Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-24 05:02:12 +00:00
Code Issues Packages Projects Releases Wiki Activity
8a69155040
linux/drivers/gpio/gpio-zynq.c
Lars-Peter Clausen 6dd8595083 gpio: zynq: Fix IRQ handlers 
The Zynq GPIO interrupt handling code as two main issues:
1) It does not support IRQF_ONESHOT interrupt since it uses handle_simple_irq()
for the interrupt handler. handle_simple_irq() does not do masking and unmasking
of the IRQ that is required for this chip to be able to support IRQF_ONESHOT
IRQs, causing the CPU to lock up in a interrupt storm if such a interrupt is
requested.
2) Interrupts are acked after the primary interrupt handlers for all asserted
interrupts in a bank have been called. For edge triggered interrupt this is to
late and may cause a interrupt to be missed. For level triggered oneshot
interrupts this is to early and causes the interrupt handler to run twice per
interrupt.

This patch addresses the issue by updating the driver to use the correct IRQ
chip handler functions that are appropriate for this kind of IRQ controller.

The following diagram gives an overview of how the interrupt detection circuit
works, it is not necessarily a accurate depiction of the real hardware though.

     INT_POL/INT_ON_ANY
           |
           | +---+                       INT_STATUS
           `-|   |                            |
             | E |-.                          |
         ,---|   |  \     |\          +----+  |  +---+
         |   +---+   `----| | ,-------|S   | ,*--|   |
GPIO_IN -*                | |-        |   Q|-    | & |-- IRQ_OUT
         |   +---+  ,-----| |       ,-|R   |   ,o|   |
         `---|   | /      |/       |  +----+  |  +---+
             | = |-        |       |          |
           ,-|   |    INT_TYPE    ACK     INT_MASK
           | +---+
           |
        INT_POL

GPIO_IN is the raw signal level connected to the hardware pin. This signal is
routed to a edge detector and to a level detector. The edge detector can be
configured to either detect a rising or falling edge or both edges. The level
detector can detect either a level high or level low event. Depending on the
setting of the INT_TYPE register either the edge or level event will be
propagated to the INT_STATUS register. As long as a interrupt condition is
detected the INT_STATUS register will be set to 1. It can be cleared to 0 if
(and only if) the interrupt condition is no longer detected and software
acknowledges the interrupt by writing a 1 to the address of the INT_STATUS
register. There is also the INT_MASK register which can be used to disable the
propagation of the INT_STATUS signal to the upstream IRQ controller. What is
important to note is that the interrupt detection logic itself can not be
disabled, only the propagation of the INT_STATUS register can be delayed. This
means that for level type interrupts the interrupt must only be acknowledged
after the interrupt source has been cleared otherwise it will stay asserted and
the interrupt handler will be run a second time. For IRQF_ONESHOT interrupts
this means that the IRQ must only be acknowledged after the threaded interrupt
has finished running. If a second interrupt comes in between handling the first
interrupt and acknowledging it the external interrupt will be asserted, which
means trying to acknowledge the first interrupt will not clear the INT_STATUS
register and the interrupt handler will be run a second time when the IRQ is
unmasked, so no interrupts will be lost. The handle_fasteoi_irq() handler in
combination with the IRQCHIP_EOI_THREADED | IRQCHIP_EOI_IF_HANDLED flags will
have the desired behavior. For edge triggered interrupts a slightly different
strategy is necessary. For edge triggered interrupts the interrupt condition is
only true when the edge itself is detected, this means this is the only time the
INT_STATUS register is set, acknowledging the interrupt any time after that will
clear the INT_STATUS register until the next interrupt happens. This means in
order to not loose any interrupts the interrupt needs to be acknowledged before
running the interrupt handler. If a second interrupt occurs after the first
interrupt handler has finished but before the interrupt is unmasked the
INT_STATUS register will be re-asserted and the interrupt handler runs a second
time once the interrupt is unmasked. This means with this flow handling strategy
no interrupts are lost for edge triggered interrupts. The handle_level_irq()
handler will have the desired behavior. (Note: The handle_edge_irq() only needs
to be used for edge triggered interrupts where the controller stops detecting
the interrupt event when the interrupt is masked, for this controller the
detection logic still works, while only the propagation is delayed when the
interrupt is masked.)

