rtc: ds1307: generalise ram size and offset

Generalise NVRAM to support RAM with other size and offset, such as the 64 bytes of SRAM on the mcp7941x. [rdunlap@xenotime.net: fix printk format warning] Signed-off-by: Austin Boyle <Austin.Boyle@aviatnet.com> Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Cc: David Anders <danders.dev@gmail.com> Cc: Alessandro Zummo <alessandro.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

rtc: ds1307: generalise ram size and offset
Generalise NVRAM to support RAM with other size and offset, such as the 64 bytes of SRAM on the mcp7941x. [rdunlap@xenotime.net: fix printk format warning] Signed-off-by: Austin Boyle <Austin.Boyle@aviatnet.com> Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Cc: David Anders <danders.dev@gmail.com> Cc: Alessandro Zummo <alessandro.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Austin Boyle · Linus Torvalds
1 parent 40ce972d59
Showing 1 changed file with 47 additions and 31 deletions Side-by-side Diff
drivers/rtc/rtc-ds1307.c
@@ -105,6 +105,8 @@
 struct ds1307 {
 	u8			offset; /* register's offset */
 	u8			regs[11];
+	u16			nvram_offset;
+	struct bin_attribute	*nvram;
 	enum ds_type		type;
 	unsigned long		flags;
 #define HAS_NVRAM	0		/* bit 0 == sysfs file active */
  
  
  
@@ -119,19 +121,22 @@
 };
  
 struct chip_desc {
-	unsigned		nvram56:1;
 	unsigned		alarm:1;
+	u16			nvram_offset;
+	u16			nvram_size;
 };
  
 static const struct chip_desc chips[last_ds_type] = {
 	[ds_1307] = {
-		.nvram56	= 1,
+		.nvram_offset	= 8,
+		.nvram_size	= 56,
 	},
 	[ds_1337] = {
 		.alarm		= 1,
 	},
 	[ds_1338] = {
-		.nvram56	= 1,
+		.nvram_offset	= 8,
+		.nvram_size	= 56,
 	},
 	[ds_1339] = {
 		.alarm		= 1,
@@ -139,6 +144,11 @@
 	[ds_3231] = {
 		.alarm		= 1,
 	},
+	[mcp7941x] = {
+		/* this is battery backed SRAM */
+		.nvram_offset	= 0x20,
+		.nvram_size	= 0x40,
+	},
 };
  
 static const struct i2c_device_id ds1307_id[] = {
@@ -543,8 +553,6 @@
  
 /*----------------------------------------------------------------------*/
  
-#define NVRAM_SIZE	56
-
 static ssize_t
 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
 		struct bin_attribute *attr,
  
  
@@ -557,14 +565,15 @@
 	client = kobj_to_i2c_client(kobj);
 	ds1307 = i2c_get_clientdata(client);
  
-	if (unlikely(off >= NVRAM_SIZE))
+	if (unlikely(off >= ds1307->nvram->size))
 		return 0;
-	if ((off + count) > NVRAM_SIZE)
-		count = NVRAM_SIZE - off;
+	if ((off + count) > ds1307->nvram->size)
+		count = ds1307->nvram->size - off;
 	if (unlikely(!count))
 		return count;
  
-	result = ds1307->read_block_data(client, 8 + off, count, buf);
+	result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
+								count, buf);
 	if (result < 0)
 		dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 	return result;
  
  
@@ -582,14 +591,15 @@
 	client = kobj_to_i2c_client(kobj);
 	ds1307 = i2c_get_clientdata(client);
  
-	if (unlikely(off >= NVRAM_SIZE))
+	if (unlikely(off >= ds1307->nvram->size))
 		return -EFBIG;
-	if ((off + count) > NVRAM_SIZE)
-		count = NVRAM_SIZE - off;
+	if ((off + count) > ds1307->nvram->size)
+		count = ds1307->nvram->size - off;
 	if (unlikely(!count))
 		return count;
  
-	result = ds1307->write_block_data(client, 8 + off, count, buf);
+	result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
+								count, buf);
 	if (result < 0) {
 		dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 		return result;
@@ -597,17 +607,6 @@
 	return count;
 }
  
