smsc can be used as an gpio io expander device also. So adding
support for configuring smsc pins as a gpio.

Cc: Benoit Cousson <b-cous...@ti.com>
Cc: Felipe Balbi <ba...@ti.com>
Cc: Santosh Shilimkar <santosh.shilim...@ti.com>
Signed-off-by: Sourav Poddar <sourav.pod...@ti.com>
---
 drivers/gpio/Kconfig        |    7 +
 drivers/gpio/Makefile       |    1 +
 drivers/gpio/gpio-smscece.c |  373 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 381 insertions(+), 0 deletions(-)
 create mode 100644 drivers/gpio/gpio-smscece.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index b16c8a7..e883929 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -444,6 +444,13 @@ config GPIO_ADP5588_IRQ
          Say yes here to enable the adp5588 to be used as an interrupt
          controller. It requires the driver to be built in the kernel.
 
+config GPIO_SMSCECE
+       tristate "SMSCECE 1099 I2C GPIO expander"
+       depends on I2C
+       help
+         This option enables support for 18 GPIOs found
+         on SMSC ECE 1099 GPIO Expanders.
+
 comment "PCI GPIO expanders:"
 
 config GPIO_CS5535
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 153cace..7c803c5 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_GPIO_74X164)     += gpio-74x164.o
 obj-$(CONFIG_GPIO_AB8500)      += gpio-ab8500.o
 obj-$(CONFIG_GPIO_ADP5520)     += gpio-adp5520.o
 obj-$(CONFIG_GPIO_ADP5588)     += gpio-adp5588.o
+obj-$(CONFIG_GPIO_SMSCECE)      += gpio-smscece.o
 obj-$(CONFIG_GPIO_AMD8111)     += gpio-amd8111.o
 obj-$(CONFIG_GPIO_ARIZONA)     += gpio-arizona.o
 obj-$(CONFIG_GPIO_BT8XX)       += gpio-bt8xx.o
diff --git a/drivers/gpio/gpio-smscece.c b/drivers/gpio/gpio-smscece.c
new file mode 100644
index 0000000..0cb0959
--- /dev/null
+++ b/drivers/gpio/gpio-smscece.c
@@ -0,0 +1,373 @@
+/*
+ * GPIO Chip driver for smsc
+ * SMSC I/O Expander and QWERTY Keypad Controller
+ *
+ * Copyright 2012 Texas Instruments Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+#include <linux/mfd/smsc.h>
+#include <linux/err.h>
+
+struct smsc_gpio {
+       struct device *dev;
+       struct smsc *smsc;
+       struct gpio_chip gpio_chip;
+       struct mutex lock;      /* protect cached dir, dat_out */
+       /* protect serialized access to the interrupt controller bus */
+       struct mutex irq_lock;
+       unsigned gpio_start;
+       int type;
+       int flags;
+       int irq;
+       int irq_base;
+       unsigned int gpio_base;
+       unsigned int dat_out[5];
+       unsigned int dir[5];
+       unsigned int int_lvl[5];
+       unsigned int int_en[5];
+       unsigned int irq_mask[5];
+       unsigned int irq_stat[5];
+};
+
+static int smsc_gpio_get_value(struct gpio_chip *chip, unsigned off)
+{
+       struct smsc_gpio *sg =
+               container_of(chip, struct smsc_gpio, gpio_chip);
+       unsigned int get;
+       return !!(smsc_read(sg->dev,
+               (SMSC_GPIO_DATA_IN_START + SMSC_BANK(off)) & SMSC_BIT(off),
+                                       &get));
+}
+
+static void smsc_gpio_set_value(struct gpio_chip *chip,
+                       unsigned off, int val)
+{
+       unsigned bank, bit;
+       struct smsc_gpio *sg =
+               container_of(chip, struct smsc_gpio, gpio_chip);
+
+       bank = SMSC_BANK(off);
+       bit = SMSC_BIT(off);
+
+       mutex_lock(&sg->lock);
+       if (val)
+               sg->dat_out[bank] |= bit;
+       else
+               sg->dat_out[bank] &= ~bit;
+
+       smsc_write(sg->dev, SMSC_GPIO_DATA_OUT_START + bank,
+                          sg->dat_out[bank]);
+       mutex_unlock(&sg->lock);
+}
+
+static int smsc_gpio_direction_input(struct gpio_chip *chip, unsigned off)
+{
+       unsigned int reg;
+       struct smsc_gpio *sg =
+           container_of(chip, struct smsc_gpio, gpio_chip);
+       int reg_dir;
+
+       mutex_lock(&sg->lock);
+       reg_dir = SMSC_CFG_START + off;
+       smsc_read(sg->dev, reg_dir, &reg);
+       reg |= SMSC_GPIO_INPUT_LOW;
+       mutex_unlock(&sg->lock);
+
+       return smsc_write(sg->dev, reg_dir, reg);
+}
+
+static int smsc_gpio_direction_output(struct gpio_chip *chip,
+                                        unsigned off, int val)
+{
