comedi: comedi_8254: Replace comedi_8254_init() and comedi_8254_mm_init()

`comedi_8254_init()` and `comedi_8254_mm_init()` return `NULL` on
failure, but the failure is not necessarily due to lack of memory.
Change them to return an `ERR_PTR` value on failure and rename the
functions to make it obvious the API has changed. `comedi_8254_init()`
has been replaced with `comedi_8254_io_alloc()`, and
`comedi_8254_mm_init()` has been replaced with `comedi_8254_mm_alloc()`.

Cc: Arnd Bergmann <[e-mail]>
Cc: Niklas Schnelle <[e-mail]>
Signed-off-by: Ian Abbott <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/comedi/drivers.c

···
 		dev->n_subdevices = 0;
 	}
 	kfree(dev->private);
-	kfree(dev->pacer);
+	if (!IS_ERR(dev->pacer))
+		kfree(dev->pacer);
 	dev->private = NULL;
 	dev->pacer = NULL;
 	dev->driver = NULL;

drivers/comedi/drivers/adl_pci9111.c

···
 			dev->irq = pcidev->irq;
 	}
 
-	dev->pacer = comedi_8254_init(dev->iobase + PCI9111_8254_BASE_REG,
-				      I8254_OSC_BASE_2MHZ, I8254_IO16, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + PCI9111_8254_BASE_REG,
+					  I8254_OSC_BASE_2MHZ, I8254_IO16, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	ret = comedi_alloc_subdevices(dev, 4);
 	if (ret)

drivers/comedi/drivers/adl_pci9118.c

···
 	devpriv->iobase_a = pci_resource_start(pcidev, 0);
 	dev->iobase = pci_resource_start(pcidev, 2);
 
-	dev->pacer = comedi_8254_init(dev->iobase + PCI9118_TIMER_BASE,
-				      I8254_OSC_BASE_4MHZ, I8254_IO32, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + PCI9118_TIMER_BASE,
+					  I8254_OSC_BASE_4MHZ, I8254_IO32, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	pci9118_reset(dev);
 

drivers/comedi/drivers/adv_pci1710.c

···
 		return ret;
 	dev->iobase = pci_resource_start(pcidev, 2);
 
-	dev->pacer = comedi_8254_init(dev->iobase + PCI171X_TIMER_BASE,
-				      I8254_OSC_BASE_10MHZ, I8254_IO16, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + PCI171X_TIMER_BASE,
+					  I8254_OSC_BASE_10MHZ, I8254_IO16, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	n_subdevices = 1;	/* all boards have analog inputs */
 	if (board->has_ao)

drivers/comedi/drivers/adv_pci_dio.c

···
 	if (board->timer_regbase) {
 		s = &dev->subdevices[subdev++];
 
-		dev->pacer = comedi_8254_init(dev->iobase +
-					      board->timer_regbase,
-					      0, I8254_IO8, 0);
-		if (!dev->pacer)
-			return -ENOMEM;
+		dev->pacer =
+		    comedi_8254_io_alloc(dev->iobase + board->timer_regbase,
+					 0, I8254_IO8, 0);
+		if (IS_ERR(dev->pacer))
+			return PTR_ERR(dev->pacer);
 
 		comedi_8254_subdevice_init(s, dev->pacer);
 	}

drivers/comedi/drivers/aio_aio12_8.c

···
 	if (ret)
 		return ret;
 
-	dev->pacer = comedi_8254_init(dev->iobase + AIO12_8_8254_BASE_REG,
-				      0, I8254_IO8, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + AIO12_8_8254_BASE_REG,
+					  0, I8254_IO8, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	ret = comedi_alloc_subdevices(dev, 4);
 	if (ret)

drivers/comedi/drivers/amplc_dio200_common.c

···
 	}
 
 	if (dev->mmio) {
-		i8254 = comedi_8254_mm_init(dev->mmio + offset,
-					    0, I8254_IO8, regshift);
+		i8254 = comedi_8254_mm_alloc(dev->mmio + offset,
+					     0, I8254_IO8, regshift);
 	} else {
-		i8254 = comedi_8254_init(dev->iobase + offset,
-					 0, I8254_IO8, regshift);
+		i8254 = comedi_8254_io_alloc(dev->iobase + offset,
+					     0, I8254_IO8, regshift);
 	}
-	if (!i8254)
-		return -ENOMEM;
+	if (IS_ERR(i8254))
+		return PTR_ERR(i8254);
 
 	comedi_8254_subdevice_init(s, i8254);
 

drivers/comedi/drivers/amplc_pci224.c

···
 	outw(devpriv->daccon | PCI224_DACCON_FIFORESET,
 	     dev->iobase + PCI224_DACCON);
 
