gpio: Use callback presence to determine need of valid_mask

After we switched the two drivers that have .need_valid_mask
set to use the callback for setting up the .valid_mask,
we can just use the presence of the .init_valid_mask()
callback (or the OF reserved ranges, nota bene) to determine
whether to allocate the mask or not and we can drop the
.need_valid_mask field altogether.

Cc: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: Amelie Delaunay <amelie.delaunay@st.com>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20190819093058.10863-1-linus.walleij@linaro.org

drivers/gpio/gpiolib.c

@@ -363,9 +363,7 @@ static unsigned long *gpiochip_allocate_mask(struct gpio_chip *chip)
 
 static int gpiochip_alloc_valid_mask(struct gpio_chip *gc)
 {
-	if (of_gpio_need_valid_mask(gc))
-		gc->need_valid_mask = true;
-	if (!gc->need_valid_mask)
+	if (!(of_gpio_need_valid_mask(gc) || gc->init_valid_mask))
 		return 0;
 
 	gc->valid_mask = gpiochip_allocate_mask(gc);

drivers/pinctrl/pinctrl-stmfx.c

@@ -662,7 +662,6 @@ static int stmfx_pinctrl_probe(struct platform_device *pdev)
 	pctl->gpio_chip.ngpio = pctl->pctl_desc.npins;
 	pctl->gpio_chip.can_sleep = true;
 	pctl->gpio_chip.of_node = np;
-	pctl->gpio_chip.need_valid_mask = true;
 	pctl->gpio_chip.init_valid_mask = stmfx_pinctrl_gpio_init_valid_mask;
 
 	ret = devm_gpiochip_add_data(pctl->dev, &pctl->gpio_chip, pctl);

drivers/pinctrl/qcom/pinctrl-msm.c

@@ -654,7 +654,6 @@ static const struct gpio_chip msm_gpio_template = {
 	.request          = gpiochip_generic_request,
 	.free             = gpiochip_generic_free,
 	.dbg_show         = msm_gpio_dbg_show,
-	.init_valid_mask  = msm_gpio_init_valid_mask,
 };
 
 /* For dual-edge interrupts in software, since some hardware has no
@@ -1016,7 +1015,8 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
 	chip->parent = pctrl->dev;
 	chip->owner = THIS_MODULE;
 	chip->of_node = pctrl->dev->of_node;
-	chip->need_valid_mask = msm_gpio_needs_valid_mask(pctrl);
+	if (msm_gpio_needs_valid_mask(pctrl))
+		chip->init_valid_mask = msm_gpio_init_valid_mask;
 
 	pctrl->irq_chip.name = "msmgpio";
 	pctrl->irq_chip.irq_enable = msm_gpio_irq_enable;

include/linux/gpio/driver.h

@@ -403,15 +403,6 @@ struct gpio_chip {
 	struct gpio_irq_chip irq;
 #endif /* CONFIG_GPIOLIB_IRQCHIP */
 
-	/**
-	 * @need_valid_mask:
-	 *
-	 * If set core allocates @valid_mask with all its values initialized
-	 * with init_valid_mask() or set to one if init_valid_mask() is not
-	 * defined
-	 */
-	bool need_valid_mask;
-
 	/**
 	 * @valid_mask:
 	 *