--- /dev/null
+/*
+ * Generic driver for memory-mapped GPIO controllers.
+ *
+ * Copyright 2008 MontaVista Software, Inc.
+ * Copyright 2008,2010 Anton Vorontsov <cbouatmailru@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * ....``.```~~~~````.`.`.`.`.```````'',,,.........`````......`.......
+ * ...`` ```````..
+ * ..The simplest form of a GPIO controller that the driver supports is``
+ * `.just a single "data" register, where GPIO state can be read and/or `
+ * `,..written. ,,..``~~~~ .....``.`.`.~~.```.`.........``````.```````
+ * `````````
+ ___
+_/~~|___/~| . ```~~~~~~ ___/___\___ ,~.`.`.`.`````.~~...,,,,...
+__________|~$@~~~ %~ /o*o*o*o*o*o\ .. Implementing such a GPIO .
+o ` ~~~~\___/~~~~ ` controller in FPGA is ,.`
+ `....trivial..'~`.```.```
+ * ```````
+ * .```````~~~~`..`.``.``.
+ * . The driver supports `... ,..```.`~~~```````````````....````.``,,
+ * . big-endian notation, just`. .. A bit more sophisticated controllers ,
+ * . register the device with -be`. .with a pair of set/clear-bit registers ,
+ * `.. suffix. ```~~`````....`.` . affecting the data register and the .`
+ * ``.`.``...``` ```.. output pins are also supported.`
+ * ^^ `````.`````````.,``~``~``~~``````
+ * . ^^
+ * ,..`.`.`...````````````......`.`.`.`.`.`..`.`.`..
+ * .. The expectation is that in at least some cases . ,-~~~-,
+ * .this will be used with roll-your-own ASIC/FPGA .` \ /
+ * .logic in Verilog or VHDL. ~~~`````````..`````~~` \ /
+ * ..````````......``````````` \o_
+ * |
+ * ^^ / \
+ *
+ * ...`````~~`.....``.`..........``````.`.``.```........``.
+ * ` 8, 16, 32 and 64 bits registers are supported, and``.
+ * . the number of GPIOs is determined by the width of ~
+ * .. the registers. ,............```.`.`..`.`.~~~.`.`.`~
+ * `.......````.```
+ */
+
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/bug.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/compiler.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/log2.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <linux/gpio.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/mod_devicetable.h>
+#include <linux/basic_mmio_gpio.h>
+
+static void bgpio_write8(void __iomem *reg, unsigned long data)
+{
+ writeb(data, reg);
+}
+
+static unsigned long bgpio_read8(void __iomem *reg)
+{
+ return readb(reg);
+}
+
+static void bgpio_write16(void __iomem *reg, unsigned long data)
+{
+ writew(data, reg);
+}
+
+static unsigned long bgpio_read16(void __iomem *reg)
+{
+ return readw(reg);
+}
+
+static void bgpio_write32(void __iomem *reg, unsigned long data)
+{
+ writel(data, reg);
+}
+
+static unsigned long bgpio_read32(void __iomem *reg)
+{
+ return readl(reg);
+}
+
+#if BITS_PER_LONG >= 64
+static void bgpio_write64(void __iomem *reg, unsigned long data)
+{
+ writeq(data, reg);
+}
+
+static unsigned long bgpio_read64(void __iomem *reg)
+{
+ return readq(reg);
+}
+#endif /* BITS_PER_LONG >= 64 */
+
+static void bgpio_write16be(void __iomem *reg, unsigned long data)
+{
+ iowrite16be(data, reg);
+}
+
+static unsigned long bgpio_read16be(void __iomem *reg)
+{
+ return ioread16be(reg);
+}
+
+static void bgpio_write32be(void __iomem *reg, unsigned long data)
+{
+ iowrite32be(data, reg);
+}
+
+static unsigned long bgpio_read32be(void __iomem *reg)
+{
+ return ioread32be(reg);
+}
+