-	dev->pacer = comedi_8254_init(devpriv->iobase1 + PCI224_Z2_BASE,
-				      I8254_OSC_BASE_10MHZ, I8254_IO8, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(devpriv->iobase1 + PCI224_Z2_BASE,
+					  I8254_OSC_BASE_10MHZ, I8254_IO8, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	ret = comedi_alloc_subdevices(dev, 1);
 	if (ret)

drivers/comedi/drivers/amplc_pci230.c

···
 			dev->irq = pci_dev->irq;
 	}
 
-	dev->pacer = comedi_8254_init(dev->iobase + PCI230_Z2_CT_BASE,
-				      0, I8254_IO8, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + PCI230_Z2_CT_BASE,
+					  0, I8254_IO8, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	rc = comedi_alloc_subdevices(dev, 3);
 	if (rc)

drivers/comedi/drivers/cb_das16_cs.c

···
 	if (!devpriv)
 		return -ENOMEM;
 
-	dev->pacer = comedi_8254_init(dev->iobase + DAS16CS_TIMER_BASE,
-				      I8254_OSC_BASE_10MHZ, I8254_IO16, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + DAS16CS_TIMER_BASE,
+					  I8254_OSC_BASE_10MHZ, I8254_IO16, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	ret = comedi_alloc_subdevices(dev, 4);
 	if (ret)

drivers/comedi/drivers/cb_pcidas.c

···
 	}
 	dev->irq = pcidev->irq;
 
-	dev->pacer = comedi_8254_init(dev->iobase + PCIDAS_AI_8254_BASE,
-				      I8254_OSC_BASE_10MHZ, I8254_IO8, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + PCIDAS_AI_8254_BASE,
+					  I8254_OSC_BASE_10MHZ, I8254_IO8, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
-	devpriv->ao_pacer = comedi_8254_init(dev->iobase + PCIDAS_AO_8254_BASE,
-					     I8254_OSC_BASE_10MHZ,
-					     I8254_IO8, 0);
-	if (!devpriv->ao_pacer)
-		return -ENOMEM;
+	devpriv->ao_pacer =
+	    comedi_8254_io_alloc(dev->iobase + PCIDAS_AO_8254_BASE,
+				 I8254_OSC_BASE_10MHZ, I8254_IO8, 0);
+	if (IS_ERR(devpriv->ao_pacer))
+		return PTR_ERR(devpriv->ao_pacer);
 
 	ret = comedi_alloc_subdevices(dev, 7);
 	if (ret)
···
 		if (devpriv->amcc)
 			outl(INTCSR_INBOX_INTR_STATUS,
 			     devpriv->amcc + AMCC_OP_REG_INTCSR);
-		kfree(devpriv->ao_pacer);
+		if (!IS_ERR(devpriv->ao_pacer))
+			kfree(devpriv->ao_pacer);
 	}
 	comedi_pci_detach(dev);
 }

drivers/comedi/drivers/cb_pcimdas.c

···
 	devpriv->BADR3 = pci_resource_start(pcidev, 3);
 	dev->iobase = pci_resource_start(pcidev, 4);
 
