gpio: Add TC35892 GPIO driver

Add a GPIO driver to support the GPIOs on the TC35892 I/O Expander.

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>

1 files changed, 381 insertions, 0 deletions

diff --git a/drivers/gpio/tc35892-gpio.c b/drivers/gpio/tc35892-gpio.c
new file mode 100644
index 000000000000..1be6288780de
--- /dev/null
+++ b/drivers/gpio/tc35892-gpio.c
@@ -0,0 +1,381 @@
+/*
+ * 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/init.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/gpio.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/tc35892.h>
+
+/*
+ * These registers are modified under the irq bus lock and cached to avoid
+ * unnecessary writes in bus_sync_unlock.
+ */
+enum { REG_IBE, REG_IEV, REG_IS, REG_IE };
+
+#define CACHE_NR_REGS   4
+#define CACHE_NR_BANKS  3
+
+struct tc35892_gpio {
+        struct gpio_chip chip;
+        struct tc35892 *tc35892;
+        struct device *dev;
+        struct mutex irq_lock;
+
+        int irq_base;
+
+        /* Caches of interrupt control registers for bus_lock */
+        u8 regs[CACHE_NR_REGS][CACHE_NR_BANKS];
+        u8 oldregs[CACHE_NR_REGS][CACHE_NR_BANKS];
+};
+
+static inline struct tc35892_gpio *to_tc35892_gpio(struct gpio_chip *chip)
+{
+        return container_of(chip, struct tc35892_gpio, chip);
+}
+
+static int tc35892_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+        struct tc35892_gpio *tc35892_gpio = to_tc35892_gpio(chip);
+        struct tc35892 *tc35892 = tc35892_gpio->tc35892;
+        u8 reg = TC35892_GPIODATA0 + (offset / 8) * 2;
+        u8 mask = 1 << (offset % 8);
+        int ret;
+
+        ret = tc35892_reg_read(tc35892, reg);
+        if (ret < 0)
+                return ret;
+
+        return ret & mask;
+}
+
+static void tc35892_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
+{
+        struct tc35892_gpio *tc35892_gpio = to_tc35892_gpio(chip);
+        struct tc35892 *tc35892 = tc35892_gpio->tc35892;
+        u8 reg = TC35892_GPIODATA0 + (offset / 8) * 2;
+        unsigned pos = offset % 8;
+        u8 data[] = {!!val << pos, 1 << pos};
+
+        tc35892_block_write(tc35892, reg, ARRAY_SIZE(data), data);
+}
+
+static int tc35892_gpio_direction_output(struct gpio_chip *chip,
+                                         unsigned offset, int val)
+{
+        struct tc35892_gpio *tc35892_gpio = to_tc35892_gpio(chip);
+        struct tc35892 *tc35892 = tc35892_gpio->tc35892;
+        u8 reg = TC35892_GPIODIR0 + offset / 8;
+        unsigned pos = offset % 8;
+
+        tc35892_gpio_set(chip, offset, val);
+
+        return tc35892_set_bits(tc35892, reg, 1 << pos, 1 << pos);
+}
+
+static int tc35892_gpio_direction_input(struct gpio_chip *chip,
+                                        unsigned offset)
+{
+        struct tc35892_gpio *tc35892_gpio = to_tc35892_gpio(chip);
+        struct tc35892 *tc35892 = tc35892_gpio->tc35892;
+        u8 reg = TC35892_GPIODIR0 + offset / 8;
+        unsigned pos = offset % 8;
+
+        return tc35892_set_bits(tc35892, reg, 1 << pos, 0);
+}
+
+static int tc35892_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+        struct tc35892_gpio *tc35892_gpio = to_tc35892_gpio(chip);
+
+        return tc35892_gpio->irq_base + offset;
+}
+
+static struct gpio_chip template_chip = {
+        .label                  = "tc35892",
+        .owner                  = THIS_MODULE,
+        .direction_input        = tc35892_gpio_direction_input,
+        .get                    = tc35892_gpio_get,
+        .direction_output       = tc35892_gpio_direction_output,
+        .set                    = tc35892_gpio_set,
+        .to_irq                 = tc35892_gpio_to_irq,
+        .can_sleep              = 1,
+};
+
+static int tc35892_gpio_irq_set_type(unsigned int irq, unsigned int type)
+{
+        struct tc35892_gpio *tc35892_gpio = get_irq_chip_data(irq);
+        int offset = irq - tc35892_gpio->irq_base;
+        int regoffset = offset / 8;