+static unsigned long bgpio_pin2mask(struct bgpio_chip *bgc, unsigned int pin)
+{
+ return 1 << pin;
+}
+
+static unsigned long bgpio_pin2mask_be(struct bgpio_chip *bgc,
+ unsigned int pin)
+{
+ return 1 << (bgc->bits - 1 - pin);
+}
+
+static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+
+ return !!(bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio));
+}
+
+static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+ unsigned long mask = bgc->pin2mask(bgc, gpio);
+ unsigned long flags;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+
+ if (val)
+ bgc->data |= mask;
+ else
+ bgc->data &= ~mask;
+
+ bgc->write_reg(bgc->reg_dat, bgc->data);
+
+ spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
+static void bgpio_set_with_clear(struct gpio_chip *gc, unsigned int gpio,
+ int val)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+ unsigned long mask = bgc->pin2mask(bgc, gpio);
+
+ if (val)
+ bgc->write_reg(bgc->reg_set, mask);
+ else
+ bgc->write_reg(bgc->reg_clr, mask);
+}
+
+static void bgpio_set_set(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+ unsigned long mask = bgc->pin2mask(bgc, gpio);
+ unsigned long flags;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+
+ if (val)
+ bgc->data |= mask;
+ else
+ bgc->data &= ~mask;
+
+ bgc->write_reg(bgc->reg_set, bgc->data);
+
+ spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
+static void bgpio_multiple_get_masks(struct bgpio_chip *bgc,
+ unsigned long *mask, unsigned long *bits,
+ unsigned long *set_mask,
+ unsigned long *clear_mask)
+{
+ int i;
+
+ *set_mask = 0;
+ *clear_mask = 0;
+
+ for (i = 0; i < bgc->bits; i++) {
+ if (*mask == 0)
+ break;
+ if (__test_and_clear_bit(i, mask)) {
+ if (test_bit(i, bits))
+ *set_mask |= bgc->pin2mask(bgc, i);
+ else
+ *clear_mask |= bgc->pin2mask(bgc, i);
+ }
+ }
+}
+
+static void bgpio_set_multiple_single_reg(struct bgpio_chip *bgc,
+ unsigned long *mask,
+ unsigned long *bits,
+ void __iomem *reg)
+{
+ unsigned long flags;
+ unsigned long set_mask, clear_mask;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+
+ bgpio_multiple_get_masks(bgc, mask, bits, &set_mask, &clear_mask);
+
+ bgc->data |= set_mask;
+ bgc->data &= ~clear_mask;
+
+ bgc->write_reg(reg, bgc->data);
+
+ spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
+static void bgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
+ unsigned long *bits)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+
+ bgpio_set_multiple_single_reg(bgc, mask, bits, bgc->reg_dat);
+}
+
+static void bgpio_set_multiple_set(struct gpio_chip *gc, unsigned long *mask,
+ unsigned long *bits)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+
+ bgpio_set_multiple_single_reg(bgc, mask, bits, bgc->reg_set);
+}
+
+static void bgpio_set_multiple_with_clear(struct gpio_chip *gc,
+ unsigned long *mask,
+ unsigned long *bits)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+ unsigned long set_mask, clear_mask;
+
+ bgpio_multiple_get_masks(bgc, mask, bits, &set_mask, &clear_mask);
+
+ if (set_mask)
+ bgc->write_reg(bgc->reg_set, set_mask);
+ if (clear_mask)
+ bgc->write_reg(bgc->reg_clr, clear_mask);
+}
+
+static int bgpio_simple_dir_in(struct gpio_chip *gc, unsigned int gpio)
+{
+ return 0;
+}
+
+static int bgpio_simple_dir_out(struct gpio_chip *gc, unsigned int gpio,
+ int val)
+{
