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Message-ID: <20110526201436.GC29060@ponder.secretlab.ca>
Date: Thu, 26 May 2011 14:14:36 -0600
From: Grant Likely <grant.likely@...retlab.ca>
To: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc: x86@...nel.org, sodaville@...utronix.de,
linux-kernel@...r.kernel.org, Torben Hohn <torbenh@...utronix.de>,
Florian Fainelli <florian@...nwrt.org>
Subject: Re: [PATCH 2/2] gpio: Add a driver for Sodaville GPIO controller
On Wed, Apr 27, 2011 at 04:37:18PM +0200, Sebastian Andrzej Siewior wrote:
> From: Hans J. Koch <hjk@...utronix.de>
>
> Sodaville has GPIO controller behind the PCI bus. To my suprissed it is
> not the same as on PXA.
>
> The interrupt & gpio chip can be referenced from the device tree like
> from any other driver. Unfortunately the driver which uses the gpio
> interrupt has to use irq_of_parse_and_map() instead of
> platform_get_irq(). The problem is that the platform device (which is
> created from the device tree) is most likely created before the
> interrupt chip is registered and therefore irq_of_parse_and_map() fails.
>
> In theory the driver works as module. In reality most of the irq
> functions are not exported to modules and it is possible that _this_
> module is unloaded while the provided irqs are still in use.
>
> Signed-off-by: Hans J. Koch <hjk@...utronix.de>
> [torbenh@...utronix.de: make it work after the irq namespace cleanup,
> add some device tree entries.]
> Signed-off-by: Torben Hohn <torbenh@...utronix.de>
> [bigeasy@...utronix.de: some refactoring, a little documentation]
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
> ---
> .../devicetree/bindings/gpio/sodaville.txt | 8 +
> arch/x86/platform/ce4100/falconfalls.dts | 7 +-
> drivers/gpio/Kconfig | 6 +
> drivers/gpio/Makefile | 1 +
> drivers/gpio/sodaville_gpio.c | 421 ++++++++++++++++++++
> 5 files changed, 441 insertions(+), 2 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/gpio/sodaville.txt
> create mode 100644 drivers/gpio/sodaville_gpio.c
>
> diff --git a/Documentation/devicetree/bindings/gpio/sodaville.txt b/Documentation/devicetree/bindings/gpio/sodaville.txt
> new file mode 100644
> index 0000000..6610cf3
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/sodaville.txt
> @@ -0,0 +1,8 @@
> +GPIO controller on CE4100 / Sodaville SoCs
> +==========================================
> +
> +The bindings for CE4100's GPIO controller match the generic description
> +which is covered by the gpio.txt file in this folder.
> +
> +The only additional property is the muxctl property which holds the
> +value which is written into the MUXCNTL register.
The expected compatible property value needs to appear here.
> diff --git a/arch/x86/platform/ce4100/falconfalls.dts b/arch/x86/platform/ce4100/falconfalls.dts
> index e70be38..751a9ec 100644
> --- a/arch/x86/platform/ce4100/falconfalls.dts
> +++ b/arch/x86/platform/ce4100/falconfalls.dts
> @@ -208,16 +208,19 @@
> interrupts = <14 1>;
> };
>
> - gpio@b,1 {
> + pcigpio: gpio@b,1 {
> + #gpio-cells = <2>;
> + #interrupt-cells = <2>;
> compatible = "pci8086,2e67.2",
> "pci8086,2e67",
> "pciclassff0000",
> "pciclassff00";
>
> - #gpio-cells = <2>;
> reg = <0x15900 0x0 0x0 0x0 0x0>;
> interrupts = <15 1>;
> + interrupt-controller;
> gpio-controller;
> + muxctl = <0>;
> };
>
> i2c-controller@b,2 {
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index d3b2953..2a665de 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -345,6 +345,12 @@ config GPIO_ML_IOH
> Hub) which is for IVI(In-Vehicle Infotainment) use.
> This driver can access the IOH's GPIO device.
>
> +config GPIO_SODAVILLE
> + bool "Intel Sodaville GPIO support"
> + depends on PCI
Looks like it depends on OF too.
