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>

drivers/sh/pfc/Kconfig

@@ -4,8 +4,21 @@ config SH_PFC
 	# XXX move off the gpio dependency
 	depends on GENERIC_GPIO
 	select GPIO_SH_PFC if ARCH_REQUIRE_GPIOLIB
+	select PINCTRL_SH_PFC
 	def_bool y
 
+#
+# Placeholder for now, rehome to drivers/pinctrl once the PFC APIs
+# have settled.
+#
+config PINCTRL_SH_PFC
+	tristate "SuperH PFC pin controller driver"
+	depends on SH_PFC
+	select PINCTRL
+	select PINMUX
+	select PINCONF
+	select GENERIC_PINCONF
+
 config GPIO_SH_PFC
 	tristate "SuperH PFC GPIO support"
 	depends on SH_PFC && GPIOLIB

drivers/sh/pfc/Makefile

@@ -1,2 +1,3 @@
 obj-y				+= core.o
+obj-$(CONFIG_PINCTRL_SH_PFC)	+= pinctrl.o
 obj-$(CONFIG_GPIO_SH_PFC)	+= gpio.o

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;
 }

drivers/sh/pfc/gpio.c

@@ -16,6 +16,7 @@
 #include <linux/spinlock.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/pinctrl/consumer.h>
 
 struct sh_pfc_chip {
 	struct sh_pfc		*pfc;
@@ -34,80 +35,12 @@ static struct sh_pfc *gpio_to_pfc(struct gpio_chip *gc)
 
 static int sh_gpio_request(struct gpio_chip *gc, unsigned offset)
 {
-	struct sh_pfc *pfc = gpio_to_pfc(gc);
-	struct pinmux_data_reg *dummy;
-	unsigned long flags;
-	int i, ret, pinmux_type;
-
-	ret = -EINVAL;
-
-	if (!pfc)
-		goto err_out;
-
-	spin_lock_irqsave(&pfc->lock, flags);
-
-	if ((pfc->gpios[offset].flags & PINMUX_FLAG_TYPE) != PINMUX_TYPE_NONE)
-		goto err_unlock;
-
-	/* setup pin function here if no data is associated with pin */
-
-	if (sh_pfc_get_data_reg(pfc, offset, &dummy, &i) != 0)
-		pinmux_type = PINMUX_TYPE_FUNCTION;
-	else
-		pinmux_type = PINMUX_TYPE_GPIO;
-
-	if (pinmux_type == PINMUX_TYPE_FUNCTION) {
-		if (sh_pfc_config_gpio(pfc, offset,
-				       pinmux_type,
-				       GPIO_CFG_DRYRUN) != 0)
-			goto err_unlock;
-
-		if (sh_pfc_config_gpio(pfc, offset,
-				       pinmux_type,
-				       GPIO_CFG_REQ) != 0)
-			BUG();
-	}
-
-	pfc->gpios[offset].flags &= ~PINMUX_FLAG_TYPE;
-	pfc->gpios[offset].flags |= pinmux_type;
-
-	ret = 0;
- err_unlock:
-	spin_unlock_irqrestore(&pfc->lock, flags);
- err_out:
-	return ret;
+	return pinctrl_request_gpio(offset);
 }
 
 static void sh_gpio_free(struct gpio_chip *gc, unsigned offset)
 {
-	struct sh_pfc *pfc = gpio_to_pfc(gc);
-	unsigned long flags;
-	int pinmux_type;
-
-	if (!pfc)
-		return;
-
-	spin_lock_irqsave(&pfc->lock, flags);
-
-	pinmux_type = pfc->gpios[offset].flags & PINMUX_FLAG_TYPE;
-	sh_pfc_config_gpio(pfc, offset, pinmux_type, GPIO_CFG_FREE);
-	pfc->gpios[offset].flags &= ~PINMUX_FLAG_TYPE;
-	pfc->gpios[offset].flags |= PINMUX_TYPE_NONE;
-
-	spin_unlock_irqrestore(&pfc->lock, flags);
-}
-
-static int sh_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
-{
-	struct sh_pfc *pfc = gpio_to_pfc(gc);
-	unsigned long flags;
-	int ret;
-
-	spin_lock_irqsave(&pfc->lock, flags);
-	ret = sh_pfc_set_direction(pfc, offset, PINMUX_TYPE_INPUT);
-	spin_unlock_irqrestore(&pfc->lock, flags);
-
-	return ret;
+	pinctrl_free_gpio(offset);
 }
 
 static void sh_gpio_set_value(struct sh_pfc *pfc, unsigned gpio, int value)
@@ -121,22 +54,6 @@ static void sh_gpio_set_value(struct sh_pfc *pfc, unsigned gpio, int value)
 		sh_pfc_write_bit(dr, bit, value);
 }
 
-static int sh_gpio_direction_output(struct gpio_chip *gc, unsigned offset,
-				    int value)
-{
-	struct sh_pfc *pfc = gpio_to_pfc(gc);
-	unsigned long flags;
-	int ret;
-
-	sh_gpio_set_value(pfc, offset, value);
-
-	spin_lock_irqsave(&pfc->lock, flags);
-	ret = sh_pfc_set_direction(pfc, offset, PINMUX_TYPE_OUTPUT);
-	spin_unlock_irqrestore(&pfc->lock, flags);
-
-	return ret;
-}
-
 static int sh_gpio_get_value(struct sh_pfc *pfc, unsigned gpio)
 {
 	struct pinmux_data_reg *dr = NULL;
@@ -148,6 +65,19 @@ static int sh_gpio_get_value(struct sh_pfc *pfc, unsigned gpio)
 	return sh_pfc_read_bit(dr, bit);
 }
 
+static int sh_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
+{
+	return pinctrl_gpio_direction_input(offset);
+}
+
+static int sh_gpio_direction_output(struct gpio_chip *gc, unsigned offset,
+				    int value)
+{
+	sh_gpio_set_value(gpio_to_pfc(gc), offset, value);
+
+	return pinctrl_gpio_direction_output(offset);
+}
+
 static int sh_gpio_get(struct gpio_chip *gc, unsigned offset)
 {
 	return sh_gpio_get_value(gpio_to_pfc(gc), offset);