// SPDX-License-Identifier: GPL-2.0
//
// IXP4 GPIO driver
// Copyright (C) 2019 Linus Walleij <linus.walleij@linaro.org>
//
// based on previous work and know-how from:
// Deepak Saxena <dsaxena@plexity.net>
#include <linux/gpio/driver.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/irqchip.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/bitops.h>
/* Include that go away with DT transition */
#include <linux/irqchip/irq-ixp4xx.h>
#include <asm/mach-types.h>
#define IXP4XX_REG_GPOUT 0x00
#define IXP4XX_REG_GPOE 0x04
#define IXP4XX_REG_GPIN 0x08
#define IXP4XX_REG_GPIS 0x0C
#define IXP4XX_REG_GPIT1 0x10
#define IXP4XX_REG_GPIT2 0x14
#define IXP4XX_REG_GPCLK 0x18
#define IXP4XX_REG_GPDBSEL 0x1C
/*
* The hardware uses 3 bits to indicate interrupt "style".
* we clear and set these three bits accordingly. The lower 24
* bits in two registers (GPIT1 and GPIT2) are used to set up
* the style for 8 lines each for a total of 16 GPIO lines.
*/
#define IXP4XX_GPIO_STYLE_ACTIVE_HIGH 0x0
#define IXP4XX_GPIO_STYLE_ACTIVE_LOW 0x1
#define IXP4XX_GPIO_STYLE_RISING_EDGE 0x2
#define IXP4XX_GPIO_STYLE_FALLING_EDGE 0x3
#define IXP4XX_GPIO_STYLE_TRANSITIONAL 0x4
#define IXP4XX_GPIO_STYLE_MASK GENMASK(2, 0)
#define IXP4XX_GPIO_STYLE_SIZE 3
/**
* struct ixp4xx_gpio - IXP4 GPIO state container
* @dev: containing device for this instance
* @fwnode: the fwnode for this GPIO chip
* @gc: gpiochip for this instance
* @domain: irqdomain for this chip instance
* @base: remapped I/O-memory base
* @irq_edge: Each bit represents an IRQ: 1: edge-triggered,
* 0: level triggered
*/
struct ixp4xx_gpio {
struct device *dev;
struct fwnode_handle *fwnode;
struct gpio_chip gc;
struct irq_domain *domain;
void __iomem *base;
unsigned long long irq_edge;
};
/**
* struct ixp4xx_gpio_map - IXP4 GPIO to parent IRQ map
* @gpio_offset: offset of the IXP4 GPIO line
* @parent_hwirq: hwirq on the parent IRQ controller
*/
struct ixp4xx_gpio_map {
int gpio_offset;
int parent_hwirq;
};
/* GPIO lines 0..12 have corresponding IRQs, GPIOs 13..15 have no IRQs */
const struct ixp4xx_gpio_map ixp4xx_gpiomap[] = {
{ .gpio_offset = 0, .parent_hwirq = 6 },
{ .gpio_offset = 1, .parent_hwirq = 7 },
{ .gpio_offset = 2, .parent_hwirq = 19 },
{ .gpio_offset = 3, .parent_hwirq = 20 },
{ .gpio_offset = 4, .parent_hwirq = 21 },
{ .gpio_offset = 5, .parent_hwirq = 22 },
{ .gpio_offset = 6, .parent_hwirq = 23 },
{ .gpio_offset = 7, .parent_hwirq = 24 },
{ .gpio_offset = 8, .parent_hwirq = 25 },
{ .gpio_offset = 9, .parent_hwirq = 26 },
{ .gpio_offset = 10, .parent_hwirq = 27 },
{ .gpio_offset = 11, .parent_hwirq = 28 },
{ .gpio_offset = 12, .parent_hwirq = 29 },
};
static void ixp4xx_gpio_irq_ack(struct irq_data *d)
{
struct ixp4xx_gpio *g = irq_data_get_irq_chip_data(d);
__raw_writel(BIT(d->hwirq), g->base + IXP4XX_REG_GPIS);
}
static void ixp4xx_gpio_irq_unmask(struct irq_data *d)
{
struct ixp4xx_gpio *g = irq_data_get_irq_chip_data(d);
/* ACK when unmasking if not edge-triggered */
if (!(g->irq_edge & BIT(d->hwirq)))
ixp4xx_gpio_irq_ack(d);
