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Message-Id: <20120302074800.C2F973E17BE@localhost>
Date: Fri, 02 Mar 2012 00:48:00 -0700
From: Grant Likely <grant.likely@...retlab.ca>
To: Alessandro Rubini <rubini@...dd.com>, linux-kernel@...r.kernel.org
Cc: giancarlo.asnaghi@...com, alan@...ux.intel.com,
sameo@...ux.intel.com, linus.walleij@...ricsson.com
Subject: Re: [PATCH V2 2/2] gpio: add STA2X11 GPIO block
On Thu, 16 Feb 2012 14:00:52 +0100, Alessandro Rubini <rubini@...dd.com> wrote:
> This introduces 128 gpio bits (for each PCI device installed) with
> working interrupt support.
>
> Signed-off-by: Alessandro Rubini <rubini@...dd.com>
> Acked-by: Giancarlo Asnaghi <giancarlo.asnaghi@...com>
> Cc: Alan Cox <alan@...ux.intel.com>
> ---
> drivers/gpio/Kconfig | 9 +
> drivers/gpio/Makefile | 1 +
> drivers/gpio/gpio-sta2x11.c | 443 +++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 453 insertions(+), 0 deletions(-)
> create mode 100644 drivers/gpio/gpio-sta2x11.c
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index dbb1909..dbae9c2 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -149,6 +149,14 @@ config GPIO_PXA
> help
> Say yes here to support the PXA GPIO device
>
> +config GPIO_STA2X11
> + bool "STA2x11/ConneXt GPIO support"
> + depends on MFD_STA2X11
> + select GENERIC_IRQ_CHIP
> + help
> + Say yes here to support the STA2x11/ConneXt GPIO device.
> + The GPIO module has 128 GPIO pins with alternate functions.
> +
> config GPIO_XILINX
> bool "Xilinx GPIO support"
> depends on PPC_OF || MICROBLAZE
> @@ -503,4 +511,5 @@ config GPIO_TPS65910
> help
> Select this option to enable GPIO driver for the TPS65910
> chip family.
> +
> endif
Unrelated whitespace change; please remove from patch
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index 593bdcd..f72313d 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -47,6 +47,7 @@ obj-$(CONFIG_PLAT_SAMSUNG) += gpio-samsung.o
> obj-$(CONFIG_ARCH_SA1100) += gpio-sa1100.o
> obj-$(CONFIG_GPIO_SCH) += gpio-sch.o
> obj-$(CONFIG_GPIO_SODAVILLE) += gpio-sodaville.o
> +obj-$(CONFIG_GPIO_STA2X11) += gpio-sta2x11.o
> obj-$(CONFIG_GPIO_STMPE) += gpio-stmpe.o
> obj-$(CONFIG_GPIO_SX150X) += gpio-sx150x.o
> obj-$(CONFIG_GPIO_TC3589X) += gpio-tc3589x.o
> diff --git a/drivers/gpio/gpio-sta2x11.c b/drivers/gpio/gpio-sta2x11.c
> new file mode 100644
> index 0000000..f1885f4
> --- /dev/null
> +++ b/drivers/gpio/gpio-sta2x11.c
> @@ -0,0 +1,443 @@
> +/*
> + * STMicroelectronics ConneXt (STA2X11) GPIO driver
> + *
> + * Copyright 2012 ST Microelectronics (Alessandro Rubini)
> + * Based on gpio-ml-ioh.c, Copyright 2010 OKI Semiconductors Ltd.
> + * Also based on previous sta2x11 work, Copyright 2011 Wind River Systems, Inc.
