[PATCH 22/89] clk: bcm: rpi: Discover the firmware clocks

[Maxime Ripard]

The firmware has an interface to discover the clocks it exposes.

Let's use it to discover, register the clocks in the clocks framework and
then expose them through the device tree for consumers to use them.

Cc: Michael Turquette <mturquette at baylibre.com>
Cc: Stephen Boyd <sboyd at kernel.org>
Cc: linux-clk at vger.kernel.org
Signed-off-by: Maxime Ripard <maxime at cerno.tech>
---
 drivers/clk/bcm/clk-raspberrypi.c          | 105 +++++++++++++++++++---
 include/soc/bcm2835/raspberrypi-firmware.h |   5 +-
 2 files changed, 98 insertions(+), 12 deletions(-)

diff --git a/drivers/clk/bcm/clk-raspberrypi.c b/drivers/clk/bcm/clk-raspberrypi.c
index 3f21888a3e3e..bf6a1e2dc099 100644
--- a/drivers/clk/bcm/clk-raspberrypi.c
+++ b/drivers/clk/bcm/clk-raspberrypi.c
@@ -285,6 +285,95 @@ static struct clk_hw *raspberrypi_register_pllb_arm(struct raspberrypi_clk *rpi)
 	return &raspberrypi_clk_pllb_arm.hw;
 }
 
+static long raspberrypi_fw_dumb_round_rate(struct clk_hw *hw,
+					   unsigned long rate,
+					   unsigned long *parent_rate)
+{
+	return rate;
+}
+
+static const struct clk_ops raspberrypi_firmware_clk_ops = {
+	.is_prepared	= raspberrypi_fw_is_prepared,
+	.recalc_rate	= raspberrypi_fw_get_rate,
+	.round_rate	= raspberrypi_fw_dumb_round_rate,
+	.set_rate	= raspberrypi_fw_set_rate,
+};
+
+static struct clk_hw *raspberrypi_clk_register(struct raspberrypi_clk *rpi,
+					       unsigned int parent,
+					       unsigned int id)
+{
+	struct raspberrypi_clk_data *data;
+	struct clk_init_data init = {};
+	int ret;
+
+	if (id == RPI_FIRMWARE_ARM_CLK_ID) {
+		struct clk_hw *hw;
+
+		hw = raspberrypi_register_pllb(rpi);
+		if (IS_ERR(hw)) {
+			dev_err(rpi->dev, "Failed to initialize pllb, %ld\n",
+				PTR_ERR(hw));
+			return hw;
+		}
+
+		hw = raspberrypi_register_pllb_arm(rpi);
+		if (IS_ERR(hw))
+			return hw;
+
+		return hw;
+	}
+
+	data = devm_kzalloc(rpi->dev, sizeof(data), GFP_KERNEL);
+	if (!data)
+		return ERR_PTR(-ENOMEM);
+	data->rpi = rpi;
+	data->id = id;
+
+	init.name = devm_kasprintf(rpi->dev, GFP_KERNEL, "fw-clk-%u", id);
+	init.ops = &raspberrypi_firmware_clk_ops;
+	init.flags = CLK_GET_RATE_NOCACHE | CLK_IGNORE_UNUSED;
+
+	data->hw.init = &init;
+
+	ret = devm_clk_hw_register(rpi->dev, &data->hw);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return &data->hw;
+}
+
+static int raspberrypi_discover_clocks(struct raspberrypi_clk *rpi,
+				       struct clk_hw_onecell_data *data)
+{
+	struct rpi_firmware_get_clocks_response *clks;
+	size_t clks_size = NUM_FW_CLKS * sizeof(*clks);
+	int ret;
+
+	clks = devm_kzalloc(rpi->dev, clks_size, GFP_KERNEL);
+	if (!clks)
+		return -ENOMEM;
+
+	ret = rpi_firmware_property(rpi->firmware, RPI_FIRMWARE_GET_CLOCKS,
+				    clks, clks_size);
+	if (ret)
+		return ret;
+
+	while (clks->id) {
+		struct clk_hw *hw;
+
+		hw = raspberrypi_clk_register(rpi, clks->parent, clks->id);
+		if (IS_ERR(hw))
+			return PTR_ERR(hw);
+
+		data->hws[clks->id] = hw;
+		data->num = clks->id + 1;
+		clks++;
+	}
+
+	return 0;
+}
+
 static int raspberrypi_clk_probe(struct platform_device *pdev)
 {
 	struct clk_hw_onecell_data *clk_data;
@@ -292,7 +381,7 @@ static int raspberrypi_clk_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct rpi_firmware *firmware;
 	struct raspberrypi_clk *rpi;
-	struct clk_hw *hw;
+	int ret;
 
 	firmware_node = of_parse_phandle(dev->of_node, "raspberrypi,firmware", 0);
 	if (!firmware_node) {
@@ -317,17 +406,9 @@ static int raspberrypi_clk_probe(struct platform_device *pdev)
 	if (!clk_data)
 		return -ENOMEM;
 
-	hw = raspberrypi_register_pllb(rpi);
-	if (IS_ERR(hw)) {
-		dev_err(dev, "Failed to initialize pllb, %ld\n", PTR_ERR(hw));
-		return PTR_ERR(hw);
-	}
-
-	hw = raspberrypi_register_pllb_arm(rpi);
-	if (IS_ERR(hw))
-		return PTR_ERR(hw);
-	clk_data->hws[RPI_FIRMWARE_ARM_CLK_ID] = hw;
-	clk_data->num = RPI_FIRMWARE_ARM_CLK_ID + 1;
+	ret = raspberrypi_discover_clocks(rpi, clk_data);
+	if (ret)
+		return ret;
 
 	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
 					  clk_data);
diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
index 7800e12ee042..e5b7a41bba6b 100644
--- a/include/soc/bcm2835/raspberrypi-firmware.h
+++ b/include/soc/bcm2835/raspberrypi-firmware.h
@@ -135,6 +135,11 @@ enum rpi_firmware_property_tag {
 	RPI_FIRMWARE_GET_DMA_CHANNELS =                       0x00060001,
 };
 
+struct rpi_firmware_get_clocks_response {
+	__le32	parent;
+	__le32	id;
+};
+
 #if IS_ENABLED(CONFIG_RASPBERRYPI_FIRMWARE)
 int rpi_firmware_property(struct rpi_firmware *fw,
 			  u32 tag, void *data, size_t len);
-- 
git-series 0.9.1