Patchwork mpc52xx-psc-spi: refactor probe and remove to make use of of_register_spi_devices()

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Submitter Grant Likely
Date Nov. 1, 2009, 1:03 a.m.
Message ID <fa686aa40910311803m43504167s1ad802aecd2b4344@mail.gmail.com>
Download mbox | patch
Permalink /patch/37364/
State Accepted, archived
Delegated to: Grant Likely
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Comments

Grant Likely - Nov. 1, 2009, 1:03 a.m.
Hi Wolfram,

Thanks for this work. Comments below.

On Fri, Oct 30, 2009 at 1:44 PM, Wolfram Sang <w.sang@pengutronix.de> wrote:
> This driver has a generic part for the probe/remove routines which probably
> used to be called from a platform driver and an of_platform driver. Meanwhile,
> the driver is of_platform only, so there is no need for the generic part
> anymore. Unifying probe/remove finally enables us to call
> of_register_spi_devices(), so spi-device nodes from the device tree will be
> parsed. This was also mentioned by:
> http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-June/073273.html

I haven't really been happy with any of the patches that added the
of_register_spi_devices() call, but I never got around to dealing with
it properly, or even replying.  I found Jon's patch too invasive, and
the patch referenced above is a little ugly.  Adding the call should
be really simple.  I've drafted a patch to do only that step and
attached it to this mail.  If this one works for you, then I'll merge
it immediately into -next.

> On the way, some patterns have been changed to current best practices (like
> using '!ptr' and 'struct resource'). Also, an older, yet uncommented, patch
> from me has been incorporated to improve the checks if the selected PSC is
> valid:
>
> http://patchwork.ozlabs.org/patch/36780/

There are at least 3 discrete changes here.  I prefer for each to be
provided as a separate patch so I can cherry pick the ones that are
ready.  I'll go back and comment on the patch you referenced above
patch right now.

Also, I'm resistant to changing the probe layout on this driver at
this time.  With the work being done to generalize the OF support
code, there is a strong possibility that of_platform will be
deprecated in favor of going back to using the platform bus directly
(just like how OF support works for i2c, spi, etc).  I'd rather not
refactor the driver until I'm certain of the direction that things are
going to go.

Cheers,
g.

