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path: root/drivers/pwm/core.c
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Diffstat (limited to 'drivers/pwm/core.c')
-rw-r--r--drivers/pwm/core.c70
1 files changed, 36 insertions, 34 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 172ef8245811..a0860b30bd93 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -137,9 +137,14 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
{
struct pwm_device *pwm;
+ /* check, whether the driver supports a third cell for flags */
if (pc->of_pwm_n_cells < 3)
return ERR_PTR(-EINVAL);
+ /* flags in the third cell are optional */
+ if (args->args_count < 2)
+ return ERR_PTR(-EINVAL);
+
if (args->args[0] >= pc->npwm)
return ERR_PTR(-EINVAL);
@@ -148,11 +153,10 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
return pwm;
pwm->args.period = args->args[1];
+ pwm->args.polarity = PWM_POLARITY_NORMAL;
- if (args->args[2] & PWM_POLARITY_INVERTED)
+ if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
pwm->args.polarity = PWM_POLARITY_INVERSED;
- else
- pwm->args.polarity = PWM_POLARITY_NORMAL;
return pwm;
}
@@ -163,9 +167,14 @@ of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
{
struct pwm_device *pwm;
+ /* sanity check driver support */
if (pc->of_pwm_n_cells < 2)
return ERR_PTR(-EINVAL);
+ /* all cells are required */
+ if (args->args_count != pc->of_pwm_n_cells)
+ return ERR_PTR(-EINVAL);
+
if (args->args[0] >= pc->npwm)
return ERR_PTR(-EINVAL);
@@ -663,24 +672,17 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
&args);
if (err) {
- pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
+ pr_err("%s(): can't parse \"pwms\" property\n", __func__);
return ERR_PTR(err);
}
pc = of_node_to_pwmchip(args.np);
if (IS_ERR(pc)) {
- pr_debug("%s(): PWM chip not found\n", __func__);
+ pr_err("%s(): PWM chip not found\n", __func__);
pwm = ERR_CAST(pc);
goto put;
}
- if (args.args_count != pc->of_pwm_n_cells) {
- pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
- args.np->full_name);
- pwm = ERR_PTR(-EINVAL);
- goto put;
- }
-
pwm = pc->of_xlate(pc, &args);
if (IS_ERR(pwm))
goto put;
@@ -757,12 +759,13 @@ void pwm_remove_table(struct pwm_lookup *table, size_t num)
*/
struct pwm_device *pwm_get(struct device *dev, const char *con_id)
{
- struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
const char *dev_id = dev ? dev_name(dev) : NULL;
- struct pwm_chip *chip = NULL;
+ struct pwm_device *pwm;
+ struct pwm_chip *chip;
unsigned int best = 0;
struct pwm_lookup *p, *chosen = NULL;
unsigned int match;
+ int err;
/* look up via DT first */
if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
@@ -817,24 +820,35 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
}
}
- if (!chosen) {
- pwm = ERR_PTR(-ENODEV);
- goto out;
- }
+ mutex_unlock(&pwm_lookup_lock);
+
+ if (!chosen)
+ return ERR_PTR(-ENODEV);
chip = pwmchip_find_by_name(chosen->provider);
+
+ /*
+ * If the lookup entry specifies a module, load the module and retry
+ * the PWM chip lookup. This can be used to work around driver load
+ * ordering issues if driver's can't be made to properly support the
+ * deferred probe mechanism.
+ */
+ if (!chip && chosen->module) {
+ err = request_module(chosen->module);
+ if (err == 0)
+ chip = pwmchip_find_by_name(chosen->provider);
+ }
+
if (!chip)
- goto out;
+ return ERR_PTR(-EPROBE_DEFER);
pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
if (IS_ERR(pwm))
- goto out;
+ return pwm;
pwm->args.period = chosen->period;
pwm->args.polarity = chosen->polarity;
-out:
- mutex_unlock(&pwm_lookup_lock);
return pwm;
}
EXPORT_SYMBOL_GPL(pwm_get);
@@ -960,18 +974,6 @@ void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
}
EXPORT_SYMBOL_GPL(devm_pwm_put);
-/**
- * pwm_can_sleep() - report whether PWM access will sleep
- * @pwm: PWM device
- *
- * Returns: True if accessing the PWM can sleep, false otherwise.
- */
-bool pwm_can_sleep(struct pwm_device *pwm)
-{
- return true;
-}
-EXPORT_SYMBOL_GPL(pwm_can_sleep);
-
#ifdef CONFIG_DEBUG_FS
static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
{