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-08-17 09:12:35 -05:00

713 lines
21 KiB
C
Raw Blame History

/*
* Xilinx Zynq GPIO device driver
*
* Copyright (C) 2009 - 2014 Xilinx, Inc.
*
* 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.
*/
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/gpio/driver.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#define DRIVER_NAME "zynq-gpio"
/* Maximum banks */
#define ZYNQ_GPIO_MAX_BANK 4
#define ZYNQ_GPIO_BANK0_NGPIO 32
#define ZYNQ_GPIO_BANK1_NGPIO 22
#define ZYNQ_GPIO_BANK2_NGPIO 32
#define ZYNQ_GPIO_BANK3_NGPIO 32
#define ZYNQ_GPIO_NR_GPIOS (ZYNQ_GPIO_BANK0_NGPIO + \
ZYNQ_GPIO_BANK1_NGPIO + \
ZYNQ_GPIO_BANK2_NGPIO + \
ZYNQ_GPIO_BANK3_NGPIO)
#define ZYNQ_GPIO_BANK0_PIN_MIN 0
#define ZYNQ_GPIO_BANK0_PIN_MAX (ZYNQ_GPIO_BANK0_PIN_MIN + \
ZYNQ_GPIO_BANK0_NGPIO - 1)
#define ZYNQ_GPIO_BANK1_PIN_MIN (ZYNQ_GPIO_BANK0_PIN_MAX + 1)
#define ZYNQ_GPIO_BANK1_PIN_MAX (ZYNQ_GPIO_BANK1_PIN_MIN + \
ZYNQ_GPIO_BANK1_NGPIO - 1)
#define ZYNQ_GPIO_BANK2_PIN_MIN (ZYNQ_GPIO_BANK1_PIN_MAX + 1)
#define ZYNQ_GPIO_BANK2_PIN_MAX (ZYNQ_GPIO_BANK2_PIN_MIN + \
ZYNQ_GPIO_BANK2_NGPIO - 1)
#define ZYNQ_GPIO_BANK3_PIN_MIN (ZYNQ_GPIO_BANK2_PIN_MAX + 1)
#define ZYNQ_GPIO_BANK3_PIN_MAX (ZYNQ_GPIO_BANK3_PIN_MIN + \
ZYNQ_GPIO_BANK3_NGPIO - 1)
/* Register offsets for the GPIO device */
/* LSW Mask & Data -WO */
#define ZYNQ_GPIO_DATA_LSW_OFFSET(BANK) (0x000 + (8 * BANK))
/* MSW Mask & Data -WO */
#define ZYNQ_GPIO_DATA_MSW_OFFSET(BANK) (0x004 + (8 * BANK))
/* Data Register-RW */
#define ZYNQ_GPIO_DATA_RO_OFFSET(BANK) (0x060 + (4 * BANK))
/* Direction mode reg-RW */
#define ZYNQ_GPIO_DIRM_OFFSET(BANK) (0x204 + (0x40 * BANK))
/* Output enable reg-RW */
#define ZYNQ_GPIO_OUTEN_OFFSET(BANK) (0x208 + (0x40 * BANK))
/* Interrupt mask reg-RO */
#define ZYNQ_GPIO_INTMASK_OFFSET(BANK) (0x20C + (0x40 * BANK))
/* Interrupt enable reg-WO */
#define ZYNQ_GPIO_INTEN_OFFSET(BANK) (0x210 + (0x40 * BANK))
/* Interrupt disable reg-WO */
#define ZYNQ_GPIO_INTDIS_OFFSET(BANK) (0x214 + (0x40 * BANK))
/* Interrupt status reg-RO */
#define ZYNQ_GPIO_INTSTS_OFFSET(BANK) (0x218 + (0x40 * BANK))
/* Interrupt type reg-RW */
#define ZYNQ_GPIO_INTTYPE_OFFSET(BANK) (0x21C + (0x40 * BANK))
/* Interrupt polarity reg-RW */
#define ZYNQ_GPIO_INTPOL_OFFSET(BANK) (0x220 + (0x40 * BANK))
/* Interrupt on any, reg-RW */
#define ZYNQ_GPIO_INTANY_OFFSET(BANK) (0x224 + (0x40 * BANK))
/* Disable all interrupts mask */
#define ZYNQ_GPIO_IXR_DISABLE_ALL 0xFFFFFFFF
/* Mid pin number of a bank */
#define ZYNQ_GPIO_MID_PIN_NUM 16
/* GPIO upper 16 bit mask */
#define ZYNQ_GPIO_UPPER_MASK 0xFFFF0000
