https://github.com/torvalds/linux
Tip revision: 2734d6c1b1a089fb593ef6a23d4b70903526fe0c authored by Linus Torvalds on 18 July 2021, 21:13:49 UTC
Linux 5.14-rc2
Linux 5.14-rc2
Tip revision: 2734d6c
gpio-ftgpio010.c
// SPDX-License-Identifier: GPL-2.0
/*
* Faraday Technolog FTGPIO010 gpiochip and interrupt routines
* Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
*
* Based on arch/arm/mach-gemini/gpio.c:
* Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
*
* Based on plat-mxc/gpio.c:
* MXC GPIO support. (c) 2008 Daniel Mack <daniel@caiaq.de>
* Copyright 2008 Juergen Beisert, kernel@pengutronix.de
*/
#include <linux/gpio/driver.h>
#include <linux/io.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/bitops.h>
#include <linux/clk.h>
/* GPIO registers definition */
#define GPIO_DATA_OUT 0x00
#define GPIO_DATA_IN 0x04
#define GPIO_DIR 0x08
#define GPIO_BYPASS_IN 0x0C
#define GPIO_DATA_SET 0x10
#define GPIO_DATA_CLR 0x14
#define GPIO_PULL_EN 0x18
#define GPIO_PULL_TYPE 0x1C
#define GPIO_INT_EN 0x20
#define GPIO_INT_STAT_RAW 0x24
#define GPIO_INT_STAT_MASKED 0x28
#define GPIO_INT_MASK 0x2C
#define GPIO_INT_CLR 0x30
#define GPIO_INT_TYPE 0x34
#define GPIO_INT_BOTH_EDGE 0x38
#define GPIO_INT_LEVEL 0x3C
#define GPIO_DEBOUNCE_EN 0x40
#define GPIO_DEBOUNCE_PRESCALE 0x44
/**
* struct ftgpio_gpio - Gemini GPIO state container
* @dev: containing device for this instance
* @gc: gpiochip for this instance
* @irq: irqchip for this instance
* @base: remapped I/O-memory base
* @clk: silicon clock
*/
struct ftgpio_gpio {
struct device *dev;
struct gpio_chip gc;
struct irq_chip irq;
void __iomem *base;
struct clk *clk;
};
static void ftgpio_gpio_ack_irq(struct irq_data *d)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct ftgpio_gpio *g = gpiochip_get_data(gc);
writel(BIT(irqd_to_hwirq(d)), g->base + GPIO_INT_CLR);
}
static void ftgpio_gpio_mask_irq(struct irq_data *d)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct ftgpio_gpio *g = gpiochip_get_data(gc);
u32 val;
val = readl(g->base + GPIO_INT_EN);
val &= ~BIT(irqd_to_hwirq(d));
writel(val, g->base + GPIO_INT_EN);
}
static void ftgpio_gpio_unmask_irq(struct irq_data *d)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct ftgpio_gpio *g = gpiochip_get_data(gc);
u32 val;
val = readl(g->base + GPIO_INT_EN);
val |= BIT(irqd_to_hwirq(d));
writel(val, g->base + GPIO_INT_EN);
}
static int ftgpio_gpio_set_irq_type(struct irq_data *d, unsigned int type)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct ftgpio_gpio *g = gpiochip_get_data(gc);
u32 mask = BIT(irqd_to_hwirq(d));
u32 reg_both, reg_level, reg_type;
reg_type = readl(g->base + GPIO_INT_TYPE);
reg_level = readl(g->base + GPIO_INT_LEVEL);
reg_both = readl(g->base + GPIO_INT_BOTH_EDGE);
switch (type) {
case IRQ_TYPE_EDGE_BOTH:
irq_set_handler_locked(d, handle_edge_irq);
reg_type &= ~mask;
reg_both |= mask;
break;
