Re: [PATCH 1/1] gpio: add a driver for the Synopsys DesignWare APBGPIO block
From: Sebastian Hesselbarth
Date: Thu Nov 07 2013 - 07:33:40 EST
On 11/06/13 23:49, Alan Tull wrote:
From: Jamie Iles <jamie@xxxxxxxxxxxxx>
The Synopsys DesignWare block is used in some ARM devices (picoxcell)
and can be configured to provide multiple banks of GPIO pins.
Signed-off-by: Alan Tull <atull@xxxxxxxxxx>
v6: - (atull) squash the set of patches
Much better to review, thanks.
[...]
diff --git a/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt b/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt
new file mode 100644
index 0000000..f7e2076
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt
@@ -0,0 +1,57 @@
+* Synopsys DesignWare APB GPIO controller
+
+Required properties:
+- compatible : Should be "snps,dw-apb-gpio"
+- reg : Address and length of the register set for the device
+
+The GPIO controller has a configurable number of banks, each of which are
+represented as child nodes with the following properties:
still, s/bank/port/g
+Required properties:
+- compatible : "snps,dw-apb-gpio-bank"
should be "snps,dw-apb-gpio-port" then. If someone badly needs
"snps,dw-apb-gpio-bank", I suggest to mark it as DEPRECATED.
+- gpio-controller : Marks the device node as a gpio controller.
+- #gpio-cells : Should be two. The first cell is the pin number and
+ the second cell is used to specify optional parameters (currently
+ unused).
+- reg : The integer bank index of the bank, a single cell.
+- nr-gpios : The number of pins in the bank, a single cell.
Missed that one, must have vendor-specific prefix, i.e. snps,nr-gpios.
Also, if you leave this property as required, there is no way for those
IP with CONFIG registers to not use it. Please, make it optional.
+Optional properties:
+- interrupt-controller : The first bank may be configured to be an interrupt
+controller.
s/bank/port/
+- #interrupt-cells : Specifies the number of cells needed to encode an
+interrupt. Shall be set to 2. The first cell defines the interrupt number,
+the second encodes the triger flags encoded as described in
+Documentation/devicetree/bindings/interrupts.txt
+- interrupt-parent : The parent interrupt controller.
+- interrupts : The interrupts to the parent controller raised when GPIOs
+generate the interrupts.
Right, here you correctly say that there may be more than just one
upstream irq.
+Example:
+
+gpio: gpio@20000 {
+ compatible = "snps,dw-apb-gpio";
+ reg = <0x20000 0x1000>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ banka: gpio-controller@0 {
+ compatible = "snps,dw-apb-gpio-bank";
+ gpio-controller;
+ #gpio-cells = <2>;
+ nr-gpio = <8>;
+ reg = <0>;
+ interrupt-controller;
+ #interrupt-cells = <2>;
+ interrupt-parent = <&vic1>;
+ interrupts = <0 1 2 3 4 5 6 7>;
+ };
+
+ bankb: gpio-controller@1 {
+ compatible = "snps,dw-apb-gpio-bank";
+ gpio-controller;
+ #gpio-cells = <2>;
+ nr-gpio = <8>;
+ reg = <1>;
+ };
s/bank/port/
BTW, what if we get rid of port child nodes completely and rather
use:
gpio: gpio-controller@20000 {
compatible = "snps,dw-apb-gpio";
reg = <0x20000 0x1000>;
gpio-controller;
#gpio-cells = <2>;
interrupt-controller;
interrupt-parent = <&vic1>;
interrupts = <0 1 2 3 4 5 6 7>;
snps,port-widths = <8 8 0 0>;
};
The only draw-back compared to child-nodes is, that you'll reference
gpios with <&gpio 13> instead of <&banka 5>. I have no strong opinion
about it, so I leave the correct answer to either LinusW or DT
maintainers.
[...]
diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
new file mode 100644
index 0000000..7957dfd
--- /dev/null
+++ b/drivers/gpio/gpio-dwapb.c
@@ -0,0 +1,458 @@
+/*
+ * Copyright (c) 2011 Jamie Iles
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * All enquiries to support@xxxxxxxxxxxx
+ */
+#include <linux/basic_mmio_gpio.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+#define GPIO_SWPORTA_DR 0x00
+#define GPIO_SWPORTA_DDR 0x04
+#define GPIO_SWPORTB_DR 0x0c
+#define GPIO_SWPORTB_DDR 0x10
+#define GPIO_SWPORTC_DR 0x18
+#define GPIO_SWPORTC_DDR 0x1c
+#define GPIO_SWPORTD_DR 0x24
+#define GPIO_SWPORTD_DDR 0x28
+#define GPIO_INTEN 0x30
+#define GPIO_INTMASK 0x34
+#define GPIO_INTTYPE_LEVEL 0x38
+#define GPIO_INT_POLARITY 0x3c
+#define GPIO_INTSTATUS 0x40
+#define GPIO_PORTA_EOI 0x4c
+#define GPIO_EXT_PORTA 0x50
+#define GPIO_EXT_PORTB 0x54
+#define GPIO_EXT_PORTC 0x58
+#define GPIO_EXT_PORTD 0x5c
+
+struct dwapb_gpio;
+
+struct dwapb_gpio_port {
+ struct bgpio_chip bgc;
+ bool is_registered;
if you make *ports an array of 4 below, you can get rid
of that awkward is_registered. On top of that, with only
struct bgpio_chip and the pointer back to dwapb_gpio you
can get rid of struct dwapb_gpio_port completely.
+ struct dwapb_gpio *gpio;
+};
+
+struct dwapb_gpio {
+ struct device *dev;
+ void __iomem *regs;
+ struct dwapb_gpio_port *ports;
#define DWAPB_MAX_PORTS 4
struct bgpio_chip port_bgc[DWAPB_MAXPORTS];
+ unsigned int nr_ports;
+ struct irq_domain *domain;
+ int hwirq;
As said earlier, hwirq is actually virq. As you'll possibly have
to request more than one upstream irq and irqdomain API requires you
to dispose the mapping before removing, I suggest to remove any
upstream reference from the above struct and use irq_find_mapping()
get the virq to dispose (example below).
+};
+
+static unsigned int dwapb_gpio_nr_ports(struct device_node *of_node)
+{
+ unsigned int nr_ports = 0;
+ struct device_node *np;
+
+ for_each_child_of_node(of_node, np)
+ ++nr_ports;
+
+ return nr_ports;
+}
+
+static int dwapb_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+ struct dwapb_gpio_port *port = container_of(bgc, struct
+ dwapb_gpio_port, bgc);
+ struct dwapb_gpio *gpio = port->gpio;
+
+ return irq_create_mapping(gpio->domain, offset);
+}
+
+static void dwapb_toggle_trigger(struct dwapb_gpio *gpio, unsigned int offs)
+{
+ u32 v = readl(gpio->regs + GPIO_INT_POLARITY);
+
+ if (gpio_get_value(gpio->ports[0].bgc.gc.base + offs))
+ v &= ~BIT(offs);
+ else
+ v |= BIT(offs);
+
+ writel(v, gpio->regs + GPIO_INT_POLARITY);
+}
+
+static void dwapb_irq_handler(u32 irq, struct irq_desc *desc)
+{
+ struct dwapb_gpio *gpio = irq_get_handler_data(irq);
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ u32 irq_status = readl(gpio->regs + GPIO_INTSTATUS);
+
+ while (irq_status) {
+ int irqoffset = fls(irq_status) - 1;
+ int gpio_irq = irq_linear_revmap(gpio->domain, irqoffset);
+ u32 irq_type = irq_get_trigger_type(gpio_irq);
+
+ generic_handle_irq(gpio_irq);
+ irq_status &= ~(1 << irqoffset);
BIT(irqoffset) as above?
+
+ if ((irq_type & IRQ_TYPE_SENSE_MASK) == IRQ_TYPE_EDGE_BOTH)
+ dwapb_toggle_trigger(gpio, irqoffset);
+ }
If you use irq_chip_generic, the whole handler can be written as:
static void dwapb_irq_handler(u32 irq, struct irq_desc *desc)
{
struct irq_domain *d = irq_get_handler_data(irq);
struct irq_chip_generic *gc = irq_get_domain_generic_chip(d, irq);
u32 irqstatus = readl_relaxed(gc->reg_base + GPIO_INTSTATUS) &
gc->mask_cache;
while (irqstatus) {
u32 hwirq = fls(irqstatus) - 1;
generic_handle_irq(irq_find_mapping(d, gc->irq_base + hwirq));
irqstatus &= ~BIT(hwirq);
if ((irq_get_trigger_type(irq) & IRQ_TYPE_SENSE_MASK)
== IRQ_TYPE_EDGE_BOTH)
dwapb_toggle_trigger(gpio, hwirq);
}
}
+
+ if (chip->irq_eoi)
+ chip->irq_eoi(irq_desc_get_irq_data(desc));
+}
+
+static void dwapb_irq_enable(struct irq_data *d)
+{
+ struct dwapb_gpio *gpio = irq_data_get_irq_chip_data(d);
+ struct bgpio_chip *bgc = &gpio->ports[0].bgc;
+ unsigned long flags;
+ u32 val;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+ val = readl(gpio->regs + GPIO_INTEN);
+ val |= 1 << d->hwirq;
BIT(d->hwirq) ?