/**
* struct zynq_gpio - gpio device private data structure
* @chip: instance of the gpio_chip
* @base_addr: base address of the GPIO device
* @clk: clock resource for this controller
*/
struct zynq_gpio {
struct gpio_chip chip;
void __iomem *base_addr;
struct clk *clk;
};
static struct irq_chip zynq_gpio_level_irqchip;
static struct irq_chip zynq_gpio_edge_irqchip;
/**
* zynq_gpio_get_bank_pin - Get the bank number and pin number within that bank
* for a given pin in the GPIO device
* @pin_num: gpio pin number within the device
* @bank_num: an output parameter used to return the bank number of the gpio
* pin
* @bank_pin_num: an output parameter used to return pin number within a bank
* for the given gpio pin
*
* Returns the bank number and pin offset within the bank.
*/
static inline void zynq_gpio_get_bank_pin(unsigned int pin_num,
unsigned int *bank_num,
unsigned int *bank_pin_num)
{
switch (pin_num) {
case ZYNQ_GPIO_BANK0_PIN_MIN ... ZYNQ_GPIO_BANK0_PIN_MAX:
*bank_num = 0;
*bank_pin_num = pin_num;
break;
case ZYNQ_GPIO_BANK1_PIN_MIN ... ZYNQ_GPIO_BANK1_PIN_MAX:
*bank_num = 1;
*bank_pin_num = pin_num - ZYNQ_GPIO_BANK1_PIN_MIN;
break;
case ZYNQ_GPIO_BANK2_PIN_MIN ... ZYNQ_GPIO_BANK2_PIN_MAX:
*bank_num = 2;
*bank_pin_num = pin_num - ZYNQ_GPIO_BANK2_PIN_MIN;
break;
case ZYNQ_GPIO_BANK3_PIN_MIN ... ZYNQ_GPIO_BANK3_PIN_MAX:
*bank_num = 3;
*bank_pin_num = pin_num - ZYNQ_GPIO_BANK3_PIN_MIN;
break;
default:
WARN(true, "invalid GPIO pin number: %u", pin_num);
*bank_num = 0;
*bank_pin_num = 0;
break;
}
}
/**
* zynq_gpio_get_value - Get the state of the specified pin of GPIO device
* @chip: gpio_chip instance to be worked on
* @pin: gpio pin number within the device
*
* This function reads the state of the specified pin of the GPIO device.
*
* Return: 0 if the pin is low, 1 if pin is high.
*/
static int zynq_gpio_get_value(struct gpio_chip *chip, unsigned int pin)
{
u32 data;
unsigned int bank_num, bank_pin_num;
struct zynq_gpio *gpio = container_of(chip, struct zynq_gpio, chip);
zynq_gpio_get_bank_pin(pin, &bank_num, &bank_pin_num);
data = readl_relaxed(gpio->base_addr +
ZYNQ_GPIO_DATA_RO_OFFSET(bank_num));
return (data >> bank_pin_num) & 1;
}
/**
* zynq_gpio_set_value - Modify the state of the pin with specified value
* @chip: gpio_chip instance to be worked on
* @pin: gpio pin number within the device
* @state: value used to modify the state of the specified pin
*
* This function calculates the register offset (i.e to lower 16 bits or
* upper 16 bits) based on the given pin number and sets the state of a
* gpio pin to the specified value. The state is either 0 or non-zero.
