Re: [PATCH 7/8] gpio-exar/8250-exar: Make set of exported GPIOs configurable
From: Andy Shevchenko <hidden>
Date: 2017-05-13 13:50:05
Also in:
linux-gpio, lkml
On Sat, May 13, 2017 at 10:29 AM, Jan Kiszka [off-list ref] wrote:
On the SIMATIC, IOT2040 only a single pin is exportable as GPIO, the rest is required to operate the UART. To allow modeling this case, use device properties to specify a (consecutive) pin subset for exporting by the gpio-exar driver.
quoted hunk ↗ jump to hunk
@@ -123,6 +132,7 @@ static int gpio_exar_probe(struct platform_device *pdev) struct exar_gpio_chip *exar_gpio; void __iomem *p; int index, ret; + u32 val; if (pcidev->vendor != PCI_VENDOR_ID_EXAR) return -ENODEV;@@ -152,9 +162,12 @@ static int gpio_exar_probe(struct platform_device *pdev) exar_gpio->gpio_chip.get = exar_get_value; exar_gpio->gpio_chip.set = exar_set_value; exar_gpio->gpio_chip.base = -1; - exar_gpio->gpio_chip.ngpio = 16;
+ device_property_read_u32(&pdev->dev, "ngpio", &val); + exar_gpio->gpio_chip.ngpio = val;
You have to check return code, otherwise you might end up with uninitialized data.
exar_gpio->regs = p;
exar_gpio->index = index;
+ device_property_read_u32(&pdev->dev, "first_gpio", &val);
+ exar_gpio->first_gpio = val;Ditto.
#include <linux/string.h> #include <linux/tty.h> #include <linux/8250_pci.h>
+#include <linux/property.h>
Alphabetical order, please.
static void *
-xr17v35x_register_gpio(struct pci_dev *pcidev)
+xr17v35x_register_gpio(struct pci_dev *pcidev, unsigned int first_gpio,
+ unsigned int ngpio)
{
+ struct property_entry properties[] = {+ PROPERTY_ENTRY_U32("first_gpio", first_gpio),This should be documented in device tree bindings, otherwise it's a linux software hook and I'm not sure it's the best what we can do here.
+ PROPERTY_ENTRY_U32("ngpio", ngpio),This should be a registered property name (I see "ngpios" in the bindings).
+ { }
+ };
struct platform_device *pdev;
pdev = platform_device_alloc("gpio_exar", PLATFORM_DEVID_AUTO); /*
- * platform_device_add_data kmemdups the data, therefore we can safely
- * pass a stack reference.
+ * platform_device_add_data and platform_device_add_properties copy
+ * the data, therefore we can safely pass a stack references.
*/Can you formulate this in an order to reduce ping-ponging lines across the series? -- With Best Regards, Andy Shevchenko