-static struct bin_attribute nvram = {
-	.attr = {
-		.name	= "nvram",
-		.mode	= S_IRUGO | S_IWUSR,
-	},
-
-	.read	= ds1307_nvram_read,
-	.write	= ds1307_nvram_write,
-	.size	= NVRAM_SIZE,
-};
-
 /*----------------------------------------------------------------------*/
  
 static int __devinit ds1307_probe(struct i2c_client *client,
  
  
@@ -894,16 +893,31 @@
 		dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
 	}
  
-	if (chip->nvram56) {
-		err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
-		if (err == 0) {
-			set_bit(HAS_NVRAM, &ds1307->flags);
-			dev_info(&client->dev, "56 bytes nvram\n");
+	if (chip->nvram_size) {
+		ds1307->nvram = kzalloc(sizeof(struct bin_attribute),
+							GFP_KERNEL);
+		if (!ds1307->nvram) {
+			err = -ENOMEM;
+			goto exit_nvram;
 		}
+		ds1307->nvram->attr.name = "nvram";
+		ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
+		ds1307->nvram->read = ds1307_nvram_read,
+		ds1307->nvram->write = ds1307_nvram_write,
+		ds1307->nvram->size = chip->nvram_size;
+		ds1307->nvram_offset = chip->nvram_offset;
+		err = sysfs_create_bin_file(&client->dev.kobj, ds1307->nvram);
+		if (err) {
+			kfree(ds1307->nvram);
+			goto exit_nvram;
+		}
+		set_bit(HAS_NVRAM, &ds1307->flags);
+		dev_info(&client->dev, "%zu bytes nvram\n", ds1307->nvram->size);
 	}
  
 	return 0;
  
+exit_nvram:
 exit_irq:
 	rtc_device_unregister(ds1307->rtc);
 exit_free:
@@ -920,8 +934,10 @@
 		cancel_work_sync(&ds1307->work);
 	}
  
-	if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
-		sysfs_remove_bin_file(&client->dev.kobj, &nvram);
+	if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags)) {
+		sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
+		kfree(ds1307->nvram);
+	}
  
