Subject: Re: [PATCH] powerpc: Xilinx: PS2: driver updates based on review

From: Peter Korsgaard <[email-masked]>
Date: Thu, 10 Jul 2008 20:27:30 +0200

>>>>> "John" == John Linn <[email-masked]> writes:

 > Review comments were incorporated to improve the driver.
 > 1. Some data was eliminated that was not needed.
 > 2. Renaming of variables for clarity.
 > 3. Removed unneeded type casting.
 > 4. Changed to use dev_err rather than other I/O.
 > 5. Merged together some functions.
 > 6. Added kerneldoc format to functions.

 > Signed-off-by: Sadanand <[email-masked]>
 > Signed-off-by: John Linn <[email-masked]>

If the minor issues below gets fixed:

Acked-by: Peter Korsgaard <[email-masked]>

 > This patch is an incremental patch to be applied to 
 > [V3] powerpc: Xilinx: PS2: Added new XPS PS2 driver.

 >  drivers/input/serio/xilinx_ps2.c |  220 +++++++++++++++++++++----------------
 >  1 files changed, 125 insertions(+), 95 deletions(-)

 > diff --git a/drivers/input/serio/xilinx_ps2.c b/drivers/input/serio/xilinx_ps2.c
 > index e86f11b..eba46c7 100644
 > --- a/drivers/input/serio/xilinx_ps2.c
 > +++ b/drivers/input/serio/xilinx_ps2.c
 > @@ -58,23 +58,20 @@
 
 >  /* Mask for all the Receive Interrupts */
 >  #define XPS2_IPIXR_RX_ALL	(XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR |  \
 > -					XPS2_IPIXR_RX_FULL)
 > +				 XPS2_IPIXR_RX_FULL)
 
 >  /* Mask for all the Interrupts */
 >  #define XPS2_IPIXR_ALL		(XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL |  \
 > -					XPS2_IPIXR_WDT_TOUT)
 > +				 XPS2_IPIXR_WDT_TOUT)
 
 >  /* Global Interrupt Enable mask */
 >  #define XPS2_GIER_GIE_MASK	0x80000000
 
 >  struct xps2data {
 >  	int irq;
 > -	u32 phys_addr;
 > -	u32 remap_size;
 >  	spinlock_t lock;
 > -	u8 rxb;				/* Rx buffer */
 >  	void __iomem *base_address;	/* virt. address of control registers */
 > -	unsigned int dfl;
 > +	unsigned int flags;
 >  	struct serio serio;		/* serio */
 >  };
 
 > @@ -82,8 +79,13 @@ struct xps2data {
 >  /* XPS PS/2 data transmission calls */
 >  /************************************/
 
 > -/*
 > - * xps2_recv() will attempt to receive a byte of data from the PS/2 port.
 > +/**
 > + * xps2_recv() - attempts to receive a byte from the PS/2 port.
 > + * @drvdata:	pointer to ps2 device private data structure
 > + * @byte:	address where the read data will be copied
 > + *
 > + * If there is any data available in the PS/2 receiver, this functions reads
 > + * the data, otherwise it returns error.
 >   */
 >  static int xps2_recv(struct xps2data *drvdata, u8 *byte)
 >  {
 > @@ -105,7 +107,7 @@ static int xps2_recv(struct xps2data *drvdata, u8 *byte)
 >  /*********************/
 >  static irqreturn_t xps2_interrupt(int irq, void *dev_id)
 >  {
 > -	struct xps2data *drvdata = (struct xps2data *)dev_id;
 > +	struct xps2data *drvdata = dev_id;
 >  	u32 intr_sr;
 >  	u8 c;
 >  	int status;
 > @@ -115,35 +117,28 @@ static irqreturn_t xps2_interrupt(int irq, void *dev_id)
 >  	out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);
 
 >  	/* Check which interrupt is active */
 > -	if (intr_sr & XPS2_IPIXR_RX_OVF) {
 > -		printk(KERN_ERR "%s: receive overrun error\n",
 > -			drvdata->serio.name);
 > -	}
 > +	if (intr_sr & XPS2_IPIXR_RX_OVF)
 > +		dev_err(drvdata->serio.dev.parent, "receive overrun error\n");
 
 >  	if (intr_sr & XPS2_IPIXR_RX_ERR)
 > -		drvdata->dfl |= SERIO_PARITY;
 > +		drvdata->flags |= SERIO_PARITY;
 