irq_chip_unmask_parent(d);
}
static int ixp4xx_gpio_irq_set_type(struct irq_data *d, unsigned int type)
{
struct ixp4xx_gpio *g = irq_data_get_irq_chip_data(d);
int line = d->hwirq;
unsigned long flags;
u32 int_style;
u32 int_reg;
u32 val;
switch (type) {
case IRQ_TYPE_EDGE_BOTH:
irq_set_handler_locked(d, handle_edge_irq);
int_style = IXP4XX_GPIO_STYLE_TRANSITIONAL;
g->irq_edge |= BIT(d->hwirq);
break;
case IRQ_TYPE_EDGE_RISING:
irq_set_handler_locked(d, handle_edge_irq);
int_style = IXP4XX_GPIO_STYLE_RISING_EDGE;
g->irq_edge |= BIT(d->hwirq);
break;
case IRQ_TYPE_EDGE_FALLING:
irq_set_handler_locked(d, handle_edge_irq);
int_style = IXP4XX_GPIO_STYLE_FALLING_EDGE;
g->irq_edge |= BIT(d->hwirq);
break;
case IRQ_TYPE_LEVEL_HIGH:
irq_set_handler_locked(d, handle_level_irq);
int_style = IXP4XX_GPIO_STYLE_ACTIVE_HIGH;
g->irq_edge &= ~BIT(d->hwirq);
break;
case IRQ_TYPE_LEVEL_LOW:
irq_set_handler_locked(d, handle_level_irq);
int_style = IXP4XX_GPIO_STYLE_ACTIVE_LOW;
g->irq_edge &= ~BIT(d->hwirq);
break;
default:
return -EINVAL;
}
if (line >= 8) {
/* pins 8-15 */
line -= 8;
int_reg = IXP4XX_REG_GPIT2;
} else {
/* pins 0-7 */
int_reg = IXP4XX_REG_GPIT1;
}
spin_lock_irqsave(&g->gc.bgpio_lock, flags);
/* Clear the style for the appropriate pin */
val = __raw_readl(g->base + int_reg);
val &= ~(IXP4XX_GPIO_STYLE_MASK << (line * IXP4XX_GPIO_STYLE_SIZE));
__raw_writel(val, g->base + int_reg);
__raw_writel(BIT(line), g->base + IXP4XX_REG_GPIS);
/* Set the new style */
val = __raw_readl(g->base + int_reg);
val |= (int_style << (line * IXP4XX_GPIO_STYLE_SIZE));
__raw_writel(val, g->base + int_reg);
/* Force-configure this line as an input */
val = __raw_readl(g->base + IXP4XX_REG_GPOE);
val |= BIT(d->hwirq);
__raw_writel(val, g->base + IXP4XX_REG_GPOE);
spin_unlock_irqrestore(&g->gc.bgpio_lock, flags);
/* This parent only accept level high (asserted) */
return irq_chip_set_type_parent(d, IRQ_TYPE_LEVEL_HIGH);
}
static struct irq_chip ixp4xx_gpio_irqchip = {
.name = "IXP4GPIO",
.irq_ack = ixp4xx_gpio_irq_ack,
.irq_mask = irq_chip_mask_parent,
.irq_unmask = ixp4xx_gpio_irq_unmask,
.irq_set_type = ixp4xx_gpio_irq_set_type,
};
static int ixp4xx_gpio_to_irq(struct gpio_chip *gc, unsigned int offset)
{
struct ixp4xx_gpio *g = gpiochip_get_data(gc);
struct irq_fwspec fwspec;
fwspec.fwnode = g->fwnode;
fwspec.param_count = 2;
fwspec.param[0] = offset;
fwspec.param[1] = IRQ_TYPE_NONE;
return irq_create_fwspec_mapping(&fwspec);
}
static int ixp4xx_gpio_irq_domain_translate(struct irq_domain *domain,
struct irq_fwspec *fwspec,
unsigned long *hwirq,
unsigned int *type)
{
int ret;
/* We support standard DT translation */
if (is_of_node(fwspec->fwnode) && fwspec->param_count == 2) {
return irq_domain_translate_twocell(domain, fwspec,
hwirq, type);
}
/* This goes away when we transition to DT */
if (is_fwnode_irqchip(fwspec->fwnode)) {
ret = irq_domain_translate_twocell(domain, fwspec,
hwirq, type);
if (ret)
return ret;
WARN_ON(*type == IRQ_TYPE_NONE);
return 0;
}
return -EINVAL;
}
