Re: [PATCH 2.6.39-rc7] RTC: rtc-ds1307 EEPROM support for ds1388 chip

Austin Boyle
2011-09-25T10:47:12Z

I understand that this patch may not be necessary. I will test the
ds1388 EEPROM with the at24-driver as Wolfram suggested.

For completeness, here is the patch applied to the current kernel tree
with the warnings fixed. I have also added the code to unregister the
dummy devices properly in module remove.

---

[PATCH 3.1-rc7] RTC: EEPROM support for DS1388

This patch adds support for different sized NVRAM, such as
the 512 bytes of EEPROM on the DS1388 chip.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: Austin Boyle <austin.boyle@aviatnet.com>
---
--- a/drivers/rtc/rtc-ds1307.c 2011-06-29 11:59:29.275414436 +1200
+++ b/drivers/rtc/rtc-ds1307.c 2011-09-25 22:39:15.598097897 +1300
@@ -95,15 +95,19 @@ enum ds_type {
# define RX8025_BIT_VDET 0x40
# define RX8025_BIT_XST 0x20

+#define DS1307_MAX_NUM_ADDRS 3

struct ds1307 {
u8 offset; /* register's offset */
+ u16 nvram_size;
+ u16 nvram_offset;
+ u8 num_addrs;
u8 regs[11];
enum ds_type type;
unsigned long flags;
#define HAS_NVRAM 0 /* bit 0 == sysfs file active */
#define HAS_ALARM 1 /* bit 1 == irq claimed */
- struct i2c_client *client;
+ struct i2c_client *client[DS1307_MAX_NUM_ADDRS];
struct rtc_device *rtc;
struct work_struct work;
s32 (*read_block_data)(const struct i2c_client *client, u8 command,
@@ -113,23 +117,26 @@ struct ds1307 {
};

struct chip_desc {
- unsigned nvram56:1;
+ unsigned nvram:1;
unsigned alarm:1;
};

static const struct chip_desc chips[] = {
[ds_1307] = {
- .nvram56 = 1,
+ .nvram = 1,
},
[ds_1337] = {
.alarm = 1,
},
[ds_1338] = {
- .nvram56 = 1,
+ .nvram = 1,
},
[ds_1339] = {
.alarm = 1,
},
+[ds_1388] = {
+ .nvram = 1,
+},
[ds_1340] = {
},
[ds_3231] = {
@@ -249,7 +256,7 @@ static void ds1307_work(struct work_stru
int stat, control;

ds1307 = container_of(work, struct ds1307, work);
- client = ds1307->client;
+ client = ds1307->client[0];
lock = &ds1307->rtc->ops_lock;

mutex_lock(lock);
@@ -295,7 +302,7 @@ static int ds1307_get_time(struct device
int tmp;

/* read the RTC date and time registers all at once */
- tmp = ds1307->read_block_data(ds1307->client,
+ tmp = ds1307->read_block_data(ds1307->client[0],
ds1307->offset, 7, ds1307->regs);
if (tmp != 7) {
dev_err(dev, "%s error %d\n", "read", tmp);
@@ -373,7 +380,7 @@ static int ds1307_set_time(struct device
"write", buf[0], buf[1], buf[2], buf[3],
buf[4], buf[5], buf[6]);

- result = ds1307->write_block_data(ds1307->client,
+ result = ds1307->write_block_data(ds1307->client[0],
ds1307->offset, 7, buf);
if (result < 0) {
dev_err(dev, "%s error %d\n", "write", result);
@@ -531,8 +538,6 @@ static const struct rtc_class_ops ds13xx

/*----------------------------------------------------------------------*/

-#define NVRAM_SIZE 56
-
static ssize_t
ds1307_nvram_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr,
@@ -541,19 +546,49 @@ ds1307_nvram_read(struct file *filp, str
struct i2c_client *client;
struct ds1307 *ds1307;
int result;
+ unsigned int addr = 0;

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);
- if (result < 0)
+ if (ds1307->nvram_offset < 0xff) {
+ result = ds1307->read_block_data(client,
+ ds1307->nvram_offset + off,
+ count, buf);
+ } else {
+ /* read spans two blocks */
+ if ((off <= 0x00ff) && (off + count > 0x00ff)) {
+ client = ds1307->client[1];
+ addr = (unsigned int)off;
+ result = ds1307->read_block_data(client, addr,
+ (0x100-addr), buf);
+ if (result < 0)
+ goto err;
+ client = ds1307->client[2];
+ result = ds1307->read_block_data(client, 0x00,
+ (count+addr-0x100),
+ (buf+0x100-addr));
+ /* read spans one blocks */
+ } else {
+ if (off <= 0x00ff) {
+ client = ds1307->client[1];
+ addr = (unsigned int)off;
+ } else if (off <= 0x0200) {
+ client = ds1307->client[2];
+ addr = (unsigned int)off - 0x100;
+ }
+ result = ds1307->read_block_data(client, addr,
+ count, buf);
+ }
+ }
+err: if (result < 0)
dev_err(&client->dev, "%s error %d\n", "nvram read", result);
return result;
}
@@ -566,19 +601,49 @@ ds1307_nvram_write(struct file *filp, st
struct i2c_client *client;
struct ds1307 *ds1307;
int result;
+ unsigned int addr = 0;

