[PATCH] SPI: at25: Parse dt settings

[PATCH] SPI: at25: Parse dt settings

[Alexandre Pereira da Silva]

This adds dt support to the at25 eeprom driver.

Signed-off-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com>
Tested-by: Roland Stigge <stigge@antcom.de>
---
 Documentation/devicetree/bindings/misc/at25.txt |   21 ++++++++
 drivers/misc/eeprom/at25.c                      |   61 +++++++++++++++++------
 2 files changed, 66 insertions(+), 16 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/misc/at25.txt

diff --git a/Documentation/devicetree/bindings/misc/at25.txt b/Documentation/devicetree/bindings/misc/at25.txt
new file mode 100644
index 0000000..ab3c327
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/at25.txt
@@ -0,0 +1,21 @@
+Atmel AT25 eeprom
+
+Required properties:
+- compatible : "atmel,at25".
+- reg : chip select number
+- spi-max-frequency : max spi frequency to use
+
+- at25,byte-len : total eeprom size in bytes
+- at25,addr-mode : addr-mode flags, as defined in include/linux/spi/eeprom.h
+- at25,page-size : size of the eeprom page
+
+Examples:
+at25@0 {
+	compatible = "atmel,at25";
+	reg = <0>
+	spi-max-frequency = <5000000>;
+
+	at25,byte-len = <0x8000>;
+	at25,addr-mode = <2>;
+	at25,page-size = <64>;
+};
diff --git a/drivers/misc/eeprom/at25.c b/drivers/misc/eeprom/at25.c
index 0842c29..25003d6 100644
--- a/drivers/misc/eeprom/at25.c
+++ b/drivers/misc/eeprom/at25.c
@@ -19,7 +19,7 @@
 
 #include <linux/spi/spi.h>
 #include <linux/spi/eeprom.h>
-
+#include <linux/of.h>
 
 /*
  * NOTE: this is an *EEPROM* driver.  The vagaries of product naming
@@ -305,25 +305,54 @@ static ssize_t at25_mem_write(struct memory_accessor *mem, const char *buf,
 static int at25_probe(struct spi_device *spi)
 {
 	struct at25_data	*at25 = NULL;
-	const struct spi_eeprom *chip;
+	struct spi_eeprom	chip;
+	struct device_node	*np = spi->dev.of_node;
 	int			err;
 	int			sr;
 	int			addrlen;
 
 	/* Chip description */
-	chip = spi->dev.platform_data;
-	if (!chip) {
-		dev_dbg(&spi->dev, "no chip description\n");
-		err = -ENODEV;
-		goto fail;
-	}
+	if (!spi->dev.platform_data) {
+		if (np) {
+			u32 val;
+
+			memset(&chip, 0, sizeof(chip));
+			strncpy(chip.name, np->name, 10);
+
+			err = of_property_read_u32(np, "at25,byte-len", &val);
+			if (err) {
+				dev_dbg(&spi->dev, "invalid chip dt description\n");
+				goto fail;
+			}
+			chip.byte_len = val;
+
+			err = of_property_read_u32(np, "at25,addr-mode", &val);
+			if (err) {
+				dev_dbg(&spi->dev, "invalid chip dt description\n");
+				goto fail;
+			}
+			chip.flags = (u16)val;
+
+			err = of_property_read_u32(np, "at25,page-size", &val);
+			if (err) {
+				dev_dbg(&spi->dev, "invalid chip dt description\n");
+				goto fail;
+			}
+			chip.page_size = (u16)val;
+		} else {
+			dev_dbg(&spi->dev, "no chip description\n");
+			err = -ENODEV;
+			goto fail;
+		}
+	} else
+		chip = *(struct spi_eeprom *)spi->dev.platform_data;
 
 	/* For now we only support 8/16/24 bit addressing */
-	if (chip->flags & EE_ADDR1)
+	if (chip.flags & EE_ADDR1)
 		addrlen = 1;
-	else if (chip->flags & EE_ADDR2)
+	else if (chip.flags & EE_ADDR2)
 		addrlen = 2;
-	else if (chip->flags & EE_ADDR3)
+	else if (chip.flags & EE_ADDR3)
 		addrlen = 3;
 	else {
 		dev_dbg(&spi->dev, "unsupported address type\n");
@@ -348,7 +377,7 @@ static int at25_probe(struct spi_device *spi)
 	}
 
 	mutex_init(&at25->lock);
-	at25->chip = *chip;
+	at25->chip = chip;
 	at25->spi = spi_dev_get(spi);
 	dev_set_drvdata(&spi->dev, at25);
 	at25->addrlen = addrlen;
@@ -369,7 +398,7 @@ static int at25_probe(struct spi_device *spi)
 	at25->mem.read = at25_mem_read;
 
 	at25->bin.size = at25->chip.byte_len;
-	if (!(chip->flags & EE_READONLY)) {
+	if (!(chip.flags & EE_READONLY)) {
 		at25->bin.write = at25_bin_write;
 		at25->bin.attr.mode |= S_IWUSR;
 		at25->mem.write = at25_mem_write;
@@ -379,8 +408,8 @@ static int at25_probe(struct spi_device *spi)
 	if (err)
 		goto fail;
 
