staging: greybus: pwm: Rework how the number of PWM lines is determined

With a later patch it becomes necessary to already now the number of PWM
lines when pwmc is allocated. So make the function not use pwmc but a
plain connection and return the number of lines instead of storing it in
pwmc. This allows to get rid of the pwm_max member.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/3efd84ac03e7dc288f20b0de20b142b6404cb1fa.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

diff --git a/drivers/staging/greybus/pwm.c b/drivers/staging/greybus/pwm.c
index c7a2e874a62be3a591a80cd6b9ad34aa0150567b..35e98e7c00c1a4068f914809f5600fb8ad68b99b 100644 (file)
--- a/drivers/staging/greybus/pwm.c
+++ b/drivers/staging/greybus/pwm.c
@@ -16,8 +16,6 @@
 
 struct gb_pwm_chip {
        struct gb_connection    *connection;
-       u8                      pwm_max;        /* max pwm number */
-
        struct pwm_chip         chip;
 };
 
@@ -26,17 +24,21 @@ static inline struct gb_pwm_chip *pwm_chip_to_gb_pwm_chip(struct pwm_chip *chip)
        return container_of(chip, struct gb_pwm_chip, chip);
 }
 
-static int gb_pwm_count_operation(struct gb_pwm_chip *pwmc)
+static int gb_pwm_get_npwm(struct gb_connection *connection)
 {
        struct gb_pwm_count_response response;
        int ret;
 
-       ret = gb_operation_sync(pwmc->connection, GB_PWM_TYPE_PWM_COUNT,
+       ret = gb_operation_sync(connection, GB_PWM_TYPE_PWM_COUNT,
                                NULL, 0, &response, sizeof(response));
        if (ret)
                return ret;
-       pwmc->pwm_max = response.count;
-       return 0;
+
+       /*
+        * The request returns the highest allowed PWM id parameter. So add one
+        * to get the number of PWMs.
+        */
+       return response.count + 1;
 }
 
 static int gb_pwm_activate_operation(struct pwm_chip *chip, u8 which)
@@ -245,7 +247,7 @@ static int gb_pwm_probe(struct gbphy_device *gbphy_dev,
        struct gb_connection *connection;
        struct gb_pwm_chip *pwmc;
        struct pwm_chip *chip;
-       int ret;
+       int ret, npwm;
 
        pwmc = kzalloc(sizeof(*pwmc), GFP_KERNEL);
        if (!pwmc)
@@ -267,15 +269,16 @@ static int gb_pwm_probe(struct gbphy_device *gbphy_dev,
                goto exit_connection_destroy;
 
        /* Query number of pwms present */
-       ret = gb_pwm_count_operation(pwmc);
-       if (ret)
+       ret = gb_pwm_get_npwm(connection);
+       if (ret < 0)
                goto exit_connection_disable;
+       npwm = ret;
 
        chip = &pwmc->chip;
 
        chip->dev = &gbphy_dev->dev;
        chip->ops = &gb_pwm_ops;
-       chip->npwm = pwmc->pwm_max + 1;
+       chip->npwm = npwm;
 
        ret = pwmchip_add(chip);
        if (ret) {