[ARM] 4947/1: htc-egpio, a driver for GPIO/IRQ expanders with fixed input/output pins

implemented in CPLD chips on several HTC devices.

The original driver was written by Kevin O'Connor, I have adapted it to
use gpiolib and made the bus/register widths configurable.

Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 440 insertions, 0 deletions

diff --git a/drivers/mfd/htc-egpio.c b/drivers/mfd/htc-egpio.c
new file mode 100644
index 000000000000..8872cc077519
--- /dev/null
+++ b/drivers/mfd/htc-egpio.c
@@ -0,0 +1,440 @@
+/*
+ * Support for the GPIO/IRQ expander chips present on several HTC phones.
+ * These are implemented in CPLD chips present on the board.
+ *
+ * Copyright (c) 2007 Kevin O'Connor <kevin@koconnor.net>
+ * Copyright (c) 2007 Philipp Zabel <philipp.zabel@gmail.com>
+ *
+ * This file may be distributed under the terms of the GNU GPL license.
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/spinlock.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/mfd/htc-egpio.h>
+
+struct egpio_chip {
+        int              reg_start;
+        int              cached_values;
+        unsigned long    is_out;
+        struct device    *dev;
+        struct gpio_chip chip;
+};
+
+struct egpio_info {
+        spinlock_t        lock;
+
+        /* iomem info */
+        void __iomem      *base_addr;
+        int               bus_shift;    /* byte shift */
+        int               reg_shift;    /* bit shift */
+        int               reg_mask;
+
+        /* irq info */
+        int               ack_register;
+        int               ack_write;
+        u16               irqs_enabled;
+        uint              irq_start;
+        int               nirqs;
+        uint              chained_irq;
+
+        /* egpio info */
+        struct egpio_chip *chip;
+        int               nchips;
+};
+
+static inline void egpio_writew(u16 value, struct egpio_info *ei, int reg)
+{
+        writew(value, ei->base_addr + (reg << ei->bus_shift));
+}
+
+static inline u16 egpio_readw(struct egpio_info *ei, int reg)
+{
+        return readw(ei->base_addr + (reg << ei->bus_shift));
+}
+
+/*
+ * IRQs
+ */
+
+static inline void ack_irqs(struct egpio_info *ei)
+{
+        egpio_writew(ei->ack_write, ei, ei->ack_register);
+        pr_debug("EGPIO ack - write %x to base+%x\n",
+                        ei->ack_write, ei->ack_register << ei->bus_shift);
+}
+
+static void egpio_ack(unsigned int irq)
+{
+}
+
+/* There does not appear to be a way to proactively mask interrupts
+ * on the egpio chip itself.  So, we simply ignore interrupts that
+ * aren't desired. */
+static void egpio_mask(unsigned int irq)
+{
+        struct egpio_info *ei = get_irq_chip_data(irq);
+        ei->irqs_enabled &= ~(1 << (irq - ei->irq_start));
+        pr_debug("EGPIO mask %d %04x\n", irq, ei->irqs_enabled);
+}
+static void egpio_unmask(unsigned int irq)
+{
+        struct egpio_info *ei = get_irq_chip_data(irq);
+        ei->irqs_enabled |= 1 << (irq - ei->irq_start);
+        pr_debug("EGPIO unmask %d %04x\n", irq, ei->irqs_enabled);
+}
+
+static struct irq_chip egpio_muxed_chip = {
+        .name   = "htc-egpio",
+        .ack    = egpio_ack,
+        .mask   = egpio_mask,
+        .unmask = egpio_unmask,
+};
+
+static void egpio_handler(unsigned int irq, struct irq_desc *desc)
+{
+        struct egpio_info *ei = get_irq_data(irq);
+        int irqpin;
+
+        /* Read current pins. */
+        unsigned long readval = egpio_readw(ei, ei->ack_register);
+        pr_debug("IRQ reg: %x\n", (unsigned int)readval);
+        /* Ack/unmask interrupts. */
+        ack_irqs(ei);
+        /* Process all set pins. */
+        readval &= ei->irqs_enabled;
+        for_each_bit(irqpin, &readval, ei->nirqs) {
+                /* Run irq handler */
+                pr_debug("got IRQ %d\n", irqpin);
+                irq = ei->irq_start + irqpin;
+                desc = &irq_desc[irq];
+                desc->handle_irq(irq, desc);
+        }
+}
+
+int htc_egpio_get_wakeup_irq(struct device *dev)
+{
+        struct egpio_info *ei = dev_get_drvdata(dev);
+
+        /* Read current pins. */
+        u16 readval = egpio_readw(ei, ei->ack_register);
+        /* Ack/unmask interrupts. */
+        ack_irqs(ei);
+        /* Return first set pin. */
+        readval &= ei->irqs_enabled;
+        return ei->irq_start + ffs(readval) - 1;
+}
+EXPORT_SYMBOL(htc_egpio_get_wakeup_irq);
+
+static inline int egpio_pos(struct egpio_info *ei, int bit)
+{
+        return bit >> ei->reg_shift;
+}
+
+static inline int egpio_bit(struct egpio_info *ei, int bit)
+{
+        return 1 << (bit & ((1 << ei->reg_shift)-1));
+}
+
+/*
+ * Input pins
+ */
+
+static int egpio_get(struct gpio_chip *chip, unsigned offset)
+{
