pwm: sti: Fix capture for st,pwm-num-chan < st,capture-num-chan

[ Upstream commit 5f62383 ]

The driver only used the number of pwm channels to set the pwm_chip's
npwm member. The result is that if there are more capture channels than
PWM channels specified in the device tree, only a part of the capture
channel is usable. Fix that by passing the bigger channel count to the
pwm framework. This makes it possible that the .apply() callback is
called with .hwpwm >= pwm_num_devs, catch that case and return an error
code.

Fixes: c97267a ("pwm: sti: Add PWM capture callback")
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Uwe Kleine-König <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
(cherry picked from commit 4745cba3703c48ad3a9c2cbd03ac6df5d90c44f6)
Signed-off-by: Vijayendra Suman <[email protected]>

Author: Uwe Kleine-König

drivers/pwm/pwm-sti.c

@@ -395,8 +395,17 @@ static int sti_pwm_capture(struct pwm_chip *chip, struct pwm_device *pwm,
 static int sti_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			 const struct pwm_state *state)
 {
+	struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
+	struct sti_pwm_compat_data *cdata = pc->cdata;
+	struct device *dev = pc->dev;
 	int err;
 
+	if (pwm->hwpwm >= cdata->pwm_num_devs) {
+		dev_err(dev, "device %u is not valid for pwm mode\n",
+			pwm->hwpwm);
+		return -EINVAL;
+	}
+
 	if (state->polarity != PWM_POLARITY_NORMAL)
 		return -EINVAL;
 
@@ -647,7 +656,7 @@ static int sti_pwm_probe(struct platform_device *pdev)
 
 	pc->chip.dev = dev;
 	pc->chip.ops = &sti_pwm_ops;
-	pc->chip.npwm = pc->cdata->pwm_num_devs;
+	pc->chip.npwm = max(cdata->pwm_num_devs, cdata->cpt_num_devs);
 
 	for (i = 0; i < cdata->cpt_num_devs; i++) {
 		struct sti_cpt_ddata *ddata = &cdata->ddata[i];