-	dev->pacer = comedi_8254_init(devpriv->BADR3 + PCIMDAS_8254_BASE,
-				      cb_pcimdas_pacer_clk(dev),
-				      I8254_IO8, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(devpriv->BADR3 + PCIMDAS_8254_BASE,
+					  cb_pcimdas_pacer_clk(dev),
+					  I8254_IO8, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	ret = comedi_alloc_subdevices(dev, 6);
 	if (ret)

drivers/comedi/drivers/comedi_8254.c

···
  *
  * This module provides the following basic functions:
  *
- * comedi_8254_init() / comedi_8254_mm_init()
+ * comedi_8254_io_alloc() / comedi_8254_mm_alloc()
  *	Initializes this module to access the 8254 registers. The _mm version
- *	sets up the module for MMIO register access the other for PIO access.
- *	The pointer returned from these functions is normally stored in the
- *	comedi_device dev->pacer and will be freed by the comedi core during
- *	the driver (*detach). If a driver has multiple 8254 devices, they need
- *	to be stored in the drivers private data and freed when the driver is
- *	detached.
+ *	sets up the module for MMIO register access; the _io version sets it
+ *	up for PIO access.  These functions return a pointer to a struct
+ *	comedi_8254 on success, or an ERR_PTR value on failure.  The pointer
+ *	returned from these functions is normally stored in the comedi_device
+ *	dev->pacer and will be freed by the comedi core during the driver
+ *	(*detach). If a driver has multiple 8254 devices, they need to be
+ *	stored in the drivers private data and freed when the driver is
+ *	detached.  If the ERR_PTR value is stored, code should check the
+ *	pointer value with !IS_ERR(pointer) before freeing.
  *
  *	NOTE: The counters are reset by setting them to I8254_MODE0 as part of
  *	this initialization.
···
 	/* sanity check that the iosize is valid */
 	if (!(iosize == I8254_IO8 || iosize == I8254_IO16 ||
 	      iosize == I8254_IO32))
-		return NULL;
+		return ERR_PTR(-EINVAL);
 
 	if (!iocb)
-		return NULL;
+		return ERR_PTR(-EINVAL);
 
 	i8254 = kzalloc(sizeof(*i8254), GFP_KERNEL);
 	if (!i8254)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	i8254->iocb	= iocb;
 	i8254->context	= context;
···
 }
 
 /**
- * comedi_8254_init - allocate and initialize the 8254 device for pio access
+ * comedi_8254_io_alloc - allocate and initialize the 8254 device for pio access
  * @iobase:	port I/O base address
  * @osc_base:	base time of the counter in ns
  *		OPTIONAL - only used by comedi_8254_cascade_ns_to_timer()
  * @iosize:	I/O register size
  * @regshift:	register gap shift
+ *
+ * Return: A pointer to a struct comedi_8254 or an ERR_PTR value.
  */
-struct comedi_8254 *comedi_8254_init(unsigned long iobase,
-				     unsigned int osc_base,
-				     unsigned int iosize,
-				     unsigned int regshift)
+struct comedi_8254 *comedi_8254_io_alloc(unsigned long iobase,
+					 unsigned int osc_base,
+					 unsigned int iosize,
+					 unsigned int regshift)
 {
 	comedi_8254_iocb_fn *iocb;
 
···
 		iocb = i8254_io32_cb;
 		break;
 	default:
-		return NULL;
+		return ERR_PTR(-EINVAL);
 	}
 	return __i8254_init(iocb, iobase, osc_base, iosize, regshift);
 }
-EXPORT_SYMBOL_GPL(comedi_8254_init);
+EXPORT_SYMBOL_GPL(comedi_8254_io_alloc);
 
 /**
- * comedi_8254_mm_init - allocate and initialize the 8254 device for mmio access
+ * comedi_8254_mm_alloc - allocate and initialize the 8254 device for mmio access
  * @mmio:	memory mapped I/O base address
  * @osc_base:	base time of the counter in ns
  *		OPTIONAL - only used by comedi_8254_cascade_ns_to_timer()
  * @iosize:	I/O register size
  * @regshift:	register gap shift
+ *
+ * Return: A pointer to a struct comedi_8254 or an ERR_PTR value.
  */
-struct comedi_8254 *comedi_8254_mm_init(void __iomem *mmio,
-					unsigned int osc_base,
-					unsigned int iosize,
-					unsigned int regshift)
+struct comedi_8254 *comedi_8254_mm_alloc(void __iomem *mmio,
+					 unsigned int osc_base,
+					 unsigned int iosize,
+					 unsigned int regshift)
 {
 	comedi_8254_iocb_fn *iocb;
 