> + *
> + * 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.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> + * See the GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/gpio.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/mfd/sta2x11-mfd.h>
> +
> +struct gsta_regs {
> + u32 dat; /* 0x00 */
> + u32 dats;
> + u32 datc;
> + u32 pdis;
> + u32 dir; /* 0x10 */
> + u32 dirs;
> + u32 dirc;
> + u32 unused_1c;
> + u32 afsela; /* 0x20 */
> + u32 unused_24[7];
> + u32 rimsc; /* 0x40 */
> + u32 fimsc;
> + u32 is;
> + u32 ic;
> +};
> +
> +struct gsta_gpio {
> + spinlock_t lock;
> + struct device *dev;
> + void __iomem *reg_base;
> + struct gsta_regs *regs[GSTA_NR_BLOCKS];
__iomem?
> + struct gpio_chip gpio;
> + int irq_base;
> + /* FIXME: save the whole config here (AF, ...) */
> + unsigned irq_type[GSTA_NR_GPIO];
> +};
> +
> +static inline struct gsta_regs __iomem *__regs(struct gsta_gpio *chip, int nr)
> +{
> + return chip->regs[nr / GSTA_GPIO_PER_BLOCK];
> +}
> +
> +static inline u32 __bit(int nr)
> +{
> + return 1U << (nr % GSTA_GPIO_PER_BLOCK);
> +}
> +
> +/*
> + * gpio methods
> + */
> +
> +static void gsta_gpio_set(struct gpio_chip *gpio, unsigned nr, int val)
> +{
> + struct gsta_gpio *chip = container_of(gpio, struct gsta_gpio, gpio);
> + struct gsta_regs __iomem *regs = __regs(chip, nr);
> + u32 bit = __bit(nr);
> +
> + if (val)
> + writel(bit, ®s->dats);
> + else
> + writel(bit, ®s->datc);
> +}
> +
> +static int gsta_gpio_get(struct gpio_chip *gpio, unsigned nr)
> +{
> + struct gsta_gpio *chip = container_of(gpio, struct gsta_gpio, gpio);
> + struct gsta_regs __iomem *regs = __regs(chip, nr);
> + u32 bit = __bit(nr);
> +
> + return readl(®s->dat) & bit;
> +}
> +
> +static int gsta_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
> + int val)
> +{
> + struct gsta_gpio *chip = container_of(gpio, struct gsta_gpio, gpio);
> + struct gsta_regs __iomem *regs = __regs(chip, nr);
> + u32 bit = __bit(nr);
> +
> + writel(bit, ®s->dirs);
> + /* Data register after direction, otherwise pullup/down is selected */
> + if (val)
> + writel(bit, ®s->dats);
> + else
> + writel(bit, ®s->datc);
> + return 0;
> +}
> +
> +static int gsta_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
> +{
> + struct gsta_gpio *chip = container_of(gpio, struct gsta_gpio, gpio);
> + struct gsta_regs __iomem *regs = __regs(chip, nr);
> + u32 bit = __bit(nr);
> +
> + writel(bit, ®s->dirc);
> + return 0;
These are plain-vanilla gpio accessors. Can you use the gpio-generic.c
library?
> +}
> +
> +static int gsta_gpio_to_irq(struct gpio_chip *gpio, unsigned offset)
> +{
> + struct gsta_gpio *chip = container_of(gpio, struct gsta_gpio, gpio);
> + return chip->irq_base + offset;
> +}
> +
> +static void gsta_gpio_setup(struct gsta_gpio *chip) /* called from probe */
> +{
> + struct gpio_chip *gpio = &chip->gpio;
> +
> + /*
> + * ARCH_NR_GPIOS is currently 256 and dynamic allocation starts
> + * from the end. However, for compatiility, we need the first
> + * ConneXt device to start from gpio 0: it's the main chipset
> + * on most boards so documents and drivers assume gpio0..gpio127
> + */
> + static int gpio_base;
> +
> + gpio->label = dev_name(chip->dev);
> + gpio->owner = THIS_MODULE;
> + gpio->direction_input = gsta_gpio_direction_input;
> + gpio->get = gsta_gpio_get;
> + gpio->direction_output = gsta_gpio_direction_output;
> + gpio->set = gsta_gpio_set;
> + gpio->dbg_show = NULL;
> + gpio->base = gpio_base;
> + gpio->base = 0;
> + gpio->ngpio = GSTA_NR_GPIO;
> + gpio->can_sleep = 0;
> + gpio->to_irq = gsta_gpio_to_irq;
> +
> +
> + /*
> + * After the first device, turn to dynamic gpio numbers.