> + help
> + Say Y here to support Intel Sodaville GPIO.
> +
> config GPIO_TIMBERDALE
> bool "Support for timberdale GPIO IP"
> depends on MFD_TIMBERDALE && GPIOLIB && HAS_IOMEM
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index becef59..7fbc00d 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -25,6 +25,7 @@ obj-$(CONFIG_GPIO_PCH) += pch_gpio.o
> obj-$(CONFIG_GPIO_PL061) += pl061.o
> obj-$(CONFIG_GPIO_STMPE) += stmpe-gpio.o
> obj-$(CONFIG_GPIO_TC3589X) += tc3589x-gpio.o
> +obj-$(CONFIG_GPIO_SODAVILLE) += sodaville_gpio.o
> obj-$(CONFIG_GPIO_TIMBERDALE) += timbgpio.o
> obj-$(CONFIG_GPIO_TWL4030) += twl4030-gpio.o
> obj-$(CONFIG_GPIO_UCB1400) += ucb1400_gpio.o
> diff --git a/drivers/gpio/sodaville_gpio.c b/drivers/gpio/sodaville_gpio.c
> new file mode 100644
> index 0000000..1fcdbb0
> --- /dev/null
> +++ b/drivers/gpio/sodaville_gpio.c
> @@ -0,0 +1,421 @@
> +/*
> + * GPIO interface for Intel Sodaville SoCs.
> + *
> + * Copyright (c) 2010, 2011 Intel Corporation
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License 2 as published
> + * by the Free Software Foundation.
> + *
> + */
> +
> +#include <linux/errno.h>
> +#include <linux/gpio.h>
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/irq.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/of_irq.h>
> +
> +static DEFINE_SPINLOCK(gpio_lock);
> +
> +#define DRV_NAME "sdv_gpio"
> +#define SDV_NUM_PUB_GPIOS 12
> +#define PCI_DEVICE_ID_SDV_GPIO 0x2e67
> +#define GPIO_BAR 0
> +
> +#define GPOUTR 0x00
> +#define GPOER 0x04
> +#define GPINR 0x08
> +#define GPSTR 0x0c
> +#define GPIT1R0 0x10
> +#define GPIO_INT 0x14
> +#define GPIT1R1 0x18
> +#define GPMUXCTL 0x1c
> +
> +void __iomem *gpio_pub_base;
> +
> +struct sdv_irq_chip_data {
> + int irq_base;
> + struct irq_domain id;
> +};
> +
> +static void sdv_gpio_pub_mask_irq(struct irq_data *irq)
> +{
> + struct sdv_irq_chip_data *data = irq_data_get_irq_chip_data(irq);
> + u32 reg;
> +
> + reg = readl(gpio_pub_base + GPIO_INT);
> + reg &= ~BIT(irq->irq - data->irq_base);
> + writel(reg, gpio_pub_base + GPIO_INT);
> +}
> +
> +static void sdv_gpio_pub_ack_irq(struct irq_data *irq)
> +{
> + struct sdv_irq_chip_data *data = irq_data_get_irq_chip_data(irq);
> + u32 reg;
> +
> + reg = (BIT(irq->irq - data->irq_base));
> + writel(reg, gpio_pub_base + GPSTR);
> +}
> +
> +static void sdv_gpio_pub_unmask_irq(struct irq_data *irq)
> +{
> + struct sdv_irq_chip_data *data = irq_data_get_irq_chip_data(irq);
> + u32 reg;
> +
> + reg = readl(gpio_pub_base + GPIO_INT);
> + reg |= (BIT(irq->irq - data->irq_base));
> + writel(reg, gpio_pub_base + GPIO_INT);
> +}
Ends up being yet another MM gpio and irq controller. Look at using
irq_chip_generic and bgpio_chip to implement the details.
