ARM: shmobile: fix regulator quirk for Gen2

The current implementation only works if the da9xxx devices are added
before their drivers are registered. Only then it can apply the fixes to
both devices. Otherwise, the driver for the first device gets probed
before the fix for the second device can be applied. This is what
fails when using the IP core switcher or when having the i2c master
driver as a module.

So, we need to disable both da9xxx once we detected one of them. We now
use i2c_transfer with hardcoded i2c_messages and device addresses, so we
don't need the da9xxx client devices to be instantiated. Because the
fixup is used on specific boards only, the addresses are not going to
change.

Fixes: 663fbb52 ("ARM: shmobile: R-Car Gen2: Add da9063/da9210 regulator quirk")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> (r8a7791/koelsch)
Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c

@@ -41,39 +41,26 @@
 
 #define REGULATOR_IRQ_MASK	BIT(2)	/* IRQ2, active low */
 
-static void __iomem *irqc;
-
-static const u8 da9063_mask_regs[] = {
-	DA9063_REG_IRQ_MASK_A,
-	DA9063_REG_IRQ_MASK_B,
-	DA9063_REG_IRQ_MASK_C,
-	DA9063_REG_IRQ_MASK_D,
-};
-
-/* DA9210 System Control and Event Registers */
+/* start of DA9210 System Control and Event Registers */
 #define DA9210_REG_MASK_A		0x54
-#define DA9210_REG_MASK_B		0x55
-
-static const u8 da9210_mask_regs[] = {
-	DA9210_REG_MASK_A,
-	DA9210_REG_MASK_B,
-};
-
-static void da9xxx_mask_irqs(struct i2c_client *client, const u8 regs[],
-			     unsigned int nregs)
-{
-	unsigned int i;
 
-	dev_info(&client->dev, "Masking %s interrupt sources\n", client->name);
+static void __iomem *irqc;
 
-	for (i = 0; i < nregs; i++) {
-		int error = i2c_smbus_write_byte_data(client, regs[i], ~0);
-		if (error) {
-			dev_err(&client->dev, "i2c error %d\n", error);
-			return;
-		}
-	}
-}
+/* first byte sets the memory pointer, following are consecutive reg values */
+static u8 da9063_irq_clr[] = { DA9063_REG_IRQ_MASK_A, 0xff, 0xff, 0xff, 0xff };
+static u8 da9210_irq_clr[] = { DA9210_REG_MASK_A, 0xff, 0xff };
+
+static struct i2c_msg da9xxx_msgs[2] = {
+	{
+		.addr = 0x58,
+		.len = ARRAY_SIZE(da9063_irq_clr),
+		.buf = da9063_irq_clr,
+	}, {
+		.addr = 0x68,
+		.len = ARRAY_SIZE(da9210_irq_clr),
+		.buf = da9210_irq_clr,
+	},
+};
 
 static int regulator_quirk_notify(struct notifier_block *nb,
 				  unsigned long action, void *data)
@@ -93,12 +80,15 @@ static int regulator_quirk_notify(struct notifier_block *nb,
 	client = to_i2c_client(dev);
 	dev_dbg(dev, "Detected %s\n", client->name);
 
-	if ((client->addr == 0x58 && !strcmp(client->name, "da9063")))
-		da9xxx_mask_irqs(client, da9063_mask_regs,
-				 ARRAY_SIZE(da9063_mask_regs));
-	else if (client->addr == 0x68 && !strcmp(client->name, "da9210"))
-		da9xxx_mask_irqs(client, da9210_mask_regs,
-				 ARRAY_SIZE(da9210_mask_regs));
+	if ((client->addr == 0x58 && !strcmp(client->name, "da9063")) ||
+	    (client->addr == 0x68 && !strcmp(client->name, "da9210"))) {
+		int ret;
+
+		dev_info(&client->dev, "clearing da9063/da9210 interrupts\n");
+		ret = i2c_transfer(client->adapter, da9xxx_msgs, ARRAY_SIZE(da9xxx_msgs));
+		if (ret != ARRAY_SIZE(da9xxx_msgs))
+			dev_err(&client->dev, "i2c error %d\n", ret);
+	}
 
 	mon = ioread32(irqc + IRQC_MONITOR);
 	if (mon & REGULATOR_IRQ_MASK)