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power: supply: sbs-battery: simplify DT parsing

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After the change to use the gpio descriptor interface, we get a warning if
-Wmaybe-uninitialized is added back to the build flags (it is currently
disabled:

drivers/power/supply/sbs-battery.c: In function 'sbs_probe':
drivers/power/supply/sbs-battery.c:760:28: error: 'pdata' may be used uninitialized in this function [-Werror=maybe-uninitialized]

The problem is that if neither the DT properties nor a platform_data
pointer are provided, the chip->pdata pointer gets set to an uninitialized
value.

Looking at the code some more, I found that the sbs_of_populate_pdata
function is more complex than necessary and has confusing calling
conventions of possibly returning a valid pointer, a NULL pointer
or an ERR_PTR pointer (in addition to the uninitialized pointer).

To fix all of that, this gets rid of the chip->pdata pointer and
simply moves the two integers into the sbs_info structure. This
makes it much clearer from reading sbs_probe() what the precedence
of the three possible values are (pdata, DT, hardcoded defaults)
and completely avoids the #ifdef CONFIG_OF guards as
of_property_read_u32() gets replaced with a compile-time stub
when that is disabled, and returns an error if passed a NULL of_node
pointer.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 3b5dd3a494 ("power: supply: sbs-battery: Use gpio_desc and sleeping calls for battery detect")
Signed-off-by: Sebastian Reichel <sre@kernel.org>
This commit is contained in:
Arnd Bergmann 2016-09-06 15:16:33 +02:00 committed by Sebastian Reichel
parent c65a8b5112
commit 9edeaada19
1 changed files with 29 additions and 65 deletions
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94
drivers/power/supply/sbs-battery.c
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@ -169,6 +169,8 @@ struct sbs_info {
bool enable_detection;
int last_state;
int poll_time;
int i2c_retry_count;
int poll_retry_count;
struct delayed_work work;
int ignore_changes;
};
@ -184,7 +186,7 @@ static int sbs_read_word_data(struct i2c_client *client, u8 address)
int retries = 1;
if (chip->pdata)
retries = max(chip->pdata->i2c_retry_count + 1, 1);
retries = max(chip->i2c_retry_count + 1, 1);
while (retries > 0) {
ret = i2c_smbus_read_word_data(client, address);
@ -212,8 +214,8 @@ static int sbs_read_string_data(struct i2c_client *client, u8 address,
u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1];
if (chip->pdata) {
retries_length = max(chip->pdata->i2c_retry_count + 1, 1);
retries_block = max(chip->pdata->i2c_retry_count + 1, 1);
retries_length = max(chip->i2c_retry_count + 1, 1);
retries_block = max(chip->i2c_retry_count + 1, 1);
}
/* Adapter needs to support these two functions */
@ -279,7 +281,7 @@ static int sbs_write_word_data(struct i2c_client *client, u8 address,
int retries = 1;
if (chip->pdata)
retries = max(chip->pdata->i2c_retry_count + 1, 1);
retries = max(chip->i2c_retry_count + 1, 1);
while (retries > 0) {
ret = i2c_smbus_write_word_data(client, address,
@ -741,61 +743,6 @@ static void sbs_delayed_work(struct work_struct *work)
}
}
#if defined(CONFIG_OF)
#include <linux/of_device.h>
#include <linux/of_gpio.h>
static const struct of_device_id sbs_dt_ids[] = {
{ .compatible = "sbs,sbs-battery" },
{ .compatible = "ti,bq20z75" },
{ }
};
MODULE_DEVICE_TABLE(of, sbs_dt_ids);
static struct sbs_platform_data *sbs_of_populate_pdata(struct sbs_info *chip)
{
struct i2c_client *client = chip->client;
struct device_node *of_node = client->dev.of_node;
struct sbs_platform_data *pdata;
int rc;
u32 prop;
/* verify this driver matches this device */
if (!of_node)
return NULL;
/* first make sure at least one property is set, otherwise
* it won't change behavior from running without pdata.
*/
if (!of_get_property(of_node, "sbs,i2c-retry-count", NULL) &&
!of_get_property(of_node, "sbs,poll-retry-count", NULL))
goto of_out;
pdata = devm_kzalloc(&client->dev, sizeof(struct sbs_platform_data),
GFP_KERNEL);
if (!pdata)
return ERR_PTR(-ENOMEM);
rc = of_property_read_u32(of_node, "sbs,i2c-retry-count", &prop);
if (!rc)
pdata->i2c_retry_count = prop;
rc = of_property_read_u32(of_node, "sbs,poll-retry-count", &prop);
if (!rc)
pdata->poll_retry_count = prop;
of_out:
return pdata;
}
#else
static struct sbs_platform_data *sbs_of_populate_pdata(
struct sbs_info *client)
{
return ERR_PTR(-ENOSYS);
}
#endif
static const struct power_supply_desc sbs_default_desc = {
.type = POWER_SUPPLY_TYPE_BATTERY,
.properties = sbs_properties,
@ -838,13 +785,23 @@ static int sbs_probe(struct i2c_client *client,
chip->ignore_changes = 1;
chip->last_state = POWER_SUPPLY_STATUS_UNKNOWN;
if (!pdata)
pdata = sbs_of_populate_pdata(chip);
/* use pdata if available, fall back to DT properties,
* or hardcoded defaults if not
*/
rc = of_property_read_u32(client->dev.of_node, "sbs,i2c-retry-count",
&chip->i2c_retry_count);
if (rc)
chip->i2c_retry_count = 1;
if (IS_ERR(pdata))
return PTR_ERR(pdata);
rc = of_property_read_u32(client->dev.of_node, "sbs,poll-retry-count",
&chip->poll_retry_count);
if (rc)
chip->poll_retry_count = 0;
chip->pdata = pdata;
if (pdata) {
chip->poll_retry_count = pdata->poll_retry_count;
chip->i2c_retry_count = pdata->i2c_retry_count;
}
chip->gpio_detect = devm_gpiod_get_optional(&client->dev,
"sbs,battery-detect", GPIOD_IN);
@ -953,13 +910,20 @@ static const struct i2c_device_id sbs_id[] = {
};
MODULE_DEVICE_TABLE(i2c, sbs_id);
static const struct of_device_id sbs_dt_ids[] = {
{ .compatible = "sbs,sbs-battery" },
{ .compatible = "ti,bq20z75" },
{ }
};
MODULE_DEVICE_TABLE(of, sbs_dt_ids);
static struct i2c_driver sbs_battery_driver = {
.probe = sbs_probe,
.remove = sbs_remove,
.id_table = sbs_id,
.driver = {
.name = "sbs-battery",
.of_match_table = of_match_ptr(sbs_dt_ids),
.of_match_table = sbs_dt_ids,
.pm = SBS_PM_OPS,
},
};