 >  	if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
 > -		drvdata->dfl |= SERIO_TIMEOUT;
 > +		drvdata->flags |= SERIO_TIMEOUT;
 
 >  	if (intr_sr & XPS2_IPIXR_RX_FULL) {
 > -		status = xps2_recv(drvdata, &drvdata->rxb);
 > +		status = xps2_recv(drvdata, &c);
 
 >  		/* Error, if a byte is not received */
 >  		if (status) {
 > -			printk(KERN_ERR
 > -				"%s: wrong rcvd byte count (%d)\n",
 > -				drvdata->serio.name, status);
 > +			dev_err(drvdata->serio.dev.parent,
 > +				"wrong rcvd byte count\n");

You used to print the byte count - Isn't that interesting debugging
data?

 >  		} else {
 > -			c = drvdata->rxb;
 > -			serio_interrupt(&drvdata->serio, c, drvdata->dfl);
 > -			drvdata->dfl = 0;
 > +			serio_interrupt(&drvdata->serio, c, drvdata->flags);
 > +			drvdata->flags = 0;
 >  		}
 >  	}
 
 > -	if (intr_sr & XPS2_IPIXR_TX_ACK)
 > -		drvdata->dfl = 0;
 > -
 >  	return IRQ_HANDLED;
 >  }
 
 > @@ -151,8 +146,15 @@ static irqreturn_t xps2_interrupt(int irq, void *dev_id)
 >  /* serio callbacks */
 >  /*******************/
 
 > -/*
 > - * sxps2_write() sends a byte out through the PS/2 interface.
 > +/**
 > + * sxps2_write() - sends a byte out through the PS/2 port.
 > + * @pserio:	pointer to the serio structure of the PS/2 port
 > + * @c:		data that needs to be written to the PS/2 port
 > + *
 > + * This fucntion checks if the PS/2 transmitter is empty and sends a byte.

s/fucntion/function/

 > + * Otherwise it returns error. Transmission fails only when nothing is connected
 > + * to the PS/2 port. Thats why, we do not try to resend the data in case of a
 > + * failure.
 >   */
 >  static int sxps2_write(struct serio *pserio, unsigned char c)
 >  {
 > @@ -173,33 +175,39 @@ static int sxps2_write(struct serio *pserio, unsigned char c)
 >  	return status;
 >  }
 
 > -/*
 > - * sxps2_open() is called when a port is open by the higher layer.
 > +/**
 > + * sxps2_open() - called when a port is opened by the higher layer.
 > + * @pserio:	pointer to the serio structure of the PS/2 device
 > + *
 > + * This function requests irq and enables interrupts for the PS/2 device.
 >   */
 >  static int sxps2_open(struct serio *pserio)
 >  {
 >  	struct xps2data *drvdata = pserio->port_data;
 >  	int retval;
 > +	u8 c;
 
 >  	retval = request_irq(drvdata->irq, &xps2_interrupt, 0,
 >  				DRIVER_NAME, drvdata);
 >  	if (retval) {
 > -		printk(KERN_ERR
 > -			"%s: Couldn't allocate interrupt %d\n",
 > -			drvdata->serio.name, drvdata->irq);
 > +		dev_err(drvdata->serio.dev.parent,
 > +			"Couldn't allocate interrupt %d\n", drvdata->irq);
 >  		return retval;
 >  	}
 
 >  	/* start reception by enabling the interrupts */
 >  	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
 >  	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
 > -	(void)xps2_recv(drvdata, &drvdata->rxb);
 > +	(void)xps2_recv(drvdata, &c);
 
 >  	return 0;		/* success */
 >  }
 
 > -/*
 > - * sxps2_close() frees the interrupt.
 > +/**
 > + * sxps2_close() - frees the interrupt.
 > + * @pserio:	pointer to the serio structure of the PS/2 device
 > + *
 > + * This function frees the irq and disables interrupts for the PS/2 device.
 >   */
 >  static void sxps2_close(struct serio *pserio)
 >  {
 > @@ -211,21 +219,60 @@ static void sxps2_close(struct serio *pserio)
 >  	free_irq(drvdata->irq, drvdata);
 >  }
 
 > -/*********************/
 > -/* Device setup code */
 > -/*********************/
 > +/***************************/
 > +/* OF Platform Bus Support */
 > +/***************************/
 
 > -static int xps2_setup(struct device *dev, struct resource *regs_res,
 > -		      struct resource *irq_res)
 > +/**
 > + * xps2_of_probe - probe method for the PS/2 device.
 > + * @of_dev:	pointer to OF device structure
 > + * @match:	pointer to the stucture used for matching a device
 > + *
 > + * This function probes for a matching PS/2 device using OF properties and
 > + * attaches it to the platform bus. It initializes the driver data structure
 > + * and also initializes the hardware.
 > + * It returns 0, if the driver is bound to the PS/2 device, or a negative value
 > + * if there is an error. It releases all the allocated resources in case of an
 > + * error.