*/
static void zynq_gpio_set_value(struct gpio_chip *chip, unsigned int pin,
int state)
{
unsigned int reg_offset, bank_num, bank_pin_num;
struct zynq_gpio *gpio = container_of(chip, struct zynq_gpio, chip);
zynq_gpio_get_bank_pin(pin, &bank_num, &bank_pin_num);
if (bank_pin_num >= ZYNQ_GPIO_MID_PIN_NUM) {
/* only 16 data bits in bit maskable reg */
bank_pin_num -= ZYNQ_GPIO_MID_PIN_NUM;
reg_offset = ZYNQ_GPIO_DATA_MSW_OFFSET(bank_num);
} else {
reg_offset = ZYNQ_GPIO_DATA_LSW_OFFSET(bank_num);
}
/*
* get the 32 bit value to be written to the mask/data register where
* the upper 16 bits is the mask and lower 16 bits is the data
*/
state = !!state;
state = ~(1 << (bank_pin_num + ZYNQ_GPIO_MID_PIN_NUM)) &
((state << bank_pin_num) | ZYNQ_GPIO_UPPER_MASK);
writel_relaxed(state, gpio->base_addr + reg_offset);
}
/**
* zynq_gpio_dir_in - Set the direction of the specified GPIO pin as input
* @chip: gpio_chip instance to be worked on
* @pin: gpio pin number within the device
*
* This function uses the read-modify-write sequence to set the direction of
* the gpio pin as input.
*
* Return: 0 always
*/
static int zynq_gpio_dir_in(struct gpio_chip *chip, unsigned int pin)
{
u32 reg;
unsigned int bank_num, bank_pin_num;
struct zynq_gpio *gpio = container_of(chip, struct zynq_gpio, chip);
zynq_gpio_get_bank_pin(pin, &bank_num, &bank_pin_num);
/* bank 0 pins 7 and 8 are special and cannot be used as inputs */
if (bank_num == 0 && (bank_pin_num == 7 || bank_pin_num == 8))
return -EINVAL;
/* clear the bit in direction mode reg to set the pin as input */
reg = readl_relaxed(gpio->base_addr + ZYNQ_GPIO_DIRM_OFFSET(bank_num));
reg &= ~BIT(bank_pin_num);
writel_relaxed(reg, gpio->base_addr + ZYNQ_GPIO_DIRM_OFFSET(bank_num));
return 0;
}
/**
* zynq_gpio_dir_out - Set the direction of the specified GPIO pin as output
* @chip: gpio_chip instance to be worked on
* @pin: gpio pin number within the device
* @state: value to be written to specified pin
*
* This function sets the direction of specified GPIO pin as output, configures
* the Output Enable register for the pin and uses zynq_gpio_set to set
* the state of the pin to the value specified.
*
* Return: 0 always
*/
static int zynq_gpio_dir_out(struct gpio_chip *chip, unsigned int pin,
int state)
{
u32 reg;
unsigned int bank_num, bank_pin_num;
struct zynq_gpio *gpio = container_of(chip, struct zynq_gpio, chip);
zynq_gpio_get_bank_pin(pin, &bank_num, &bank_pin_num);
/* set the GPIO pin as output */
reg = readl_relaxed(gpio->base_addr + ZYNQ_GPIO_DIRM_OFFSET(bank_num));
reg |= BIT(bank_pin_num);
writel_relaxed(reg, gpio->base_addr + ZYNQ_GPIO_DIRM_OFFSET(bank_num));
/* configure the output enable reg for the pin */
reg = readl_relaxed(gpio->base_addr + ZYNQ_GPIO_OUTEN_OFFSET(bank_num));
reg |= BIT(bank_pin_num);
writel_relaxed(reg, gpio->base_addr + ZYNQ_GPIO_OUTEN_OFFSET(bank_num));
/* set the state of the pin */
zynq_gpio_set_value(chip, pin, state);
return 0;
}
/**
* zynq_gpio_irq_mask - Disable the interrupts for a gpio pin
* @irq_data: per irq and chip data passed down to chip functions
*
* This function calculates gpio pin number from irq number and sets the
* bit in the Interrupt Disable register of the corresponding bank to disable
* interrupts for that pin.