-	if (chip->setup)
-		chip->setup(&at25->mem, chip->context);
+	if (chip.setup)
+		chip.setup(&at25->mem, chip.context);
 
 	dev_info(&spi->dev, "%Zd %s %s eeprom%s, pagesize %u\n",
 		(at25->bin.size < 1024)
@@ -388,7 +417,7 @@ static int at25_probe(struct spi_device *spi)
 			: (at25->bin.size / 1024),
 		(at25->bin.size < 1024) ? "Byte" : "KByte",
 		at25->chip.name,
-		(chip->flags & EE_READONLY) ? " (readonly)" : "",
+		(chip.flags & EE_READONLY) ? " (readonly)" : "",
 		at25->chip.page_size);
 	return 0;
 fail:
-- 
1.7.10

Re: [PATCH] SPI: at25: Parse dt settings

[Ivo Sieben]

Hi,

2012/6/14 Alexandre Pereira da Silva <aletes.xgr@gmail.com>:
> @@ -305,25 +305,54 @@ static ssize_t at25_mem_write(struct memory_accessor *mem, const char *buf,
> +       if (!spi->dev.platform_data) {
> +               if (np) {
> +                       u32 val;
> +
> +                       memset(&chip, 0, sizeof(chip));
> +                       strncpy(chip.name, np->name, 10);
> +
> +                       err = of_property_read_u32(np, "at25,byte-len", &val);
> +                       if (err) {
> +                               dev_dbg(&spi->dev, "invalid chip dt description\n");
> +                               goto fail;
> +                       }
> +                       chip.byte_len = val;
> +
> +                       err = of_property_read_u32(np, "at25,addr-mode", &val);
> +                       if (err) {
> +                               dev_dbg(&spi->dev, "invalid chip dt description\n");
> +                               goto fail;
> +                       }
> +                       chip.flags = (u16)val;
> +
> +                       err = of_property_read_u32(np, "at25,page-size", &val);
> +                       if (err) {
> +                               dev_dbg(&spi->dev, "invalid chip dt description\n");
> +                               goto fail;
> +                       }
> +                       chip.page_size = (u16)val;
> +               } else {
> +                       dev_dbg(&spi->dev, "no chip description\n");
> +                       err = -ENODEV;
> +                       goto fail;
> +               }
> +       } else
> +               chip = *(struct spi_eeprom *)spi->dev.platform_data;

One small remark:
In case of platform_data, the "if (!chip)" check has been removed and
is now only handled in the device tree initialization.
Maybe add this check to the platform initialization as well:

} else {
        if (!spi->dev.platform_data) {
                dev_dbg(&spi->dev, "no chip description\n");
                err = -ENODEV;
                goto fail;
        }
        chip =  *(struct spi_eeprom *)spi->dev.platform_data;
}

Furthermore looks good to me...
(Note: I am not familiar with device trees, so I cannot judge that
part of this patch)

Regards,
Ivo Sieben

Re: [PATCH] SPI: at25: Parse dt settings

[Alexandre Pereira da Silva]

On Thu, Jun 21, 2012 at 6:49 AM, Ivo Sieben <meltedpianoman@gmail.com> wrote:
> One small remark:
> In case of platform_data, the "if (!chip)" check has been removed and
> is now only handled in the device tree initialization.
> Maybe add this check to the platform initialization as well:
>
> } else {
>        if (!spi->dev.platform_data) {
>                dev_dbg(&spi->dev, "no chip description\n");
>                err = -ENODEV;
>                goto fail;
>        }
>        chip =  *(struct spi_eeprom *)spi->dev.platform_data;
> }

Thanks for finding that out. I will fix that case.

This patch was already merged to gregh/char-misc:
http://git.kernel.org/?p=linux/kernel/git/gregkh/char-misc.git;a=shortlog;h=refs/heads/char-misc-next

I will implement a patch to fix this against the original one.

Re: [PATCH] SPI: at25: Parse dt settings

[Alexandre Pereira da Silva]

On Thu, Jun 21, 2012 at 8:10 AM, Alexandre Pereira da Silva
<aletes.xgr@gmail.com> wrote:
> On Thu, Jun 21, 2012 at 6:49 AM, Ivo Sieben <meltedpianoman@gmail.com> wrote:
>> One small remark:
>> In case of platform_data, the "if (!chip)" check has been removed and
>> is now only handled in the device tree initialization.
>> Maybe add this check to the platform initialization as well:
>>
>> } else {
>>        if (!spi->dev.platform_data) {
>>                dev_dbg(&spi->dev, "no chip description\n");
>>                err = -ENODEV;
>>                goto fail;
>>        }
>>        chip =  *(struct spi_eeprom *)spi->dev.platform_data;
>> }

Please ignore my last email. Not enough coffee.

I'm sorry. The code looks right to me.

-       chip = spi->dev.platform_data;
-       if (!chip) {
-               dev_dbg(&spi->dev, "no chip description\n");
-               err = -ENODEV;
-               goto fail;
-       }
+       if (!spi->dev.platform_data) {
+               if (np) {
                             /* No platform data and DT node present,
DT handling */
+               } else {
                            /* No DT and No platform description,
handle error */
+                       dev_dbg(&spi->dev, "no chip description\n");
+                       err = -ENODEV;
+                       goto fail;
+               }
+       } else
                 /* At this point chip is guaranteed to have valid data */
+               chip = *(struct spi_eeprom *)spi->dev.platform_data;

Re: [PATCH] SPI: at25: Parse dt settings

[Ivo Sieben]

Hi,

2012/6/21 Alexandre Pereira da Silva <aletes.xgr@gmail.com>:
>
> Please ignore my last email. Not enough coffee.
>
> I'm sorry. The code looks right to me.
>

Yup, sorry... you're right
not enough coffee for me also.

Regards,
Ivo