case IRQ_TYPE_EDGE_RISING:
irq_set_handler_locked(d, handle_edge_irq);
reg_type &= ~mask;
reg_both &= ~mask;
reg_level &= ~mask;
break;
case IRQ_TYPE_EDGE_FALLING:
irq_set_handler_locked(d, handle_edge_irq);
reg_type &= ~mask;
reg_both &= ~mask;
reg_level |= mask;
break;
case IRQ_TYPE_LEVEL_HIGH:
irq_set_handler_locked(d, handle_level_irq);
reg_type |= mask;
reg_level &= ~mask;
break;
case IRQ_TYPE_LEVEL_LOW:
irq_set_handler_locked(d, handle_level_irq);
reg_type |= mask;
reg_level |= mask;
break;
default:
irq_set_handler_locked(d, handle_bad_irq);
return -EINVAL;
}
writel(reg_type, g->base + GPIO_INT_TYPE);
writel(reg_level, g->base + GPIO_INT_LEVEL);
writel(reg_both, g->base + GPIO_INT_BOTH_EDGE);
ftgpio_gpio_ack_irq(d);
return 0;
}
static void ftgpio_gpio_irq_handler(struct irq_desc *desc)
{
struct gpio_chip *gc = irq_desc_get_handler_data(desc);
struct ftgpio_gpio *g = gpiochip_get_data(gc);
struct irq_chip *irqchip = irq_desc_get_chip(desc);
int offset;
unsigned long stat;
chained_irq_enter(irqchip, desc);
stat = readl(g->base + GPIO_INT_STAT_RAW);
if (stat)
for_each_set_bit(offset, &stat, gc->ngpio)
generic_handle_irq(irq_find_mapping(gc->irq.domain,
offset));
chained_irq_exit(irqchip, desc);
}
static int ftgpio_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
unsigned long config)
{
enum pin_config_param param = pinconf_to_config_param(config);
u32 arg = pinconf_to_config_argument(config);
struct ftgpio_gpio *g = gpiochip_get_data(gc);
unsigned long pclk_freq;
u32 deb_div;
u32 val;
if (param != PIN_CONFIG_INPUT_DEBOUNCE)
return -ENOTSUPP;
/*
* Debounce only works if interrupts are enabled. The manual
* states that if PCLK is 66 MHz, and this is set to 0x7D0, then
* PCLK is divided down to 33 kHz for the debounce timer. 0x7D0 is
* 2000 decimal, so what they mean is simply that the PCLK is
* divided by this value.
*
* As we get a debounce setting in microseconds, we calculate the
* desired period time and see if we can get a suitable debounce
* time.
*/
pclk_freq = clk_get_rate(g->clk);
deb_div = DIV_ROUND_CLOSEST(pclk_freq, arg);
/* This register is only 24 bits wide */
if (deb_div > (1 << 24))
return -ENOTSUPP;
dev_dbg(g->dev, "prescale divisor: %08x, resulting frequency %lu Hz\n",
deb_div, (pclk_freq/deb_div));
val = readl(g->base + GPIO_DEBOUNCE_PRESCALE);
if (val == deb_div) {
/*
* The debounce timer happens to already be set to the
* desirable value, what a coincidence! We can just enable
* debounce on this GPIO line and return. This happens more
* often than you think, for example when all GPIO keys
* on a system are requesting the same debounce interval.
*/
val = readl(g->base + GPIO_DEBOUNCE_EN);
val |= BIT(offset);
writel(val, g->base + GPIO_DEBOUNCE_EN);
return 0;
}
val = readl(g->base + GPIO_DEBOUNCE_EN);
if (val) {
/*
* Oh no! Someone is already using the debounce with
* another setting than what we need. Bummer.
