Re: [PATCH] RTC subsystem, Add ISL1208 support

From: Andrew Morton
Date: Tue Jul 11 2006 - 06:52:41 EST

On Tue, 11 Jul 2006 04:06:37 -0400
Herbert Valerio Riedel <hvr@xxxxxxx> wrote:

> This patch adds support for the I2C-attached Intersil ISL1208 RTC chip.

The driver does a lot of:

if (foo())
return -EIO.

It's more conventional to preserve the error code:

ret = foo();
if (ret < 0)
return ret;

Also, the return value from device_create_file() is ignored. We should check
these things.


I see no device_remove_file() calls on the teardown path. Should they be
there?


The driver does a lot of

if ((foo = something()) < 0)

whereas perferred kernel style (ie: super-simple style) is

foo = something();
if (foo < 0)


Here's a hastily-flung-together update. Please consider.

From: Andrew Morton <akpm@xxxxxxxx>

- Correctly propagate error codes

- Coding style consistency

- Clean up if device_create_file() failed.

Cc: Herbert Valerio Riedel <hvr@xxxxxxx>
Cc: Alessandro Zummo <a.zummo@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---

drivers/rtc/rtc-isl1208.c | 163 +++++++++++++++++++++---------------
linux/i2c-id.h | 0
2 files changed, 99 insertions(+), 64 deletions(-)

diff -puN drivers/rtc/Kconfig~rtc-subsystem-add-isl1208-support-tweaks drivers/rtc/Kconfig
diff -puN drivers/rtc/Makefile~rtc-subsystem-add-isl1208-support-tweaks drivers/rtc/Makefile
diff -puN drivers/rtc/rtc-isl1208.c~rtc-subsystem-add-isl1208-support-tweaks drivers/rtc/rtc-isl1208.c
--- a/drivers/rtc/rtc-isl1208.c~rtc-subsystem-add-isl1208-support-tweaks
+++ a/drivers/rtc/rtc-isl1208.c
@@ -66,8 +66,8 @@ static unsigned short normal_i2c[] = {
};
I2C_CLIENT_INSMOD; /* defines addr_data */

-static int isl1208_attach_adapter (struct i2c_adapter *adapter);
-static int isl1208_detach_client (struct i2c_client *client);
+static int isl1208_attach_adapter(struct i2c_adapter *adapter);
+static int isl1208_detach_client(struct i2c_client *client);

static struct i2c_driver isl1208_driver = {
.driver = {
@@ -80,7 +80,7 @@ static struct i2c_driver isl1208_driver

/* block read */
static int
-isl1208_i2c_read_regs (struct i2c_client *client, u8 reg, u8 buf[],
+isl1208_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[],
unsigned len)
{
u8 reg_addr[1] = { reg };
@@ -88,25 +88,28 @@ isl1208_i2c_read_regs (struct i2c_client
{ client->addr, client->flags, sizeof(reg_addr), reg_addr },
{ client->addr, client->flags | I2C_M_RD, len, buf }
};
+ int ret;

BUG_ON(len == 0);
BUG_ON(reg > ISL1208_REG_USR2);
BUG_ON(reg + len > ISL1208_REG_USR2 + 1);

- if (i2c_transfer (client->adapter, msgs, 2) < 0)
- return -EIO;
- return 0;
+ ret = i2c_transfer(client->adapter, msgs, 2);
+ if (ret > 0)
+ ret = 0;
+ return ret;
}

/* block write */
static int
-isl1208_i2c_set_regs (struct i2c_client *client, u8 reg, u8 const buf[],
+isl1208_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[],
unsigned len)
{
u8 i2c_buf[ISL1208_REG_USR2 + 2];
struct i2c_msg msgs[1] = {
{ client->addr, client->flags, len + 1, i2c_buf }
};
+ int ret;

BUG_ON(len == 0);
BUG_ON(reg > ISL1208_REG_USR2);
@@ -115,9 +118,10 @@ isl1208_i2c_set_regs (struct i2c_client
i2c_buf[0] = reg;
memcpy(&i2c_buf[1], &buf[0], len);