···
 		iocb = i8254_mmio32_cb;
 		break;
 	default:
-		return NULL;
+		return ERR_PTR(-EINVAL);
 	}
 	return __i8254_init(iocb, (unsigned long)mmio, osc_base, iosize, regshift);
 }
-EXPORT_SYMBOL_GPL(comedi_8254_mm_init);
+EXPORT_SYMBOL_GPL(comedi_8254_mm_alloc);
 
 static int __init comedi_8254_module_init(void)
 {

drivers/comedi/drivers/das08.c

···
 	/* Counter subdevice (8254) */
 	s = &dev->subdevices[5];
 	if (board->i8254_offset) {
-		dev->pacer = comedi_8254_init(dev->iobase + board->i8254_offset,
-					      0, I8254_IO8, 0);
-		if (!dev->pacer)
-			return -ENOMEM;
+		dev->pacer =
+		    comedi_8254_io_alloc(dev->iobase + board->i8254_offset,
+					 0, I8254_IO8, 0);
+		if (IS_ERR(dev->pacer))
+			return PTR_ERR(dev->pacer);
 
 		comedi_8254_subdevice_init(s, dev->pacer);
 	} else {

drivers/comedi/drivers/das16.c

···
 			osc_base = I8254_OSC_BASE_1MHZ / it->options[3];
 	}
 
-	dev->pacer = comedi_8254_init(dev->iobase + DAS16_TIMER_BASE_REG,
-				      osc_base, I8254_IO8, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + DAS16_TIMER_BASE_REG,
+					  osc_base, I8254_IO8, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	das16_alloc_dma(dev, it->options[2]);
 

drivers/comedi/drivers/das16m1.c

···
 			dev->irq = it->options[1];
 	}
 
-	dev->pacer = comedi_8254_init(dev->iobase + DAS16M1_8254_IOBASE2,
-				      I8254_OSC_BASE_10MHZ, I8254_IO8, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + DAS16M1_8254_IOBASE2,
+					  I8254_OSC_BASE_10MHZ, I8254_IO8, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
-	devpriv->counter = comedi_8254_init(dev->iobase + DAS16M1_8254_IOBASE1,
-					    0, I8254_IO8, 0);
-	if (!devpriv->counter)
-		return -ENOMEM;
+	devpriv->counter =
+	    comedi_8254_io_alloc(dev->iobase + DAS16M1_8254_IOBASE1,
+				 0, I8254_IO8, 0);
+	if (IS_ERR(devpriv->counter))
+		return PTR_ERR(devpriv->counter);
 
 	ret = comedi_alloc_subdevices(dev, 4);
 	if (ret)
···
 	if (devpriv) {
 		if (devpriv->extra_iobase)
 			release_region(devpriv->extra_iobase, DAS16M1_SIZE2);
-		kfree(devpriv->counter);
+		if (!IS_ERR(devpriv->counter))
+			kfree(devpriv->counter);
 	}
 	comedi_legacy_detach(dev);
 }

drivers/comedi/drivers/das1800.c

···
 	if (!devpriv->fifo_buf)
 		return -ENOMEM;
 
-	dev->pacer = comedi_8254_init(dev->iobase + DAS1800_COUNTER,
-				      I8254_OSC_BASE_5MHZ, I8254_IO8, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + DAS1800_COUNTER,
+					  I8254_OSC_BASE_5MHZ, I8254_IO8, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	ret = comedi_alloc_subdevices(dev, 4);
 	if (ret)

drivers/comedi/drivers/das6402.c

···
 		}
 	}
 
-	dev->pacer = comedi_8254_init(dev->iobase + DAS6402_TIMER_BASE,
-				      I8254_OSC_BASE_10MHZ, I8254_IO8, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + DAS6402_TIMER_BASE,
+					  I8254_OSC_BASE_10MHZ, I8254_IO8, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	ret = comedi_alloc_subdevices(dev, 4);
 	if (ret)

drivers/comedi/drivers/das800.c

···
 			dev->irq = irq;
 	}
 
-	dev->pacer = comedi_8254_init(dev->iobase + DAS800_8254,
-				      I8254_OSC_BASE_1MHZ, I8254_IO8, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + DAS800_8254,
+					  I8254_OSC_BASE_1MHZ, I8254_IO8, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	ret = comedi_alloc_subdevices(dev, 3);
 	if (ret)

drivers/comedi/drivers/me4000.c

···
 		if (!timer_base)
 			return -ENODEV;
 