*/
return -ENOTSUPP;
}
/* First come, first serve */
writel(deb_div, g->base + GPIO_DEBOUNCE_PRESCALE);
/* Enable debounce */
val |= BIT(offset);
writel(val, g->base + GPIO_DEBOUNCE_EN);
return 0;
}
static int ftgpio_gpio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct ftgpio_gpio *g;
struct gpio_irq_chip *girq;
int irq;
int ret;
g = devm_kzalloc(dev, sizeof(*g), GFP_KERNEL);
if (!g)
return -ENOMEM;
g->dev = dev;
g->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(g->base))
return PTR_ERR(g->base);
irq = platform_get_irq(pdev, 0);
if (irq <= 0)
return irq ? irq : -EINVAL;
g->clk = devm_clk_get(dev, NULL);
if (!IS_ERR(g->clk)) {
ret = clk_prepare_enable(g->clk);
if (ret)
return ret;
} else if (PTR_ERR(g->clk) == -EPROBE_DEFER) {
/*
* Percolate deferrals, for anything else,
* just live without the clocking.
*/
return PTR_ERR(g->clk);
}
ret = bgpio_init(&g->gc, dev, 4,
g->base + GPIO_DATA_IN,
g->base + GPIO_DATA_SET,
g->base + GPIO_DATA_CLR,
g->base + GPIO_DIR,
NULL,
0);
if (ret) {
dev_err(dev, "unable to init generic GPIO\n");
goto dis_clk;
}
g->gc.label = "FTGPIO010";
g->gc.base = -1;
g->gc.parent = dev;
g->gc.owner = THIS_MODULE;
/* ngpio is set by bgpio_init() */
/* We need a silicon clock to do debounce */
if (!IS_ERR(g->clk))
g->gc.set_config = ftgpio_gpio_set_config;
g->irq.name = "FTGPIO010";
g->irq.irq_ack = ftgpio_gpio_ack_irq;
g->irq.irq_mask = ftgpio_gpio_mask_irq;
g->irq.irq_unmask = ftgpio_gpio_unmask_irq;
g->irq.irq_set_type = ftgpio_gpio_set_irq_type;
girq = &g->gc.irq;
girq->chip = &g->irq;
girq->parent_handler = ftgpio_gpio_irq_handler;
girq->num_parents = 1;
girq->parents = devm_kcalloc(dev, 1, sizeof(*girq->parents),
GFP_KERNEL);
if (!girq->parents) {
ret = -ENOMEM;
goto dis_clk;
}
girq->default_type = IRQ_TYPE_NONE;
girq->handler = handle_bad_irq;
girq->parents[0] = irq;
/* Disable, unmask and clear all interrupts */
writel(0x0, g->base + GPIO_INT_EN);
writel(0x0, g->base + GPIO_INT_MASK);
writel(~0x0, g->base + GPIO_INT_CLR);
/* Clear any use of debounce */
writel(0x0, g->base + GPIO_DEBOUNCE_EN);
ret = devm_gpiochip_add_data(dev, &g->gc, g);
if (ret)
goto dis_clk;
platform_set_drvdata(pdev, g);
dev_info(dev, "FTGPIO010 @%p registered\n", g->base);
return 0;
dis_clk:
if (!IS_ERR(g->clk))
clk_disable_unprepare(g->clk);
return ret;
}
static int ftgpio_gpio_remove(struct platform_device *pdev)
{
struct ftgpio_gpio *g = platform_get_drvdata(pdev);
if (!IS_ERR(g->clk))
clk_disable_unprepare(g->clk);
return 0;
}
static const struct of_device_id ftgpio_gpio_of_match[] = {
{
.compatible = "cortina,gemini-gpio",
},
{
.compatible = "moxa,moxart-gpio",
},
{
.compatible = "faraday,ftgpio010",
},
{},
};
static struct platform_driver ftgpio_gpio_driver = {
.driver = {
.name = "ftgpio010-gpio",
.of_match_table = of_match_ptr(ftgpio_gpio_of_match),
},
.probe = ftgpio_gpio_probe,
.remove = ftgpio_gpio_remove,
};
builtin_platform_driver(ftgpio_gpio_driver);