The function doesn't have anything to do with the platform bus, and
the comment is imho more verbose than needed.

 > + *
 > + */
 > +static int __devinit xps2_of_probe(struct of_device *ofdev, const struct
 > +				   of_device_id * match)
 >  {
 > +	struct resource r_irq; /* Interrupt resources */
 > +	struct resource r_mem; /* IO mem resources */
 >  	struct xps2data *drvdata;
 >  	struct serio *serio;
 > -	unsigned long remap_size;
 > -	int retval;
 > +	struct device *dev;
 > +	resource_size_t remap_size, phys_addr;
 > +	int rc = 0;
 
 > +	dev = &ofdev->dev;
 >  	if (!dev)
 >  		return -EINVAL;
 
 > +	dev_info(dev, "Device Tree Probing \'%s\'\n",
 > +			ofdev->node->name);
 > +
 > +	/* Get iospace for the device */
 > +	rc = of_address_to_resource(ofdev->node, 0, &r_mem);
 > +	if (rc) {
 > +		dev_err(dev, "invalid address\n");
 > +		return rc;
 > +	}
 > +
 > +	/* Get IRQ for the device */
 > +	rc = of_irq_to_resource(ofdev->node, 0, &r_irq);
 > +	if (rc == NO_IRQ) {
 > +		dev_err(dev, "no IRQ found\n");
 > +		return rc;
 > +	}
 > +
 > +	if (!(&r_mem) || !(&r_irq)) {
 > +		dev_err(dev, "IO resource(s) not found\n");
 > +		return -EFAULT;
 > +	}

How can this ever fail? They are local structures, not pointers

 > +
 >  	drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
 >  	if (!drvdata) {
 >  		dev_err(dev, "Couldn't allocate device private record\n");
 > @@ -234,31 +281,24 @@ static int xps2_setup(struct device *dev, struct resource *regs_res,
 >  	spin_lock_init(&drvdata->lock);
 >  	dev_set_drvdata(dev, drvdata);
 
 > -	if (!regs_res || !irq_res) {
 > -		dev_err(dev, "IO resource(s) not found\n");
 > -		retval = -EFAULT;
 > -		goto failed1;
 > -	}
 > -
 > -	drvdata->irq = irq_res->start;
 > -	remap_size = regs_res->end - regs_res->start + 1;
 > -	if (!request_mem_region(regs_res->start, remap_size, DRIVER_NAME)) {
 > +	drvdata->irq = r_irq.start;
 > +	phys_addr = r_mem.start;
 > +	remap_size = r_mem.end - r_mem.start + 1;
 > +	if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
 
 >  		dev_err(dev, "Couldn't lock memory region at 0x%08X\n",
 > -			(unsigned int)regs_res->start);
 > -		retval = -EBUSY;
 > +			(unsigned int)phys_addr);
 > +		rc = -EBUSY;
 >  		goto failed1;
 >  	}
 
 >  	/* Fill in configuration data and add them to the list */
 > -	drvdata->phys_addr = regs_res->start;
 > -	drvdata->remap_size = remap_size;
 > -	drvdata->base_address = ioremap(regs_res->start, remap_size);
 > +	drvdata->base_address = ioremap(phys_addr, remap_size);
 >  	if (drvdata->base_address == NULL) {
 
 >  		dev_err(dev, "Couldn't ioremap memory at 0x%08X\n",
 > -			(unsigned int)regs_res->start);
 > -		retval = -EFAULT;
 > +			(unsigned int)phys_addr);
 > +		rc = -EFAULT;
 >  		goto failed2;
 >  	}
 
 > @@ -270,7 +310,8 @@ static int xps2_setup(struct device *dev, struct resource *regs_res,
 >  	out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
 