+ writel(val, gpio->regs + GPIO_INTEN);
+ spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
+static void dwapb_irq_disable(struct irq_data *d)
+{
+ struct dwapb_gpio *gpio = irq_data_get_irq_chip_data(d);
+ struct bgpio_chip *bgc = &gpio->ports[0].bgc;
+ unsigned long flags;
+ u32 val;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+ val = readl(gpio->regs + GPIO_INTEN);
+ val &= ~(1 << d->hwirq);
ditto.
+ writel(val, gpio->regs + GPIO_INTEN);
+ spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
+static int dwapb_irq_set_type(struct irq_data *d, u32 type)
+{
+ struct dwapb_gpio *gpio = irq_data_get_irq_chip_data(d);
+ struct bgpio_chip *bgc = &gpio->ports[0].bgc;
+ int bit = d->hwirq;
+ unsigned long level, polarity, flags;
+
+ if (type & ~(IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING |
+ IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
+ return -EINVAL;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+ level = readl(gpio->regs + GPIO_INTTYPE_LEVEL);
+ polarity = readl(gpio->regs + GPIO_INT_POLARITY);
+
+ switch (type) {
+ case IRQ_TYPE_EDGE_BOTH:
+ level |= (1 << bit);
+ dwapb_toggle_trigger(gpio, bit);
+ break;
+ case IRQ_TYPE_EDGE_RISING:
+ level |= (1 << bit);
+ polarity |= (1 << bit);
+ break;
+ case IRQ_TYPE_EDGE_FALLING:
+ level |= (1 << bit);
+ polarity &= ~(1 << bit);
+ break;
+ case IRQ_TYPE_LEVEL_HIGH:
+ level &= ~(1 << bit);
+ polarity |= (1 << bit);
+ break;
+ case IRQ_TYPE_LEVEL_LOW:
+ level &= ~(1 << bit);
+ polarity &= ~(1 << bit);
ditto for all above and below.
+ break;
+ }
+
+ writel(level, gpio->regs + GPIO_INTTYPE_LEVEL);
+ writel(polarity, gpio->regs + GPIO_INT_POLARITY);
+ spin_unlock_irqrestore(&bgc->lock, flags);
+
+ return 0;
+}
+
+static void dwapb_irq_ack(struct irq_data *d)
+{
+ struct dwapb_gpio *gpio = irq_data_get_irq_chip_data(d);
+ struct bgpio_chip *bgc = &gpio->ports[0].bgc;
+ unsigned long flags;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+ writel(1 << d->hwirq, gpio->regs + GPIO_PORTA_EOI);
+ spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
+static void dwapb_irq_mask(struct irq_data *d)
+{
+ struct dwapb_gpio *gpio = irq_data_get_irq_chip_data(d);
+ struct bgpio_chip *bgc = &gpio->ports[0].bgc;
+ unsigned long value, flags;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+ value = readl(gpio->regs + GPIO_INTMASK);
+ value |= 1 << d->hwirq;
+ writel(value, gpio->regs + GPIO_INTMASK);
+ spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
+static void dwapb_irq_unmask(struct irq_data *d)
+{
+ struct dwapb_gpio *gpio = irq_data_get_irq_chip_data(d);
+ struct bgpio_chip *bgc = &gpio->ports[0].bgc;
+ unsigned long value, flags;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+ value = readl(gpio->regs + GPIO_INTMASK);
+ value &= ~(1 << d->hwirq);
+ writel(value, gpio->regs + GPIO_INTMASK);
+ spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
+static struct irq_chip dwapb_irq_chip = {
+ .name = "gpio-dwapb",
+ .irq_ack = dwapb_irq_ack,
+ .irq_mask = dwapb_irq_mask,
+ .irq_unmask = dwapb_irq_unmask,
+ .irq_set_type = dwapb_irq_set_type,
+ .irq_enable = dwapb_irq_enable,
+ .irq_disable = dwapb_irq_disable,
+};
If you use irq_chip_generic, that should allow you to get rid of
ack/mask/unmask callbacks above. If you need an example, look at
drivers/irqchip/irq-orion.c.