>
> Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
> Cc: Kári Davíðsson <kari.davidsson@marel.com>
> Cc: Grant Likely <grant.likely@secretlab.ca>
> ---
>  drivers/spi/mpc52xx_psc_spi.c |  110 +++++++++++++++++++---------------------
>  1 files changed, 52 insertions(+), 58 deletions(-)
>
> diff --git a/drivers/spi/mpc52xx_psc_spi.c b/drivers/spi/mpc52xx_psc_spi.c
> index 1b74d5c..3fa8c78 100644
> --- a/drivers/spi/mpc52xx_psc_spi.c
> +++ b/drivers/spi/mpc52xx_psc_spi.c
> @@ -17,6 +17,7 @@
>  #include <linux/errno.h>
>  #include <linux/interrupt.h>
>  #include <linux/of_platform.h>
> +#include <linux/of_spi.h>
>  #include <linux/workqueue.h>
>  #include <linux/completion.h>
>  #include <linux/io.h>
> @@ -27,6 +28,7 @@
>  #include <asm/mpc52xx.h>
>  #include <asm/mpc52xx_psc.h>
>
> +#define DRIVER_NAME "mpc52xx-psc-spi"
>  #define MCLK 20000000 /* PSC port MClk in hz */
>
>  struct mpc52xx_psc_spi {
> @@ -358,32 +360,54 @@ static irqreturn_t mpc52xx_psc_spi_isr(int irq, void *dev_id)
>        return IRQ_NONE;
>  }
>
> -/* bus_num is used only for the case dev->platform_data == NULL */
> -static int __init mpc52xx_psc_spi_do_probe(struct device *dev, u32 regaddr,
> -                               u32 size, unsigned int irq, s16 bus_num)
> +static int __init mpc52xx_psc_spi_of_probe(struct of_device *op,
> +       const struct of_device_id *match)
>  {
> -       struct fsl_spi_platform_data *pdata = dev->platform_data;
> +       struct fsl_spi_platform_data *pdata = op->dev.platform_data;
>        struct mpc52xx_psc_spi *mps;
>        struct spi_master *master;
> +       struct resource mem;
> +       s16 id = -1;
>        int ret;
>
> -       master = spi_alloc_master(dev, sizeof *mps);
> -       if (master == NULL)
> +       /* get PSC id (only 1,2,3,6 can do SPI) */
> +       if (!pdata) {
> +               const u32 *psc_nump;
> +
> +               psc_nump = of_get_property(op->node, "cell-index", NULL);
> +               if (!psc_nump || (*psc_nump > 2 && *psc_nump != 5)) {
> +                       dev_err(&op->dev, "PSC can't do SPI\n");
> +                       return -EINVAL;
> +               }
> +               id = *psc_nump + 1;
> +       }
> +
> +       ret = of_address_to_resource(op->node, 0, &mem);
> +       if (ret)
> +               return ret;
> +
> +       master = spi_alloc_master(&op->dev, sizeof *mps);
> +       if (!master)
>                return -ENOMEM;
>
> -       dev_set_drvdata(dev, master);
> +       if (!request_mem_region(mem.start, resource_size(&mem), DRIVER_NAME)) {
> +               ret = -ENOMEM;
> +               goto free_master;
> +       }
> +
> +       dev_set_drvdata(&op->dev, master);
>        mps = spi_master_get_devdata(master);
>
>        /* the spi->mode bits understood by this driver: */
>        master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
>
> -       mps->irq = irq;
> -       if (pdata == NULL) {
> -               dev_warn(dev, "probe called without platform data, no "
> +       mps->irq = irq_of_parse_and_map(op->node, 0);
> +       if (!pdata) {
> +               dev_info(&op->dev, "probe called without platform data, no "
>                                "cs_control function will be called\n");
>                mps->cs_control = NULL;
>                mps->sysclk = 0;
> -               master->bus_num = bus_num;
> +               master->bus_num = id;
>                master->num_chipselect = 255;
>        } else {
>                mps->cs_control = pdata->cs_control;
> @@ -395,19 +419,18 @@ static int __init mpc52xx_psc_spi_do_probe(struct device *dev, u32 regaddr,
>        master->transfer = mpc52xx_psc_spi_transfer;
>        master->cleanup = mpc52xx_psc_spi_cleanup;
>
> -       mps->psc = ioremap(regaddr, size);
> +       mps->psc = ioremap(mem.start, resource_size(&mem));
>        if (!mps->psc) {
> -               dev_err(dev, "could not ioremap I/O port range\n");
> +               dev_err(&op->dev, "could not ioremap I/O port range\n");
>                ret = -EFAULT;
> -               goto free_master;
> +               goto free_unmap;
>        }
>        /* On the 5200, fifo regs are immediately ajacent to the psc regs */
>        mps->fifo = ((void __iomem *)mps->psc) + sizeof(struct mpc52xx_psc);
>
> -       ret = request_irq(mps->irq, mpc52xx_psc_spi_isr, 0, "mpc52xx-psc-spi",
> -                               mps);
> +       ret = request_irq(mps->irq, mpc52xx_psc_spi_isr, 0, DRIVER_NAME, mps);
>        if (ret)
> -               goto free_master;
> +               goto free_unmap;
>
>        ret = mpc52xx_psc_spi_port_config(master->bus_num, mps);
>        if (ret < 0)
> @@ -429,24 +452,29 @@ static int __init mpc52xx_psc_spi_do_probe(struct device *dev, u32 regaddr,
>        if (ret < 0)
>                goto unreg_master;
>
> +       of_register_spi_devices(master, op->node);
> +
>        return ret;
>
>  unreg_master:
>        destroy_workqueue(mps->workqueue);
>  free_irq:
>        free_irq(mps->irq, mps);
> -free_master:
> +free_unmap:
>        if (mps->psc)
>                iounmap(mps->psc);
> +       release_mem_region(mem.start, resource_size(&mem));
> +free_master:
>        spi_master_put(master);
>
>        return ret;
>  }
>
> -static int __exit mpc52xx_psc_spi_do_remove(struct device *dev)
> +static int __exit mpc52xx_psc_spi_of_remove(struct of_device *op)
>  {
> -       struct spi_master *master = dev_get_drvdata(dev);
> +       struct spi_master *master = dev_get_drvdata(&op->dev);
>        struct mpc52xx_psc_spi *mps = spi_master_get_devdata(master);
> +       struct resource mem;
>
>        flush_workqueue(mps->workqueue);
>        destroy_workqueue(mps->workqueue);
> @@ -454,46 +482,12 @@ static int __exit mpc52xx_psc_spi_do_remove(struct device *dev)
>        free_irq(mps->irq, mps);
>        if (mps->psc)
>                iounmap(mps->psc);
> +       if (of_address_to_resource(op->node, 0, &mem) == 0)
> +               release_mem_region(mem.start, resource_size(&mem));
>
>        return 0;
>  }
>
> -static int __init mpc52xx_psc_spi_of_probe(struct of_device *op,
> -       const struct of_device_id *match)
> -{
> -       const u32 *regaddr_p;
> -       u64 regaddr64, size64;
> -       s16 id = -1;
> -
> -       regaddr_p = of_get_address(op->node, 0, &size64, NULL);
> -       if (!regaddr_p) {
> -               printk(KERN_ERR "Invalid PSC address\n");
> -               return -EINVAL;
> -       }
> -       regaddr64 = of_translate_address(op->node, regaddr_p);
> -
> -       /* get PSC id (1..6, used by port_config) */
> -       if (op->dev.platform_data == NULL) {
> -               const u32 *psc_nump;
> -
> -               psc_nump = of_get_property(op->node, "cell-index", NULL);
> -               if (!psc_nump || *psc_nump > 5) {
> -                       printk(KERN_ERR "mpc52xx_psc_spi: Device node %s has invalid "
> -                                       "cell-index property\n", op->node->full_name);
> -                       return -EINVAL;
> -               }
> -               id = *psc_nump + 1;
> -       }
> -
> -       return mpc52xx_psc_spi_do_probe(&op->dev, (u32)regaddr64, (u32)size64,
> -                                       irq_of_parse_and_map(op->node, 0), id);
> -}
> -
> -static int __exit mpc52xx_psc_spi_of_remove(struct of_device *op)
> -{
> -       return mpc52xx_psc_spi_do_remove(&op->dev);
> -}
> -
>  static struct of_device_id mpc52xx_psc_spi_of_match[] = {
>        { .compatible = "fsl,mpc5200-psc-spi", },
>        { .compatible = "mpc5200-psc-spi", }, /* old */
> @@ -504,12 +498,12 @@ MODULE_DEVICE_TABLE(of, mpc52xx_psc_spi_of_match);
>
>  static struct of_platform_driver mpc52xx_psc_spi_of_driver = {
>        .owner = THIS_MODULE,
> -       .name = "mpc52xx-psc-spi",
> +       .name = DRIVER_NAME,
>        .match_table = mpc52xx_psc_spi_of_match,
>        .probe = mpc52xx_psc_spi_of_probe,
>        .remove = __exit_p(mpc52xx_psc_spi_of_remove),
>        .driver = {
> -               .name = "mpc52xx-psc-spi",
> +               .name = DRIVER_NAME,
>                .owner = THIS_MODULE,
>        },
>  };
> --
> 1.6.3.3
>
>
Wolfram Sang - Nov. 2, 2009, 1:14 p.m.
Hi Grant,