+       unsigned int reg;
+       struct smsc_gpio *sg =
+           container_of(chip, struct smsc_gpio, gpio_chip);
+       int reg_dir;
+
+       mutex_lock(&sg->lock);
+       reg_dir = SMSC_CFG_START + off;
+       smsc_read(sg->dev, reg_dir, &reg);
+       reg |= SMSC_GPIO_OUTPUT_PP;
+       mutex_unlock(&sg->lock);
+
+       return smsc_write(sg->dev, reg_dir, reg);
+}
+
+static int smsc_gpio_to_irq(struct gpio_chip *chip, unsigned off)
+{
+       struct smsc_gpio *sg =
+               container_of(chip, struct smsc_gpio, gpio_chip);
+       return sg->irq_base + off;
+}
+
+static void smsc_irq_bus_lock(struct irq_data *d)
+{
+       struct smsc_gpio *sg = irq_data_get_irq_chip_data(d);
+
+       mutex_lock(&sg->irq_lock);
+}
+
+static void smsc_irq_bus_sync_unlock(struct irq_data *d)
+{
+       struct smsc_gpio *sg = irq_data_get_irq_chip_data(d);
+       int i;
+
+       for (i = 0; i < SMSC_BANK(SMSC_MAXGPIO); i++)
+               if (sg->int_en[i] ^ sg->irq_mask[i]) {
+                       sg->int_en[i] = sg->irq_mask[i];
+                       smsc_write(sg->dev, SMSC_GPIO_INT_MASK_START + i,
+                                          sg->int_en[i]);
+               }
+
+       mutex_unlock(&sg->irq_lock);
+}
+
+static void smsc_irq_mask(struct irq_data *d)
+{
+       struct smsc_gpio *sg = irq_data_get_irq_chip_data(d);
+       unsigned gpio = d->irq - sg->irq_base;
+
+       sg->irq_mask[SMSC_BANK(gpio)] &= ~SMSC_BIT(gpio);
+}
+
+static void smsc_irq_unmask(struct irq_data *d)
+{
+       struct smsc_gpio *sg = irq_data_get_irq_chip_data(d);
+       unsigned gpio = d->irq - sg->irq_base;
+
+       sg->irq_mask[SMSC_BANK(gpio)] |= SMSC_BIT(gpio);
+}
+
+static int smsc_irq_set_type(struct irq_data *d, unsigned int type)
+{
+       struct smsc_gpio *sg = irq_data_get_irq_chip_data(d);
+       uint16_t gpio = d->irq - sg->irq_base;
+       unsigned bank, bit;
+
+       if ((type & IRQ_TYPE_EDGE_BOTH)) {
+               dev_err(sg->dev, "irq %d: unsupported type %d\n",
+                       d->irq, type);
+               return -EINVAL;
+       }
+
+       bank = SMSC_BANK(gpio);
+       bit = SMSC_BIT(gpio);
+
+       if (type & IRQ_TYPE_LEVEL_HIGH)
+               sg->int_lvl[bank] |= bit;
+       else if (type & IRQ_TYPE_LEVEL_LOW)
+               sg->int_lvl[bank] &= ~bit;
+       else
+               return -EINVAL;
+
+       smsc_gpio_direction_input(&sg->gpio_chip, gpio);
+       smsc_write(sg->dev, SMSC_CFG_START + gpio,
+                       sg->int_lvl[bank]);
+
+       return 0;
+}
+
+static struct irq_chip smsc_irq_chip = {
+       .name                   = "smsc",
+       .irq_mask               = smsc_irq_mask,
+       .irq_unmask             = smsc_irq_unmask,
+       .irq_bus_lock           = smsc_irq_bus_lock,
+       .irq_bus_sync_unlock    = smsc_irq_bus_sync_unlock,
+       .irq_set_type           = smsc_irq_set_type,
+};
+
+static int smsc_gpio_read_intstat(struct smsc_gpio *sg,
+                               unsigned int *buf, int i)
+{
+       int ret = smsc_read(sg->dev,
+                       SMSC_GPIO_INT_STAT_START + i, buf);
+
+       if (ret < 0)
+               dev_err(sg->dev, "Read INT_STAT Error\n");
+
+       return ret;
+}
+
+static irqreturn_t smsc_irq_handler(int irq, void *devid)
+{
+       struct smsc_gpio *sg = devid;
+       unsigned int status, bank, pending;
+       int ret;
+       smsc_read(sg->dev, GRP_INT_STAT, &status);
+
+       if (!(status & SMSC_GPI_INT))
+               goto out;
+
+       for (bank = 0; bank <= SMSC_BANK(SMSC_MAXGPIO);
+               bank++) {
+               pending = sg->irq_stat[bank] & sg->irq_mask[bank];
+               ret = smsc_gpio_read_intstat(sg,
+                               &sg->irq_stat[bank], bank);
+               if (ret < 0)
+                       memset(&sg->irq_stat[bank], 0,
+                               ARRAY_SIZE(sg->irq_stat));
+
+               while (pending) {
+                       unsigned long   bit = __ffs(pending);
+                       unsigned int    irq;
+
+                       pending &= ~BIT(bit);
+                       irq = bit + sg->irq_base;
+                       handle_nested_irq(irq);