> +
> +static int sdv_gpio_pub_set_type(struct irq_data *irq, unsigned int type)
> +{
> + struct sdv_irq_chip_data *data = irq_data_get_irq_chip_data(irq);
> + u32 irq_offs = irq->irq - data->irq_base;
> + u32 reg;
> +
> + if (irq_offs < 8)
> + reg = readl(gpio_pub_base + GPIT1R0);
> + else
> + reg = readl(gpio_pub_base + GPIT1R1);
> +
> + switch (type) {
> + case IRQ_TYPE_LEVEL_HIGH:
> + reg &= ~BIT(4 * (irq_offs % 8));
> + break;
> +
> + case IRQ_TYPE_LEVEL_LOW:
> + reg |= BIT(4 * (irq_offs % 8));
> + break;
> +
> + default:
> + return -EINVAL;
> + }
> +
> + if (irq_offs < 8)
> + writel(reg, gpio_pub_base + GPIT1R0);
> + else
> + writel(reg, gpio_pub_base + GPIT1R1);
Perhaps this pattern would be more concise:
writel(reg, gpio_pub_base + ((irq_offs < 8) ? GPIT1R0 : GPIT1R1));
> +
> + return 0;
> +}
> +
> +static irqreturn_t sdv_gpio_pub_irq_handler(int irq, void *data)
> +{
> + struct sdv_irq_chip_data *sdv_data = data;
> + u32 irq_stat = readl(gpio_pub_base + GPSTR);
> +
> + irq_stat &= readl(gpio_pub_base + GPIO_INT);
> + if (!irq_stat)
> + return IRQ_NONE;
> +
> + while (irq_stat) {
> + int irq_bit = __fls(irq_stat);
> +
> + generic_handle_irq(sdv_data->irq_base + irq_bit);
> + irq_stat &= ~BIT(irq_bit);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +static struct irq_chip sdv_gpio_pub_irq_chip = {
> + .name = "sdv-gpio",
> + .irq_mask = sdv_gpio_pub_mask_irq,
> + .irq_eoi = sdv_gpio_pub_ack_irq,
> + .irq_unmask = sdv_gpio_pub_unmask_irq,
> + .irq_set_type = sdv_gpio_pub_set_type,
> +};
> +
> +static int sdv_xlate(struct irq_domain *h, const u32 *intspec, u32 intsize,
> + u32 *out_hwirq, u32 *out_type)
> +{
> + struct sdv_irq_chip_data *sdv_data = h->priv;
> + u32 line, type;
> +
> + if (intsize < 2)
> + return -EINVAL;
> +
> + /* irqs are offset by sdv_data->irq_base */
> + line = *intspec;
> + *out_hwirq = line + sdv_data->irq_base;
> +
> + intspec++;
> + type = *intspec;
The format of intspec[1] flags needs to be documented in the
devicetree binding document. It is convenient if the flags happen to
line up with linux irq type values.
> +
> + /* Only level interrupts are supported by the IRQ chip */
> + switch (type) {
> + case 1:
> + *out_type = IRQ_TYPE_LEVEL_LOW;
> + break;
> + case 2:
> + *out_type = IRQ_TYPE_LEVEL_HIGH;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static __devinit int register_irqsupport(struct pci_dev *pdev)
> +{
> + struct sdv_irq_chip_data *sdv_data;
> + int irq;
> + int last_irq;
> + int ret = -1;
> +
> + sdv_data = kzalloc(sizeof(struct sdv_irq_chip_data), GFP_KERNEL);
> + if (!sdv_data) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> + ret = irq_alloc_descs(-1, 0, SDV_NUM_PUB_GPIOS, -1);
> + if (ret < 0)
> + goto out_kfree;
> +
> + sdv_data->irq_base = ret;
> +
> + /* mask + ACK all interrupt sources */
> + writel(0, gpio_pub_base + GPIO_INT);
> + writel((1 << 11) - 1, gpio_pub_base + GPSTR);
> +
> + ret = request_irq(pdev->irq, sdv_gpio_pub_irq_handler, IRQF_SHARED,
> + "sdv_gpio", sdv_data);
> + if (ret)
> + goto out_free_desc;
> +
> + /*
> + * This gpio irq controller latches level irqs. Testing shows that if
> + * we unmask & ACK the IRQ before the source of the interrupt is gone
> + * then the interrupt is active again.