-		dev->pacer = comedi_8254_init(timer_base, 0, I8254_IO8, 0);
-		if (!dev->pacer)
-			return -ENOMEM;
+		dev->pacer = comedi_8254_io_alloc(timer_base, 0, I8254_IO8, 0);
+		if (IS_ERR(dev->pacer))
+			return PTR_ERR(dev->pacer);
 
 		comedi_8254_subdevice_init(s, dev->pacer);
 	} else {

drivers/comedi/drivers/ni_at_a2150.c

···
 	/* an IRQ and DMA are required to support async commands */
 	a2150_alloc_irq_and_dma(dev, it);
 
-	dev->pacer = comedi_8254_init(dev->iobase + I8253_BASE_REG,
-				      0, I8254_IO8, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + I8253_BASE_REG,
+					  0, I8254_IO8, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	ret = comedi_alloc_subdevices(dev, 1);
 	if (ret)

drivers/comedi/drivers/ni_at_ao.c

···
 	if (!devpriv)
 		return -ENOMEM;
 
-	dev->pacer = comedi_8254_init(dev->iobase + ATAO_82C53_BASE,
-				      0, I8254_IO8, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + ATAO_82C53_BASE,
+					  0, I8254_IO8, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	ret = comedi_alloc_subdevices(dev, 4);
 	if (ret)

drivers/comedi/drivers/ni_labpc_common.c

···
 	}
 
 	if (dev->mmio) {
-		dev->pacer = comedi_8254_mm_init(dev->mmio + COUNTER_B_BASE_REG,
-						 I8254_OSC_BASE_2MHZ,
-						 I8254_IO8, 0);
-		devpriv->counter = comedi_8254_mm_init(dev->mmio +
-						       COUNTER_A_BASE_REG,
-						       I8254_OSC_BASE_2MHZ,
-						       I8254_IO8, 0);
+		dev->pacer =
+		    comedi_8254_mm_alloc(dev->mmio + COUNTER_B_BASE_REG,
+					 I8254_OSC_BASE_2MHZ, I8254_IO8, 0);
+		devpriv->counter =
+		    comedi_8254_mm_alloc(dev->mmio + COUNTER_A_BASE_REG,
+					 I8254_OSC_BASE_2MHZ, I8254_IO8, 0);
 	} else {
-		dev->pacer = comedi_8254_init(dev->iobase + COUNTER_B_BASE_REG,
-					      I8254_OSC_BASE_2MHZ,
-					      I8254_IO8, 0);
-		devpriv->counter = comedi_8254_init(dev->iobase +
-						    COUNTER_A_BASE_REG,
-						    I8254_OSC_BASE_2MHZ,
-						    I8254_IO8, 0);
+		dev->pacer =
+		    comedi_8254_io_alloc(dev->iobase + COUNTER_B_BASE_REG,
+					 I8254_OSC_BASE_2MHZ, I8254_IO8, 0);
+		devpriv->counter =
+		    comedi_8254_io_alloc(dev->iobase + COUNTER_A_BASE_REG,
+					 I8254_OSC_BASE_2MHZ, I8254_IO8, 0);
 	}
-	if (!dev->pacer || !devpriv->counter)
-		return -ENOMEM;
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
+	if (IS_ERR(devpriv->counter))
+		return PTR_ERR(devpriv->counter);
 
 	ret = comedi_alloc_subdevices(dev, 5);
 	if (ret)
···
 {
 	struct labpc_private *devpriv = dev->private;
 
