Re: [PATCH v7 3/5] clk: aspeed: Add platform driver and register PLLs

[Benjamin Herrenschmidt]

On Fri, 2017-12-22 at 13:15 +1030, Joel Stanley wrote:
> 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@xxxxxxxx>
> Signed-off-by: Joel Stanley <joel@xxxxxxxxx>

Reviewed-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> --
> 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 5adedda82d26..cf5ea63feb31 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>
> @@ -107,6 +109,18 @@ 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 },
> @@ -172,6 +186,122 @@ 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;