> + */
> + last_irq = sdv_data->irq_base + SDV_NUM_PUB_GPIOS;
> + for (irq = sdv_data->irq_base; irq < last_irq; irq++) {
> + irq_set_chip_and_handler_name(irq, &sdv_gpio_pub_irq_chip,
> + handle_fasteoi_irq, "fasteoi");
> + irq_set_chip_data(irq, sdv_data);
> + }
> +
> + pci_set_drvdata(pdev, sdv_data);
> +
> + sdv_data->id.controller = pdev->dev.of_node;
> + sdv_data->id.xlate = sdv_xlate;
> + sdv_data->id.priv = sdv_data;
> + irq_add_of_interrupt_host(&sdv_data->id);
> +
> + return 0;
> +
> +out_free_desc:
> + irq_free_descs(sdv_data->irq_base, SDV_NUM_PUB_GPIOS);
> +out_kfree:
> + kfree(sdv_data);
> +out:
> + pdev->dev.p = 0;
> + return ret;
> +}
> +
> +static void unregister_irqsupport(struct pci_dev *pdev)
> +{
> + struct sdv_irq_chip_data *sdv_data = pci_get_drvdata(pdev);
> +
> + if (sdv_data) {
> + irq_remove_of_interrupt_host(&sdv_data->id);
> + free_irq(pdev->irq, sdv_data);
> + irq_free_descs(sdv_data->irq_base, SDV_NUM_PUB_GPIOS);
> + kfree(sdv_data);
> + }
> +}
> +
> +static int sdv_gpio_is_output(unsigned gpio_num)
> +{
> + return readl(gpio_pub_base + GPOER) & BIT(gpio_num);
> +}
> +
> +static int sdv_gpio_pub_get(struct gpio_chip *gc, unsigned gpio_num)
> +{
> + u32 reg;
> +
> + if (sdv_gpio_is_output(gpio_num))
> + reg = readl(gpio_pub_base + GPOUTR);
> + else
> + reg = readl(gpio_pub_base + GPINR);
> +
> + return (reg & BIT(gpio_num)) ? 1 : 0;
> +}
> +
> +static void sdv_gpio_pub_set(struct gpio_chip *gc,
> + unsigned gpio_num, int val)
> +{
> + u32 curr_vals;
> +
> + spin_lock(&gpio_lock);
> +
> + curr_vals = readl(gpio_pub_base + GPOUTR);
> +
> + if (val)
> + curr_vals |= BIT(gpio_num);
> + else
> + curr_vals &= ~BIT(gpio_num);
> +
> + writel(curr_vals, gpio_pub_base + GPOUTR);
> + spin_unlock(&gpio_lock);
> +}
> +
> +static int sdv_gpio_pub_direction_in(struct gpio_chip *gc,
> + unsigned gpio_num)
> +{
> + u32 curr_dirs;
> +
> + spin_lock(&gpio_lock);
> +
> + curr_dirs = readl(gpio_pub_base + GPOER);
> +
> + if (curr_dirs & BIT(gpio_num))
> + writel(curr_dirs & ~BIT(gpio_num), gpio_pub_base + GPOER);
> +
> + spin_unlock(&gpio_lock);
> + return 0;
> +}
> +
> +static int sdv_gpio_pub_direction_out(struct gpio_chip *gc,
> + unsigned gpio_num, int val)
> +{
> + u32 curr_dirs;
> +
> + sdv_gpio_pub_set(gc, gpio_num, val);
> +
> + spin_lock(&gpio_lock);
> +
> + curr_dirs = readl(gpio_pub_base + GPOER);
> +
> + if (!(curr_dirs & BIT(gpio_num)))
> + writel(curr_dirs | BIT(gpio_num), gpio_pub_base + GPOER);
> +
> + spin_unlock(&gpio_lock);
> + return 0;
> +}
> +
> +static struct gpio_chip sdv_gpio_pub = {
> + .label = "sdv_gpio",
> + .owner = THIS_MODULE,
> + .get = sdv_gpio_pub_get,
> + .set = sdv_gpio_pub_set,
> + .direction_input = sdv_gpio_pub_direction_in,
> + .direction_output = sdv_gpio_pub_direction_out,
> +};
> +
> +static int __devinit sdv_gpio_probe(struct pci_dev *pdev,
