);
+                set_irq_chip_data(irq, NULL);
+        }
+}
+
+static int tc35892_chip_init(struct tc35892 *tc35892)
+{
+        int manf, ver, ret;
+
+        manf = tc35892_reg_read(tc35892, TC35892_MANFCODE);
+        if (manf < 0)
+                return manf;
+
+        ver = tc35892_reg_read(tc35892, TC35892_VERSION);
+        if (ver < 0)
+                return ver;
+
+        if (manf != TC35892_MANFCODE_MAGIC) {
+                dev_err(tc35892->dev, "unknown manufacturer: %#x\n", manf);
+                return -EINVAL;
+        }
+
+        dev_info(tc35892->dev, "manufacturer: %#x, version: %#x\n", manf, ver);
+
+        /* Put everything except the IRQ module into reset */
+        ret = tc35892_reg_write(tc35892, TC35892_RSTCTRL,
+                                TC35892_RSTCTRL_TIMRST
+                                | TC35892_RSTCTRL_ROTRST
+                                | TC35892_RSTCTRL_KBDRST
+                                | TC35892_RSTCTRL_GPIRST);
+        if (ret < 0)
+                return ret;
+
+        /* Clear the reset interrupt. */
+        return tc35892_reg_write(tc35892, TC35892_RSTINTCLR, 0x1);
+}
+
+static int __devinit tc35892_probe(struct i2c_client *i2c,
+                                   const struct i2c_device_id *id)
+{
+        struct tc35892_platform_data *pdata = i2c->dev.platform_data;
+        struct tc35892 *tc35892;
+        int ret;
+
+        if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA
+                                     | I2C_FUNC_SMBUS_I2C_BLOCK))
+                return -EIO;
+
+        tc35892 = kzalloc(sizeof(struct tc35892), GFP_KERNEL);
+        if (!tc35892)
+                return -ENOMEM;
+
+        mutex_init(&tc35892->lock);
+
+        tc35892->dev = &i2c->dev;
+        tc35892->i2c = i2c;
+        tc35892->pdata = pdata;
+        tc35892->irq_base = pdata->irq_base;
+        tc35892->num_gpio = id->driver_data;
+
+        i2c_set_clientdata(i2c, tc35892);
+
+        ret = tc35892_chip_init(tc35892);
+        if (ret)
+                goto out_free;
+
+        ret = tc35892_irq_init(tc35892);
+        if (ret)
+                goto out_free;
+
+        ret = request_threaded_irq(tc35892->i2c->irq, NULL, tc35892_irq,
+                                   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+                                   "tc35892", tc35892);
+        if (ret) {
+                dev_err(tc35892->dev, "failed to request IRQ: %d\n", ret);
+                goto out_removeirq;
+        }
+
+        ret = mfd_add_devices(tc35892->dev, -1, tc35892_devs,
+                              ARRAY_SIZE(tc35892_devs), NULL,
+                              tc35892->irq_base);
+        if (ret) {
+                dev_err(tc35892->dev, "failed to add children\n");
+                goto out_freeirq;
+        }
+
+        return 0;
+
+out_freeirq:
+        free_irq(tc35892->i2c->irq, tc35892);
+out_removeirq:
+        tc35892_irq_remove(tc35892);
+out_free:
+        i2c_set_clientdata(i2c, NULL);
+        kfree(tc35892);
+        return ret;
+}
+
+static int __devexit tc35892_remove(struct i2c_client *client)
+{
+        struct tc35892 *tc35892 = i2c_get_clientdata(client);
+
+        mfd_remove_devices(tc35892->dev);
+
+        free_irq(tc35892->i2c->irq, tc35892);
+        tc35892_irq_remove(tc35892);
+
+        i2c_set_clientdata(client, NULL);
+        kfree(tc35892);
+
+        return 0;
+}
+
+static const struct i2c_device_id tc35892_id[] = {
+        { "tc35892", 24 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, tc35892_id);
+
+static struct i2c_driver tc35892_driver = {
+        .driver.name    = "tc35892",
+        .driver.owner   = THIS_MODULE,
+        .probe          = tc35892_probe,
+        .remove         = __devexit_p(tc35892_remove),
+        .id_table       = tc35892_id,
+};
+
+static int __init tc35892_init(void)
+{
+        return i2c_add_driver(&tc35892_driver);
+}
+subsys_initcall(tc35892_init);
+
+static void __exit tc35892_exit(void)
+{
+        i2c_del_driver(&tc35892_driver);
+}
+module_exit(tc35892_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("TC35892 MFD core driver");
+MODULE_AUTHOR("Hanumath Prasad, Rabin Vincent");