+ gc->set(gc, gpio, val);
+
+ return 0;
+}
+
+static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+ unsigned long flags;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+
+ bgc->dir &= ~bgc->pin2mask(bgc, gpio);
+ bgc->write_reg(bgc->reg_dir, bgc->dir);
+
+ spin_unlock_irqrestore(&bgc->lock, flags);
+
+ return 0;
+}
+
+static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+ unsigned long flags;
+
+ gc->set(gc, gpio, val);
+
+ spin_lock_irqsave(&bgc->lock, flags);
+
+ bgc->dir |= bgc->pin2mask(bgc, gpio);
+ bgc->write_reg(bgc->reg_dir, bgc->dir);
+
+ spin_unlock_irqrestore(&bgc->lock, flags);
+
+ return 0;
+}
+
+static int bgpio_dir_in_inv(struct gpio_chip *gc, unsigned int gpio)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+ unsigned long flags;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+
+ bgc->dir |= bgc->pin2mask(bgc, gpio);
+ bgc->write_reg(bgc->reg_dir, bgc->dir);
+
+ spin_unlock_irqrestore(&bgc->lock, flags);
+
+ return 0;
+}
+
+static int bgpio_dir_out_inv(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+ unsigned long flags;
+
+ gc->set(gc, gpio, val);
+
+ spin_lock_irqsave(&bgc->lock, flags);
+
+ bgc->dir &= ~bgc->pin2mask(bgc, gpio);
+ bgc->write_reg(bgc->reg_dir, bgc->dir);
+
+ spin_unlock_irqrestore(&bgc->lock, flags);
+
+ return 0;
+}
+
+static int bgpio_setup_accessors(struct device *dev,
+ struct bgpio_chip *bgc,
+ bool bit_be,
+ bool byte_be)
+{
+
+ switch (bgc->bits) {
+ case 8:
+ bgc->read_reg = bgpio_read8;
+ bgc->write_reg = bgpio_write8;
+ break;
+ case 16:
+ if (byte_be) {
+ bgc->read_reg = bgpio_read16be;
+ bgc->write_reg = bgpio_write16be;
+ } else {
+ bgc->read_reg = bgpio_read16;
+ bgc->write_reg = bgpio_write16;
+ }
+ break;
+ case 32:
+ if (byte_be) {
+ bgc->read_reg = bgpio_read32be;
+ bgc->write_reg = bgpio_write32be;
+ } else {
+ bgc->read_reg = bgpio_read32;
+ bgc->write_reg = bgpio_write32;
+ }
+ break;
+#if BITS_PER_LONG >= 64
+ case 64:
+ if (byte_be) {
+ dev_err(dev,
+ "64 bit big endian byte order unsupported\n");
+ return -EINVAL;
+ } else {
+ bgc->read_reg = bgpio_read64;
+ bgc->write_reg = bgpio_write64;
+ }
+ break;
+#endif /* BITS_PER_LONG >= 64 */
+ default:
+ dev_err(dev, "unsupported data width %u bits\n", bgc->bits);
+ return -EINVAL;
+ }
+
+ bgc->pin2mask = bit_be ? bgpio_pin2mask_be : bgpio_pin2mask;
+
+ return 0;
+}
+
+/*
+ * Create the device and allocate the resources. For setting GPIO's there are
+ * three supported configurations:
+ *
+ * - single input/output register resource (named "dat").
+ * - set/clear pair (named "set" and "clr").
+ * - single output register resource and single input resource ("set" and
+ * dat").
+ *
+ * For the single output register, this drives a 1 by setting a bit and a zero
+ * by clearing a bit. For the set clr pair, this drives a 1 by setting a bit
+ * in the set register and clears it by setting a bit in the clear register.
+ * The configuration is detected by which resources are present.
+ *
+ * For setting the GPIO direction, there are three supported configurations:
+ *
+ * - simple bidirection GPIO that requires no configuration.
+ * - an output direction register (named "dirout") where a 1 bit
+ * indicates the GPIO is an output.
+ * - an input direction register (named "dirin") where a 1 bit indicates
+ * the GPIO is an input.