+static int dwapb_gpio_irq_map(struct irq_domain *domain,
+ unsigned int irq,
+ irq_hw_number_t hwirq)
+{
+ struct dwapb_gpio *gpio = domain->host_data;
+
+ irq_set_chip_data(irq, gpio);
+ irq_set_chip_and_handler(irq, &dwapb_irq_chip, handle_level_irq);
+ irq_set_irq_type(irq, IRQ_TYPE_NONE);
+ irq_set_handler_data(irq, gpio);
+
+ return 0;
+}
+
+static struct irq_domain_ops dwapb_gpio_irq_ops = {
+ .map = dwapb_gpio_irq_map,
+ .xlate = irq_domain_xlate_twocell,
+};
+
+static void dwapb_configure_irqs(struct dwapb_gpio *gpio,
+ struct dwapb_gpio_port *port)
+{
+ struct gpio_chip *gc = &port->bgc.gc;
+ struct device_node *node = gc->of_node;
+ unsigned int ngpio = gc->ngpio;
+ int reg;
+
+ if (of_get_property(node, "interrupts", ®) == NULL)
+ return;
+
+ gpio->hwirq = irq_of_parse_and_map(node, 0);
Loop over all "interrupts" passed and register them to
dwapb_irq_handler, as said before, there can be more than
one upstream irq. And better use devm_request_irq, all interrupts
have been converted to resources by platform bus already.
+ if (gpio->hwirq == NO_IRQ)
+ return;
+
+ gpio->domain = irq_domain_add_linear(node, ngpio, &dwapb_gpio_irq_ops,
+ gpio);
+ if (!gpio->domain) {
+ irq_dispose_mapping(gpio->hwirq);
+ return;
+ }
+
+ irq_set_handler_data(gpio->hwirq, gpio);
+ irq_set_chained_handler(gpio->hwirq, dwapb_irq_handler);
+ port->bgc.gc.to_irq = dwapb_gpio_to_irq;
+}
+
+static int dwapb_gpio_add_port(struct dwapb_gpio *gpio,
+ struct device_node *port_np,
+ unsigned int offs)
+{
+ struct dwapb_gpio_port *port;
+ u32 port_idx, ngpio;
+ void __iomem *dat, *set, *dirout;
+ int err;
+
+ if (of_property_read_u32(port_np, "reg", &port_idx)) {
+ dev_err(gpio->dev, "missing port index for %s\n",
+ port_np->full_name);
+ return -EINVAL;
+ }
+
+ if (port_idx > 3) {
+ dev_err(gpio->dev, "invalid port index for %s\n",
+ port_np->full_name);
+ return -EINVAL;
+ }
join the two above to
if (of_property_read_u32(port_np, "reg", &port_idx) ||
port_idx >= DWAPB_MAX_PORTS) {
dev_err(.., "missing/invalid port index ...", ...)
return -EINVAL;
}
+ port = &gpio->ports[offs];
if you devm_kzalloc each gpio_chip locally here and assign it
after successful gpiochip_add, you have your is_registered
back implicitly.
+ port->gpio = gpio;
+
+ if (of_property_read_u32(port_np, "nr-gpios", &ngpio)) {
+ dev_err(gpio->dev, "failed to get number of gpios for %s\n",
+ port_np->full_name);
+ return -EINVAL;
+ }
+
+ dat = gpio->regs + GPIO_EXT_PORTA +
+ (port_idx * (GPIO_EXT_PORTB - GPIO_EXT_PORTA));
#define GPIO_EXT_PORT_SIZE 0xc
dat = gpio->reg + GPIO_EXT_PORTA + (port_idx * GPIO_EXT_PORT_SIZE);
+ set = gpio->regs + GPIO_SWPORTA_DR +
+ (port_idx * (GPIO_SWPORTB_DR - GPIO_SWPORTA_DR));
ditto.
+ dirout = gpio->regs + GPIO_SWPORTA_DDR +
+ (port_idx * (GPIO_SWPORTB_DDR - GPIO_SWPORTA_DDR));
ditto.
+ err = bgpio_init(&port->bgc, gpio->dev, 4, dat, set, NULL, dirout,
+ NULL, false);
+ if (err) {
+ dev_err(gpio->dev, "failed to init gpio chip for %s\n",
+ port_np->full_name);
+ return err;
+ }
+
+ port->bgc.gc.ngpio = ngpio;
+ port->bgc.gc.of_node = port_np;
+
+ /*
+ * Only port A can provide interrupts in all configurations of the IP.
