RE: [PATCH net-next v8 6/9] net: txgbe: Support GPIO to SFP socket

Jiawen Wu
2023-05-23T02:09:16Z

On Tuesday, May 23, 2023 5:37 AM, Andy Shevchenko wrote:
> On Mon, May 22, 2023 at 06:58:19PM +0800, Jiawen Wu wrote:
> > On Monday, May 22, 2023 5:01 PM, Jiawen Wu wrote:
> > > On Friday, May 19, 2023 9:13 PM, Andrew Lunn wrote:
> > > > > I have one MSI-X interrupt for all general MAC interrupt (see TXGBE_PX_MISC_IEN_MASK).
> > > > > It has 32 bits to indicate various interrupts, GPIOs are the one of them. When GPIO
> > > > > interrupt is determined, GPIO_INT_STATUS register should be read to determine
> > > > > which GPIO line has changed state.
> > > >
> > > > So you have another interrupt controller above the GPIO interrupt
> > > > controller. regmap-gpio is pushing you towards describing this
> > > > interrupt controller as a Linux interrupt controller.
> > > >
> > > > When you look at drivers handling interrupts, most leaf interrupt
> > > > controllers are not described as Linux interrupt controllers. The
> > > > driver interrupt handler reads the interrupt status register and
> > > > internally dispatches to the needed handler. This works well when
> > > > everything is internal to one driver.
> > > >
> > > > However, here, you have two drivers involved, your MAC driver and a
> > > > GPIO driver instantiated by the MAC driver. So i think you are going
> > > > to need to described the MAC interrupt controller as a Linux interrupt
> > > > controller.
> > > >
> > > > Take a look at the mv88e6xxx driver, which does this. It has two
> > > > interrupt controller embedded within it, and they are chained.
> > >
> > > Now I add two interrupt controllers, the first one for the MAC interrupt,
> > > and the second one for regmap-gpio. In the second adding flow,
> > >
> > > irq = irq_find_mapping(txgbe->misc.domain, TXGBE_PX_MISC_GPIO_OFFSET);
> > > err = regmap_add_irq_chip_fwnode(fwnode, regmap, irq, 0, 0,
> > > chip, &chip_data);
> > >
> > > and then,
> > >
> > > config.irq_domain = regmap_irq_get_domain(chip_data);
> > > gpio_regmap = gpio_regmap_register(&config);
> > >
> > > "txgbe->misc.domain" is the MAC interrupt domain. I think this flow should
> > > be correct, but still failed to get gpio_irq from gpio_desc with err -517.
> > >
> > > And I still have doubts about what I said earlier:
> > > https://lore.kernel.org/netdev/20230515063200.301026-1-
> > > jiawenwu@trustnetic.com/T/#me1be68e1a1e44426ecc0dd8edf0f6b224e50630d
> > >
> > > There really is nothing wrong with gpiochip_to_irq()??
> >
> > There is indeed something wrong in gpiochip_to_irq(), since commit 5467801 ("gpio:
> > Restrict usage of GPIO chip irq members before initialization"):
> > https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit?id=5467801f1fcbdc46bc7298a84dbf3ca1ff2a7320
> >
> > When I use gpio_regmap_register() to add gpiochip, gpiochip_add_irqchip() will just
> > return 0 since irqchip = NULL, then gc->irq.initialized = false.
>
> As far as I understood your hardware, you need to provide an IRQ chip for your
> GPIOs. The driver that provides an IRQ chip for GPIO and uses GPIO regmap is
> drivers/gpio/gpio-sl28cpld.c.
>
> So, you need to create a proper IRQ domain tree before calling for GPIO
> registration.

I've already created it. There is the full code snippet:

+static int txgbe_gpio_init(struct txgbe *txgbe)
+{
+ struct regmap_irq_chip_data *chip_data;
+ struct gpio_regmap_config config = {};
+ struct gpio_regmap *gpio_regmap;
+ struct fwnode_handle *fwnode;
+ struct regmap_irq_chip *chip;
+ struct regmap *regmap;
+ struct pci_dev *pdev;
+ struct device *dev;
+ unsigned int irq;
+ struct wx *wx;
+ int err;
+
+ wx = txgbe->wx;
+ pdev = wx->pdev;
+ dev = &pdev->dev;
+ fwnode = software_node_fwnode(txgbe->nodes.group[SWNODE_GPIO]);
+
+ regmap = devm_regmap_init(dev, NULL, wx, &gpio_regmap_config);
+ if (IS_ERR(regmap)) {
+ wx_err(wx, "failed to init GPIO regmap\n");
+ return PTR_ERR(regmap);
+ }
+
+ chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ chip->name = "txgbe-gpio-irq";
+ chip->irq_drv_data = wx;
+ chip->num_regs = 1;
+ chip->irqs = txgbe_gpio_irqs;
+ chip->num_irqs = ARRAY_SIZE(txgbe_gpio_irqs);
+ chip->status_base = WX_GPIO_INTSTATUS;
+ chip->ack_base = WX_GPIO_EOI;
+ chip->mask_base = WX_GPIO_INTMASK;
+ chip->get_irq_reg = txgbe_get_irq_reg;
+ chip->handle_post_irq = txgbe_handle_post_irq;
+
+ irq = irq_find_mapping(txgbe->misc.domain, TXGBE_PX_MISC_GPIO_OFFSET);
+ err = regmap_add_irq_chip_fwnode(fwnode, regmap, irq, 0, 0,
+ chip, &chip_data);
+ if (err) {
+ wx_err(wx, "GPIO IRQ register failed\n");
+ return err;
+ }
+
+ txgbe->gpio_irq = irq;
+ txgbe->gpio_data = chip_data;
+
+ config.label = devm_kasprintf(dev, GFP_KERNEL, "txgbe_gpio-%x",
+ (pdev->bus->number << 8) | pdev->devfn);
+ config.parent = dev;
+ config.regmap = regmap;
+ config.fwnode = fwnode;
+ config.drvdata = txgbe;
+ config.ngpio = 6;
+ config.reg_mask_xlate = txgbe_reg_mask_xlate;
+ config.reg_dat_base = WX_GPIO_EXT;
+ config.reg_set_base = WX_GPIO_DR;
+ config.reg_dir_out_base = WX_GPIO_DDR;
+ config.irq_domain = regmap_irq_get_domain(chip_data);
+
+ gpio_regmap = gpio_regmap_register(&config);
+ if (IS_ERR(gpio_regmap)) {
+ wx_err(wx, "GPIO regmap register failed\n");
+ regmap_del_irq_chip(irq, chip_data);
+ return PTR_ERR(gpio_regmap);
+ }
+
+ txgbe->gpio_regmap = gpio_regmap;
+
+ return 0;
+}

>
> > Cc the committer: Shreeya Patel.
>
> You meant "author", right?

Yes, author.
I think "gpiochip_add_data" does not take gpio-regmap case into account.