+        struct egpio_chip *egpio;
+        struct egpio_info *ei;
+        unsigned           bit;
+        int                reg;
+        int                value;
+
+        pr_debug("egpio_get_value(%d)\n", chip->base + offset);
+
+        egpio = container_of(chip, struct egpio_chip, chip);
+        ei    = dev_get_drvdata(egpio->dev);
+        bit   = egpio_bit(ei, offset);
+        reg   = egpio->reg_start + egpio_pos(ei, offset);
+
+        value = egpio_readw(ei, reg);
+        pr_debug("readw(%p + %x) = %x\n",
+                        ei->base_addr, reg << ei->bus_shift, value);
+        return value & bit;
+}
+
+static int egpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+        struct egpio_chip *egpio;
+
+        egpio = container_of(chip, struct egpio_chip, chip);
+        return test_bit(offset, &egpio->is_out) ? -EINVAL : 0;
+}
+
+
+/*
+ * Output pins
+ */
+
+static void egpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+        unsigned long     flag;
+        struct egpio_chip *egpio;
+        struct egpio_info *ei;
+        unsigned          bit;
+        int               pos;
+        int               reg;
+        int               shift;
+
+        pr_debug("egpio_set(%s, %d(%d), %d)\n",
+                        chip->label, offset, offset+chip->base, value);
+
+        egpio = container_of(chip, struct egpio_chip, chip);
+        ei    = dev_get_drvdata(egpio->dev);
+        bit   = egpio_bit(ei, offset);
+        pos   = egpio_pos(ei, offset);
+        reg   = egpio->reg_start + pos;
+        shift = pos << ei->reg_shift;
+
+        pr_debug("egpio %s: reg %d = 0x%04x\n", value ? "set" : "clear",
+                        reg, (egpio->cached_values >> shift) & ei->reg_mask);
+
+        spin_lock_irqsave(&ei->lock, flag);
+        if (value)
+                egpio->cached_values |= (1 << offset);
+        else
+                egpio->cached_values &= ~(1 << offset);
+        egpio_writew((egpio->cached_values >> shift) & ei->reg_mask, ei, reg);
+        spin_unlock_irqrestore(&ei->lock, flag);
+}
+
+static int egpio_direction_output(struct gpio_chip *chip,
+                                        unsigned offset, int value)
+{
+        struct egpio_chip *egpio;
+
+        egpio = container_of(chip, struct egpio_chip, chip);
+        if (test_bit(offset, &egpio->is_out)) {
+                egpio_set(chip, offset, value);
+                return 0;
+        } else {
+                return -EINVAL;
+        }
+}
+
+static void egpio_write_cache(struct egpio_info *ei)
+{
+        int               i;
+        struct egpio_chip *egpio;
+        int               shift;
+
+        for (i = 0; i < ei->nchips; i++) {
+                egpio = &(ei->chip[i]);
+                if (!egpio->is_out)
+                        continue;
+
+                for (shift = 0; shift < egpio->chip.ngpio;
+                                shift += (1<<ei->reg_shift)) {
+
+                        int reg = egpio->reg_start + egpio_pos(ei, shift);
+
+                        if (!((egpio->is_out >> shift) & ei->reg_mask))
+                                continue;
+
+                        pr_debug("EGPIO: setting %x to %x, was %x\n", reg,
+                                (egpio->cached_values >> shift) & ei->reg_mask,
+                                egpio_readw(ei, reg));
+
+                        egpio_writew((egpio->cached_values >> shift)
+                                        & ei->reg_mask, ei, reg);
+                }
+        }
+}
+
+
+/*
+ * Setup
+ */
+
+static int __init egpio_probe(struct platform_device *pdev)
+{
+        struct htc_egpio_platform_data *pdata = pdev->dev.platform_data;
+        struct resource   *res;
+        struct egpio_info *ei;
+        struct gpio_chip  *chip;
+        unsigned int      irq, irq_end;
+        int               i;
+        int               ret;
+
+        /* Initialize ei data structure. */
+        ei = kzalloc(sizeof(*ei), GFP_KERNEL);
+        if (!ei)
+                return -ENOMEM;
+
+        spin_lock_init(&ei->lock);
+
+        /* Find chained irq */
+        ret = -EINVAL;
+        res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+        if (res)
+                ei->chained_irq = res->start;
+
+        /* Map egpio chip into virtual address space. */
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!res)
+                goto fail;
+        ei->base_addr = ioremap_nocache(res->start, res->end - res->start);
+        if (!ei->base_addr)
+                goto fail;
+        pr_debug("EGPIO phys=%08x virt=%p\n", res->start, ei->base_addr);
+
+        if ((pdata->bus_width != 16) && (pdata->bus_width != 32))
+                goto fail;
+        ei->bus_shift = fls(pdata->bus_width - 1) - 3;
