[PATCH] spi: meson-spicc: add support for Amlogic G12A

[Neil Armstrong]

Add support for the SPICC controllers on the Amlogic G12A SoCs family.

The G12A SPICC controllers inherit from the AXG enhanced registers but
takes an external pclk for the baud rate generator and can achieve up to
166MHz SCLK.

Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200312133131.26430-10-narmstrong@xxxxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
 drivers/spi/spi-meson-spicc.c | 54 +++++++++++++++++++++++++++++------
 1 file changed, 46 insertions(+), 8 deletions(-)

diff --git a/drivers/spi/spi-meson-spicc.c b/drivers/spi/spi-meson-spicc.c
index 351ccd8dd2c2..77f7d0e0e46a 100644
--- a/drivers/spi/spi-meson-spicc.c
+++ b/drivers/spi/spi-meson-spicc.c
@@ -147,6 +147,7 @@ struct meson_spicc_data {
 	unsigned int			fifo_size;
 	bool				has_oen;
 	bool				has_enhance_clk_div;
+	bool				has_pclk;
 };
 
 struct meson_spicc_device {
@@ -154,6 +155,7 @@ struct meson_spicc_device {
 	struct platform_device		*pdev;
 	void __iomem			*base;
 	struct clk			*core;
+	struct clk			*pclk;
 	struct clk			*clk;
 	struct spi_message		*message;
 	struct spi_transfer		*xfer;
@@ -514,6 +516,10 @@ static void meson_spicc_cleanup(struct spi_device *spi)
  * Clk path for AXG series:
  *    src -> pow2 fixed div -> pow2 div -> mux -> out
  *    src -> enh fixed div -> enh div -> mux -> out
+ *
+ * Clk path for G12A series:
+ *    pclk -> pow2 fixed div -> pow2 div -> mux -> out
+ *    pclk -> enh fixed div -> enh div -> mux -> out
  */
 
 static int meson_spicc_clk_init(struct meson_spicc_device *spicc)
@@ -542,7 +548,10 @@ static int meson_spicc_clk_init(struct meson_spicc_device *spicc)
 	init.name = name;
 	init.ops = &clk_fixed_factor_ops;
 	init.flags = 0;
-	parent_data[0].hw = __clk_get_hw(spicc->core);
+	if (spicc->data->has_pclk)
+		parent_data[0].hw = __clk_get_hw(spicc->pclk);
+	else
+		parent_data[0].hw = __clk_get_hw(spicc->core);
 	init.num_parents = 1;
 
 	pow2_fixed_div->mult = 1,
@@ -589,7 +598,10 @@ static int meson_spicc_clk_init(struct meson_spicc_device *spicc)
 	init.name = name;
 	init.ops = &clk_fixed_factor_ops;
 	init.flags = 0;
-	parent_data[0].hw = __clk_get_hw(spicc->core);
+	if (spicc->data->has_pclk)
+		parent_data[0].hw = __clk_get_hw(spicc->pclk);
+	else
+		parent_data[0].hw = __clk_get_hw(spicc->core);
 	init.num_parents = 1;
 
 	enh_fixed_div->mult = 1,
@@ -648,7 +660,7 @@ static int meson_spicc_probe(struct platform_device *pdev)
 {
 	struct spi_master *master;
 	struct meson_spicc_device *spicc;
-	int ret, irq, rate;
+	int ret, irq;
 
 	master = spi_alloc_master(&pdev->dev, sizeof(*spicc));
 	if (!master) {
@@ -697,12 +709,26 @@ static int meson_spicc_probe(struct platform_device *pdev)
 		goto out_master;
 	}
 
+	if (spicc->data->has_pclk) {
+		spicc->pclk = devm_clk_get(&pdev->dev, "pclk");
+		if (IS_ERR(spicc->pclk)) {
+			dev_err(&pdev->dev, "pclk clock request failed\n");
+			ret = PTR_ERR(spicc->pclk);
+			goto out_master;
+		}
+	}
+
 	ret = clk_prepare_enable(spicc->core);
 	if (ret) {
 		dev_err(&pdev->dev, "core clock enable failed\n");
 		goto out_master;
 	}
-	rate = clk_get_rate(spicc->core);
+
+	ret = clk_prepare_enable(spicc->pclk);
+	if (ret) {
+		dev_err(&pdev->dev, "pclk clock enable failed\n");
+		goto out_master;
+	}
 
 	device_reset_optional(&pdev->dev);
 
@@ -715,6 +741,7 @@ static int meson_spicc_probe(struct platform_device *pdev)
 				     SPI_BPW_MASK(8);
 	master->flags = (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX);
 	master->min_speed_hz = spicc->data->min_speed_hz;
+	master->max_speed_hz = spicc->data->max_speed_hz;
 	master->setup = meson_spicc_setup;
 	master->cleanup = meson_spicc_cleanup;
 	master->prepare_message = meson_spicc_prepare_message;
@@ -722,10 +749,6 @@ static int meson_spicc_probe(struct platform_device *pdev)
 	master->transfer_one = meson_spicc_transfer_one;
 	master->use_gpio_descriptors = true;
 
-	/* Setup max rate according to the Meson datasheet */
-	master->max_speed_hz = min_t(unsigned int, rate >> 1,
-				     spicc->data->max_speed_hz);
-
 	meson_spicc_oen_enable(spicc);
 
 	ret = meson_spicc_clk_init(spicc);
@@ -744,6 +767,7 @@ static int meson_spicc_probe(struct platform_device *pdev)
 
 out_clk:
 	clk_disable_unprepare(spicc->core);
+	clk_disable_unprepare(spicc->pclk);
 
 out_master:
 	spi_master_put(master);
@@ -759,6 +783,7 @@ static int meson_spicc_remove(struct platform_device *pdev)
 	writel(0, spicc->base + SPICC_CONREG);
 
 	clk_disable_unprepare(spicc->core);
+	clk_disable_unprepare(spicc->pclk);
 
 	return 0;
 }
@@ -777,6 +802,15 @@ static const struct meson_spicc_data meson_spicc_axg_data = {
 	.has_enhance_clk_div	= true,
 };
 
+static const struct meson_spicc_data meson_spicc_g12a_data = {
+	.max_speed_hz		= 166666666,
+	.min_speed_hz		= 50000,
+	.fifo_size		= 15,
+	.has_oen		= true,
+	.has_enhance_clk_div	= true,
+	.has_pclk		= true,
+};
+
 static const struct of_device_id meson_spicc_of_match[] = {
 	{
 		.compatible	= "amlogic,meson-gx-spicc",
@@ -786,6 +820,10 @@ static const struct of_device_id meson_spicc_of_match[] = {
 		.compatible = "amlogic,meson-axg-spicc",
 		.data		= &meson_spicc_axg_data,
 	},
+	{
+		.compatible = "amlogic,meson-g12a-spicc",
+		.data		= &meson_spicc_g12a_data,
+	},
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, meson_spicc_of_match);
-- 
2.20.1