misc/at24: parse device tree data

Information about the pagesize and read-only-status may also come from the devicetree. Parse this data, too, and act accordingly. While we are here, change the initialization printout a bit. write_max is useful to know to detect performance bottlenecks, the rest is superfluous. Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

misc/at24: parse device tree data
Information about the pagesize and read-only-status may also come from the devicetree. Parse this data, too, and act accordingly. While we are here, change the initialization printout a bit. write_max is useful to know to detect performance bottlenecks, the rest is superfluous. Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Wolfram Sang · Grant Likely
1 parent 1945886047
Showing 2 changed files with 55 additions and 6 deletions Side-by-side Diff
Documentation/powerpc/dts-bindings/eeprom.txt
drivers/misc/eeprom/at24.c
+EEPROMs (I2C)
+
+Required properties:
+
+  - compatible : should be "<manufacturer>,<type>"
+		 If there is no specific driver for <manufacturer>, a generic
+		 driver based on <type> is selected. Possible types are:
+		 24c00, 24c01, 24c02, 24c04, 24c08, 24c16, 24c32, 24c64,
+		 24c128, 24c256, 24c512, 24c1024, spd
+
+  - reg : the I2C address of the EEPROM
+
+Optional properties:
+
+  - pagesize : the length of the pagesize for writing. Please consult the
+               manual of your device, that value varies a lot. A wrong value
+	       may result in data loss! If not specified, a safety value of
+	       '1' is used which will be very slow.
+
+  - read-only: this parameterless property disables writes to the eeprom
+
+Example:
+
+eeprom@52 {
+	compatible = "atmel,24c32";
+	reg = <0x52>;
+	pagesize = <32>;
+};
@@ -20,6 +20,7 @@
 #include <linux/log2.h>
 #include <linux/bitops.h>
 #include <linux/jiffies.h>
+#include <linux/of.h>
 #include <linux/i2c.h>
 #include <linux/i2c/at24.h>
  
@@ -457,6 +458,27 @@
  
 /*-------------------------------------------------------------------------*/
  
+#ifdef CONFIG_OF
+static void at24_get_ofdata(struct i2c_client *client,
+		struct at24_platform_data *chip)
+{
+	const __be32 *val;
+	struct device_node *node = client->dev.of_node;
+
+	if (node) {
+		if (of_get_property(node, "read-only", NULL))
+			chip->flags |= AT24_FLAG_READONLY;
+		val = of_get_property(node, "pagesize", NULL);
+		if (val)
+			chip->page_size = be32_to_cpup(val);
+	}
+}
+#else
+static void at24_get_ofdata(struct i2c_client *client,
+		struct at24_platform_data *chip)
+{ }
+#endif /* CONFIG_OF */
+
 static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
 	struct at24_platform_data chip;
@@ -485,6 +507,9 @@
 		 */
 		chip.page_size = 1;
  
+		/* update chipdata if OF is present */
+		at24_get_ofdata(client, &chip);
+
 		chip.setup = NULL;
 		chip.context = NULL;
 	}
  
  
@@ -597,19 +622,15 @@
  
 	i2c_set_clientdata(client, at24);
  
-	dev_info(&client->dev, "%zu byte %s EEPROM %s\n",
+	dev_info(&client->dev, "%zu byte %s EEPROM, %s, %u bytes/write\n",
 		at24->bin.size, client->name,
-		writable ? "(writable)" : "(read-only)");
+		writable ? "writable" : "read-only", at24->write_max);
 	if (use_smbus == I2C_SMBUS_WORD_DATA ||
 	    use_smbus == I2C_SMBUS_BYTE_DATA) {
 		dev_notice(&client->dev, "Falling back to %s reads, "
 			   "performance will suffer\n", use_smbus ==
 			   I2C_SMBUS_WORD_DATA ? "word" : "byte");
 	}
-	dev_dbg(&client->dev,
-		"page_size %d, num_addresses %d, write_max %d, use_smbus %d\n",
-		chip.page_size, num_addresses,
-		at24->write_max, use_smbus);
  