+ */
+static int bgpio_setup_io(struct bgpio_chip *bgc,
+ void __iomem *dat,
+ void __iomem *set,
+ void __iomem *clr)
+{
+
+ bgc->reg_dat = dat;
+ if (!bgc->reg_dat)
+ return -EINVAL;
+
+ if (set && clr) {
+ bgc->reg_set = set;
+ bgc->reg_clr = clr;
+ bgc->gc.set = bgpio_set_with_clear;
+ bgc->gc.set_multiple = bgpio_set_multiple_with_clear;
+ } else if (set && !clr) {
+ bgc->reg_set = set;
+ bgc->gc.set = bgpio_set_set;
+ bgc->gc.set_multiple = bgpio_set_multiple_set;
+ } else {
+ bgc->gc.set = bgpio_set;
+ bgc->gc.set_multiple = bgpio_set_multiple;
+ }
+
+ bgc->gc.get = bgpio_get;
+
+ return 0;
+}
+
+static int bgpio_setup_direction(struct bgpio_chip *bgc,
+ void __iomem *dirout,
+ void __iomem *dirin)
+{
+ if (dirout && dirin) {
+ return -EINVAL;
+ } else if (dirout) {
+ bgc->reg_dir = dirout;
+ bgc->gc.direction_output = bgpio_dir_out;
+ bgc->gc.direction_input = bgpio_dir_in;
+ } else if (dirin) {
+ bgc->reg_dir = dirin;
+ bgc->gc.direction_output = bgpio_dir_out_inv;
+ bgc->gc.direction_input = bgpio_dir_in_inv;
+ } else {
+ bgc->gc.direction_output = bgpio_simple_dir_out;
+ bgc->gc.direction_input = bgpio_simple_dir_in;
+ }
+
+ return 0;
+}
+
+static int bgpio_request(struct gpio_chip *chip, unsigned gpio_pin)
+{
+ if (gpio_pin < chip->ngpio)
+ return 0;
+
+ return -EINVAL;
+}
+
+int bgpio_remove(struct bgpio_chip *bgc)
+{
+ gpiochip_remove(&bgc->gc);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(bgpio_remove);
+
+int bgpio_init(struct bgpio_chip *bgc, struct device *dev,
+ unsigned long sz, void __iomem *dat, void __iomem *set,
+ void __iomem *clr, void __iomem *dirout, void __iomem *dirin,
+ unsigned long flags)
+{
+ int ret;
+
+ if (!is_power_of_2(sz))
+ return -EINVAL;
+
+ bgc->bits = sz * 8;
+ if (bgc->bits > BITS_PER_LONG)
+ return -EINVAL;
+
+ spin_lock_init(&bgc->lock);
+ bgc->gc.dev = dev;
+ bgc->gc.label = dev_name(dev);
+ bgc->gc.base = -1;
+ bgc->gc.ngpio = bgc->bits;
+ bgc->gc.request = bgpio_request;
+
+ ret = bgpio_setup_io(bgc, dat, set, clr);
+ if (ret)
+ return ret;
+
+ ret = bgpio_setup_accessors(dev, bgc, flags & BGPIOF_BIG_ENDIAN,
+ flags & BGPIOF_BIG_ENDIAN_BYTE_ORDER);
+ if (ret)
+ return ret;
+
+ ret = bgpio_setup_direction(bgc, dirout, dirin);
+ if (ret)
+ return ret;
+
+ bgc->data = bgc->read_reg(bgc->reg_dat);
+ if (bgc->gc.set == bgpio_set_set &&
+ !(flags & BGPIOF_UNREADABLE_REG_SET))
+ bgc->data = bgc->read_reg(bgc->reg_set);
+ if (bgc->reg_dir && !(flags & BGPIOF_UNREADABLE_REG_DIR))
+ bgc->dir = bgc->read_reg(bgc->reg_dir);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(bgpio_init);
+
+#ifdef CONFIG_GPIO_GENERIC_PLATFORM
+
+static void __iomem *bgpio_map(struct platform_device *pdev,
+ const char *name,
