diff options
Diffstat (limited to 'kernel/drivers/gpio/gpio-generic.c')
| -rw-r--r-- | kernel/drivers/gpio/gpio-generic.c | 663 |
1 files changed, 663 insertions, 0 deletions
diff --git a/kernel/drivers/gpio/gpio-generic.c b/kernel/drivers/gpio/gpio-generic.c new file mode 100644 index 000000000..b92a690f5 --- /dev/null +++ b/kernel/drivers/gpio/gpio-generic.c @@ -0,0 +1,663 @@ +/* + * 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"); |