+        int mask = 1 << (offset % 8);
+
+        if (type == IRQ_TYPE_EDGE_BOTH) {
+                tc35892_gpio->regs[REG_IBE][regoffset] |= mask;
+                return 0;
+        }
+
+        tc35892_gpio->regs[REG_IBE][regoffset] &= ~mask;
+
+        if (type == IRQ_TYPE_LEVEL_LOW || type == IRQ_TYPE_LEVEL_HIGH)
+                tc35892_gpio->regs[REG_IS][regoffset] |= mask;
+        else
+                tc35892_gpio->regs[REG_IS][regoffset] &= ~mask;
+
+        if (type == IRQ_TYPE_EDGE_RISING || type == IRQ_TYPE_LEVEL_HIGH)
+                tc35892_gpio->regs[REG_IEV][regoffset] |= mask;
+        else
+                tc35892_gpio->regs[REG_IEV][regoffset] &= ~mask;
+
+        return 0;
+}
+
+static void tc35892_gpio_irq_lock(unsigned int irq)
+{
+        struct tc35892_gpio *tc35892_gpio = get_irq_chip_data(irq);
+
+        mutex_lock(&tc35892_gpio->irq_lock);
+}
+
+static void tc35892_gpio_irq_sync_unlock(unsigned int irq)
+{
+        struct tc35892_gpio *tc35892_gpio = get_irq_chip_data(irq);
+        struct tc35892 *tc35892 = tc35892_gpio->tc35892;
+        static const u8 regmap[] = {
+                [REG_IBE]       = TC35892_GPIOIBE0,
+                [REG_IEV]       = TC35892_GPIOIEV0,
+                [REG_IS]        = TC35892_GPIOIS0,
+                [REG_IE]        = TC35892_GPIOIE0,
+        };
+        int i, j;
+
+        for (i = 0; i < CACHE_NR_REGS; i++) {
+                for (j = 0; j < CACHE_NR_BANKS; j++) {
+                        u8 old = tc35892_gpio->oldregs[i][j];
+                        u8 new = tc35892_gpio->regs[i][j];
+
+                        if (new == old)
+                                continue;
+
+                        tc35892_gpio->oldregs[i][j] = new;
+                        tc35892_reg_write(tc35892, regmap[i] + j * 8, new);
+                }
+        }
+
+        mutex_unlock(&tc35892_gpio->irq_lock);
+}
+
+static void tc35892_gpio_irq_mask(unsigned int irq)
+{
+        struct tc35892_gpio *tc35892_gpio = get_irq_chip_data(irq);
+        int offset = irq - tc35892_gpio->irq_base;
+        int regoffset = offset / 8;
+        int mask = 1 << (offset % 8);
+
+        tc35892_gpio->regs[REG_IE][regoffset] &= ~mask;
+}
+
+static void tc35892_gpio_irq_unmask(unsigned int irq)
+{
+        struct tc35892_gpio *tc35892_gpio = get_irq_chip_data(irq);
+        int offset = irq - tc35892_gpio->irq_base;
+        int regoffset = offset / 8;
+        int mask = 1 << (offset % 8);
+
+        tc35892_gpio->regs[REG_IE][regoffset] |= mask;
+}
+
+static struct irq_chip tc35892_gpio_irq_chip = {
+        .name                   = "tc35892-gpio",
+        .bus_lock               = tc35892_gpio_irq_lock,
+        .bus_sync_unlock        = tc35892_gpio_irq_sync_unlock,
+        .mask                   = tc35892_gpio_irq_mask,
+        .unmask                 = tc35892_gpio_irq_unmask,
+        .set_type               = tc35892_gpio_irq_set_type,
+};
+
+static irqreturn_t tc35892_gpio_irq(int irq, void *dev)
+{
+        struct tc35892_gpio *tc35892_gpio = dev;
+        struct tc35892 *tc35892 = tc35892_gpio->tc35892;
+        u8 status[CACHE_NR_BANKS];
+        int ret;
+        int i;
+
+        ret = tc35892_block_read(tc35892, TC35892_GPIOMIS0,
+                                 ARRAY_SIZE(status), status);
+        if (ret < 0)
+                return IRQ_NONE;
+
+        for (i = 0; i < ARRAY_SIZE(status); i++) {
+                unsigned int stat = status[i];
+                if (!stat)
+                        continue;
+
+                while (stat) {
+                        int bit = __ffs(stat);
+                        int line = i * 8 + bit;
+
+                        handle_nested_irq(tc35892_gpio->irq_base + line);
+                        stat &= ~(1 << bit);
+                }
+
+                tc35892_reg_write(tc35892, TC35892_GPIOIC0 + i, status[i]);
+        }
+
+        return IRQ_HANDLED;
+}
+
+static int tc35892_gpio_irq_init(struct tc35892_gpio *tc35892_gpio)
