Merge tag 'gpio-updates-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux

Pull gpio updates from Bartosz Golaszewski:
 "We mostly have various improvements and refactoring all over the place
  but also some interesting new features - like the virtio GPIO driver
  that allows guest VMs to use host's GPIOs. We also have a new/old GPIO
  driver for rockchip - this one has been split out of the pinctrl
  driver.

  Summary:

   - new driver: gpio-virtio allowing a guest VM running linux to access
     GPIO lines provided by the host

   - split the GPIO driver out of the rockchip pin control driver

   - add support for a new model to gpio-aspeed-sgpio, refactor the
     driver and use generic device property interfaces, improve property
     sanitization

   - add ACPI support to gpio-tegra186

   - improve the code setting the line names to support multiple GPIO
     banks per device

   - constify a bunch of OF functions in the core GPIO code and make the
     declaration for one of the core OF functions we use consistent
     within its header

   - use software nodes in intel_quark_i2c_gpio

   - add support for the gpio-line-names property in gpio-mt7621

   - use the standard GPIO function for setting the GPIO names in
     gpio-brcmstb

   - fix a bunch of leaks and other bugs in gpio-mpc8xxx

   - use generic pm callbacks in gpio-ml-ioh

   - improve resource management and PM handling in gpio-mlxbf2

   - modernize and improve the gpio-dwapb driver

   - coding style improvements in gpio-rcar

   - documentation fixes and improvements

   - update the MAINTAINERS entry for gpio-zynq

   - minor tweaks in several drivers"

* tag 'gpio-updates-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: (35 commits)
  gpio: mpc8xxx: Use 'devm_gpiochip_add_data()' to simplify the code and avoid a leak
  gpio: mpc8xxx: Fix a potential double iounmap call in 'mpc8xxx_probe()'
  gpio: mpc8xxx: Fix a resources leak in the error handling path of 'mpc8xxx_probe()'
  gpio: viperboard: remove platform_set_drvdata() call in probe
  gpio: virtio: Add missing mailings lists in MAINTAINERS entry
  gpio: virtio: Fix sparse warnings
  gpio: remove the obsolete MX35 3DS BOARD MC9S08DZ60 GPIO functions
  gpio: max730x: Use the right include
  gpio: Add virtio-gpio driver
  gpio: mlxbf2: Use DEFINE_RES_MEM_NAMED() helper macro
  gpio: mlxbf2: Use devm_platform_ioremap_resource()
  gpio: mlxbf2: Drop wrong use of ACPI_PTR()
  gpio: mlxbf2: Convert to device PM ops
  gpio: dwapb: Get rid of legacy platform data
  mfd: intel_quark_i2c_gpio: Convert GPIO to use software nodes
  gpio: dwapb: Read GPIO base from gpio-base property
  gpio: dwapb: Unify ACPI enumeration checks in get_irq() and configure_irqs()
  gpiolib: Deduplicate forward declaration in the consumer.h header
  MAINTAINERS: update gpio-zynq.yaml reference
  gpio: tegra186: Add ACPI support
  ...

1 files changed, 27 insertions, 5 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 27c07108496d..d1b9b721218f 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -382,10 +382,18 @@ static int devprop_gpiochip_set_names(struct gpio_chip *chip)
 	if (count < 0)
 		return 0;
 
-	if (count > gdev->ngpio) {
-		dev_warn(&gdev->dev, "gpio-line-names is length %d but should be at most length %d",
-			 count, gdev->ngpio);
-		count = gdev->ngpio;
+	/*
+	 * When offset is set in the driver side we assume the driver internally
+	 * is using more than one gpiochip per the same device. We have to stop
+	 * setting friendly names if the specified ones with 'gpio-line-names'
+	 * are less than the offset in the device itself. This means all the
+	 * lines are not present for every single pin within all the internal
+	 * gpiochips.
+	 */
+	if (count <= chip->offset) {
+		dev_warn(&gdev->dev, "gpio-line-names too short (length %d), cannot map names for the gpiochip at offset %u\n",
+			 count, chip->offset);
+		return 0;
 	}
 
 	names = kcalloc(count, sizeof(*names), GFP_KERNEL);
@@ -400,8 +408,22 @@ static int devprop_gpiochip_set_names(struct gpio_chip *chip)
 		return ret;
 	}
 
+	/*
+	 * When more that one gpiochip per device is used, 'count' can
+	 * contain at most number gpiochips x chip->ngpio. We have to
+	 * correctly distribute all defined lines taking into account
+	 * chip->offset as starting point from where we will assign
+	 * the names to pins from the 'names' array. Since property
+	 * 'gpio-line-names' cannot contains gaps, we have to be sure
+	 * we only assign those pins that really exists since chip->ngpio
+	 * can be different of the chip->offset.
+	 */
+	count = (count > chip->offset) ? count - chip->offset : count;
+	if (count > chip->ngpio)
+		count = chip->ngpio;
+
 	for (i = 0; i < count; i++)
-		gdev->descs[i].name = names[i];
+		gdev->descs[i].name = names[chip->offset + i];
 
 	kfree(names);