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Date: Tue, 8 Dec 2015 15:15:24 -0700
From: Joshua Henderson <joshua.henderson@...rochip.com>
To: Linus Walleij <linus.walleij@...aro.org>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Linux MIPS <linux-mips@...ux-mips.org>,
Andrei Pistirica <andrei.pistirica@...rochip.com>,
"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>
Subject: Re: [PATCH 08/14] pinctrl: Add PIC32 pin control driver
Linus,
On 11/30/2015 06:41 AM, Linus Walleij wrote:
> On Sat, Nov 21, 2015 at 1:17 AM, Joshua Henderson
> <joshua.henderson@...rochip.com> wrote:
>
>> From: Andrei Pistirica <andrei.pistirica@...rochip.com>
>>
>> Add a driver for the pin controller present on the Microchip PIC32
>> including the specific variant PIC32MZDA. This driver provides pinmux
>> and pinconfig operations as well as GPIO and IRQ chips for the GPIO
>> banks.
>>
>> Signed-off-by: Andrei Pistirica <andrei.pistirica@...rochip.com>
>> Signed-off-by: Joshua Henderson <joshua.henderson@...rochip.com>
>
>> +config PINCTRL_PIC32
>> + bool "Microchip PIC32 pin controller driver"
>> + depends on OF
>> + depends on MACH_PIC32
>> + select PINMUX
>> + select GENERIC_PINCONF
>> + select GPIOLIB_IRQCHIP
>
> Nice but...
>
>> +struct pic32_gpio_irq {
>> + struct irq_chip gpio_irqchip;
>> + struct irq_domain *domain;
>
>
> If you're using GPIOLIB_IRQCHIP with a separate irq_domain
> you are totally missing the point of GPIOLIB_IRQCHIP.
>
> Look closer at other drivers using GPIOLIB_IRQCHIP and
> get your driver to use the infrastructure properly.
>
Consider it done.
>> +#define to_pic32_gpio_chip(c) container_of(c, struct pic32_gpio_chip, chip)
>
> Make this a static inline function instead. #defines are
> hard to read.
>
Ack.
>> +static struct pic32_gpio_chip *gpio_chips[MAX_PIO_BANKS];
>
> Why? You should not need to keep track of the chips
> in some local array.
Ack.
>
>> +int pic32_pinconf_open_drain_runtime(unsigned pin_id, int value)
>> +{
>> + struct pic32_gpio_chip *pic32_chip = gpio_to_pic32_gpio_chip(pin_id);
>> + unsigned pin = pin_id % PINS_PER_BANK;
>> +
>> + if (IS_ERR_OR_NULL(pic32_chip))
>> + return -ENODEV;
>> +
>> + return pic32_pinconf_open_drain(pic32_chip, pin, value);
>> +}
>> +EXPORT_SYMBOL(pic32_pinconf_open_drain_runtime);
>
> NO WAY are you going to call this from outside of the driver, even
> less other modules.
>
> Use pin control states to control the pins, no cross calling of
> functions in the middle of everything thanks.
>
> You shouldn't need one set of calls for "runtime" either, all pin
> control states are possible to control at runtime, we have no
> distinction between boot time and any other time.
>
Ack.
>> +static int pic32_gpio_request(struct gpio_chip *chip, unsigned offset)
>> +{
>> + int gpio = chip->base + offset;
>> + int bank = chip->base / chip->ngpio;
>> +
>> + dev_dbg(chip->dev, "%s: request GPIO-%c:%d(%d)\n", __func__,
>> + 'A' + bank, offset, gpio);
>> +
>> + return pinctrl_request_gpio(gpio);
>> +}
>> +
>> +static void pic32_gpio_free(struct gpio_chip *chip, unsigned offset)
>> +{
>> + int gpio = chip->base + offset;
>> + int bank = chip->base / chip->ngpio;
>> +
>> + dev_dbg(chip->dev, "%s: free GPIO-%c:%d(%d)\n", __func__,
>> + 'A' + bank, offset, gpio);
>> +
>> + pinctrl_free_gpio(gpio);
>> +}
>
> This looks nice.
>
With existing rework, these are gone.
>> +static int pic32_gpio_get(struct gpio_chip *chip, unsigned gpio)
>> +{
>> + struct pic32_gpio_chip *pic32_chip = to_pic32_gpio_chip(chip);
>> + struct pic32_reg __iomem *port_reg = (struct pic32_reg __iomem *)
>> + pic32_pio_get_reg(pic32_chip, PIC32_PORT);
>> + u32 mask = BIT(gpio);
>> +
>> + if (WARN_ON(port_reg == NULL || gpio >= chip->ngpio))
>> + return -EINVAL;
>> +
>> + return readl(&port_reg->val) & mask;
>
> return !!(readl(&port_reg->val) & mask);
>
> to clamp it to 0/1.