+ resource_size_t sane_sz,
+ int *err)
+{
+ struct device *dev = &pdev->dev;
+ struct resource *r;
+ resource_size_t start;
+ resource_size_t sz;
+ void __iomem *ret;
+
+ *err = 0;
+
+ r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
+ if (!r)
+ return NULL;
+
+ sz = resource_size(r);
+ if (sz != sane_sz) {
+ *err = -EINVAL;
+ return NULL;
+ }
+
+ start = r->start;
+ if (!devm_request_mem_region(dev, start, sz, r->name)) {
+ *err = -EBUSY;
+ return NULL;
+ }
+
+ ret = devm_ioremap(dev, start, sz);
+ if (!ret) {
+ *err = -ENOMEM;
+ return NULL;
+ }
+
+ return ret;
+}
+
+static int bgpio_pdev_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct resource *r;
+ void __iomem *dat;
+ void __iomem *set;
+ void __iomem *clr;
+ void __iomem *dirout;
+ void __iomem *dirin;
+ unsigned long sz;
+ unsigned long flags = pdev->id_entry->driver_data;
+ int err;
+ struct bgpio_chip *bgc;
+ struct bgpio_pdata *pdata = dev_get_platdata(dev);
+
+ r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
+ if (!r)
+ return -EINVAL;
+
+ sz = resource_size(r);
+
+ dat = bgpio_map(pdev, "dat", sz, &err);
+ if (!dat)
+ return err ? err : -EINVAL;
+
+ set = bgpio_map(pdev, "set", sz, &err);
+ if (err)
+ return err;
+
+ clr = bgpio_map(pdev, "clr", sz, &err);
+ if (err)
+ return err;
+
+ dirout = bgpio_map(pdev, "dirout", sz, &err);
+ if (err)
+ return err;
+
+ dirin = bgpio_map(pdev, "dirin", sz, &err);
+ if (err)
+ return err;
+
+ bgc = devm_kzalloc(&pdev->dev, sizeof(*bgc), GFP_KERNEL);
+ if (!bgc)
+ return -ENOMEM;
+
+ err = bgpio_init(bgc, dev, sz, dat, set, clr, dirout, dirin, flags);
+ if (err)
+ return err;
+
+ if (pdata) {
+ if (pdata->label)
+ bgc->gc.label = pdata->label;
+ bgc->gc.base = pdata->base;
+ if (pdata->ngpio > 0)
+ bgc->gc.ngpio = pdata->ngpio;
+ }
+
+ platform_set_drvdata(pdev, bgc);
+
+ return gpiochip_add(&bgc->gc);
+}
+
+static int bgpio_pdev_remove(struct platform_device *pdev)
+{
+ struct bgpio_chip *bgc = platform_get_drvdata(pdev);
+
+ return bgpio_remove(bgc);
+}
+
+static const struct platform_device_id bgpio_id_table[] = {
+ {
+ .name = "basic-mmio-gpio",
+ .driver_data = 0,
+ }, {
+ .name = "basic-mmio-gpio-be",
+ .driver_data = BGPIOF_BIG_ENDIAN,
+ },
+ { }
+};
+MODULE_DEVICE_TABLE(platform, bgpio_id_table);
+
+static struct platform_driver bgpio_driver = {
+ .driver = {
+ .name = "basic-mmio-gpio",
+ },
+ .id_table = bgpio_id_table,
+ .probe = bgpio_pdev_probe,
+ .remove = bgpio_pdev_remove,
+};
+
+module_platform_driver(bgpio_driver);
+
+#endif /* CONFIG_GPIO_GENERIC_PLATFORM */
+
+MODULE_DESCRIPTION("Driver for basic memory-mapped GPIO controllers");
+MODULE_AUTHOR("Anton Vorontsov <cbouatmailru@gmail.com>");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff