Re: [PATCH v9 4/5] clk: imx: add imx composite clock

[Stephen Boyd <sboyd@kernel.org>]

Quoting Abel Vesa (2018-09-24 03:39:56)
> diff --git a/drivers/clk/imx/clk-composite.c b/drivers/clk/imx/clk-composite.c
> new file mode 100644
> index 0000000..4b03107
> --- /dev/null
> +++ b/drivers/clk/imx/clk-composite.c
> @@ -0,0 +1,181 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2018 NXP
> + */
> +
> +#include <linux/errno.h>
> +#include <linux/slab.h>
> +#include <linux/clk-provider.h>
> +#include <linux/clk.h>

Is this include used?

> +
> +#include "clk.h"
> +
> +#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 imx_clk_composite_divider_recalc_rate(struct clk_hw *hw,
> +                                               unsigned long parent_rate)
> +{
> +       struct clk_divider *divider = to_clk_divider(hw);
> +       unsigned long prediv_rate;
> +       unsigned int prediv_value;
> +       unsigned int div_value;
> +
> +       prediv_value = clk_readl(divider->reg) >> divider->shift;
> +       prediv_value &= clk_div_mask(divider->width);
> +
> +       prediv_rate = divider_recalc_rate(hw, parent_rate, prediv_value,
> +                                               NULL, divider->flags,
> +                                               divider->width);
> +
> +       div_value = clk_readl(divider->reg) >> PCG_DIV_SHIFT;
> +       div_value &= clk_div_mask(PCG_DIV_WIDTH);
> +
> +       return divider_recalc_rate(hw, prediv_rate, div_value, NULL,
> +                                  divider->flags, PCG_DIV_WIDTH);
> +}
> +
> +static int imx_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;
> +
> +       /* default values */
> +       *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;
> +}
> +
> +static long imx_clk_composite_divider_round_rate(struct clk_hw *hw,
> +                                               unsigned long rate,
> +                                               unsigned long *prate)
> +{
> +       int prediv_value;
> +       int div_value;
> +
> +       imx_clk_composite_compute_dividers(rate, *prate,
> +                                               &prediv_value, &div_value);
> +
> +       rate = DIV_ROUND_UP_ULL((u64)*prate, prediv_value);
> +       rate = DIV_ROUND_UP_ULL((u64)rate, div_value);
> +
> +       return rate;

Looks the same as another patch, maybe it is?

Anyway, same nitpick about returning the DIV_ROUND_UP_ULL() result.

> +}
> +
> +static int imx_clk_composite_divider_set_rate(struct clk_hw *hw,
> +                                       unsigned long rate,
> +                                       unsigned long parent_rate)
> +{
> +       struct clk_divider *divider = to_clk_divider(hw);
> +       unsigned long flags = 0;
> +       int prediv_value;
> +       int div_value;
> +       int ret = 0;
> +       u32 val;
> +
> +       ret = imx_clk_composite_compute_dividers(rate, parent_rate,
> +                                               &prediv_value, &div_value);
> +       if (ret)
> +               return -EINVAL;
> +
> +       spin_lock_irqsave(divider->lock, flags);
> +
> +       val = clk_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;
> +       clk_writel(val, divider->reg);

Please don't use clk_writel().

> +
> +       spin_unlock_irqrestore(divider->lock, flags);
> +
> +       return ret;
> +}
> +
> +static const struct clk_ops imx_clk_composite_divider_ops = {
> +       .recalc_rate = imx_clk_composite_divider_recalc_rate,
> +       .round_rate = imx_clk_composite_divider_round_rate,
> +       .set_rate = imx_clk_composite_divider_set_rate,
> +};
> +
> +struct clk *imx_clk_composite_flags(const char *name,
> +                                       const char **parent_names,
> +                                       int num_parents, void __iomem *reg,
> +                                       unsigned long flags)
> +{
> +       struct clk_hw *mux_hw = NULL, *div_hw = NULL, *gate_hw = NULL;
> +       struct clk_divider *div = NULL;
> +       struct clk_gate *gate = NULL;
> +       struct clk_mux *mux = NULL;
> +       struct clk *clk = ERR_PTR(-ENOMEM);
> +
> +       mux = kzalloc(sizeof(*mux), GFP_KERNEL);
> +       if (!mux)
> +               goto fail;
> +
> +       mux_hw = &mux->hw;
> +       mux->reg = reg;
> +       mux->shift = PCG_PCS_SHIFT;
> +       mux->mask = PCG_PCS_MASK;
> +
> +       div = kzalloc(sizeof(*div), GFP_KERNEL);
> +       if (!div)
> +               goto fail;
> +
> +       div_hw = &div->hw;
> +       div->reg = reg;
> +       div->shift = PCG_PREDIV_SHIFT;
> +       div->width = PCG_PREDIV_WIDTH;
> +       div->lock = &imx_ccm_lock;
> +       div->flags = CLK_DIVIDER_ROUND_CLOSEST;
> +
> +       gate = kzalloc(sizeof(*gate), GFP_KERNEL);
> +       if (!gate)
> +               goto fail;
> +
> +       gate_hw = &gate->hw;
> +       gate->reg = reg;
> +       gate->bit_idx = PCG_CGC_SHIFT;
> +
> +       clk = clk_register_composite(NULL, name, parent_names, num_parents,
> +                                       mux_hw, &clk_mux_ops, div_hw,
> +                                       &imx_clk_composite_divider_ops, gate_hw,
> +                                       &clk_gate_ops, flags);

Didn't I already review this? I'd prefer we move this to using clk_hw
based APIs and then return the clk pointer if needed.

> +       if (IS_ERR(clk))
> +               goto fail;
> +
> +       return clk;
> +
> +fail:
> +       kfree(gate);
> +       kfree(div);
> +       kfree(mux);
> +       return clk;
> +}