Ack.
>
>> +static int pic32_gpio_get_dir(struct gpio_chip *chip, unsigned offset)
>> +{
>> + struct pic32_gpio_chip *pic32_chip = to_pic32_gpio_chip(chip);
>> + struct pic32_reg __iomem *tris_reg = (struct pic32_reg __iomem *)
>> + pic32_pio_get_reg(pic32_chip, PIC32_TRIS);
>> + u32 mask = BIT(offset);
>> +
>> + if (WARN_ON(tris_reg == NULL))
>> + return -EINVAL;
>> +
>> + return readl(&tris_reg->val) & mask;
>
> Dito.
Ack.
>
>> +static int pic32_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
>> +{
>> + struct pic32_gpio_chip *pic32_chip = to_pic32_gpio_chip(chip);
>> + struct pic32_gpio_irq *gpio_irq = &pic32_chip->gpio_irq;
>> + int virq;
>> +
>> + if (offset < chip->ngpio)
>> + virq = irq_create_mapping(gpio_irq->domain, offset);
>> + else
>> + virq = -ENXIO;
>> +
>> + dev_dbg(chip->dev, "%s: request IRQ for GPIO:%d, return:%d\n",
>> + __func__, offset + chip->base, virq);
>> +
>> + return virq;
>> +}
>
> This is handled by GPIOLIB_IRQCHIP and you should not define
> .to_irq() for a driver using that.
>
Ack.
>> +static void pic32_gpio_ranges_setup(struct platform_device *pdev,
>> + struct pic32_gpio_chip *pic32_chip)
>> +{
>> + struct device_node *np = pdev->dev.of_node;
>> + struct pinctrl_gpio_range *range;
>> + struct of_phandle_args args;
>> + int ret;
>> +
>> + ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 0, &args);
>> + pic32_chip->gpio_base = (ret == 0) ? args.args[1] + args.args[0] :
>> + pic32_chip->pio_idx * PINS_PER_BANK;
>> + pic32_chip->ngpio = (ret == 0) ? args.args[2] - args.args[0] :
>> + PINS_PER_BANK;
>> +
>> + range = &pic32_chip->range;
>> + range->name = dev_name(&pdev->dev);
>> + range->id = pic32_chip->pio_idx;
>> + range->pin_base = range->base = pic32_chip->gpio_base;
>> +
>> + range->npins = pic32_chip->ngpio;
>> + range->gc = &pic32_chip->chip;
>> +
>> + dev_dbg(&pdev->dev, "%s: GPIO-%c ranges: (%d,%d)\n", __func__,
>> + 'A' + range->id,
>> + pic32_chip->gpio_base, pic32_chip->ngpio);
>> +}
>
> What is the point of this? We alread add the ranged in the gpiolib
> core.
>
Ack. It's no longer necessary when using gpiolib properly.
>> +static unsigned int gpio_irq_startup(struct irq_data *d)
>
> This is a too generic name for a function, rename all of these
> prefixed with your custom name like pic32_irq_type() etc.
>
Ack.
>> +{
>> + struct pic32_gpio_chip *pic32_chip = irq_data_get_irq_chip_data(d);
>> + struct pic32_gpio_irq *gpio_irq = &pic32_chip->gpio_irq;
>> + unsigned pin = d->hwirq;
>> + int ret;
>> +
>> + ret = gpiochip_lock_as_irq(&pic32_chip->chip, pin);
>> + if (ret) {
>> + dev_err(pic32_chip->chip.dev, "unable to lock pind %lu IRQ\n",
>> + d->hwirq);
>> + return ret;
>> + }
>
> This should not be called in .irq_startup() but in .irq_request_resources()
> and will not be needed at all if you use GPIOLIB_IRQCHIP properly
> since it defines these callbacks for you and handle them in the
> gpiolib core.
>
Ack.
