misc/at25, dt: Improve at25 SPI eeprom device tree bindings.

Commit 002176db (misc: at25: Parse dt settings) added device tree bindings the differ significantly in style from the I2C EEPROM bindings and don't seem well vetted. Here I deprecate (but still support) the "at25,*" properties, and add what I hope is a better alternative. These new bindings also happen to be deployed in the field and were previously submitted for consideration here: https://lists.ozlabs.org/pipermail/devicetree-discuss/2012-May/015556.html The advantages of the new bindings are that they are similar to the I2C EEPROMs and they don't conflate read-only and the address width modes in a binary encoded blob. Signed-off-by: David Daney <david.daney@cavium.com> Cc: Alexandre Pereira da Silva <aletes.xgr@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Michael Hennerich <michael.hennerich@analog.com> Cc: Axel Lin <axel.lin@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

misc/at25, dt: Improve at25 SPI eeprom device tree bindings.
Commit 002176db (misc: at25: Parse dt settings) added device tree bindings the differ significantly in style from the I2C EEPROM bindings and don't seem well vetted. Here I deprecate (but still support) the "at25,*" properties, and add what I hope is a better alternative. These new bindings also happen to be deployed in the field and were previously submitted for consideration here: https://lists.ozlabs.org/pipermail/devicetree-discuss/2012-May/015556.html The advantages of the new bindings are that they are similar to the I2C EEPROMs and they don't conflate read-only and the address width modes in a binary encoded blob. Signed-off-by: David Daney <david.daney@cavium.com> Cc: Alexandre Pereira da Silva <aletes.xgr@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Michael Hennerich <michael.hennerich@analog.com> Cc: Axel Lin <axel.lin@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
David Daney · Greg Kroah-Hartman
1 parent 9af514232e
Showing 2 changed files with 82 additions and 35 deletions Side-by-side Diff
Documentation/devicetree/bindings/misc/at25.txt
drivers/misc/eeprom/at25.c
-Atmel AT25 eeprom
+EEPROMs (SPI) compatible with Atmel at25.
  
 Required properties:
 - compatible : "atmel,at25".
 - reg : chip select number
 - spi-max-frequency : max spi frequency to use
+- pagesize : size of the eeprom page
+- size : total eeprom size in bytes
+- address-width : number of address bits (one of 8, 16, or 24)
  
+Optional properties:
+- spi-cpha : SPI shifted clock phase, as per spi-bus bindings.
+- spi-cpol : SPI inverse clock polarity, as per spi-bus bindings.
+- read-only : this parameter-less property disables writes to the eeprom
+
+Obsolete legacy properties are can be used in place of "size", "pagesize",
+"address-width", and "read-only":
 - 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>;
+Additional compatible properties are also allowed.
  
-	at25,byte-len = <0x8000>;
-	at25,addr-mode = <2>;
-	at25,page-size = <64>;
-};
+Example:
+	at25@0 {
+		compatible = "atmel,at25", "st,m95256";
+		reg = <0>
+		spi-max-frequency = <5000000>;
+		spi-cpha;
+		spi-cpol;
+
+		pagesize = <64>;
+		size = <32768>;
+		address-width = <16>;
+	};
@@ -302,6 +302,61 @@
  
 /*-------------------------------------------------------------------------*/
  
+static int at25_np_to_chip(struct device *dev,
+			   struct device_node *np,
+			   struct spi_eeprom *chip)
+{
+	u32 val;
+
+	memset(chip, 0, sizeof(*chip));
+	strncpy(chip->name, np->name, sizeof(chip->name));
+
+	if (of_property_read_u32(np, "size", &val) == 0 ||
+	    of_property_read_u32(np, "at25,byte-len", &val) == 0) {
+		chip->byte_len = val;
+	} else {
+		dev_err(dev, "Error: missing \"size\" property\n");
+		return -ENODEV;
+	}
+
+	if (of_property_read_u32(np, "pagesize", &val) == 0 ||
+	    of_property_read_u32(np, "at25,page-size", &val) == 0) {
+		chip->page_size = (u16)val;
+	} else {
+		dev_err(dev, "Error: missing \"pagesize\" property\n");
+		return -ENODEV;
+	}
+
+	if (of_property_read_u32(np, "at25,addr-mode", &val) == 0) {
+		chip->flags = (u16)val;
+	} else {
+		if (of_property_read_u32(np, "address-width", &val)) {
+			dev_err(dev,
+				"Error: missing \"address-width\" property\n");
+			return -ENODEV;
+		}
+		switch (val) {
+		case 8:
+			chip->flags |= EE_ADDR1;
+			break;
+		case 16:
+			chip->flags |= EE_ADDR2;
+			break;
+		case 24:
+			chip->flags |= EE_ADDR3;
+			break;
+		default:
+			dev_err(dev,
+				"Error: bad \"address-width\" property: %u\n",
+				val);
+			return -ENODEV;
+		}
+		if (of_find_property(np, "read-only", NULL))
+			chip->flags |= EE_READONLY;
+	}
+	return 0;
+}
+
 static int at25_probe(struct spi_device *spi)
 {
 	struct at25_data	*at25 = NULL;
  