*/
static void zynq_gpio_irq_mask(struct irq_data *irq_data)
{
unsigned int device_pin_num, bank_num, bank_pin_num;
struct zynq_gpio *gpio = irq_data_get_irq_chip_data(irq_data);
device_pin_num = irq_data->hwirq;
zynq_gpio_get_bank_pin(device_pin_num, &bank_num, &bank_pin_num);
writel_relaxed(BIT(bank_pin_num),
gpio->base_addr + ZYNQ_GPIO_INTDIS_OFFSET(bank_num));
}
/**
* zynq_gpio_irq_unmask - Enable the interrupts for a gpio pin
* @irq_data: irq data containing irq number of gpio pin for the interrupt
* to enable
*
* This function calculates the gpio pin number from irq number and sets the
* bit in the Interrupt Enable register of the corresponding bank to enable
* interrupts for that pin.
*/
static void zynq_gpio_irq_unmask(struct irq_data *irq_data)
{
unsigned int device_pin_num, bank_num, bank_pin_num;
struct zynq_gpio *gpio = irq_data_get_irq_chip_data(irq_data);
device_pin_num = irq_data->hwirq;
zynq_gpio_get_bank_pin(device_pin_num, &bank_num, &bank_pin_num);
writel_relaxed(BIT(bank_pin_num),
gpio->base_addr + ZYNQ_GPIO_INTEN_OFFSET(bank_num));
}
/**
* zynq_gpio_irq_ack - Acknowledge the interrupt of a gpio pin
* @irq_data: irq data containing irq number of gpio pin for the interrupt
* to ack
*
* This function calculates gpio pin number from irq number and sets the bit
* in the Interrupt Status Register of the corresponding bank, to ACK the irq.
*/
static void zynq_gpio_irq_ack(struct irq_data *irq_data)
{
unsigned int device_pin_num, bank_num, bank_pin_num;
struct zynq_gpio *gpio = irq_data_get_irq_chip_data(irq_data);
device_pin_num = irq_data->hwirq;
zynq_gpio_get_bank_pin(device_pin_num, &bank_num, &bank_pin_num);
writel_relaxed(BIT(bank_pin_num),
gpio->base_addr + ZYNQ_GPIO_INTSTS_OFFSET(bank_num));
}
/**
* zynq_gpio_irq_enable - Enable the interrupts for a gpio pin
* @irq_data: irq data containing irq number of gpio pin for the interrupt
* to enable
*
* Clears the INTSTS bit and unmasks the given interrrupt.
*/
static void zynq_gpio_irq_enable(struct irq_data *irq_data)
{
/*
* The Zynq GPIO controller does not disable interrupt detection when
* the interrupt is masked and only disables the propagation of the
* interrupt. This means when the controller detects an interrupt
* condition while the interrupt is logically disabled it will propagate
* that interrupt event once the interrupt is enabled. This will cause
* the interrupt consumer to see spurious interrupts to prevent this
* first make sure that the interrupt is not asserted and then enable
* it.
*/
zynq_gpio_irq_ack(irq_data);
zynq_gpio_irq_unmask(irq_data);
}
/**
* zynq_gpio_set_irq_type - Set the irq type for a gpio pin
* @irq_data: irq data containing irq number of gpio pin
* @type: interrupt type that is to be set for the gpio pin
*
* This function gets the gpio pin number and its bank from the gpio pin number
* and configures the INT_TYPE, INT_POLARITY and INT_ANY registers.
*
* Return: 0, negative error otherwise.