 	/* export data to kernel code */
 	if (chip.setup)
	1	+EEPROMs (I2C)
	2	+
	3	+Required properties:
	4	+
	5	+ - compatible : should be "<manufacturer>,<type>"
	6	+ If there is no specific driver for <manufacturer>, a generic
	7	+ driver based on <type> is selected. Possible types are:
	8	+ 24c00, 24c01, 24c02, 24c04, 24c08, 24c16, 24c32, 24c64,
	9	+ 24c128, 24c256, 24c512, 24c1024, spd
	10	+
	11	+ - reg : the I2C address of the EEPROM
	12	+
	13	+Optional properties:
	14	+
	15	+ - pagesize : the length of the pagesize for writing. Please consult the
	16	+ manual of your device, that value varies a lot. A wrong value
	17	+ may result in data loss! If not specified, a safety value of
	18	+ '1' is used which will be very slow.
	19	+
	20	+ - read-only: this parameterless property disables writes to the eeprom
	21	+
	22	+Example:
	23	+
	24	+eeprom@52 {
	25	+ compatible = "atmel,24c32";
	26	+ reg = <0x52>;
	27	+ pagesize = <32>;
	28	+};
...	...	@@ -20,6 +20,7 @@
20	20	#include <linux/log2.h>
21	21	#include <linux/bitops.h>
22	22	#include <linux/jiffies.h>
	23	+#include <linux/of.h>
23	24	#include <linux/i2c.h>
24	25	#include <linux/i2c/at24.h>
25	26
...	...	@@ -457,6 +458,27 @@
457	458
458	459	/-------------------------------------------------------------------------/
459	460
	461	+#ifdef CONFIG_OF
	462	+static void at24_get_ofdata(struct i2c_client *client,
	463	+ struct at24_platform_data *chip)
	464	+{
	465	+ const __be32 *val;
	466	+ struct device_node *node = client->dev.of_node;
	467	+
	468	+ if (node) {
	469	+ if (of_get_property(node, "read-only", NULL))
	470	+ chip->flags \|= AT24_FLAG_READONLY;
	471	+ val = of_get_property(node, "pagesize", NULL);
	472	+ if (val)
	473	+ chip->page_size = be32_to_cpup(val);
	474	+ }
	475	+}
	476	+#else
	477	+static void at24_get_ofdata(struct i2c_client *client,
	478	+ struct at24_platform_data *chip)
	479	+{ }
	480	+#endif /* CONFIG_OF */
	481	+
460	482	static int at24_probe(struct i2c_client client, const struct i2c_device_id id)
461	483	{
462	484	struct at24_platform_data chip;
...	...	@@ -485,6 +507,9 @@
485	507	*/
486	508	chip.page_size = 1;
487	509
	510	+ /* update chipdata if OF is present */
	511	+ at24_get_ofdata(client, &chip);
	512	+
488	513	chip.setup = NULL;
489	514	chip.context = NULL;
490	515	}
491	516
492	517
...	...	@@ -597,19 +622,15 @@
597	622
598	623	i2c_set_clientdata(client, at24);
599	624
600		- dev_info(&client->dev, "%zu byte %s EEPROM %s\n",
	625	+ dev_info(&client->dev, "%zu byte %s EEPROM, %s, %u bytes/write\n",
601	626	at24->bin.size, client->name,
602		- writable ? "(writable)" : "(read-only)");
	627	+ writable ? "writable" : "read-only", at24->write_max);
603	628	if (use_smbus == I2C_SMBUS_WORD_DATA \|\|
604	629	use_smbus == I2C_SMBUS_BYTE_DATA) {
605	630	dev_notice(&client->dev, "Falling back to %s reads, "
606	631	"performance will suffer\n", use_smbus ==
607	632	I2C_SMBUS_WORD_DATA ? "word" : "byte");
608	633	}
609		- dev_dbg(&client->dev,
610		- "page_size %d, num_addresses %d, write_max %d, use_smbus %d\n",
611		- chip.page_size, num_addresses,
612		- at24->write_max, use_smbus);
613	634
614	635	/* export data to kernel code */
615	636	if (chip.setup)