- if (i2c_transfer (client->adapter, msgs, 1) < 0)
- return -EIO;
- return 0;
+ ret = i2c_transfer(client->adapter, msgs, 1);
+ if (ret > 0)
+ ret = 0;
+ return ret;
}

/* simple check to see wether we have a isl1208 */
@@ -128,9 +132,11 @@ static int isl1208_i2c_validate_client(s
0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
};
int i;
+ int ret;

- if (isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN))
- return -EIO;
+ ret = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
+ if (ret < 0)
+ return ret;

for (i = 0; i < ISL1208_RTC_SECTION_LEN; ++i) {
if (regs[i] & zero_mask[i]) /* check if bits are cleared */
@@ -142,14 +148,15 @@ static int isl1208_i2c_validate_client(s

static int isl1208_i2c_get_sr(struct i2c_client *client)
{
- return i2c_smbus_read_byte_data (client, ISL1208_REG_SR);
+ return i2c_smbus_read_byte_data(client, ISL1208_REG_SR) == -1 ? -EIO:0;
}

static int isl1208_i2c_get_atr(struct i2c_client *client)
{
- int atr = i2c_smbus_read_byte_data (client, ISL1208_REG_ATR);
+ int atr = i2c_smbus_read_byte_data(client, ISL1208_REG_ATR);
+
if (atr < 0)
- return -1;
+ return -EIO;

/* The 6bit value in the ATR register controls the load
* capacitance C_load * in steps of 0.25pF
@@ -171,9 +178,10 @@ static int isl1208_i2c_get_atr(struct i2

static int isl1208_i2c_get_dtr(struct i2c_client *client)
{
- int dtr = i2c_smbus_read_byte_data (client, ISL1208_REG_DTR);
+ int dtr = i2c_smbus_read_byte_data(client, ISL1208_REG_DTR);
+
if (dtr < 0)
- return -1;
+ return -EIO;

/* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
dtr = ((dtr & 0x3) * 20) * (dtr & (1<<2) ? -1 : 1);
@@ -184,10 +192,12 @@ static int isl1208_i2c_get_dtr(struct i2
static int isl1208_i2c_get_usr(struct i2c_client *client)
{
u8 buf[ISL1208_USR_SECTION_LEN] = { 0, };
+ int ret;

- if (isl1208_i2c_read_regs (client, ISL1208_REG_USR1, buf,
- ISL1208_USR_SECTION_LEN))
- return -EIO;
+ ret = isl1208_i2c_read_regs (client, ISL1208_REG_USR1, buf,
+ ISL1208_USR_SECTION_LEN);
+ if (ret < 0)
+ return ret;

return (buf[1] << 8) | buf[0];
}
@@ -208,9 +218,10 @@ static int isl1208_rtc_proc(struct devic
struct i2c_client *const client = to_i2c_client(dev);
int sr, dtr, atr, usr;

- if ((sr = isl1208_i2c_get_sr(client)) < 0) {
+ sr = isl1208_i2c_get_sr(client);
+ if (sr < 0) {
dev_err(&client->dev, "%s: reading SR failed\n", __func__);
- return -EIO;
+ return sr;
}

seq_printf(seq, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
@@ -226,16 +237,16 @@ static int isl1208_rtc_proc(struct devic
(sr & ISL1208_REG_SR_RTCF) ? "bad" : "okay");

dtr = isl1208_i2c_get_dtr(client);
- if (dtr != -1)
+ if (dtr >= 0 -1)
seq_printf(seq, "digital_trim\t: %d ppm\n", dtr);

atr = isl1208_i2c_get_atr(client);
- if (atr != -1)
+ if (atr >= 0)
seq_printf(seq, "analog_trim\t: %d.%.2d pF\n",
atr>>2, (atr&0x3)*25);

usr = isl1208_i2c_get_usr(client);
- if (usr != -1)
+ if (usr >= 0)
seq_printf(seq, "user_data\t: 0x%.4x\n", usr);

return 0;
@@ -248,16 +259,17 @@ static int isl1208_i2c_read_time(struct
int sr;
u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };

- if ((sr = isl1208_i2c_get_sr(client)) < 0) {
+ sr = isl1208_i2c_get_sr(client);
+ if (sr < 0) {
dev_err(&client->dev, "%s: reading SR failed\n", __func__);
return -EIO;
}

- if (isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN))
- {
+ sr = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
+ if (sr < 0) {
dev_err(&client->dev, "%s: reading RTC section failed\n",
__func__);
- return -EIO;
+ return sr;
}

tm->tm_sec = BCD2BIN(regs[ISL1208_REG_SC]);
@@ -288,17 +300,18 @@ static int isl1208_i2c_read_alarm(struct
u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
int sr;

- if ((sr = isl1208_i2c_get_sr(client)) < 0) {
+ sr = isl1208_i2c_get_sr(client);
+ if (sr < 0) {
dev_err(&client->dev, "%s: reading SR failed\n", __func__);
- return -EIO;
+ return sr;
}

- if (isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
- ISL1208_ALARM_SECTION_LEN))
- {
+ sr = isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
+ ISL1208_ALARM_SECTION_LEN);
+ if (sr < 0) {
dev_err(&client->dev, "%s: reading alarm section failed\n",
__func__);
- return -EIO;
+ return sr;
}

/* MSB of each alarm register is an enable bit */
@@ -333,30 +346,34 @@ static int isl1208_i2c_set_time(struct i

regs[ISL1208_REG_DW] = BIN2BCD(tm->tm_wday & 7);

- if ((sr = isl1208_i2c_get_sr(client)) < 0) {
+ sr = isl1208_i2c_get_sr(client);
+ if (sr < 0) {
dev_err(&client->dev, "%s: reading SR failed\n", __func__);
- return -EIO;
+ return sr;
}

/* set WRTC */
- if (i2c_smbus_write_byte_data (client, ISL1208_REG_SR,
- sr | ISL1208_REG_SR_WRTC) < 0) {
+ sr = i2c_smbus_write_byte_data (client, ISL1208_REG_SR,
+ sr | ISL1208_REG_SR_WRTC);
+ if (sr < 0) {
dev_err(&client->dev, "%s: writing SR failed\n", __func__);
- return -EIO;
+ return sr;
}

/* write RTC registers */
- if (isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN)) {
+ sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
+ if (sr < 0) {
dev_err(&client->dev, "%s: writing RTC section failed\n",
__func__);
- return -EIO;
+ return sr;
}

/* clear WRTC again */
- if (i2c_smbus_write_byte_data (client, ISL1208_REG_SR,
- sr & ~ISL1208_REG_SR_WRTC) < 0) {
+ sr = i2c_smbus_write_byte_data (client, ISL1208_REG_SR,
+ sr & ~ISL1208_REG_SR_WRTC);
+ if (sr < 0) {
dev_err(&client->dev, "%s: writing SR failed\n", __func__);
- return -EIO;
+ return sr;
}

return 0;
@@ -389,8 +406,9 @@ static ssize_t isl1208_sysfs_show_atrim(
{
int atr;

- if ((atr = isl1208_i2c_get_atr(to_i2c_client(dev))) == -1)
- return -EIO;
+ atr = isl1208_i2c_get_atr(to_i2c_client(dev));
+ if (atr < 0)
+ return atr;

return sprintf(buf, "%d.%.2d pF\n", atr>>2, (atr&0x3)*25);
}
@@ -402,8 +420,9 @@ static ssize_t isl1208_sysfs_show_dtrim(
{
int dtr;

- if ((dtr = isl1208_i2c_get_dtr(to_i2c_client(dev))) == -1)
- return -EIO;
+ dtr = isl1208_i2c_get_dtr(to_i2c_client(dev));
+ if (dtr < 0)
+ return dtr;

return sprintf(buf, "%d ppm\n", dtr);
}
@@ -415,8 +434,9 @@ static ssize_t isl1208_sysfs_show_usr(st
{
int usr;

