clk: bcm: rpi: Add variant structure

We only export a bunch of firmware clocks, and some of them require
special treatment.

This has been do so far using some tests on the clock id in various
places, but this is fairly hard to extend and doesn't scale very well.

Since we'll need some more cases in the next patches, let's switch to a
variant structure that defines the behaviour we need to have for a given
clock.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220225143534.405820-9-maxime@cerno.tech
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/bcm/clk-raspberrypi.c

@@ -56,6 +56,8 @@ static char *rpi_firmware_clk_names[] = {
 #define RPI_FIRMWARE_STATE_ENABLE_BIT	BIT(0)
 #define RPI_FIRMWARE_STATE_WAIT_BIT	BIT(1)
 
+struct raspberrypi_clk_variant;
+
 struct raspberrypi_clk {
 	struct device *dev;
 	struct rpi_firmware *firmware;
@@ -66,10 +68,36 @@ struct raspberrypi_clk_data {
 	struct clk_hw hw;
 
 	unsigned int id;
+	struct raspberrypi_clk_variant *variant;
 
 	struct raspberrypi_clk *rpi;
 };
 
+struct raspberrypi_clk_variant {
+	bool		export;
+	char		*clkdev;
+};
+
+static struct raspberrypi_clk_variant
+raspberrypi_clk_variants[RPI_FIRMWARE_NUM_CLK_ID] = {
+	[RPI_FIRMWARE_ARM_CLK_ID] = {
+		.export = true,
+		.clkdev = "cpu0",
+	},
+	[RPI_FIRMWARE_CORE_CLK_ID] = {
+		.export = true,
+	},
+	[RPI_FIRMWARE_M2MC_CLK_ID] = {
+		.export = true,
+	},
+	[RPI_FIRMWARE_V3D_CLK_ID] = {
+		.export = true,
+	},
+	[RPI_FIRMWARE_PIXEL_BVB_CLK_ID] = {
+		.export = true,
+	},
+};
+
 /*
  * Structure of the message passed to Raspberry Pi's firmware in order to
  * change clock rates. The 'disable_turbo' option is only available to the ARM
@@ -183,7 +211,8 @@ static const struct clk_ops raspberrypi_firmware_clk_ops = {
 
 static struct clk_hw *raspberrypi_clk_register(struct raspberrypi_clk *rpi,
 					       unsigned int parent,
-					       unsigned int id)
+					       unsigned int id,
+					       struct raspberrypi_clk_variant *variant)
 {
 	struct raspberrypi_clk_data *data;
 	struct clk_init_data init = {};
@@ -195,6 +224,7 @@ static struct clk_hw *raspberrypi_clk_register(struct raspberrypi_clk *rpi,
 		return ERR_PTR(-ENOMEM);
 	data->rpi = rpi;
 	data->id = id;
+	data->variant = variant;
 
 	init.name = devm_kasprintf(rpi->dev, GFP_KERNEL,
 				   "fw-clk-%s",
@@ -228,9 +258,9 @@ static struct clk_hw *raspberrypi_clk_register(struct raspberrypi_clk *rpi,
 
 	clk_hw_set_rate_range(&data->hw, min_rate, max_rate);
 
-	if (id == RPI_FIRMWARE_ARM_CLK_ID) {
+	if (variant->clkdev) {
 		ret = devm_clk_hw_register_clkdev(rpi->dev, &data->hw,
-						  NULL, "cpu0");
+						  NULL, variant->clkdev);
 		if (ret) {
 			dev_err(rpi->dev, "Failed to initialize clkdev\n");
 			return ERR_PTR(ret);
@@ -264,27 +294,27 @@ static int raspberrypi_discover_clocks(struct raspberrypi_clk *rpi,
 		return ret;
 
 	while (clks->id) {
-		struct clk_hw *hw;
-
-		switch (clks->id) {
-		case RPI_FIRMWARE_ARM_CLK_ID:
-		case RPI_FIRMWARE_CORE_CLK_ID:
-		case RPI_FIRMWARE_M2MC_CLK_ID:
-		case RPI_FIRMWARE_V3D_CLK_ID:
-		case RPI_FIRMWARE_PIXEL_BVB_CLK_ID:
+		struct raspberrypi_clk_variant *variant;
+
+		if (clks->id > RPI_FIRMWARE_NUM_CLK_ID) {
+			dev_err(rpi->dev, "Unknown clock id: %u", clks->id);
+			return -EINVAL;
+		}
+
+		variant = &raspberrypi_clk_variants[clks->id];
+		if (variant->export) {
+			struct clk_hw *hw;
+
 			hw = raspberrypi_clk_register(rpi, clks->parent,
-						      clks->id);
+						      clks->id, variant);
 			if (IS_ERR(hw))
 				return PTR_ERR(hw);
 
 			data->hws[clks->id] = hw;
 			data->num = clks->id + 1;
-			fallthrough;
-
-		default:
-			clks++;
-			break;
 		}
+
+		clks++;
 	}
 
 	return 0;