[PATCH v2 1/2] pwm: Introduce single-PWM of_xlate function

[Bjorn Andersson]

The existing pxa driver and the upcoming addition of PWM support in the
TI sn565dsi86 DSI/eDP bridge driver both has a single PWM channel and
thereby a need for a of_xlate function with the period as its single
argument.

Introduce a common helper function in the core that can be used as
of_xlate by such drivers and migrate the pxa driver to use this.

Signed-off-by: Bjorn Andersson <bjorn.anders...@linaro.org>
---

Changes since v1:
- Pick up the optional flags cell as well

 drivers/pwm/core.c    | 26 ++++++++++++++++++++++++++
 drivers/pwm/pwm-pxa.c | 16 +---------------
 include/linux/pwm.h   |  2 ++
 3 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index a42999f877d2..5e9c876fccc4 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -152,6 +152,32 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct 
of_phandle_args *args)
 }
 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
 
+struct pwm_device *
+of_pwm_single_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
+{
+       struct pwm_device *pwm;
+
+       if (pc->of_pwm_n_cells < 1)
+               return ERR_PTR(-EINVAL);
+
+       /* validate that one cell is specified, optionally with flags */
+       if (args->args_count != 1 && args->args_count != 2)
+               return ERR_PTR(-EINVAL);
+
+       pwm = pwm_request_from_chip(pc, 0, NULL);
+       if (IS_ERR(pwm))
+               return pwm;
+
+       pwm->args.period = args->args[0];
+       pwm->args.polarity = PWM_POLARITY_NORMAL;
+
+       if (args->args_count == 2 && args->args[2] & PWM_POLARITY_INVERTED)
+               pwm->args.polarity = PWM_POLARITY_INVERSED;
+
+       return pwm;
+}
+EXPORT_SYMBOL_GPL(of_pwm_single_xlate);
+
 static void of_pwmchip_add(struct pwm_chip *chip)
 {
        if (!chip->dev || !chip->dev->of_node)
diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c
index cfb683827d32..8cd82fb54483 100644
--- a/drivers/pwm/pwm-pxa.c
+++ b/drivers/pwm/pwm-pxa.c
@@ -148,20 +148,6 @@ static const struct platform_device_id 
*pxa_pwm_get_id_dt(struct device *dev)
        return id ? id->data : NULL;
 }
 
-static struct pwm_device *
-pxa_pwm_of_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
-{
-       struct pwm_device *pwm;
-
-       pwm = pwm_request_from_chip(pc, 0, NULL);
-       if (IS_ERR(pwm))
-               return pwm;
-
-       pwm->args.period = args->args[0];
-
-       return pwm;
-}
-
 static int pwm_probe(struct platform_device *pdev)
 {
        const struct platform_device_id *id = platform_get_device_id(pdev);
@@ -187,7 +173,7 @@ static int pwm_probe(struct platform_device *pdev)
        pwm->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1;
 
        if (IS_ENABLED(CONFIG_OF)) {
-               pwm->chip.of_xlate = pxa_pwm_of_xlate;
+               pwm->chip.of_xlate = of_pwm_single_xlate;
                pwm->chip.of_pwm_n_cells = 1;
        }
 
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 5a73251d28e3..6aff1fa4fe5d 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -411,6 +411,8 @@ struct pwm_device *pwm_request_from_chip(struct pwm_chip 
*chip,
 
 struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc,
                const struct of_phandle_args *args);
+struct pwm_device *of_pwm_single_xlate(struct pwm_chip *pc,
+                                      const struct of_phandle_args *args);
 
 struct pwm_device *pwm_get(struct device *dev, const char *con_id);
 struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
-- 
2.31.0