>> +
>> + /* start CN */
>> + switch (gpio_irq->type[pin]) {
>> + case IRQ_TYPE_EDGE_RISING:
>> + pic32_gpio_irq_rise_dset(pic32_chip, pin);
>> + break;
>> + case IRQ_TYPE_EDGE_FALLING:
>> + pic32_gpio_irq_fall_dset(pic32_chip, pin);
>> + break;
>> + case IRQ_TYPE_EDGE_BOTH:
>> + pic32_gpio_irq_rise_dset(pic32_chip, pin);
>> + pic32_gpio_irq_fall_dset(pic32_chip, pin);
>> + break;
>> + default:
>> + return -EINVAL;
>> + }
>
> Why are you doin this in the .startup() callback? This should be done
> in .set_type().
>
Agreed.
>> +static int gpio_irq_type(struct irq_data *d, unsigned type)
>
> This is a too generic name for a function, rename all of these
> prefixed with your custom name like pic32_irq_type() etc.
>
Ack.
>> +{
>> + struct pic32_gpio_chip *pic32_chip = irq_data_get_irq_chip_data(d);
>> + struct pic32_gpio_irq *gpio_irq = &pic32_chip->gpio_irq;
>> + unsigned pin = d->hwirq;
>> +
>> + dev_dbg(pic32_chip->chip.dev, "%s: irq type:%u\n", __func__, type);
>> +
>> + switch (type) {
>> + case IRQ_TYPE_EDGE_RISING:
>> + case IRQ_TYPE_EDGE_FALLING:
>> + case IRQ_TYPE_EDGE_BOTH:
>> + gpio_irq->type[pin] = type;
>> + return IRQ_SET_MASK_OK;
>> + default:
>> + gpio_irq->type[pin] = IRQ_TYPE_NONE;
>> + return -EINVAL;
>> + }
>> +}
>
> Do you rely on semantic call order like this being called before startup?
>
> I do't think that's good, why can't you write to the hardware directly
> in this function?
Agreed. I see no reason why we can't write to the hardware directly. Simpler and cleaner.
>
>> +/* map virtual irq on hw irq: domain translation */
>> +static int pic32_gpio_irq_map(struct irq_domain *d,
>> + unsigned int virq,
>> + irq_hw_number_t hw)
>> +/* decode irq number: base + pin */
>> +static int pic32_gpio_irq_domain_xlate(struct irq_domain *d,
>> + struct device_node *ctrlr,
>> + const u32 *intspec,
>> + unsigned int intsize,
>> + irq_hw_number_t *out_hwirq,
>> + unsigned int *out_type)
>> +{
>
> None of these should be needed if you use GPIOLIB_IRQCHIP.
Ack.
>
>> +static int pic32_gpio_irq_map(struct irq_domain *d,
>> + unsigned int virq,
>> + irq_hw_number_t hw)
>> +{
>> + struct pic32_gpio_chip *pic32_chip = d->host_data;
>> + struct pic32_gpio_irq *gpio_irq = &pic32_chip->gpio_irq;
>> + struct irq_chip *irqchip = &gpio_irq->gpio_irqchip;
>> +
>> + dev_dbg(pic32_chip->chip.dev, "%s: GPIO-%c:%d map virq:%u\n", __func__,
>> + 'A' + pic32_chip->pio_idx, virq, virq);
>> +
>> + /* set the gpioX chip */
>> + irq_set_chip(virq, irqchip);
>> + irq_set_chip_data(virq, pic32_chip);
>> + irq_set_handler(virq, handle_simple_irq);
>
> This driver should use handle_edge_irq() and implement .irq_ack().
Ack.
>
>> +static struct irq_domain_ops pic32_gpio_irqd_ops = {
>> + .map = pic32_gpio_irq_map,
>> + .xlate = pic32_gpio_irq_domain_xlate,
>> +};
>
> And no custom domain at all.
Removed.
>
>> +static int pic32_gpio_of_irq_setup(struct platform_device *pdev,
>> + struct pic32_gpio_chip *pic32_chip)
>> +{
>> + struct device_node *node = pdev->dev.of_node;
>> + struct pic32_gpio_irq *gpio_irq = &pic32_chip->gpio_irq;
>> + struct irq_chip *irqchip = &gpio_irq->gpio_irqchip;
>> + int base_irq;
>> +
>> + /* set irqchip */
>> + irqchip->name = kasprintf(GFP_KERNEL, "GPIO-%c",
>> + pic32_chip->pio_idx + 'A');
>> + irqchip->irq_startup = gpio_irq_startup;
>> + irqchip->irq_shutdown = gpio_irq_shutdown;
>> + irqchip->irq_set_type = gpio_irq_type;
>
> Since you are supporting *only* edge IRQs you should
> implement and ->irq_ack() callback that ACKs the IRQ.
> Most likely the gpio controller is holding a level IRQ to the
> next interrupt controller active until you do this.