+        pr_debug("bus_shift = %d\n", ei->bus_shift);
+
+        if ((pdata->reg_width != 8) && (pdata->reg_width != 16))
+                goto fail;
+        ei->reg_shift = fls(pdata->reg_width - 1);
+        pr_debug("reg_shift = %d\n", ei->reg_shift);
+
+        ei->reg_mask = (1 << pdata->reg_width) - 1;
+
+        platform_set_drvdata(pdev, ei);
+
+        ei->nchips = pdata->num_chips;
+        ei->chip = kzalloc(sizeof(struct egpio_chip) * ei->nchips, GFP_KERNEL);
+        if (!ei) {
+                ret = -ENOMEM;
+                goto fail;
+        }
+        for (i = 0; i < ei->nchips; i++) {
+                ei->chip[i].reg_start = pdata->chip[i].reg_start;
+                ei->chip[i].cached_values = pdata->chip[i].initial_values;
+                ei->chip[i].is_out = pdata->chip[i].direction;
+                ei->chip[i].dev = &(pdev->dev);
+                chip = &(ei->chip[i].chip);
+                chip->label           = "htc-egpio";
+                chip->get             = egpio_get;
+                chip->set             = egpio_set;
+                chip->direction_input = egpio_direction_input;
+                chip->direction_output = egpio_direction_output;
+                chip->base            = pdata->chip[i].gpio_base;
+                chip->ngpio           = pdata->chip[i].num_gpios;
+
+                gpiochip_add(chip);
+        }
+
+        /* Set initial pin values */
+        egpio_write_cache(ei);
+
+        ei->irq_start = pdata->irq_base;
+        ei->nirqs = pdata->num_irqs;
+        ei->ack_register = pdata->ack_register;
+
+        if (ei->chained_irq) {
+                /* Setup irq handlers */
+                ei->ack_write = 0xFFFF;
+                if (pdata->invert_acks)
+                        ei->ack_write = 0;
+                irq_end = ei->irq_start + ei->nirqs;
+                for (irq = ei->irq_start; irq < irq_end; irq++) {
+                        set_irq_chip(irq, &egpio_muxed_chip);
+                        set_irq_chip_data(irq, ei);
+                        set_irq_handler(irq, handle_simple_irq);
+                        set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
+                }
+                set_irq_type(ei->chained_irq, IRQ_TYPE_EDGE_RISING);
+                set_irq_data(ei->chained_irq, ei);
+                set_irq_chained_handler(ei->chained_irq, egpio_handler);
+                ack_irqs(ei);
+
+                device_init_wakeup(&pdev->dev, 1);
+        }
+
+        return 0;
+
+fail:
+        printk(KERN_ERR "EGPIO failed to setup\n");
+        kfree(ei);
+        return ret;
+}
+
+static int __exit egpio_remove(struct platform_device *pdev)
+{
+        struct egpio_info *ei = platform_get_drvdata(pdev);
+        unsigned int      irq, irq_end;
+
+        if (ei->chained_irq) {
+                irq_end = ei->irq_start + ei->nirqs;
+                for (irq = ei->irq_start; irq < irq_end; irq++) {
+                        set_irq_chip(irq, NULL);
+                        set_irq_handler(irq, NULL);
+                        set_irq_flags(irq, 0);
+                }
+                set_irq_chained_handler(ei->chained_irq, NULL);
+                device_init_wakeup(&pdev->dev, 0);
+        }
+        iounmap(ei->base_addr);
+        kfree(ei->chip);
+        kfree(ei);
+
+        return 0;
+}
+
+#ifdef CONFIG_PM
+static int egpio_suspend(struct platform_device *pdev, pm_message_t state)
+{
+        struct egpio_info *ei = platform_get_drvdata(pdev);
+
+        if (ei->chained_irq && device_may_wakeup(&pdev->dev))
+                enable_irq_wake(ei->chained_irq);
+        return 0;
+}
+
+static int egpio_resume(struct platform_device *pdev)
+{
+        struct egpio_info *ei = platform_get_drvdata(pdev);
+
+        if (ei->chained_irq && device_may_wakeup(&pdev->dev))
+                disable_irq_wake(ei->chained_irq);
+
+        /* Update registers from the cache, in case
+           the CPLD was powered off during suspend */
+        egpio_write_cache(ei);
+        return 0;
+}
+#else
+#define egpio_suspend NULL
+#define egpio_resume NULL
+#endif
+
+
+static struct platform_driver egpio_driver = {
+        .driver = {
+                .name = "htc-egpio",
+        },
+        .remove       = __exit_p(egpio_remove),
+        .suspend      = egpio_suspend,
+        .resume       = egpio_resume,
+};
+
+static int __init egpio_init(void)
+{
+        return platform_driver_probe(&egpio_driver, egpio_probe);
+}
+
+static void __exit egpio_exit(void)
+{
+        platform_driver_unregister(&egpio_driver);
+}
+
+/* start early for dependencies */
+subsys_initcall(egpio_init);
+module_exit(egpio_exit)
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Kevin O'Connor <kevin@koconnor.net>");