[U-Boot] [PATCH V3 3/4] clk: imx: add i.MX8M composite clk support

[Ye Li]

> Import i.MX8M composite clk from Linux Kernel 5.3.0-rc2
> 
> Signed-off-by: Peng Fan <peng.fan at nxp.com>
> ---
>  drivers/clk/imx/clk-composite-8m.c | 170 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 170 insertions(+)
>  create mode 100644 drivers/clk/imx/clk-composite-8m.c
> 
> diff --git a/drivers/clk/imx/clk-composite-8m.c b/drivers/clk/imx/clk-composite-8m.c
> new file mode 100644
> index 0000000000..57ebbc3bb0
> --- /dev/null
> +++ b/drivers/clk/imx/clk-composite-8m.c
> @@ -0,0 +1,170 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2019 NXP
> + */
> +
> +#include <common.h>
> +#include <asm/io.h>
> +#include <malloc.h>
> +#include <clk-uclass.h>
> +#include <dm/device.h>
> +#include <linux/clk-provider.h>
> +#include <clk.h>
> +#include "clk.h"
> +
> +#define UBOOT_DM_CLK_IMX_COMPOSITE "imx_clk_composite"
> +
> +#define PCG_PREDIV_SHIFT	16
> +#define PCG_PREDIV_WIDTH	3
> +#define PCG_PREDIV_MAX		8
> +
> +#define PCG_DIV_SHIFT		0
> +#define PCG_DIV_WIDTH		6
> +#define PCG_DIV_MAX		64
> +
> +#define PCG_PCS_SHIFT		24
> +#define PCG_PCS_MASK		0x7
> +
> +#define PCG_CGC_SHIFT		28
> +
> +static unsigned long imx8m_clk_composite_divider_recalc_rate(struct clk *clk)
> +{
> +	struct clk_divider *divider = (struct clk_divider *)to_clk_divider(clk);
> +	struct clk_composite *composite = (struct clk_composite *)clk->data;
> +	ulong parent_rate = clk_get_parent_rate(&composite->clk);
> +	unsigned long prediv_rate;
> +	unsigned int prediv_value;
> +	unsigned int div_value;
> +
> +	debug("%s: name %s prate: %lu reg: %p\n", __func__,
> +	      (&composite->clk)->dev->name, parent_rate, divider->reg);
> +	prediv_value = readl(divider->reg) >> divider->shift;
> +	prediv_value &= clk_div_mask(divider->width);
> +
> +	prediv_rate = divider_recalc_rate(clk, parent_rate, prediv_value,
> +					  NULL, divider->flags,
> +					  divider->width);
> +
> +	div_value = readl(divider->reg) >> PCG_DIV_SHIFT;
> +	div_value &= clk_div_mask(PCG_DIV_WIDTH);
> +
> +	return divider_recalc_rate(clk, prediv_rate, div_value, NULL,
> +				   divider->flags, PCG_DIV_WIDTH);
> +}
> +
> +static int imx8m_clk_composite_compute_dividers(unsigned long rate,
> +						unsigned long parent_rate,
> +						int *prediv, int *postdiv)
> +{
> +	int div1, div2;
> +	int error = INT_MAX;
> +	int ret = -EINVAL;
> +
> +	*prediv = 1;
> +	*postdiv = 1;
> +
> +	for (div1 = 1; div1 <= PCG_PREDIV_MAX; div1++) {
> +		for (div2 = 1; div2 <= PCG_DIV_MAX; div2++) {
> +			int new_error = ((parent_rate / div1) / div2) - rate;
> +
> +			if (abs(new_error) < abs(error)) {
> +				*prediv = div1;
> +				*postdiv = div2;
> +				error = new_error;
> +				ret = 0;
> +			}
> +		}
> +	}
> +	return ret;
> +}
> +
> +/*
> + * The clk are not binded to a dev, because it is part of composite clk
> + * use composite clk to get dev
> + */
> +static ulong imx8m_clk_composite_divider_set_rate(struct clk *clk,
> +						  unsigned long rate)
> +{
> +	struct clk_divider *divider = (struct clk_divider *)to_clk_divider(clk);
> +	struct clk_composite *composite = (struct clk_composite *)clk->data;
> +	ulong parent_rate = clk_get_parent_rate(&composite->clk);
> +	int prediv_value;
> +	int div_value;
> +	int ret;
> +	u32 val;
> +
> +	ret = imx8m_clk_composite_compute_dividers(rate, parent_rate,
> +						   &prediv_value, &div_value);
> +	if (ret)
> +		return -EINVAL;
> +
> +	val = readl(divider->reg);
> +	val &= ~((clk_div_mask(divider->width) << divider->shift) |
> +			(clk_div_mask(PCG_DIV_WIDTH) << PCG_DIV_SHIFT));
> +
> +	val |= (u32)(prediv_value  - 1) << divider->shift;
> +	val |= (u32)(div_value - 1) << PCG_DIV_SHIFT;
> +	writel(val, divider->reg);
> +
> +	return clk_get_rate(&composite->clk);
> +}
> +
> +static const struct clk_ops imx8m_clk_composite_divider_ops = {
> +	.get_rate = imx8m_clk_composite_divider_recalc_rate,
> +	.set_rate = imx8m_clk_composite_divider_set_rate,
> +};
> +
> +struct clk *imx8m_clk_composite_flags(const char *name,
> +				      const char * const *parent_names,
> +				      int num_parents, void __iomem *reg,
> +				      unsigned long flags)
> +{
> +	struct clk *clk = ERR_PTR(-ENOMEM);
> +	struct clk_divider *div = NULL;
> +	struct clk_gate *gate = NULL;
> +	struct clk_mux *mux = NULL;
> +
> +	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
> +	if (!mux)
> +		goto fail;
> +
> +	mux->reg = reg;
> +	mux->shift = PCG_PCS_SHIFT;
> +	mux->mask = PCG_PCS_MASK;
> +	mux->num_parents = num_parents;
> +	mux->flags = flags;
> +	mux->parent_names = parent_names;
> +
> +	div = kzalloc(sizeof(*div), GFP_KERNEL);
> +	if (!div)
> +		goto fail;
> +
> +	div->reg = reg;
> +	div->shift = PCG_PREDIV_SHIFT;
> +	div->width = PCG_PREDIV_WIDTH;
> +	div->flags = CLK_DIVIDER_ROUND_CLOSEST | flags;
> +
> +	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
> +	if (!gate)
> +		goto fail;
> +
> +	gate->reg = reg;
> +	gate->bit_idx = PCG_CGC_SHIFT;
> +	gate->flags = flags;
> +
> +	clk = clk_register_composite(NULL, name,
> +				     parent_names, num_parents,
> +				     &mux->clk, &clk_mux_ops, &div->clk,
> +				     &imx8m_clk_composite_divider_ops,
> +				     &gate->clk, &clk_gate_ops, flags);
> +	if (IS_ERR(clk))
> +		goto fail;
> +
> +	return clk;
> +
> +fail:
> +	kfree(gate);
> +	kfree(div);
> +	kfree(mux);
> +	return ERR_CAST(clk);
> +}
> 
Reviewed-by: Ye Li <ye.li at nxp.com>

Best regards,
Ye Li