+ */
+ if (port_idx == 0 &&
+ of_get_property(port_np, "interrupt-controller", NULL))
of_property_read_bool(port_np, "interrupt-controller")
+ dwapb_configure_irqs(gpio, port);
+
+ err = gpiochip_add(&port->bgc.gc);
+ if (err)
+ dev_err(gpio->dev, "failed to register gpiochip for %s\n",
+ port_np->full_name);
+ else
+ port->is_registered = true;
+
+ return err;
+}
+
+static void dwapb_gpio_unregister(struct dwapb_gpio *gpio)
+{
+ unsigned int m;
+
+ for (m = 0; m < gpio->nr_ports; ++m)
+ if (gpio->ports[m].is_registered)
+ WARN_ON(gpiochip_remove(&gpio->ports[m].bgc.gc));
if (gpio->port_bgc[m])
...
+}
+
+static int dwapb_gpio_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ struct dwapb_gpio *gpio;
+ struct device_node *np;
+ int err;
+ unsigned int offs = 0;
+
+ gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
+ if (!gpio)
+ return -ENOMEM;
+ gpio->dev = &pdev->dev;
+
+ gpio->nr_ports = dwapb_gpio_nr_ports(pdev->dev.of_node);
+ if (!gpio->nr_ports) {
+ err = -EINVAL;
+ goto out_err;
+ }
+ gpio->ports = devm_kzalloc(&pdev->dev, gpio->nr_ports *
+ sizeof(*gpio->ports), GFP_KERNEL);
+ if (!gpio->ports) {
+ err = -ENOMEM;
+ goto out_err;
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ gpio->regs = devm_ioremap_resource(&pdev->dev, res);
+ if (!gpio->regs) {
+ err = -ENOMEM;
if (!gpio->regs)
return PTR_ERR(gpio->regs);
Jamie already mentioned it.
+ goto out_free_ports;
+ }
+
+ for_each_child_of_node(pdev->dev.of_node, np) {
+ err = dwapb_gpio_add_port(gpio, np, offs++);
+ if (err)
+ goto out_unregister;
+ }
+ platform_set_drvdata(pdev, gpio);
+
+ return 0;
+
+out_unregister:
+ dwapb_gpio_unregister(gpio);
+
+ if (gpio->domain) {
+ irq_dispose_mapping(gpio->hwirq);
+ irq_domain_remove(gpio->domain);
pseudo-code:
for hwirq in #gpios-porta loop
irq_dispose_mapping(
irq_find_mapping(domain,gc->irq_base + hwirq))
end loop
irq_domain_remove(domain)
+ }
+
+out_free_ports:
+ devm_kfree(&pdev->dev, gpio->ports);
+
+out_err:
+ devm_kfree(&pdev->dev, gpio);
Still, remove devm_kfree above.
+ return err;
+}
+
+static int dwapb_gpio_remove(struct platform_device *pdev)
+{
+ struct dwapb_gpio *gpio = platform_get_drvdata(pdev);
+
+ dwapb_gpio_unregister(gpio);
+ if (gpio->domain) {
+ irq_dispose_mapping(gpio->hwirq);
+ irq_domain_remove(gpio->domain);
+ }
+ devm_kfree(&pdev->dev, gpio->ports);
+ devm_kfree(&pdev->dev, gpio);
ditto.
+ return 0;
+}
+
+static const struct of_device_id dwapb_of_match[] = {
+ { .compatible = "snps,dw-apb-gpio" },
+ { /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, dwapb_of_match);
+
+static struct platform_driver dwapb_gpio_driver = {
+ .driver = {
+ .name = "gpio-dwapb",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(dwapb_of_match),
+ },
+ .probe = dwapb_gpio_probe,
+ .remove = dwapb_gpio_remove,
+};
+
+static int __init dwapb_gpio_init(void)
+{
+ return platform_driver_register(&dwapb_gpio_driver);
+}
+postcore_initcall(dwapb_gpio_init);
+
+static void __exit dwapb_gpio_exit(void)
+{
+ platform_driver_unregister(&dwapb_gpio_driver);
+}
+module_exit(dwapb_gpio_exit);
Jamie already mentioned to use module_platform_driver(), of course
this will remove the postcore_initcall and move gpio init to some
later point. I know GPIO is important, but nevertheless I suggest
to remove it. Deferred probing will sort out initialization order.
Sebastian
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jamie Iles");
+MODULE_DESCRIPTION("Synopsys DesignWare APB GPIO driver");
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