ramips: pinctrl: support requesting different functions for same group

MT7620 wireless radio needs change the pin group function between
"gpio" and "pa" during the calibration process. However, ralink
pinctrl driver doesn't support requesting different functions for
the same group. This patch enables pinctrl consumers to perform
such operations.

Signed-off-by: Shiji Yang <yangshiji66@qq.com>
(cherry picked from commit b4ea49ad442d2884d0b86009f404f125635c4153)

diff --git a/target/linux/ramips/patches-5.15/808-pinctrl-mtmips-support-requesting-different-function.patch b/target/linux/ramips/patches-5.15/808-pinctrl-mtmips-support-requesting-different-function.patch
new file mode 100644 (file)
index 0000000..047808f
--- /dev/null
+++ b/target/linux/ramips/patches-5.15/808-pinctrl-mtmips-support-requesting-different-function.patch
@@ -0,0 +1,45 @@
+From: Shiji Yang <yangshiji66@outlook.com>
+Date: Wed, 26 Jul 2023 01:32:55 +0800
+Subject: [PATCH] pinctrl: mtmips: support requesting different functions for
+ same group
+
+Sometimes pinctrl consumers may request different functions for the
+same pin group in different situations. This patch can help to reset
+the group function flag when requesting a different function.
+
+Signed-off-by: Shiji Yang <yangshiji66@outlook.com>
+---
+ drivers/pinctrl/ralink/pinctrl-ralink.c | 21 +++++++++++++++++----
+ 1 file changed, 17 insertions(+), 4 deletions(-)
+
+--- a/drivers/pinctrl/ralink/pinctrl-ralink.c
++++ b/drivers/pinctrl/ralink/pinctrl-ralink.c
+@@ -123,11 +123,24 @@ static int ralink_pmx_group_enable(struc
+       int i;
+       int shift;
+ 
+-      /* dont allow double use */
++      /*
++       * for the same pin group, if request a different function,
++       * then clear the group function flag and continue, else exit.
++       */
+       if (p->groups[group].enabled) {
+-              dev_err(p->dev, "%s is already enabled\n",
+-                      p->groups[group].name);
+-              return 0;
++              for (i = 0; i < p->groups[group].func_count; i++) {
++                      if (p->groups[group].func[i].enabled == 1) {
++                              if (!strcmp(p->func[func]->name,
++                                      p->groups[group].func[i].name))
++                                      return 0;
++                              p->groups[group].func[i].enabled = 0;
++                              break;
++                      }
++              }
++
++              /* exit if request the "gpio" function again */
++              if (i == p->groups[group].func_count && func == 0)
++                      return 0;
+       }
+ 
+       p->groups[group].enabled = 1;