+               }
+       }
+
+out:
+       smsc_write(sg->dev, GRP_INT_STAT, status); /* Status is W1C */
+
+       return IRQ_HANDLED;
+}
+
+static int smsc_irq_setup(struct smsc_gpio *sg)
+{
+       unsigned gpio;
+       int ret;
+
+       mutex_init(&sg->irq_lock);
+
+       for (gpio = 0; gpio < sg->gpio_chip.ngpio; gpio++) {
+               int irq = gpio + sg->irq_base;
+               irq_set_chip_data(irq, sg);
+               irq_set_chip_and_handler(irq, &smsc_irq_chip,
+                               handle_level_irq);
+               irq_set_nested_thread(irq, 1);
+#ifdef CONFIG_ARM
+               set_irq_flags(irq, IRQF_VALID);
+#else
+               irq_set_noprobe(irq);
+#endif
+       }
+
+       ret = request_threaded_irq(sg->irq, NULL,
+                       smsc_irq_handler, sg->flags,
+                       "smsc_gpio", sg);
+       if (ret) {
+               dev_err(sg->dev, "failed to request irq %d\n",
+                       sg->irq);
+       }
+
+       sg->gpio_chip.to_irq = smsc_gpio_to_irq;
+
+       return 0;
+}
+
+static int __devinit smsc_gpio_probe(struct platform_device *pdev)
+{
+       struct smsc_gpio *sg;
+       struct gpio_chip *gc;
+       struct smsc *smsc = dev_get_drvdata(pdev->dev.parent);
+       int ret, i, temp;
+       struct device *dev = &pdev->dev;
+       struct device_node *np = dev->of_node;
+       int irq_base;
+
+       sg = devm_kzalloc(dev, sizeof(*sg), GFP_KERNEL);
+       if (sg == NULL) {
+               dev_err(&pdev->dev, "failed to alloc memory\n");
+               return -ENOMEM;
+       }
+
+       sg->irq = platform_get_irq(pdev, 0);
+       if (np) {
+               of_property_read_u32(np, "gpio,base", &temp);
+               of_property_read_u32(np, "flags", &sg->flags);
+       }
+
+       gc = &sg->gpio_chip;
+       gc->direction_input = smsc_gpio_direction_input;
+       gc->direction_output = smsc_gpio_direction_output;
+       gc->get = smsc_gpio_get_value;
+       gc->set = smsc_gpio_set_value;
+       gc->can_sleep = 1;
+
+       gc->base = temp;
+       gc->ngpio = SMSC_MAXGPIO;
+       gc->owner = THIS_MODULE;
+
+       sg->smsc = smsc;
+       sg->dev = dev;
+       mutex_init(&sg->lock);
+
+       for (i = 0; i <= SMSC_BANK(SMSC_MAXGPIO); i++)
+               smsc_read(sg->dev, SMSC_GPIO_DATA_OUT_START + i,
+                                       &sg->dat_out[i]);
+
+       for (i = 0; i < SMSC_MAXGPIO; i++)
+               smsc_read(sg->dev, SMSC_CFG_START + i, &sg->dir[i]);
+
+       irq_base = irq_alloc_descs(-1, 0, sg->gpio_chip.ngpio, 0);
+       if (IS_ERR_VALUE(irq_base)) {
+               dev_err(sg->dev, "Fail to allocate IRQ descs\n");
+               return irq_base;
+       }
+       sg->irq_base = irq_base;
+
+       irq_domain_add_legacy(pdev->dev.of_node, sg->gpio_chip.ngpio,
+               sg->irq_base, 0, &irq_domain_simple_ops, NULL);
+
+       ret = smsc_irq_setup(sg);
+       if (ret)
+               goto err;
+
+       ret = gpiochip_add(&sg->gpio_chip);
+       if (ret)
+               goto err;
+
+       return 0;
+
+err:
+       kfree(sg);
+
+       return ret;
+}
+
+static int __devexit smsc_gpio_remove(struct platform_device *pdev)
+{
+       struct smsc_gpio *sg = dev_get_drvdata(&pdev->dev);
+       int ret;
+
+       ret = gpiochip_remove(&sg->gpio_chip);
+       if (ret) {
+               dev_err(&pdev->dev, "gpiochip_remove failed %d\n", ret);
+               return ret;
+       }
+
+       return 0;
+}
+
+static const struct of_device_id smsc_gpio_dt_match[] = {
+       { .compatible = "smsc,gpio" },
+       {},
+};
+MODULE_DEVICE_TABLE(of, smsc_gpio_dt_match);
+
+static struct platform_driver smsc_gpio_driver = {
+       .driver = {
+                  .name = "smsc_gpio",
+                  .of_match_table = of_match_ptr(smsc_gpio_dt_match),
+                  },
+       .probe = smsc_gpio_probe,
+       .remove = __devexit_p(smsc_gpio_remove),
+};
+
+module_platform_driver(smsc_gpio_driver);
+
+MODULE_AUTHOR("Sourav Poddar <sourav.pod...@ti.com>");
+MODULE_DESCRIPTION("GPIO SMSC Driver");
+MODULE_LICENSE("GPL v2");
-- 
1.7.1

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