static int ixp4xx_gpio_irq_domain_alloc(struct irq_domain *d,
unsigned int irq, unsigned int nr_irqs,
void *data)
{
struct ixp4xx_gpio *g = d->host_data;
irq_hw_number_t hwirq;
unsigned int type = IRQ_TYPE_NONE;
struct irq_fwspec *fwspec = data;
int ret;
int i;
ret = ixp4xx_gpio_irq_domain_translate(d, fwspec, &hwirq, &type);
if (ret)
return ret;
dev_dbg(g->dev, "allocate IRQ %d..%d, hwirq %lu..%lu\n",
irq, irq + nr_irqs - 1,
hwirq, hwirq + nr_irqs - 1);
for (i = 0; i < nr_irqs; i++) {
struct irq_fwspec parent_fwspec;
const struct ixp4xx_gpio_map *map;
int j;
/* Not all lines support IRQs */
for (j = 0; j < ARRAY_SIZE(ixp4xx_gpiomap); j++) {
map = &ixp4xx_gpiomap[j];
if (map->gpio_offset == hwirq)
break;
}
if (j == ARRAY_SIZE(ixp4xx_gpiomap)) {
dev_err(g->dev, "can't look up hwirq %lu\n", hwirq);
return -EINVAL;
}
dev_dbg(g->dev, "found parent hwirq %u\n", map->parent_hwirq);
/*
* We set handle_bad_irq because the .set_type() should
* always be invoked and set the right type of handler.
*/
irq_domain_set_info(d,
irq + i,
hwirq + i,
&ixp4xx_gpio_irqchip,
g,
handle_bad_irq,
NULL, NULL);
irq_set_probe(irq + i);
/*
* Create a IRQ fwspec to send up to the parent irqdomain:
* specify the hwirq we address on the parent and tie it
* all together up the chain.
*/
parent_fwspec.fwnode = d->parent->fwnode;
parent_fwspec.param_count = 2;
parent_fwspec.param[0] = map->parent_hwirq;
/* This parent only handles asserted level IRQs */
parent_fwspec.param[1] = IRQ_TYPE_LEVEL_HIGH;
dev_dbg(g->dev, "alloc_irqs_parent for %d parent hwirq %d\n",
irq + i, map->parent_hwirq);
ret = irq_domain_alloc_irqs_parent(d, irq + i, 1,
&parent_fwspec);
if (ret)
dev_err(g->dev,
"failed to allocate parent hwirq %d for hwirq %lu\n",
map->parent_hwirq, hwirq);
}
return 0;
}
static const struct irq_domain_ops ixp4xx_gpio_irqdomain_ops = {
.translate = ixp4xx_gpio_irq_domain_translate,
.alloc = ixp4xx_gpio_irq_domain_alloc,
.free = irq_domain_free_irqs_common,
};
static int ixp4xx_gpio_probe(struct platform_device *pdev)
{
unsigned long flags;
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct irq_domain *parent;
struct resource *res;
struct ixp4xx_gpio *g;
int ret;
int i;
g = devm_kzalloc(dev, sizeof(*g), GFP_KERNEL);
if (!g)
return -ENOMEM;
g->dev = dev;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
g->base = devm_ioremap_resource(dev, res);
if (IS_ERR(g->base)) {
dev_err(dev, "ioremap error\n");
return PTR_ERR(g->base);
}
/*
* Make sure GPIO 14 and 15 are NOT used as clocks but GPIO on
* specific machines.
*/
if (machine_is_dsmg600() || machine_is_nas100d())
__raw_writel(0x0, g->base + IXP4XX_REG_GPCLK);
/*
* This is a very special big-endian ARM issue: when the IXP4xx is
* run in big endian mode, all registers in the machine are switched
* around to the CPU-native endianness. As you see mostly in the
* driver we use __raw_readl()/__raw_writel() to access the registers
* in the appropriate order. With the GPIO library we need to specify
* byte order explicitly, so this flag needs to be set when compiling
* for big endian.