* TYPE-EDGE_RISING, INT_TYPE - 1, INT_POLARITY - 1, INT_ANY - 0;
* TYPE-EDGE_FALLING, INT_TYPE - 1, INT_POLARITY - 0, INT_ANY - 0;
* TYPE-EDGE_BOTH, INT_TYPE - 1, INT_POLARITY - NA, INT_ANY - 1;
* TYPE-LEVEL_HIGH, INT_TYPE - 0, INT_POLARITY - 1, INT_ANY - NA;
* TYPE-LEVEL_LOW, INT_TYPE - 0, INT_POLARITY - 0, INT_ANY - NA
*/
static int zynq_gpio_set_irq_type(struct irq_data *irq_data, unsigned int type)
{
u32 int_type, int_pol, int_any;
unsigned int device_pin_num, bank_num, bank_pin_num;
struct zynq_gpio *gpio = irq_data_get_irq_chip_data(irq_data);
device_pin_num = irq_data->hwirq;
zynq_gpio_get_bank_pin(device_pin_num, &bank_num, &bank_pin_num);
int_type = readl_relaxed(gpio->base_addr +
ZYNQ_GPIO_INTTYPE_OFFSET(bank_num));
int_pol = readl_relaxed(gpio->base_addr +
ZYNQ_GPIO_INTPOL_OFFSET(bank_num));
int_any = readl_relaxed(gpio->base_addr +
ZYNQ_GPIO_INTANY_OFFSET(bank_num));
/*
* based on the type requested, configure the INT_TYPE, INT_POLARITY
* and INT_ANY registers
*/
switch (type) {
case IRQ_TYPE_EDGE_RISING:
int_type |= BIT(bank_pin_num);
int_pol |= BIT(bank_pin_num);
int_any &= ~BIT(bank_pin_num);
break;
case IRQ_TYPE_EDGE_FALLING:
int_type |= BIT(bank_pin_num);
int_pol &= ~BIT(bank_pin_num);
int_any &= ~BIT(bank_pin_num);
break;
case IRQ_TYPE_EDGE_BOTH:
int_type |= BIT(bank_pin_num);
int_any |= BIT(bank_pin_num);
break;
case IRQ_TYPE_LEVEL_HIGH:
int_type &= ~BIT(bank_pin_num);
int_pol |= BIT(bank_pin_num);
break;
case IRQ_TYPE_LEVEL_LOW:
int_type &= ~BIT(bank_pin_num);
int_pol &= ~BIT(bank_pin_num);
break;
default:
return -EINVAL;
}
writel_relaxed(int_type,
gpio->base_addr + ZYNQ_GPIO_INTTYPE_OFFSET(bank_num));
writel_relaxed(int_pol,
gpio->base_addr + ZYNQ_GPIO_INTPOL_OFFSET(bank_num));
writel_relaxed(int_any,
gpio->base_addr + ZYNQ_GPIO_INTANY_OFFSET(bank_num));
if (type & IRQ_TYPE_LEVEL_MASK) {
__irq_set_chip_handler_name_locked(irq_data->irq,
&zynq_gpio_level_irqchip, handle_fasteoi_irq, NULL);
} else {
__irq_set_chip_handler_name_locked(irq_data->irq,
&zynq_gpio_edge_irqchip, handle_level_irq, NULL);
}
return 0;
}
static int zynq_gpio_set_wake(struct irq_data *data, unsigned int on)
{
if (on)
zynq_gpio_irq_unmask(data);
else
zynq_gpio_irq_mask(data);
return 0;
}
/* irq chip descriptor */
static struct irq_chip zynq_gpio_level_irqchip = {
.name = DRIVER_NAME,
.irq_enable = zynq_gpio_irq_enable,
.irq_eoi = zynq_gpio_irq_ack,
.irq_mask = zynq_gpio_irq_mask,
.irq_unmask = zynq_gpio_irq_unmask,
.irq_set_type = zynq_gpio_set_irq_type,
.irq_set_wake = zynq_gpio_set_wake,
.flags = IRQCHIP_EOI_THREADED | IRQCHIP_EOI_IF_HANDLED,
};
static struct irq_chip zynq_gpio_edge_irqchip = {
.name = DRIVER_NAME,
.irq_enable = zynq_gpio_irq_enable,
.irq_ack = zynq_gpio_irq_ack,
.irq_mask = zynq_gpio_irq_mask,
.irq_unmask = zynq_gpio_irq_unmask,
.irq_set_type = zynq_gpio_set_irq_type,
.irq_set_wake = zynq_gpio_set_wake,
};
/**
* zynq_gpio_irqhandler - IRQ handler for the gpio banks of a gpio device
* @irq: irq number of the gpio bank where interrupt has occurred
* @desc: irq descriptor instance of the 'irq'
*
* This function reads the Interrupt Status Register of each bank to get the
* gpio pin number which has triggered an interrupt. It then acks the triggered
* interrupt and calls the pin specific handler set by the higher layer
* application for that pin.