- if ((usr = isl1208_i2c_get_usr(to_i2c_client(dev))) < 0)
- return -EIO;
+ usr = isl1208_i2c_get_usr(to_i2c_client(dev));
+ if (usr < 0)
+ return usr;

return sprintf(buf, "0x%.4x\n", usr);
}
@@ -430,10 +450,10 @@ static ssize_t isl1208_sysfs_store_usr(s
if (buf[0] == '0' && (buf[1] == 'x' || buf[1] == 'X')) {
if (sscanf(buf, "%x", &usr) != 1)
return -EINVAL;
- }
- else
+ } else {
if (sscanf(buf, "%d", &usr) != 1)
return -EINVAL;
+ }

if (usr < 0 || usr > 0xffff)
return -EINVAL;
@@ -444,7 +464,7 @@ static DEVICE_ATTR(usr, S_IRUGO | S_IWUS
isl1208_sysfs_store_usr);

static int
-isl1208_probe (struct i2c_adapter *adapter, int addr, int kind)
+isl1208_probe(struct i2c_adapter *adapter, int addr, int kind)
{
int rc = 0;
struct i2c_client *new_client = NULL;
@@ -455,7 +475,8 @@ isl1208_probe (struct i2c_adapter *adapt
goto failout;
}

- if (!(new_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) {
+ new_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
+ if (new_client == NULL) {
rc = -ENOMEM;
goto failout;
}
@@ -464,14 +485,16 @@ isl1208_probe (struct i2c_adapter *adapt
new_client->adapter = adapter;
new_client->driver = &isl1208_driver;
new_client->flags = 0;
- strcpy (new_client->name, DRV_NAME);
+ strcpy(new_client->name, DRV_NAME);

if (kind < 0) {
- if ((rc = isl1208_i2c_validate_client(new_client)) < 0)
+ rc = isl1208_i2c_validate_client(new_client);
+ if (rc < 0)
goto failout;
}

- if ((rc = i2c_attach_client(new_client)))
+ rc = i2c_attach_client(new_client);
+ if (rc < 0)
goto failout;

dev_info(&new_client->dev,
@@ -488,7 +511,8 @@ isl1208_probe (struct i2c_adapter *adapt

i2c_set_clientdata(new_client, rtc);

- if ((rc = isl1208_i2c_get_sr (new_client)) < 0) {
+ rc = isl1208_i2c_get_sr(new_client);
+ if (rc < 0) {
dev_err(&new_client->dev, "reading status failed\n");
goto failout_unregister;
}
@@ -497,12 +521,22 @@ isl1208_probe (struct i2c_adapter *adapt
dev_warn(&new_client->dev, "rtc power failure detected, "
"please set clock.\n");

- device_create_file(&new_client->dev, &dev_attr_atrim);
- device_create_file(&new_client->dev, &dev_attr_dtrim);
- device_create_file(&new_client->dev, &dev_attr_usr);
+ rc = device_create_file(&new_client->dev, &dev_attr_atrim);
+ if (rc < 0)
+ goto failout_unregister;
+ rc = device_create_file(&new_client->dev, &dev_attr_dtrim);
+ if (rc < 0)
+ goto failout_atrim;
+ rc = device_create_file(&new_client->dev, &dev_attr_usr);
+ if (rc < 0)
+ goto failout_dtrim;

return 0;

+ failout_dtrim:
+ device_remove_file(&new_client->dev, &dev_attr_dtrim);
+ failout_atrim:
+ device_remove_file(&new_client->dev, &dev_attr_atrim);
failout_unregister:
rtc_device_unregister(rtc);
failout_detach:
@@ -515,7 +549,7 @@ isl1208_probe (struct i2c_adapter *adapt
static int
isl1208_attach_adapter (struct i2c_adapter *adapter)
{
- return i2c_probe (adapter, &addr_data, isl1208_probe);
+ return i2c_probe(adapter, &addr_data, isl1208_probe);
}

static int
@@ -527,7 +561,8 @@ isl1208_detach_client(struct i2c_client
if (rtc)
rtc_device_unregister(rtc); /* do we need to kfree? */

- if ((rc = i2c_detach_client(client)))
+ rc = i2c_detach_client(client);
+ if (rc)
return rc;

kfree(client);
diff -puN include/linux/i2c-id.h~rtc-subsystem-add-isl1208-support-tweaks include/linux/i2c-id.h
_

-
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