> the patch referenced above is a little ugly.  Adding the call should

Agreed. I just referenced it to show there are more people wanting this
feature.

> be really simple.  I've drafted a patch to do only that step and
> attached it to this mail.  If this one works for you, then I'll merge
> it immediately into -next.

One minor comment, but works in general:

Acked-by: Wolfram Sang <w.sang@pengutronix.de>

> Also, I'm resistant to changing the probe layout on this driver at
> this time.  With the work being done to generalize the OF support
> code, there is a strong possibility that of_platform will be
> deprecated in favor of going back to using the platform bus directly
> (just like how OF support works for i2c, spi, etc).  I'd rather not
> refactor the driver until I'm certain of the direction that things are
> going to go.

And this was possibly the best answer I could get \o/ Sounds really promising,
is there somewhere a discussion about how OF-generalization could happen?

> From 7629d40dc343ff216b752d5c68654dc9d30f0c91 Mon Sep 17 00:00:00 2001
> From: Grant Likely <grant.likely@secretlab.ca>
> Date: Sat, 31 Oct 2009 17:49:38 -0600
> Subject: [PATCH] spi/mpc5200: Register SPI devices described in device tree
> 
> Add call to of_register_spi_devices() to register SPI devices described
> in the OF device tree.
> 
> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
> ---
>  drivers/spi/mpc52xx_psc_spi.c |    8 +++++++-
>  1 files changed, 7 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/spi/mpc52xx_psc_spi.c b/drivers/spi/mpc52xx_psc_spi.c
> index 1b74d5c..b445464 100644
> --- a/drivers/spi/mpc52xx_psc_spi.c
> +++ b/drivers/spi/mpc52xx_psc_spi.c
> @@ -17,6 +17,7 @@
>  #include <linux/errno.h>
>  #include <linux/interrupt.h>
>  #include <linux/of_platform.h>
> +#include <linux/of_spi.h>
>  #include <linux/workqueue.h>
>  #include <linux/completion.h>
>  #include <linux/io.h>
> @@ -464,6 +465,7 @@ static int __init mpc52xx_psc_spi_of_probe(struct of_device *op,
>  	const u32 *regaddr_p;
>  	u64 regaddr64, size64;
>  	s16 id = -1;
> +	int rc;
>  
>  	regaddr_p = of_get_address(op->node, 0, &size64, NULL);
>  	if (!regaddr_p) {
> @@ -485,8 +487,12 @@ static int __init mpc52xx_psc_spi_of_probe(struct of_device *op,
>  		id = *psc_nump + 1;
>  	}
>  
> -	return mpc52xx_psc_spi_do_probe(&op->dev, (u32)regaddr64, (u32)size64,
> +	rc = mpc52xx_psc_spi_do_probe(&op->dev, (u32)regaddr64, (u32)size64,
>  					irq_of_parse_and_map(op->node, 0), id);
> +	if (!rc)

A matter of taste, maybe: I'd prefer

	if (rc == 0)

as (!ptr) is often used for catching errors with pointers, but here it is the
'all went OK'-path.

