sh: pfc: Rudimentary pinctrl-backed GPIO support.

This begins the migration of the PFC core to the pinctrl subsystem.
Initial support is very basic, with the bulk of the implementation simply
being nopped out in such a way to allow registration with the pinctrl
core to succeed.

The gpio chip driver is stripped down considerably now relying purely on
pinctrl API calls to manage the bulk of its operations.

This provides a basis for further PFC refactoring, including decoupling
pin functions from the GPIO API, establishing pin groups, and so forth.
These will all be dealt with incrementally so as to introduce as few
growing and migratory pains to tree-wide PFC pinmux users today.

When the interfaces have been well established and in-tree users have
been migrated off of the legacy interfaces it will be possible to strip
down the core considerably, leading to eventual drivers/pinctrl rehoming.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 36 insertions, 45 deletions

diff --git a/drivers/sh/pfc/core.c b/drivers/sh/pfc/core.c
index ce4579ebd60..02e9f62e2b2 100644
--- a/drivers/sh/pfc/core.c
+++ b/drivers/sh/pfc/core.c
@@ -19,6 +19,7 @@
 #include <linux/bitops.h>
 #include <linux/slab.h>
 #include <linux/ioport.h>
+#include <linux/pinctrl/machine.h>
 
 static struct sh_pfc *sh_pfc __read_mostly;
 
@@ -501,49 +502,6 @@ int sh_pfc_config_gpio(struct sh_pfc *pfc, unsigned gpio, int pinmux_type,
 }
 EXPORT_SYMBOL_GPL(sh_pfc_config_gpio);
 
-int sh_pfc_set_direction(struct sh_pfc *pfc, unsigned gpio,
-			 int new_pinmux_type)
-{
-	int pinmux_type;
-	int ret = -EINVAL;
-
-	if (!pfc)
-		goto err_out;
-
-	pinmux_type = pfc->gpios[gpio].flags & PINMUX_FLAG_TYPE;
-
-	switch (pinmux_type) {
-	case PINMUX_TYPE_GPIO:
-		break;
-	case PINMUX_TYPE_OUTPUT:
-	case PINMUX_TYPE_INPUT:
-	case PINMUX_TYPE_INPUT_PULLUP:
-	case PINMUX_TYPE_INPUT_PULLDOWN:
-		sh_pfc_config_gpio(pfc, gpio, pinmux_type, GPIO_CFG_FREE);
-		break;
-	default:
-		goto err_out;
-	}
-
-	if (sh_pfc_config_gpio(pfc, gpio,
-			       new_pinmux_type,
-			       GPIO_CFG_DRYRUN) != 0)
-		goto err_out;
-
-	if (sh_pfc_config_gpio(pfc, gpio,
-			       new_pinmux_type,
-			       GPIO_CFG_REQ) != 0)
-		BUG();
-
-	pfc->gpios[gpio].flags &= ~PINMUX_FLAG_TYPE;
-	pfc->gpios[gpio].flags |= new_pinmux_type;
-
-	ret = 0;
- err_out:
-	return ret;
-}
-EXPORT_SYMBOL_GPL(sh_pfc_set_direction);
-
 int register_sh_pfc(struct sh_pfc *pfc)
 {
 	int (*initroutine)(struct sh_pfc *) = NULL;
@@ -563,16 +521,49 @@ int register_sh_pfc(struct sh_pfc *pfc)
 
 	spin_lock_init(&pfc->lock);
 
+	pinctrl_provide_dummies();
 	setup_data_regs(pfc);
 
 	sh_pfc = pfc;
-	pr_info("%s support registered\n", pfc->name);
 
+	/*
+	 * Initialize pinctrl bindings first
+	 */
+	initroutine = symbol_request(sh_pfc_register_pinctrl);
+	if (initroutine) {
+		ret = (*initroutine)(pfc);
+		symbol_put_addr(initroutine);
+
+		if (unlikely(ret != 0))
+			goto err;
+	}
+
+	/*
+	 * Then the GPIO chip
+	 */
 	initroutine = symbol_request(sh_pfc_register_gpiochip);
 	if (initroutine) {
-		(*initroutine)(pfc);
+		ret = (*initroutine)(pfc);
 		symbol_put_addr(initroutine);
+
+		/*
+		 * If the GPIO chip fails to come up we still leave the
+		 * PFC state as it is, given that there are already
+		 * extant users of it that have succeeded by this point.
+		 */
+		if (unlikely(ret != 0)) {
+			pr_notice("failed to init GPIO chip, ignoring...\n");
+			ret = 0;
+		}
 	}
 
+	pr_info("%s support registered\n", pfc->name);
+
 	return 0;
+
+err:
+	pfc_iounmap(pfc);
+	sh_pfc = NULL;
+
+	return ret;
 }