  
@@ -314,33 +369,11 @@
 	/* Chip description */
 	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");
+			err = at25_np_to_chip(&spi->dev, np, &chip);
+			if (err)
 				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");
+			dev_err(&spi->dev, "Error: no chip description\n");
 			err = -ENODEV;
 			goto fail;
 		}
1		-Atmel AT25 eeprom
	1	+EEPROMs (SPI) compatible with Atmel at25.
2	2
3	3	Required properties:
4	4	- compatible : "atmel,at25".
5	5	- reg : chip select number
6	6	- spi-max-frequency : max spi frequency to use
	7	+- pagesize : size of the eeprom page
	8	+- size : total eeprom size in bytes
	9	+- address-width : number of address bits (one of 8, 16, or 24)
7	10
	11	+Optional properties:
	12	+- spi-cpha : SPI shifted clock phase, as per spi-bus bindings.
	13	+- spi-cpol : SPI inverse clock polarity, as per spi-bus bindings.
	14	+- read-only : this parameter-less property disables writes to the eeprom
	15	+
	16	+Obsolete legacy properties are can be used in place of "size", "pagesize",
	17	+"address-width", and "read-only":
8	18	- at25,byte-len : total eeprom size in bytes
9	19	- at25,addr-mode : addr-mode flags, as defined in include/linux/spi/eeprom.h
10	20	- at25,page-size : size of the eeprom page
11	21
12		-Examples:
13		-at25@0 {
14		- compatible = "atmel,at25";
15		- reg = <0>
16		- spi-max-frequency = <5000000>;
	22	+Additional compatible properties are also allowed.
17	23
18		- at25,byte-len = <0x8000>;
19		- at25,addr-mode = <2>;
20		- at25,page-size = <64>;
21		-};
	24	+Example:
	25	+ at25@0 {
	26	+ compatible = "atmel,at25", "st,m95256";
	27	+ reg = <0>
	28	+ spi-max-frequency = <5000000>;
	29	+ spi-cpha;
	30	+ spi-cpol;
	31	+
	32	+ pagesize = <64>;
	33	+ size = <32768>;
	34	+ address-width = <16>;
	35	+ };
...	...	@@ -302,6 +302,61 @@
302	302
303	303	/-------------------------------------------------------------------------/
304	304
	305	+static int at25_np_to_chip(struct device *dev,
	306	+ struct device_node *np,
	307	+ struct spi_eeprom *chip)
	308	+{
	309	+ u32 val;
	310	+
	311	+ memset(chip, 0, sizeof(*chip));
	312	+ strncpy(chip->name, np->name, sizeof(chip->name));
	313	+
	314	+ if (of_property_read_u32(np, "size", &val) == 0 \|\|
	315	+ of_property_read_u32(np, "at25,byte-len", &val) == 0) {
	316	+ chip->byte_len = val;
	317	+ } else {
	318	+ dev_err(dev, "Error: missing \"size\" property\n");
	319	+ return -ENODEV;
	320	+ }
	321	+
	322	+ if (of_property_read_u32(np, "pagesize", &val) == 0 \|\|
	323	+ of_property_read_u32(np, "at25,page-size", &val) == 0) {
	324	+ chip->page_size = (u16)val;
	325	+ } else {
	326	+ dev_err(dev, "Error: missing \"pagesize\" property\n");
	327	+ return -ENODEV;
	328	+ }
	329	+
	330	+ if (of_property_read_u32(np, "at25,addr-mode", &val) == 0) {
	331	+ chip->flags = (u16)val;
	332	+ } else {
	333	+ if (of_property_read_u32(np, "address-width", &val)) {
	334	+ dev_err(dev,
	335	+ "Error: missing \"address-width\" property\n");
	336	+ return -ENODEV;
	337	+ }
	338	+ switch (val) {
	339	+ case 8:
	340	+ chip->flags \|= EE_ADDR1;
	341	+ break;
	342	+ case 16:
	343	+ chip->flags \|= EE_ADDR2;
	344	+ break;
	345	+ case 24:
	346	+ chip->flags \|= EE_ADDR3;
	347	+ break;
	348	+ default:
	349	+ dev_err(dev,
	350	+ "Error: bad \"address-width\" property: %u\n",
	351	+ val);
	352	+ return -ENODEV;
	353	+ }
	354	+ if (of_find_property(np, "read-only", NULL))
	355	+ chip->flags \|= EE_READONLY;
	356	+ }
	357	+ return 0;
	358	+}
	359	+
305	360	static int at25_probe(struct spi_device *spi)
306	361	{
307	362	struct at25_data *at25 = NULL;
308	363
309	364
...	...	@@ -314,33 +369,11 @@
314	369	/* Chip description */
315	370	if (!spi->dev.platform_data) {
316	371	if (np) {
317		- u32 val;
318		-
319		- memset(&chip, 0, sizeof(chip));
320		- strncpy(chip.name, np->name, 10);
321		-
322		- err = of_property_read_u32(np, "at25,byte-len", &val);
323		- if (err) {
324		- dev_dbg(&spi->dev, "invalid chip dt description\n");
	372	+ err = at25_np_to_chip(&spi->dev, np, &chip);
	373	+ if (err)
325	374	goto fail;
326		- }
327		- chip.byte_len = val;
328		-
329		- err = of_property_read_u32(np, "at25,addr-mode", &val);
330		- if (err) {
331		- dev_dbg(&spi->dev, "invalid chip dt description\n");
332		- goto fail;
333		- }
334		- chip.flags = (u16)val;
335		-
336		- err = of_property_read_u32(np, "at25,page-size", &val);
337		- if (err) {
338		- dev_dbg(&spi->dev, "invalid chip dt description\n");
339		- goto fail;
340		- }
341		- chip.page_size = (u16)val;
342	375	} else {
343		- dev_dbg(&spi->dev, "no chip description\n");
	376	+ dev_err(&spi->dev, "Error: no chip description\n");
344	377	err = -ENODEV;
345	378	goto fail;
346	379	}