-	if (devpriv)
-		kfree(devpriv->counter);
+	if (devpriv) {
+		if (!IS_ERR(devpriv->counter))
+			kfree(devpriv->counter);
+	}
 }
 EXPORT_SYMBOL_GPL(labpc_common_detach);
 

drivers/comedi/drivers/pcl711.c

···
 			dev->irq = it->options[1];
 	}
 
-	dev->pacer = comedi_8254_init(dev->iobase + PCL711_TIMER_BASE,
-				      I8254_OSC_BASE_2MHZ, I8254_IO8, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + PCL711_TIMER_BASE,
+					  I8254_OSC_BASE_2MHZ, I8254_IO8, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	ret = comedi_alloc_subdevices(dev, 4);
 	if (ret)

drivers/comedi/drivers/pcl812.c

···
 		return ret;
 
 	if (board->irq_bits) {
-		dev->pacer = comedi_8254_init(dev->iobase + PCL812_TIMER_BASE,
-					      I8254_OSC_BASE_2MHZ,
-					      I8254_IO8, 0);
-		if (!dev->pacer)
-			return -ENOMEM;
+		dev->pacer =
+		    comedi_8254_io_alloc(dev->iobase + PCL812_TIMER_BASE,
+					 I8254_OSC_BASE_2MHZ, I8254_IO8, 0);
+		if (IS_ERR(dev->pacer))
+			return PTR_ERR(dev->pacer);
 
 		if ((1 << it->options[1]) & board->irq_bits) {
 			ret = request_irq(it->options[1], pcl812_interrupt, 0,

drivers/comedi/drivers/pcl816.c

···
 	/* an IRQ and DMA are required to support async commands */
 	pcl816_alloc_irq_and_dma(dev, it);
 
-	dev->pacer = comedi_8254_init(dev->iobase + PCL816_TIMER_BASE,
-				      I8254_OSC_BASE_10MHZ, I8254_IO8, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + PCL816_TIMER_BASE,
+					  I8254_OSC_BASE_10MHZ, I8254_IO8, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	ret = comedi_alloc_subdevices(dev, 4);
 	if (ret)

drivers/comedi/drivers/pcl818.c

···
 	else
 		osc_base = I8254_OSC_BASE_1MHZ;
 
-	dev->pacer = comedi_8254_init(dev->iobase + PCL818_TIMER_BASE,
-				      osc_base, I8254_IO8, 0);
-	if (!dev->pacer)
-		return -ENOMEM;
+	dev->pacer = comedi_8254_io_alloc(dev->iobase + PCL818_TIMER_BASE,
+					  osc_base, I8254_IO8, 0);
+	if (IS_ERR(dev->pacer))
+		return PTR_ERR(dev->pacer);
 
 	/* max sampling speed */
 	devpriv->ns_min = board->ns_min;

drivers/comedi/drivers/rtd520.c

···
 
 	/* 8254 Timer/Counter subdevice */
 	s = &dev->subdevices[3];
-	dev->pacer = comedi_8254_mm_init(dev->mmio + LAS0_8254_TIMER_BASE,
-					 RTD_CLOCK_BASE, I8254_IO8, 2);
-	if (!dev->pacer)
+	dev->pacer = comedi_8254_mm_alloc(dev->mmio + LAS0_8254_TIMER_BASE,
+					  RTD_CLOCK_BASE, I8254_IO8, 2);
+	if (IS_ERR(dev->pacer))
 		return -ENOMEM;
 
 	comedi_8254_subdevice_init(s, dev->pacer);

include/linux/comedi/comedi_8254.h

···
 void comedi_8254_subdevice_init(struct comedi_subdevice *s,
 				struct comedi_8254 *i8254);
 
-struct comedi_8254 *comedi_8254_init(unsigned long iobase,
-				     unsigned int osc_base,
-				     unsigned int iosize,
-				     unsigned int regshift);
-struct comedi_8254 *comedi_8254_mm_init(void __iomem *mmio,
-					unsigned int osc_base,
-					unsigned int iosize,
-					unsigned int regshift);
+struct comedi_8254 *comedi_8254_io_alloc(unsigned long iobase,
+					 unsigned int osc_base,
+					 unsigned int iosize,
+					 unsigned int regshift);
+struct comedi_8254 *comedi_8254_mm_alloc(void __iomem *mmio,
+					 unsigned int osc_base,
+					 unsigned int iosize,
+					 unsigned int regshift);
 
 #endif	/* _COMEDI_8254_H */