> + const struct pci_device_id *pci_id)
> +{
> + unsigned long addr;
> + const void *prop;
> + int len;
> + int ret;
> + u32 mux_val;
> +
> + if (gpio_pub_base) {
> + dev_err(&pdev->dev, KERN_ERR "Driver does not (yet) support "
> + "multiple devices.\n");
> + return -EBUSY;
> + }
> + ret = pci_enable_device(pdev);
> + if (ret) {
> + dev_err(&pdev->dev, "can't enable device.\n");
> + goto done;
> + }
> +
> + ret = pci_request_region(pdev, GPIO_BAR, DRV_NAME);
> + if (ret) {
> + dev_err(&pdev->dev, "can't alloc PCI BAR #%d\n", GPIO_BAR);
> + goto disable_pci;
> + }
> +
> + addr = pci_resource_start(pdev, GPIO_BAR);
> + if (!addr)
> + goto release_reg;
> + gpio_pub_base = ioremap(addr, pci_resource_len(pdev, GPIO_BAR));
> +
> + prop = of_get_property(pdev->dev.of_node, "muxctl", &len);
It is common to prefix custom properties with a manufacturer name,
like "intex,muxctl".
> + if (prop && len == 4) {
> + mux_val = of_read_number(prop, 1);
> + writel(mux_val, gpio_pub_base + GPMUXCTL);
> + }
> +
> + sdv_gpio_pub.base = -1;
> + sdv_gpio_pub.ngpio = SDV_NUM_PUB_GPIOS;
> + sdv_gpio_pub.dev = &pdev->dev;
> +
> + ret = gpiochip_add(&sdv_gpio_pub);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "gpiochip_add() failed.\n");
> + goto unmap;
> + }
> +
> + ret = register_irqsupport(pdev);
> + if (ret)
> + goto unmap;
> +
> + dev_info(&pdev->dev, "Sodaville GPIO driver registered.\n");
> +
> + return 0;
> +
> +unmap:
> + iounmap(gpio_pub_base);
> + gpio_pub_base = NULL;
> +release_reg:
> + pci_release_region(pdev, GPIO_BAR);
> +disable_pci:
> + pci_disable_device(pdev);
> +done:
> + return ret;
> +}
> +
> +static void sdv_gpio_remove(struct pci_dev *pdev)
> +{
> + if (!gpio_pub_base)
> + return;
> +
> + unregister_irqsupport(pdev);
> +
> + if (gpiochip_remove(&sdv_gpio_pub))
> + dev_err(&pdev->dev, "gpiochip_remove() failed.\n");
> +
> + pci_release_region(pdev, GPIO_BAR);
> + gpio_pub_base = NULL;
> + pci_disable_device(pdev);
> +}
> +
> +static struct pci_device_id sdv_gpio_pci_ids[] __devinitdata = {
> + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_SDV_GPIO) },
> + { 0, },
> +};
> +
> +static struct pci_driver sdv_gpio_driver = {
> + .name = DRV_NAME,
> + .id_table = sdv_gpio_pci_ids,
> + .probe = sdv_gpio_probe,
> + .remove = sdv_gpio_remove,
> +};
> +
> +static int __init sdv_gpio_init(void)
> +{
> + return pci_register_driver(&sdv_gpio_driver);
> +}
> +module_init(sdv_gpio_init);
> +
> +static void __exit sdv_gpio_exit(void)
> +{
> + pci_unregister_driver(&sdv_gpio_driver);
> +}
> +module_exit(sdv_gpio_exit);
> +
> +MODULE_AUTHOR("Hans J. Koch <hjk@...utronix.de>");
> +MODULE_DESCRIPTION("GPIO interface for Intel Sodaville SoCs");
> +MODULE_LICENSE("GPL v2");
> --
> 1.7.4.4
>
> --
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