* Note: A bug is reported if no handler is set for the gpio pin.
*/
static void zynq_gpio_irqhandler(unsigned int irq, struct irq_desc *desc)
{
u32 int_sts, int_enb;
unsigned int bank_num;
struct zynq_gpio *gpio = irq_get_handler_data(irq);
struct irq_chip *irqchip = irq_desc_get_chip(desc);
chained_irq_enter(irqchip, desc);
for (bank_num = 0; bank_num < ZYNQ_GPIO_MAX_BANK; bank_num++) {
int_sts = readl_relaxed(gpio->base_addr +
ZYNQ_GPIO_INTSTS_OFFSET(bank_num));
int_enb = readl_relaxed(gpio->base_addr +
ZYNQ_GPIO_INTMASK_OFFSET(bank_num));
int_sts &= ~int_enb;
if (int_sts) {
int offset;
unsigned long pending = int_sts;
for_each_set_bit(offset, &pending, 32) {
unsigned int gpio_irq =
irq_find_mapping(gpio->chip.irqdomain,
offset);
generic_handle_irq(gpio_irq);
}
}
}
chained_irq_exit(irqchip, desc);
}
static int __maybe_unused zynq_gpio_suspend(struct device *dev)
{
if (!device_may_wakeup(dev))
return pm_runtime_force_suspend(dev);
return 0;
}
static int __maybe_unused zynq_gpio_resume(struct device *dev)
{
if (!device_may_wakeup(dev))
return pm_runtime_force_resume(dev);
return 0;
}
static int __maybe_unused zynq_gpio_runtime_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct zynq_gpio *gpio = platform_get_drvdata(pdev);
clk_disable_unprepare(gpio->clk);
return 0;
}
static int __maybe_unused zynq_gpio_runtime_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct zynq_gpio *gpio = platform_get_drvdata(pdev);
return clk_prepare_enable(gpio->clk);
}
static int zynq_gpio_request(struct gpio_chip *chip, unsigned offset)
{
int ret;
ret = pm_runtime_get_sync(chip->dev);
/*
* If the device is already active pm_runtime_get() will return 1 on
* success, but gpio_request still needs to return 0.
*/
return ret < 0 ? ret : 0;
}
static void zynq_gpio_free(struct gpio_chip *chip, unsigned offset)
{
pm_runtime_put(chip->dev);
}
static const struct dev_pm_ops zynq_gpio_dev_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(zynq_gpio_suspend, zynq_gpio_resume)
SET_PM_RUNTIME_PM_OPS(zynq_gpio_runtime_suspend,
zynq_gpio_runtime_resume, NULL)
};
/**
* zynq_gpio_probe - Initialization method for a zynq_gpio device
* @pdev: platform device instance
*
* This function allocates memory resources for the gpio device and registers
* all the banks of the device. It will also set up interrupts for the gpio
* pins.
* Note: Interrupts are disabled for all the banks during initialization.
*
* Return: 0 on success, negative error otherwise.