> + * With ARCH_NR_GPIOS = 256 we can fit for example two steval cards
> + */
> + if (!gpio_base)
> + gpio_base = 1;
> +}
> +
> +/*
> + * Special method: alternate functions and pullup/pulldown. This will
> + * need to be exported to other drivers, adding a way to retrieve
> + * the gsta_gpio structure from their own pci device
> + */
> +void gsta_set_config(struct gsta_gpio *chip, int nr, unsigned cfg)
> +{
> + struct gsta_regs __iomem *regs = __regs(chip, nr);
> + unsigned long flags;
> + u32 bit = __bit(nr);
> + u32 val;
> + int err = 0;
> +
> + printk("%s: %p %i %i\n", __func__, chip, nr, cfg);
pr_info()
> +
> + if (cfg == PINMUX_TYPE_NONE)
> + return;
> +
> + /* Alternate function or not? */
> + spin_lock_irqsave(&chip->lock, flags);
> + val = readl(®s->afsela);
> + if (cfg == PINMUX_TYPE_FUNCTION)
> + val |= bit;
> + else
> + val &= ~bit;
> + writel(val | bit, ®s->afsela);
> + if (cfg == PINMUX_TYPE_FUNCTION) {
> + spin_unlock_irqrestore(&chip->lock, flags);
> + return;
> + }
> +
> + /* not alternate function: set details */
> + switch(cfg) {
> + case PINMUX_TYPE_OUTPUT_LOW:
> + writel(bit, ®s->dirs);
> + writel(bit, ®s->datc);
> + break;
> + case PINMUX_TYPE_OUTPUT_HIGH:
> + writel(bit, ®s->dirs);
> + writel(bit, ®s->dats);
> + break;
> + case PINMUX_TYPE_INPUT:
> + writel(bit, ®s->dirc);
> + val = readl(®s->pdis) | bit;
> + writel (val, ®s->pdis);
> + break;
> + case PINMUX_TYPE_INPUT_PULLUP:
> + writel(bit, ®s->dirc);
> + val = readl(®s->pdis) &~ bit;
> + writel (val, ®s->pdis);
> + writel(bit, ®s->dats);
> + break;
> + case PINMUX_TYPE_INPUT_PULLDOWN:
> + writel(bit, ®s->dirc);
> + val = readl(®s->pdis) &~ bit;
> + writel (val, ®s->pdis);
> + writel(bit, ®s->datc);
> + break;
> + default:
> + err = 1;
> + }
> + spin_unlock_irqrestore(&chip->lock, flags);
> + if (err)
> + pr_err("%s: chip %p, pin %i, cfg %i is invalid\n",
> + __func__, chip, nr, cfg);
> +}
> +
> +/*
> + * Irq methods
> + */
> +
> +static void gsta_irq_disable(struct irq_data *data)
> +{
> + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
> + struct gsta_gpio *chip = gc->private;
> + int nr = data->irq - chip->irq_base;
we have data->hwirq now. Use it. In fact, you should look at using irqdomain to manage the
hwirq to linuxirq number mapping for you. irqdomain will be merged for v3.4.