+{
+        int base = tc35892_gpio->irq_base;
+        int irq;
+
+        for (irq = base; irq < base + tc35892_gpio->chip.ngpio; irq++) {
+                set_irq_chip_data(irq, tc35892_gpio);
+                set_irq_chip_and_handler(irq, &tc35892_gpio_irq_chip,
+                                         handle_simple_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_gpio_irq_remove(struct tc35892_gpio *tc35892_gpio)
+{
+        int base = tc35892_gpio->irq_base;
+        int irq;
+
+        for (irq = base; irq < base + tc35892_gpio->chip.ngpio; 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 __devinit tc35892_gpio_probe(struct platform_device *pdev)
+{
+        struct tc35892 *tc35892 = dev_get_drvdata(pdev->dev.parent);
+        struct tc35892_gpio_platform_data *pdata;
+        struct tc35892_gpio *tc35892_gpio;
+        int ret;
+        int irq;
+
+        pdata = tc35892->pdata->gpio;
+        if (!pdata)
+                return -ENODEV;
+
+        irq = platform_get_irq(pdev, 0);
+        if (irq < 0)
+                return irq;
+
+        tc35892_gpio = kzalloc(sizeof(struct tc35892_gpio), GFP_KERNEL);
+        if (!tc35892_gpio)
+                return -ENOMEM;
+
+        mutex_init(&tc35892_gpio->irq_lock);
+
+        tc35892_gpio->dev = &pdev->dev;
+        tc35892_gpio->tc35892 = tc35892;
+
+        tc35892_gpio->chip = template_chip;
+        tc35892_gpio->chip.ngpio = tc35892->num_gpio;
+        tc35892_gpio->chip.dev = &pdev->dev;
+        tc35892_gpio->chip.base = pdata->gpio_base;
+
+        tc35892_gpio->irq_base = tc35892->irq_base + TC35892_INT_GPIO(0);
+
+        /* Bring the GPIO module out of reset */
+        ret = tc35892_set_bits(tc35892, TC35892_RSTCTRL,
+                               TC35892_RSTCTRL_GPIRST, 0);
+        if (ret < 0)
+                goto out_free;
+
+        ret = tc35892_gpio_irq_init(tc35892_gpio);
+        if (ret)
+                goto out_free;
+
+        ret = request_threaded_irq(irq, NULL, tc35892_gpio_irq, IRQF_ONESHOT,
+                                   "tc35892-gpio", tc35892_gpio);
+        if (ret) {
+                dev_err(&pdev->dev, "unable to get irq: %d\n", ret);
+                goto out_removeirq;
+        }
+
+        ret = gpiochip_add(&tc35892_gpio->chip);
+        if (ret) {
+                dev_err(&pdev->dev, "unable to add gpiochip: %d\n", ret);
+                goto out_freeirq;
+        }
+
+        platform_set_drvdata(pdev, tc35892_gpio);
+
+        return 0;
+
+out_freeirq:
+        free_irq(irq, tc35892_gpio);
+out_removeirq:
+        tc35892_gpio_irq_remove(tc35892_gpio);
+out_free:
+        kfree(tc35892_gpio);
+        return ret;
+}
+
+static int __devexit tc35892_gpio_remove(struct platform_device *pdev)
+{
+        struct tc35892_gpio *tc35892_gpio = platform_get_drvdata(pdev);
+        int irq = platform_get_irq(pdev, 0);
+        int ret;
+
+        ret = gpiochip_remove(&tc35892_gpio->chip);
+        if (ret < 0) {
+                dev_err(tc35892_gpio->dev,
+                        "unable to remove gpiochip: %d\n", ret);
+                return ret;
+        }
+
+        free_irq(irq, tc35892_gpio);
+        tc35892_gpio_irq_remove(tc35892_gpio);
+
+        platform_set_drvdata(pdev, NULL);
+        kfree(tc35892_gpio);
+
+        return 0;
+}
+
+static struct platform_driver tc35892_gpio_driver = {
+        .driver.name    = "tc35892-gpio",
+        .driver.owner   = THIS_MODULE,
+        .probe          = tc35892_gpio_probe,
+        .remove         = __devexit_p(tc35892_gpio_remove),
+};
+
+static int __init tc35892_gpio_init(void)
+{
+        return platform_driver_register(&tc35892_gpio_driver);
+}
+subsys_initcall(tc35892_gpio_init);
+
+static void __exit tc35892_gpio_exit(void)
+{
+        platform_driver_unregister(&tc35892_gpio_driver);
+}
+module_exit(tc35892_gpio_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("TC35892 GPIO driver");
+MODULE_AUTHOR("Hanumath Prasad, Rabin Vincent");