> +		of_register_spi_devices(dev_get_drvdata(&op->dev), op->node);
> +
> +	return rc;
>  }
>  
>  static int __exit mpc52xx_psc_spi_of_remove(struct of_device *op)
> -- 
> 1.6.3.3
> 

Regards,

   Wolfram
Grant Likely - Nov. 2, 2009, 4:08 p.m.
On Mon, Nov 2, 2009 at 6:14 AM, Wolfram Sang <w.sang@pengutronix.de> wrote:
>> Also, I'm resistant to changing the probe layout on this driver at
>> this time.  With the work being done to generalize the OF support
>> code, there is a strong possibility that of_platform will be
>> deprecated in favor of going back to using the platform bus directly
>> (just like how OF support works for i2c, spi, etc).  I'd rather not
>> refactor the driver until I'm certain of the direction that things are
>> going to go.
>
> And this was possibly the best answer I could get \o/ Sounds really promising,
> is there somewhere a discussion about how OF-generalization could happen?

It has been discussed on-and-off on the mailing list and on IRC.
There are 2 major problems that need to be solved before it can be
done:
1. Figure out how to do OF-style driver probing with the platform bus.
 I could use the same heuristic as used by i2c & spi, but that
approach isn't very scalable, and doesn't handle backwards
compatibility very well.
2. Figure out the best way to extract platform data from the device
tree without having a huge impact on the device drivers.  The adapter
code still driver specific, so it needs to be part of the device
driver itself, but I want to establish a pattern which does not
require major surgery to platform drivers in order to add OF support.

>> -     return mpc52xx_psc_spi_do_probe(&op->dev, (u32)regaddr64, (u32)size64,
>> +     rc = mpc52xx_psc_spi_do_probe(&op->dev, (u32)regaddr64, (u32)size64,
>>                                       irq_of_parse_and_map(op->node, 0), id);
>> +     if (!rc)
>
> A matter of taste, maybe: I'd prefer
>
>        if (rc == 0)
>
> as (!ptr) is often used for catching errors with pointers, but here it is the
> 'all went OK'-path.

Okay, I'll change this.  Thanks for the feedback.

g.

Patch

From 7629d40dc343ff216b752d5c68654dc9d30f0c91 Mon Sep 17 00:00:00 2001
From: Grant Likely <grant.likely@secretlab.ca>
Date: Sat, 31 Oct 2009 17:49:38 -0600
Subject: [PATCH] spi/mpc5200: Register SPI devices described in device tree

Add call to of_register_spi_devices() to register SPI devices described
in the OF device tree.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
 drivers/spi/mpc52xx_psc_spi.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/drivers/spi/mpc52xx_psc_spi.c b/drivers/spi/mpc52xx_psc_spi.c
index 1b74d5c..b445464 100644
--- a/drivers/spi/mpc52xx_psc_spi.c
+++ b/drivers/spi/mpc52xx_psc_spi.c
@@ -17,6 +17,7 @@ 
 #include <linux/errno.h>
 #include <linux/interrupt.h>
 #include <linux/of_platform.h>
+#include <linux/of_spi.h>
 #include <linux/workqueue.h>
 #include <linux/completion.h>
 #include <linux/io.h>
@@ -464,6 +465,7 @@  static int __init mpc52xx_psc_spi_of_probe(struct of_device *op,
 	const u32 *regaddr_p;
 	u64 regaddr64, size64;
 	s16 id = -1;
+	int rc;
 
 	regaddr_p = of_get_address(op->node, 0, &size64, NULL);
 	if (!regaddr_p) {
@@ -485,8 +487,12 @@  static int __init mpc52xx_psc_spi_of_probe(struct of_device *op,
 		id = *psc_nump + 1;
 	}
 
-	return mpc52xx_psc_spi_do_probe(&op->dev, (u32)regaddr64, (u32)size64,
+	rc = mpc52xx_psc_spi_do_probe(&op->dev, (u32)regaddr64, (u32)size64,
 					irq_of_parse_and_map(op->node, 0), id);
+	if (!rc)
+		of_register_spi_devices(dev_get_drvdata(&op->dev), op->node);
+
+	return rc;
 }
 
 static int __exit mpc52xx_psc_spi_of_remove(struct of_device *op)
-- 
1.6.3.3