irqchip/renesas-intc-irqpin: Improve clock error handling and reporting

If the Renesas External IRQ Pin driver cannot find a functional clock,
it prints a warning, .e.g.

    renesas_intc_irqpin fe78001c.interrupt-controller: unable to get clock

and continues, as the clock is optional, depending on the SoC type.
This warning may confuse users.

To fix this, add a flag to indicate that the clock is mandatory or
optional, and add a few more compatible entries:
  - If the clock is mandatory (on R-Mobile A1 or SH-Mobile AG5), a
    missing clock is now treated as a fatal error,
  - If the clock is optional (on R-Car Gen1, or using the generic
    "renesas,intc-irqpin" compatible value), the warning is no longer
    printed.

This requires making struct intc_irqpin_irlm_config more generic by
renaming it to intc_irqpin_config, and adding a flag to indicate if IRLM
is needed.
The new clock flag is merged with the existing shared_irqs boolean into
a bitfield to save space.

Suggested-by: Magnus Damm <magnus.damm@gmail.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lkml.kernel.org/r/1448377693-19597-1-git-send-email-geert+renesas@glider.be
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

drivers/irqchip/irq-renesas-intc-irqpin.c

@@ -79,12 +79,15 @@ struct intc_irqpin_priv {
 	struct irq_chip irq_chip;
 	struct irq_domain *irq_domain;
 	struct clk *clk;
-	bool shared_irqs;
+	unsigned shared_irqs:1;
+	unsigned needs_clk:1;
 	u8 shared_irq_mask;
 };
 
-struct intc_irqpin_irlm_config {
+struct intc_irqpin_config {
 	unsigned int irlm_bit;
+	unsigned needs_irlm:1;
+	unsigned needs_clk:1;
 };
 
 static unsigned long intc_irqpin_read32(void __iomem *iomem)
@@ -359,8 +362,15 @@ static const struct irq_domain_ops intc_irqpin_irq_domain_ops = {
 	.xlate  = irq_domain_xlate_twocell,
 };
 
-static const struct intc_irqpin_irlm_config intc_irqpin_irlm_r8a777x = {
+static const struct intc_irqpin_config intc_irqpin_irlm_r8a777x = {
 	.irlm_bit = 23, /* ICR0.IRLM0 */
+	.needs_irlm = 1,
+	.needs_clk = 0,
+};
+
+static const struct intc_irqpin_config intc_irqpin_rmobile = {
+	.needs_irlm = 0,
+	.needs_clk = 1,
 };
 
 static const struct of_device_id intc_irqpin_dt_ids[] = {
@@ -369,12 +379,17 @@ static const struct of_device_id intc_irqpin_dt_ids[] = {
 	  .data = &intc_irqpin_irlm_r8a777x },
 	{ .compatible = "renesas,intc-irqpin-r8a7779",
 	  .data = &intc_irqpin_irlm_r8a777x },
+	{ .compatible = "renesas,intc-irqpin-r8a7740",
+	  .data = &intc_irqpin_rmobile },
+	{ .compatible = "renesas,intc-irqpin-sh73a0",
+	  .data = &intc_irqpin_rmobile },
 	{},
 };
 MODULE_DEVICE_TABLE(of, intc_irqpin_dt_ids);
 
 static int intc_irqpin_probe(struct platform_device *pdev)
 {
+	const struct intc_irqpin_config *config = NULL;
 	struct device *dev = &pdev->dev;
 	const struct of_device_id *of_id;
 	struct intc_irqpin_priv *p;
@@ -407,9 +422,19 @@ static int intc_irqpin_probe(struct platform_device *pdev)
 	p->pdev = pdev;
 	platform_set_drvdata(pdev, p);
 
+	of_id = of_match_device(intc_irqpin_dt_ids, dev);
+	if (of_id && of_id->data) {
+		config = of_id->data;
+		p->needs_clk = config->needs_clk;
+	}
+
 	p->clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(p->clk)) {
-		dev_warn(dev, "unable to get clock\n");
+		if (p->needs_clk) {
+			dev_err(dev, "unable to get clock\n");
+			ret = PTR_ERR(p->clk);
+			goto err0;
+		}
 		p->clk = NULL;
 	}
 
@@ -479,14 +504,10 @@ static int intc_irqpin_probe(struct platform_device *pdev)
 	}
 
 	/* configure "individual IRQ mode" where needed */
-	of_id = of_match_device(intc_irqpin_dt_ids, dev);
-	if (of_id && of_id->data) {
-		const struct intc_irqpin_irlm_config *irlm_config = of_id->data;
-
+	if (config && config->needs_irlm) {
 		if (io[INTC_IRQPIN_REG_IRLM])
 			intc_irqpin_read_modify_write(p, INTC_IRQPIN_REG_IRLM,
-						      irlm_config->irlm_bit,
-						      1, 1);
+						      config->irlm_bit, 1, 1);
 		else
 			dev_warn(dev, "unable to select IRLM mode\n");
 	}
@@ -500,10 +521,10 @@ static int intc_irqpin_probe(struct platform_device *pdev)
 
 	/* scan for shared interrupt lines */
 	ref_irq = p->irq[0].requested_irq;
-	p->shared_irqs = true;
+	p->shared_irqs = 1;
 	for (k = 1; k < nirqs; k++) {
 		if (ref_irq != p->irq[k].requested_irq) {
-			p->shared_irqs = false;
+			p->shared_irqs = 0;
 			break;
 		}
 	}