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);
- if (result < 0) {
+ if (ds1307->nvram_offset < 0xff) {
+ result = ds1307->write_block_data(client,
+ ds1307->nvram_offset + off,
+ count, buf);
+ } else {
+ /* read spans two blocks */
+ if ((off <= 0x00ff) && ((off + count) > 0x00ff)) {
+ client = ds1307->client[1];
+ addr = (unsigned int)off;
+ result = ds1307->write_block_data(client, addr,
+ (0x100-addr), buf);
+ if (result < 0)
+ goto err;
+ client = ds1307->client[2];
+ result = ds1307->write_block_data(client, 0x00,
+ (addr+count-0x100),
+ (buf+0x100-addr));
+ /* read spans one blocks */
+ } else {
+ if (off <= 0x00ff) {
+ client = ds1307->client[1];
+ addr = (unsigned int)off;
+ } else if (off <= 0x0200) {
+ client = ds1307->client[2];
+ addr = (unsigned int)off - 0x100;
+ }
+ result = ds1307->write_block_data(client, addr,
+ count, buf);
+ }
+ }
+err: if (result < 0) {
dev_err(&client->dev, "%s error %d\n", "nvram write", result);
return result;
}
@@ -593,7 +658,6 @@ static struct bin_attribute nvram = {

.read = ds1307_nvram_read,
.write = ds1307_nvram_write,
- .size = NVRAM_SIZE,
};

/*----------------------------------------------------------------------*/
@@ -606,6 +670,7 @@ static int __devinit ds1307_probe(struct
struct ds1307 *ds1307;
int err = -ENODEV;
int tmp;
+ int i;
const struct chip_desc *chip = &chips[id->driver_data];
struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
int want_irq = false;
@@ -625,9 +690,10 @@ static int __devinit ds1307_probe(struct

i2c_set_clientdata(client, ds1307);

- ds1307->client = client;
+ ds1307->client[0] = client;
ds1307->type = id->driver_data;
ds1307->offset = 0;
+ ds1307->num_addrs = 1;

buf = ds1307->regs;
if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
@@ -643,12 +709,12 @@ static int __devinit ds1307_probe(struct
case ds_1339:
case ds_3231:
/* has IRQ? */
- if (ds1307->client->irq > 0 && chip->alarm) {
+ if (client->irq > 0 && chip->alarm) {
INIT_WORK(&ds1307->work, ds1307_work);
want_irq = true;
}
/* get registers that the "rtc" read below won't read... */
- tmp = ds1307->read_block_data(ds1307->client,
+ tmp = ds1307->read_block_data(client,
DS1337_REG_CONTROL, 2, buf);
if (tmp != 2) {
pr_debug("read error %d\n", tmp);
@@ -682,7 +748,7 @@ static int __devinit ds1307_probe(struct
break;

case rx_8025:
- tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
+ tmp = i2c_smbus_read_i2c_block_data(client,
RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
if (tmp != 2) {
pr_debug("read error %d\n", tmp);
@@ -726,7 +792,7 @@ static int __devinit ds1307_probe(struct
ds1307->regs[0] |
RX8025_BIT_2412);

- tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
+ tmp = i2c_smbus_read_i2c_block_data(client,
RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
if (tmp != 2) {
pr_debug("read error %d\n", tmp);
@@ -748,6 +814,14 @@ static int __devinit ds1307_probe(struct
break;
case ds_1388:
ds1307->offset = 1; /* Seconds starts at 1 */
+ ds1307->num_addrs = 3; /* uses 3 I2C addrs */
+ ds1307->nvram_size = 512; /* 512 bytes EEPROM */
+ ds1307->nvram_offset = 0xff;
+ break;
+ case ds_1307:
+ case ds_1338:
+ ds1307->nvram_size = 56; /* 56 bytes NVRAM */
+ ds1307->nvram_offset = 8;
break;
default:
break;
@@ -755,7 +829,7 @@ static int __devinit ds1307_probe(struct

read_rtc:
/* read RTC registers */
- tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
+ tmp = ds1307->read_block_data(client, ds1307->offset, 8, buf);
if (tmp != 8) {
pr_debug("read error %d\n", tmp);
err = -EIO;
@@ -867,16 +941,34 @@ read_rtc:
dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
}

- if (chip->nvram56) {
+ if (chip->nvram) {
+ nvram.size = ds1307->nvram_size;
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");
+ dev_info(&client->dev, "%zd bytes nvram\n", nvram.size);
}
}

+ /* use dummy devices for multiple address chips */
+ for (i = 1; i < ds1307->num_addrs; i++) {
+ ds1307->client[i] = i2c_new_dummy(client->adapter,
+ client->addr + i);
+ if (!ds1307->client[i]) {
+ dev_err(&client->dev, "Address %02x unavailable\n",
+ client->addr + i);
+ err = -EBUSY;
+ goto exit_dummy;
+ }
+ i2c_set_clientdata(ds1307->client[i], ds1307);
+ }
+
return 0;

+exit_dummy:
+ for (i = 1; i < ds1307->num_addrs; i++)
+ if (ds1307->client[i])
+ i2c_unregister_device(ds1307->client[i]);
exit_irq:
rtc_device_unregister(ds1307->rtc);
exit_free:
@@ -887,6 +979,7 @@ exit_free:
static int __devexit ds1307_remove(struct i2c_client *client)
{
struct ds1307 *ds1307 = i2c_get_clientdata(client);
+ int i;

if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
free_irq(client->irq, client);
@@ -896,6 +989,10 @@ static int __devexit ds1307_remove(struc
if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
sysfs_remove_bin_file(&client->dev.kobj, &nvram);

+ for (i = 1; i < ds1307->num_addrs; i++)
+ if (ds1307->client[i])
+ i2c_unregister_device(ds1307->client[i]);
+
rtc_device_unregister(ds1307->rtc);
kfree(ds1307);
return 0;