 	rtc_device_unregister(ds1307->rtc);
 	kfree(ds1307);
...	...	@@ -105,6 +105,8 @@
105	105	struct ds1307 {
106	106	u8 offset; /* register's offset */
107	107	u8 regs[11];
	108	+ u16 nvram_offset;
	109	+ struct bin_attribute *nvram;
108	110	enum ds_type type;
109	111	unsigned long flags;
110	112	#define HAS_NVRAM 0 /* bit 0 == sysfs file active */
111	113
112	114
113	115
...	...	@@ -119,19 +121,22 @@
119	121	};
120	122
121	123	struct chip_desc {
122		- unsigned nvram56:1;
123	124	unsigned alarm:1;
	125	+ u16 nvram_offset;
	126	+ u16 nvram_size;
124	127	};
125	128
126	129	static const struct chip_desc chips[last_ds_type] = {
127	130	[ds_1307] = {
128		- .nvram56 = 1,
	131	+ .nvram_offset = 8,
	132	+ .nvram_size = 56,
129	133	},
130	134	[ds_1337] = {
131	135	.alarm = 1,
132	136	},
133	137	[ds_1338] = {
134		- .nvram56 = 1,
	138	+ .nvram_offset = 8,
	139	+ .nvram_size = 56,
135	140	},
136	141	[ds_1339] = {
137	142	.alarm = 1,
...	...	@@ -139,6 +144,11 @@
139	144	[ds_3231] = {
140	145	.alarm = 1,
141	146	},
	147	+ [mcp7941x] = {
	148	+ /* this is battery backed SRAM */
	149	+ .nvram_offset = 0x20,
	150	+ .nvram_size = 0x40,
	151	+ },
142	152	};
143	153
144	154	static const struct i2c_device_id ds1307_id[] = {
...	...	@@ -543,8 +553,6 @@
543	553
544	554	/----------------------------------------------------------------------/
545	555
546		-#define NVRAM_SIZE 56
547		-
548	556	static ssize_t
549	557	ds1307_nvram_read(struct file filp, struct kobject kobj,
550	558	struct bin_attribute *attr,
551	559
552	560
...	...	@@ -557,14 +565,15 @@
557	565	client = kobj_to_i2c_client(kobj);
558	566	ds1307 = i2c_get_clientdata(client);
559	567
560		- if (unlikely(off >= NVRAM_SIZE))
	568	+ if (unlikely(off >= ds1307->nvram->size))
561	569	return 0;
562		- if ((off + count) > NVRAM_SIZE)
563		- count = NVRAM_SIZE - off;
	570	+ if ((off + count) > ds1307->nvram->size)
	571	+ count = ds1307->nvram->size - off;
564	572	if (unlikely(!count))
565	573	return count;
566	574
567		- result = ds1307->read_block_data(client, 8 + off, count, buf);
	575	+ result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
	576	+ count, buf);
568	577	if (result < 0)
569	578	dev_err(&client->dev, "%s error %d\n", "nvram read", result);
570	579	return result;
571	580
572	581
...	...	@@ -582,14 +591,15 @@
582	591	client = kobj_to_i2c_client(kobj);
583	592	ds1307 = i2c_get_clientdata(client);
584	593
585		- if (unlikely(off >= NVRAM_SIZE))
	594	+ if (unlikely(off >= ds1307->nvram->size))
586	595	return -EFBIG;
587		- if ((off + count) > NVRAM_SIZE)
588		- count = NVRAM_SIZE - off;
	596	+ if ((off + count) > ds1307->nvram->size)
	597	+ count = ds1307->nvram->size - off;
589	598	if (unlikely(!count))
590	599	return count;
591	600
592		- result = ds1307->write_block_data(client, 8 + off, count, buf);
	601	+ result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
	602	+ count, buf);
593	603	if (result < 0) {
594	604	dev_err(&client->dev, "%s error %d\n", "nvram write", result);
595	605	return result;
...	...	@@ -597,17 +607,6 @@
597	607	return count;
598	608	}
599	609
600		-static struct bin_attribute nvram = {
601		- .attr = {
602		- .name = "nvram",
603		- .mode = S_IRUGO \| S_IWUSR,
604		- },
605		-
606		- .read = ds1307_nvram_read,
607		- .write = ds1307_nvram_write,
608		- .size = NVRAM_SIZE,
609		-};
610		-
611	610	/----------------------------------------------------------------------/
612	611
613	612	static int __devinit ds1307_probe(struct i2c_client *client,
614	613
615	614
...	...	@@ -894,16 +893,31 @@
894	893	dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
895	894	}
896	895
897		- if (chip->nvram56) {
898		- err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
899		- if (err == 0) {
900		- set_bit(HAS_NVRAM, &ds1307->flags);
901		- dev_info(&client->dev, "56 bytes nvram\n");
	896	+ if (chip->nvram_size) {
	897	+ ds1307->nvram = kzalloc(sizeof(struct bin_attribute),
	898	+ GFP_KERNEL);
	899	+ if (!ds1307->nvram) {
	900	+ err = -ENOMEM;
	901	+ goto exit_nvram;
902	902	}
	903	+ ds1307->nvram->attr.name = "nvram";
	904	+ ds1307->nvram->attr.mode = S_IRUGO \| S_IWUSR;
	905	+ ds1307->nvram->read = ds1307_nvram_read,
	906	+ ds1307->nvram->write = ds1307_nvram_write,
	907	+ ds1307->nvram->size = chip->nvram_size;
	908	+ ds1307->nvram_offset = chip->nvram_offset;
	909	+ err = sysfs_create_bin_file(&client->dev.kobj, ds1307->nvram);
	910	+ if (err) {
	911	+ kfree(ds1307->nvram);
	912	+ goto exit_nvram;
	913	+ }
	914	+ set_bit(HAS_NVRAM, &ds1307->flags);
	915	+ dev_info(&client->dev, "%zu bytes nvram\n", ds1307->nvram->size);
903	916	}
904	917
905	918	return 0;
906	919
	920	+exit_nvram:
907	921	exit_irq:
908	922	rtc_device_unregister(ds1307->rtc);
909	923	exit_free:
...	...	@@ -920,8 +934,10 @@
920	934	cancel_work_sync(&ds1307->work);
921	935	}
922	936
923		- if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
924		- sysfs_remove_bin_file(&client->dev.kobj, &nvram);
	937	+ if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags)) {
	938	+ sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
	939	+ kfree(ds1307->nvram);
	940	+ }
925	941
926	942	rtc_device_unregister(ds1307->rtc);
927	943	kfree(ds1307);