>
> You should also make sure to use handle_edge_irq() as IRQ
> handler as this is what the chip supports.
Ack. The hardware only supports edge interrupts for gpios. I am curious what impact only supporting edge here will be. Would you suggest emulating level interrupts in this case?
>
>> + base_irq = platform_get_irq(pdev, 0);
>> + if (base_irq < 0)
>> + return base_irq;
>> +
>> + gpio_irq->pio_irq = base_irq;
>> +
>> + /* Setup irq domain of ngpio lines */
>> + gpio_irq->domain = irq_domain_add_linear(
>> + node,
>> + pic32_chip->chip.ngpio,
>> + &pic32_gpio_irqd_ops, pic32_chip);
>> + if (!gpio_irq->domain) {
>> + dev_err(pic32_chip->chip.dev, "Couldn't allocate IRQ domain\n");
>> + return -ENXIO;
>> + }
>
> This stuff should not be needed with GPIOLIB_IRQCHIP.
>
Ack.
>> + dev_dbg(&pdev->dev, "%s: irq GPIO-%c, base_irq:%d, domain:%d\n",
>> + __func__, pic32_chip->pio_idx + 'A',
>> + base_irq, pic32_chip->chip.ngpio);
>> +
>> + /* setup chained handler */
>> + irq_set_chip_data(gpio_irq->pio_irq, pic32_chip);
>> + irq_set_chained_handler(gpio_irq->pio_irq, gpio_irq_handler);
>
> And you should add the GPIO irqchip with
> gpiolib_add_irqchip().
Ack.
>
>> +int pic32_gpio_probe(struct platform_device *pdev,
>> + unsigned (*reg_lookup_off)[],
>> + unsigned lookup_size)
>> +{
>> + struct device_node *np = pdev->dev.of_node;
>> + int alias_idx = of_alias_get_id(np, "gpio");
>> + struct pic32_gpio_chip *pic32_chip = NULL;
>> + struct gpio_chip *chip;
>> + struct resource *r;
>> + int ret = 0;
>> +
>> + dev_dbg(&pdev->dev, "%s: probing...\n", __func__);
>> +
>> + if (!np)
>> + return -ENODEV;
>> +
>> + if (WARN_ON(alias_idx >= ARRAY_SIZE(gpio_chips)))
>> + return -EINVAL;
>> +
>> + if (gpio_chips[alias_idx]) {
>> + dev_err(&pdev->dev, "Failure %i for GPIO %i\n", ret, alias_idx);
>> + return -EBUSY;
>> + }
>> +
>> + /* pic32 gpio chip - private data */
>> + pic32_chip = devm_kzalloc(&pdev->dev, sizeof(*pic32_chip),
>> + GFP_KERNEL);
>> + if (!pic32_chip)
>> + return -ENOMEM;
>> +
>> + /* base address of pio(alias_idx) registers */
>> + r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + if (!r) {
>> + ret = -EINVAL;
>> + goto probe_err;
>> + }
>> + pic32_chip->pio_base = devm_ioremap_nocache(&pdev->dev, r->start,
>> + resource_size(r));
>> + if (IS_ERR(pic32_chip->pio_base)) {
>> + ret = PTR_ERR(pic32_chip->pio_base);
>> + goto probe_err;
>> + }
>> +
>> + /* clocks */
>> + pic32_chip->clk = devm_clk_get(&pdev->dev, NULL);
>> + if (IS_ERR(pic32_chip->clk)) {
>> + ret = PTR_ERR(pic32_chip->clk);
>> + dev_err(&pdev->dev, "clk get failed\n");
>> + goto probe_err;
>> + }
>> +
>> + ret = clk_prepare_enable(pic32_chip->clk);
>> + if (ret) {
>> + dev_err(&pdev->dev, "clk enable failed\n");
>> + goto probe_err;
>> + }
>> +
>> + pic32_chip->reg_lookup_off = *reg_lookup_off;
>> + pic32_chip->lookup_size = lookup_size;
>> + pic32_chip->pio_idx = alias_idx;
>> + pic32_chip->chip = gpio_template;
>> + pic32_gpio_ranges_setup(pdev, pic32_chip);/* pin_ranges: unsupported */
>
> I can't see why you have this. The gpiolib core handles this.
>
> Please fix the above and repost, and I can look at the pin control
> parts. As it is now there are too many problems with the GPIO
> parts.
>
Agreed.
> Yours,
> Linus Walleij
>
Thanks,
Josh
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