[PATCH v6 3/5] clk: aspeed: Add platform driver and register PLLs

[Joel Stanley]

This registers a platform driver to set up all of the non-core clocks.

The clocks that have configurable rates are now registered.

Reviewed-by: Andrew Jeffery <andrew at aj.id.au>
Signed-off-by: Joel Stanley <joel at jms.id.au>
--
v6:
 - Add Andrew's reviewed-by
v5:
 - Remove eclk configuration. We do not have enough information to
 correctly implement the mux and divisor, so it will have to be
 implemented in the future
v4:
 - Add eclk div table to fix ast2500 calculation
 - Add defines to document the BIT() macros
 - Pass dev where we can when registering clocks
 - Check for errors when registering clk_hws
v3:
 - Fix bclk and eclk calculation
 - Separate out ast2400 and ast25000 for pll calculation
---
 drivers/clk/clk-aspeed.c | 130 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 130 insertions(+)

diff --git a/drivers/clk/clk-aspeed.c b/drivers/clk/clk-aspeed.c
index 9742f1d0977f..839243691b26 100644
--- a/drivers/clk/clk-aspeed.c
+++ b/drivers/clk/clk-aspeed.c
@@ -5,6 +5,8 @@
 #include <linux/clk-provider.h>
 #include <linux/mfd/syscon.h>
 #include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
@@ -105,6 +107,18 @@ static const struct aspeed_gate_data aspeed_gates[] = {
 	[ASPEED_CLK_GATE_LHCCLK] =	{ 28, -1, "lhclk-gate",		"lhclk", 0 }, /* LPC master/LPC+ */
 };
 
+static const struct clk_div_table ast2500_mac_div_table[] = {
+	{ 0x0, 4 }, /* Yep, really. Aspeed confirmed this is correct */
+	{ 0x1, 4 },
+	{ 0x2, 6 },
+	{ 0x3, 8 },
+	{ 0x4, 10 },
+	{ 0x5, 12 },
+	{ 0x6, 14 },
+	{ 0x7, 16 },
+	{ 0 }
+};
+
 static const struct clk_div_table ast2400_div_table[] = {
 	{ 0x0, 2 },
 	{ 0x1, 4 },
@@ -170,6 +184,122 @@ static struct clk_hw *aspeed_ast2500_calc_pll(const char *name, u32 val)
 			mult, div);
 }
 
+struct aspeed_clk_soc_data {
+	const struct clk_div_table *div_table;
+	const struct clk_div_table *mac_div_table;
+	struct clk_hw *(*calc_pll)(const char *name, u32 val);
+};
+
+static const struct aspeed_clk_soc_data ast2500_data = {
+	.div_table = ast2500_div_table,
+	.mac_div_table = ast2500_mac_div_table,
+	.calc_pll = aspeed_ast2500_calc_pll,
+};
+
+static const struct aspeed_clk_soc_data ast2400_data = {
+	.div_table = ast2400_div_table,
+	.mac_div_table = ast2400_div_table,
+	.calc_pll = aspeed_ast2400_calc_pll,
+};
+
+static int aspeed_clk_probe(struct platform_device *pdev)
+{
+	const struct aspeed_clk_soc_data *soc_data;
+	struct device *dev = &pdev->dev;
+	struct regmap *map;
+	struct clk_hw *hw;
+	u32 val, rate;
+
+	map = syscon_node_to_regmap(dev->of_node);
+	if (IS_ERR(map)) {
+		dev_err(dev, "no syscon regmap\n");
+		return PTR_ERR(map);
+	}
+
+	/* SoC generations share common layouts but have different divisors */
+	soc_data = of_device_get_match_data(dev);
+	if (!soc_data) {
+		dev_err(dev, "no match data for platform\n");
+		return -EINVAL;
+	}
+
+	/* UART clock div13 setting */
+	regmap_read(map, ASPEED_MISC_CTRL, &val);
+	if (val & UART_DIV13_EN)
+		rate = 24000000 / 13;
+	else
+		rate = 24000000;
+	/* TODO: Find the parent data for the uart clock */
+	hw = clk_hw_register_fixed_rate(dev, "uart", NULL, 0, rate);
+	if (IS_ERR(hw))
+		return PTR_ERR(hw);
+	aspeed_clk_data->hws[ASPEED_CLK_UART] = hw;
+
+	/*
+	 * Memory controller (M-PLL) PLL. This clock is configured by the
+	 * bootloader, and is exposed to Linux as a read-only clock rate.
+	 */
+	regmap_read(map, ASPEED_MPLL_PARAM, &val);
+	hw = soc_data->calc_pll("mpll", val);
+	if (IS_ERR(hw))
+		return PTR_ERR(hw);
+	aspeed_clk_data->hws[ASPEED_CLK_MPLL] =	hw;
+
+	/* SD/SDIO clock divider (TODO: There's a gate too) */
+	hw = clk_hw_register_divider_table(dev, "sdio", "hpll", 0,
+			scu_base + ASPEED_CLK_SELECTION, 12, 3, 0,
+			soc_data->div_table,
+			&aspeed_clk_lock);
+	if (IS_ERR(hw))
+		return PTR_ERR(hw);
+	aspeed_clk_data->hws[ASPEED_CLK_SDIO] = hw;
+
+	/* MAC AHB bus clock divider */
+	hw = clk_hw_register_divider_table(dev, "mac", "hpll", 0,
+			scu_base + ASPEED_CLK_SELECTION, 16, 3, 0,
+			soc_data->mac_div_table,
+			&aspeed_clk_lock);
+	if (IS_ERR(hw))
+		return PTR_ERR(hw);
+	aspeed_clk_data->hws[ASPEED_CLK_MAC] = hw;
+
+	/* LPC Host (LHCLK) clock divider */
+	hw = clk_hw_register_divider_table(dev, "lhclk", "hpll", 0,
+			scu_base + ASPEED_CLK_SELECTION, 20, 3, 0,
+			soc_data->div_table,
+			&aspeed_clk_lock);
+	if (IS_ERR(hw))
+		return PTR_ERR(hw);
+	aspeed_clk_data->hws[ASPEED_CLK_LHCLK] = hw;
+
+	/* P-Bus (BCLK) clock divider */
+	hw = clk_hw_register_divider_table(dev, "bclk", "hpll", 0,
+			scu_base + ASPEED_CLK_SELECTION_2, 0, 2, 0,
+			soc_data->div_table,
+			&aspeed_clk_lock);
+	if (IS_ERR(hw))
+		return PTR_ERR(hw);
+	aspeed_clk_data->hws[ASPEED_CLK_BCLK] = hw;
+
+	return 0;
+};
+
+static const struct of_device_id aspeed_clk_dt_ids[] = {
+	{ .compatible = "aspeed,ast2400-scu", .data = &ast2400_data },
+	{ .compatible = "aspeed,ast2500-scu", .data = &ast2500_data },
+	{ }
+};
+
+static struct platform_driver aspeed_clk_driver = {
+	.probe  = aspeed_clk_probe,
+	.driver = {
+		.name = "aspeed-clk",
+		.of_match_table = aspeed_clk_dt_ids,
+		.suppress_bind_attrs = true,
+	},
+};
+builtin_platform_driver(aspeed_clk_driver);
+
 static void __init aspeed_ast2400_cc(struct regmap *map)
 {
 	struct clk_hw *hw;
-- 
2.14.1