*/
#if defined(CONFIG_CPU_BIG_ENDIAN)
flags = BGPIOF_BIG_ENDIAN_BYTE_ORDER;
#else
flags = 0;
#endif
/* Populate and register gpio chip */
ret = bgpio_init(&g->gc, dev, 4,
g->base + IXP4XX_REG_GPIN,
g->base + IXP4XX_REG_GPOUT,
NULL,
NULL,
g->base + IXP4XX_REG_GPOE,
flags);
if (ret) {
dev_err(dev, "unable to init generic GPIO\n");
return ret;
}
g->gc.to_irq = ixp4xx_gpio_to_irq;
g->gc.ngpio = 16;
g->gc.label = "IXP4XX_GPIO_CHIP";
/*
* TODO: when we have migrated to device tree and all GPIOs
* are fetched using phandles, set this to -1 to get rid of
* the fixed gpiochip base.
*/
g->gc.base = 0;
g->gc.parent = &pdev->dev;
g->gc.owner = THIS_MODULE;
ret = devm_gpiochip_add_data(dev, &g->gc, g);
if (ret) {
dev_err(dev, "failed to add SoC gpiochip\n");
return ret;
}
/*
* When we convert to device tree we will simply look up the
* parent irqdomain using irq_find_host(parent) as parent comes
* from IRQCHIP_DECLARE(), then use of_node_to_fwnode() to get
* the fwnode. For now we need this boardfile style code.
*/
if (np) {
struct device_node *irq_parent;
irq_parent = of_irq_find_parent(np);
if (!irq_parent) {
dev_err(dev, "no IRQ parent node\n");
return -ENODEV;
}
parent = irq_find_host(irq_parent);
if (!parent) {
dev_err(dev, "no IRQ parent domain\n");
return -ENODEV;
}
g->fwnode = of_node_to_fwnode(np);
} else {
parent = ixp4xx_get_irq_domain();
g->fwnode = irq_domain_alloc_fwnode(g->base);
if (!g->fwnode) {
dev_err(dev, "no domain base\n");
return -ENODEV;
}
}
g->domain = irq_domain_create_hierarchy(parent,
IRQ_DOMAIN_FLAG_HIERARCHY,
ARRAY_SIZE(ixp4xx_gpiomap),
g->fwnode,
&ixp4xx_gpio_irqdomain_ops,
g);
if (!g->domain) {
irq_domain_free_fwnode(g->fwnode);
dev_err(dev, "no hierarchical irq domain\n");
return ret;
}
/*
* After adding OF support, this is no longer needed: irqs
* will be allocated for the respective fwnodes.
*/
if (!np) {
for (i = 0; i < ARRAY_SIZE(ixp4xx_gpiomap); i++) {
const struct ixp4xx_gpio_map *map = &ixp4xx_gpiomap[i];
struct irq_fwspec fwspec;
fwspec.fwnode = g->fwnode;
/* This is the hwirq for the GPIO line side of things */
fwspec.param[0] = map->gpio_offset;
fwspec.param[1] = IRQ_TYPE_EDGE_RISING;
fwspec.param_count = 2;
ret = __irq_domain_alloc_irqs(g->domain,
-1, /* just pick something */
1,
NUMA_NO_NODE,
&fwspec,
false,
NULL);
if (ret < 0) {
irq_domain_free_fwnode(g->fwnode);
dev_err(dev,
"can not allocate irq for GPIO line %d parent hwirq %d in hierarchy domain: %d\n",
map->gpio_offset, map->parent_hwirq,
ret);
return ret;
}
}
}
platform_set_drvdata(pdev, g);
dev_info(dev, "IXP4 GPIO @%p registered\n", g->base);
return 0;
}
static const struct of_device_id ixp4xx_gpio_of_match[] = {
{
.compatible = "intel,ixp4xx-gpio",
},
{},
};
static struct platform_driver ixp4xx_gpio_driver = {
.driver = {
.name = "ixp4xx-gpio",
.of_match_table = of_match_ptr(ixp4xx_gpio_of_match),
},
.probe = ixp4xx_gpio_probe,
};
builtin_platform_driver(ixp4xx_gpio_driver);