> + struct gsta_regs __iomem *regs = __regs(chip, nr);
> + u32 bit = __bit(nr);
> + u32 val;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&chip->lock, flags);
> + if (chip->irq_type[nr] & IRQ_TYPE_EDGE_RISING) {
> + val = readl(®s->rimsc) & ~bit;
> + writel(val, ®s->rimsc);
> + }
> + if (chip->irq_type[nr] & IRQ_TYPE_EDGE_FALLING) {
> + val = readl(®s->fimsc) & ~bit;
> + writel(val, ®s->fimsc);
> + }
> + spin_unlock_irqrestore(&chip->lock, flags);
> + return;
> +}
> +
> +static void gsta_irq_enable(struct irq_data *data)
> +{
> + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
> + struct gsta_gpio *chip = gc->private;
> + int nr = data->irq - chip->irq_base;
> + struct gsta_regs __iomem *regs = __regs(chip, nr);
> + u32 bit = __bit(nr);
> + u32 val;
> + int type;
> + unsigned long flags;
> +
> + type = chip->irq_type[nr];
> +
> + spin_lock_irqsave(&chip->lock, flags);
> + val = readl(®s->rimsc);
> + if (type & IRQ_TYPE_EDGE_RISING)
> + writel(val | bit, ®s->rimsc);
> + else
> + writel(val & ~bit, ®s->rimsc);
> + val = readl(®s->rimsc);
> + if (type & IRQ_TYPE_EDGE_FALLING)
> + writel(val | bit, ®s->fimsc);
> + else
> + writel(val & ~bit, ®s->fimsc);
> + spin_unlock_irqrestore(&chip->lock, flags);
> + return;
> +}
> +
> +static int gsta_irq_type(struct irq_data *d, unsigned int type)
> +{
> + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
> + struct gsta_gpio *chip = gc->private;
> + int nr = d->irq - chip->irq_base;
> +
> + /* We only support edge interrupts */
> + if (!(type & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING))) {
> + pr_debug("%s: unsupported type 0x%x\n", __func__, type);
> + return -EINVAL;
> + }
> +
> + chip->irq_type[nr] = type; /* used for enable/disable */
> +
> + gsta_irq_enable(d);
> + return 0;
> +}
> +
> +static irqreturn_t gsta_gpio_handler(int irq, void *dev_id)
> +{
> + struct gsta_gpio *chip = dev_id;
> + struct gsta_regs __iomem *regs;
> + u32 is;
> + int i, nr, base;
> + irqreturn_t ret = IRQ_NONE;
> +
> + for (i = 0; i < GSTA_NR_BLOCKS; i++) {
> + regs = chip->regs[i];
> + base = chip->irq_base + i * GSTA_GPIO_PER_BLOCK;
> + while ((is = readl(®s->is))) {
> + nr = __ffs(is);
> + irq = base + nr;
> + generic_handle_irq(irq);
> + writel(1 << nr, ®s->ic);
> + ret = IRQ_HANDLED;
> + }
> + }
> + return ret;
> +}
> +
> +static __devinit void gsta_alloc_irq_chip(struct gsta_gpio *chip)
> +{
> + struct irq_chip_generic *gc;
> + struct irq_chip_type *ct;
> +
> + gc = irq_alloc_generic_chip(KBUILD_MODNAME, 1, chip->irq_base,
> + chip->reg_base, handle_simple_irq);
> + gc->private = chip;
> + ct = gc->chip_types;
> +
> + ct->chip.irq_set_type = gsta_irq_type;
> + ct->chip.irq_disable = gsta_irq_disable;
> + ct->chip.irq_enable = gsta_irq_enable;
> +
> + /* FIXME: this makes at most 32 interrupts. Request 0 by now */
> + irq_setup_generic_chip(gc, 0 /* IRQ_MSK(GSTA_GPIO_PER_BLOCK) */, 0,
> + IRQ_NOREQUEST | IRQ_NOPROBE, 0);
> +
> + /* Set up all all 128 interrupts: code from setup_generic_chip */
> + {
> + struct irq_chip_type *ct = gc->chip_types;
> + int i, j;
> + for (j = 0; j < GSTA_NR_GPIO; j++) {
> + i = chip->irq_base + j;
> + irq_set_chip_and_handler(i, &ct->chip, ct->handler);
> + irq_set_chip_data(i, gc);
> + irq_modify_status(i, IRQ_NOREQUEST | IRQ_NOPROBE, 0);
> + }
> + gc->irq_cnt = i - gc->irq_base;
> + }
> +}
> +
> +/* The platform device used here is instantiated by the MFD device */
> +static int __devinit gsta_probe(struct platform_device *dev)
> +{
> + int i, err;
> + struct pci_dev *pdev;
> + struct sta2x11_gpio_pdata *gpio_pdata;
> + struct gsta_gpio *chip;
> + struct resource *res;
> +
> + pdev = *(struct pci_dev **)(dev->dev.platform_data);
> + gpio_pdata = dev_get_platdata(&pdev->dev);
> +
> + if (gpio_pdata == NULL)
> + dev_err(&dev->dev, "no gpio config\n");
> + printk("gpio config: %p\n", gpio_pdata);
> +
> + res = platform_get_resource(dev, IORESOURCE_MEM, 0);
> + request_mem_region(res->start, resource_size(res), KBUILD_MODNAME);
> +
> +
> + chip = kzalloc(sizeof(*chip), GFP_KERNEL);
devm_kzalloc() will make this code simpler (don't need to kfree on
error or remove).