 >  	dev_info(dev, "Xilinx PS2 at 0x%08X mapped to 0x%08X, irq=%d\n",
 > -		drvdata->phys_addr, (u32)drvdata->base_address, drvdata->irq);
 > +		 (unsigned int)phys_addr, (u32)drvdata->base_address,
 > +		 drvdata->irq);
 
 >  	serio = &drvdata->serio;
 serio-> id.type = SERIO_8042;
 > @@ -280,58 +321,38 @@ static int xps2_setup(struct device *dev, struct resource *regs_res,
 serio-> port_data = drvdata;
 serio-> dev.parent = dev;
 >  	snprintf(drvdata->serio.name, sizeof(serio->name),
 > -		 "Xilinx XPS PS/2 at %08X", drvdata->phys_addr);
 > +		 "Xilinx XPS PS/2 at %08X", (unsigned int)phys_addr);
 >  	snprintf(drvdata->serio.phys, sizeof(serio->phys),
 > -		 "xilinxps2/serio at %08X", drvdata->phys_addr);
 > +		 "xilinxps2/serio at %08X", (unsigned int)phys_addr);
 >  	serio_register_port(serio);
 
 >  	return 0;		/* success */
 
 >  failed2:
 > -	release_mem_region(regs_res->start, remap_size);
 > +	release_mem_region(phys_addr, remap_size);
 
 >  failed1:
 >  	kfree(drvdata);
 >  	dev_set_drvdata(dev, NULL);
 
 > -	return retval;
 > -}
 > -
 > -/***************************/
 > -/* OF Platform Bus Support */
 > -/***************************/
 > -
 > -static int __devinit xps2_of_probe(struct of_device *ofdev, const struct
 > -				   of_device_id * match)
 > -{
 > -	struct resource r_irq; /* Interrupt resources */
 > -	struct resource r_mem; /* IO mem resources */
 > -	int rc = 0;
 > -
 > -	printk(KERN_INFO "Device Tree Probing \'%s\'\n",
 > -			ofdev->node->name);
 > -
 > -	/* Get iospace for the device */
 > -	rc = of_address_to_resource(ofdev->node, 0, &r_mem);
 > -	if (rc) {
 > -		dev_err(&ofdev->dev, "invalid address\n");
 > -		return rc;
 > -	}
 > -
 > -	/* Get IRQ for the device */
 > -	rc = of_irq_to_resource(ofdev->node, 0, &r_irq);
 > -	if (rc == NO_IRQ) {
 > -		dev_err(&ofdev->dev, "no IRQ found\n");
 > -		return rc;
 > -	}
 > -
 > -	return xps2_setup(&ofdev->dev, &r_mem, &r_irq);
 > +	return rc;
 >  }
 
 > +/**
 > + * xps2_of_remove - unbinds the driver from the PS/2 device.
 > + * @of_dev:	pointer to OF device structure
 > + *
 > + * This function is called if a device is physically removed from the system or
 > + * if the driver module is being unloaded. It checks if the device is present

Where's that check?

 > + * and frees any resources allocated to the device.
 > + */
 >  static int __devexit xps2_of_remove(struct of_device *of_dev)
 >  {
 >  	struct xps2data *drvdata;
 >  	struct device *dev;
 > +	struct resource r_mem; /* IO mem resources */
 > +	resource_size_t phys_addr, remap_size;
 > +	int rc;
 
 >  	dev = &of_dev->dev;
 >  	if (!dev)
 > @@ -343,7 +364,16 @@ static int __devexit xps2_of_remove(struct of_device *of_dev)
 
 >  	iounmap(drvdata->base_address);
 
 > -	release_mem_region(drvdata->phys_addr, drvdata->remap_size);
 > +	/* Get iospace of the device */
 > +	rc = of_address_to_resource(of_dev->node, 0, &r_mem);
 > +	if (rc) {
 > +		dev_err(dev, "invalid address\n");
 > +		return rc;
 > +	}
 > +
 > +	phys_addr = r_mem.start;
 > +	remap_size = r_mem.end - r_mem.start + 1;
 > +	release_mem_region(phys_addr, remap_size);

You only use phys_addr / remap_size once - just use r_mem directly instead.

 >  	kfree(drvdata);
 >  	dev_set_drvdata(dev, NULL);
 > -- 
 > 1.5.2.1

-- 
Bye, Peter Korsgaard