*/
static int zynq_gpio_probe(struct platform_device *pdev)
{
int ret, bank_num, irq;
struct zynq_gpio *gpio;
struct gpio_chip *chip;
struct resource *res;
gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
if (!gpio)
return -ENOMEM;
platform_set_drvdata(pdev, gpio);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
gpio->base_addr = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(gpio->base_addr))
return PTR_ERR(gpio->base_addr);
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "invalid IRQ\n");
return irq;
}
/* configure the gpio chip */
chip = &gpio->chip;
chip->label = "zynq_gpio";
chip->owner = THIS_MODULE;
chip->dev = &pdev->dev;
chip->get = zynq_gpio_get_value;
chip->set = zynq_gpio_set_value;
chip->request = zynq_gpio_request;
chip->free = zynq_gpio_free;
chip->direction_input = zynq_gpio_dir_in;
chip->direction_output = zynq_gpio_dir_out;
chip->base = -1;
chip->ngpio = ZYNQ_GPIO_NR_GPIOS;
/* Enable GPIO clock */
gpio->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(gpio->clk)) {
dev_err(&pdev->dev, "input clock not found.\n");
return PTR_ERR(gpio->clk);
}
ret = clk_prepare_enable(gpio->clk);
if (ret) {
dev_err(&pdev->dev, "Unable to enable clock.\n");
return ret;
}
/* report a bug if gpio chip registration fails */
ret = gpiochip_add(chip);
if (ret) {
dev_err(&pdev->dev, "Failed to add gpio chip\n");
goto err_disable_clk;
}
/* disable interrupts for all banks */
for (bank_num = 0; bank_num < ZYNQ_GPIO_MAX_BANK; bank_num++)
writel_relaxed(ZYNQ_GPIO_IXR_DISABLE_ALL, gpio->base_addr +
ZYNQ_GPIO_INTDIS_OFFSET(bank_num));
ret = gpiochip_irqchip_add(chip, &zynq_gpio_edge_irqchip, 0,
handle_level_irq, IRQ_TYPE_NONE);
if (ret) {
dev_err(&pdev->dev, "Failed to add irq chip\n");
goto err_rm_gpiochip;
}
gpiochip_set_chained_irqchip(chip, &zynq_gpio_edge_irqchip, irq,
zynq_gpio_irqhandler);
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);
device_set_wakeup_capable(&pdev->dev, 1);
return 0;
err_rm_gpiochip:
if (gpiochip_remove(chip))
dev_err(&pdev->dev, "Failed to remove gpio chip\n");
err_disable_clk:
clk_disable_unprepare(gpio->clk);
return ret;
}
/**
* zynq_gpio_remove - Driver removal function
* @pdev: platform device instance
*
* Return: 0 always
*/
static int zynq_gpio_remove(struct platform_device *pdev)
{
int ret;
struct zynq_gpio *gpio = platform_get_drvdata(pdev);
pm_runtime_get_sync(&pdev->dev);
ret = gpiochip_remove(&gpio->chip);
if (ret) {
dev_err(&pdev->dev, "Failed to remove gpio chip\n");
return ret;
}
clk_disable_unprepare(gpio->clk);
device_set_wakeup_capable(&pdev->dev, 0);
return 0;
}
static struct of_device_id zynq_gpio_of_match[] = {
{ .compatible = "xlnx,zynq-gpio-1.0", },
{ /* end of table */ }
};
MODULE_DEVICE_TABLE(of, zynq_gpio_of_match);
static struct platform_driver zynq_gpio_driver = {
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
.pm = &zynq_gpio_dev_pm_ops,
.of_match_table = zynq_gpio_of_match,
},
.probe = zynq_gpio_probe,
.remove = zynq_gpio_remove,
};
/**
* zynq_gpio_init - Initial driver registration call
*
* Return: value from platform_driver_register
*/
static int __init zynq_gpio_init(void)
{
return platform_driver_register(&zynq_gpio_driver);
}
postcore_initcall(zynq_gpio_init);
MODULE_AUTHOR("Xilinx Inc.");
MODULE_DESCRIPTION("Zynq GPIO driver");
MODULE_LICENSE("GPL");
Reference in New Issue View Git Blame Copy Permalink