> + chip->dev = &dev->dev;
> + chip->reg_base = ioremap(res->start, resource_size(res));
> + chip->irq_base = -1;
This line is meaningless.
> + for (i = 0; i < GSTA_NR_BLOCKS; i++) {
> + chip->regs[i] = chip->reg_base + i * 4096;
> + /* disable all irqs */
> + writel(0, &chip->regs[i]->rimsc);
> + writel(0, &chip->regs[i]->fimsc);
> + writel(~0, &chip->regs[i]->ic);
> + }
> + spin_lock_init(&chip->lock);
> + gsta_gpio_setup(chip);
> + for (i = 0; i < GSTA_NR_GPIO; i++)
> + gsta_set_config(chip, i, gpio_pdata->pinconfig[i]);
> + err = gpiochip_add(&chip->gpio);
> + if (err < 0) {
> + dev_err(&dev->dev, "sta2x11 gpio: Can't register (%i)\n",
> + -err);
> + kfree(chip);
> + return err;
> + }
> + /* 384 was used in previous code: be compatible for other drivers */
> + err = irq_alloc_descs(-1, 384, GSTA_NR_GPIO, NUMA_NO_NODE);
That's a lot of irqs. Will they all be used? How do other drivers
determine which irq number to use (is it statically assigned, or is there
a dynamic mechanism)? If only a portion are used, then the irq_domain
linear mapping would be a win here.
> +
> + if (err < 0) {
> + dev_warn(&dev->dev, "sta2x11 gpio: Can't get irq base (%i)\n",
> + -err);
> + goto err_out;
> + }
> + chip->irq_base = err;
> + gsta_alloc_irq_chip(chip);
> +
> + err = request_irq(pdev->irq, gsta_gpio_handler,
> + IRQF_SHARED, KBUILD_MODNAME, chip);
> + if (err < 0) {
> + dev_err(&dev->dev, "sta2x11 gpio: Can't request irq (%i)\n",
> + -err);
> + goto err_out;
> + }
> +
> + platform_set_drvdata(dev, chip);
> + return 0;
> +
> +err_out:
> + if (chip->irq_base > 0)
> + irq_free_descs(chip->irq_base, GSTA_NR_GPIO);
> + kfree(chip);
> + return err;
> +}
> +
> +static struct platform_driver sta2x11_gpio_platform_driver = {
> + .driver = {
> + .name = "sta2x11-gpio",
> + .owner = THIS_MODULE,
> + },
> + .probe = gsta_probe,
> +};
> +
> +static int __init sta2x11_gpio_init(void)
> +{
> + return platform_driver_register(&sta2x11_gpio_platform_driver);
> +}
> +
> +module_init(sta2x11_gpio_init);
module_platform_driver()
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("sta2x11_gpio GPIO driver");
> --
> 1.7.7.2
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