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>

Change-Id: Ib9fe0f306c241284be763e8c65ce1bee44d22d5a
Signed-off-by: Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>

3 files changed, 357 insertions, 0 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 41a3e482cb5..d3879b9c469 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -331,6 +331,17 @@ config MFD_TC3589X
 	  additional drivers must be enabled in order to use the
 	  functionality of the device.
 
+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 e1f64f9403a..cfed0402931 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_MFD_STMPE)		+= stmpe.o
 obj-$(CONFIG_STMPE_I2C)		+= stmpe-i2c.o
 obj-$(CONFIG_STMPE_SPI)		+= stmpe-spi.o
 obj-$(CONFIG_MFD_TC3589X)	+= tc3589x.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 00000000000..e619e2a5599
--- /dev/null
+++ b/drivers/mfd/tc35892.c
@@ -0,0 +1,345 @@
+/*
+ * 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:
+	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);
+
+	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");