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SubjectRe: [PATCH v6 1/3] clk: meson: add emmc sub clock phase delay driver
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Quoting Jianxin Pan (2018-11-01 09:30:53)
> diff --git a/drivers/clk/meson/clk-phase-delay.c b/drivers/clk/meson/clk-phase-delay.c
> new file mode 100644
> index 0000000..83e74ed
> --- /dev/null
> +++ b/drivers/clk/meson/clk-phase-delay.c
> @@ -0,0 +1,66 @@
> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> +/*
> + * Amlogic Meson MMC Sub Clock Controller Driver
> + *
> + * Copyright (c) 2017 Baylibre SAS.
> + * Author: Jerome Brunet <jbrunet@baylibre.com>
> + *
> + * Copyright (c) 2018 Amlogic, inc.
> + * Author: Yixun Lan <yixun.lan@amlogic.com>
> + * Author: Jianxin Pan <jianxin.pan@amlogic.com>
> + */
> +
> +#include <linux/clk-provider.h>
> +#include "clkc.h"
> +
> +static int meson_clk_phase_delay_get_phase(struct clk_hw *hw)
> +{
> + struct clk_regmap *clk = to_clk_regmap(hw);
> + struct meson_clk_phase_delay_data *ph =
> + meson_clk_get_phase_delay_data(clk);

Nitpick: Do this after declaring variables because it splits a line.

> + unsigned long period_ps, p, d;
> + int degrees;
> +
> + p = meson_parm_read(clk->map, &ph->phase);
> + degrees = p * 360 / (1 << (ph->phase.width));

Nitpick: Remove useless parenthesis.

> +
> + period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,

Is the cast necessary?

> + clk_hw_get_rate(hw));
> +
> + d = meson_parm_read(clk->map, &ph->delay);
> + degrees += d * ph->delay_step_ps * 360 / period_ps;
> + degrees %= 360;
> +
> + return degrees;
> +}
> +
> +static int meson_clk_phase_delay_set_phase(struct clk_hw *hw, int degrees)
> +{
> + struct clk_regmap *clk = to_clk_regmap(hw);
> + struct meson_clk_phase_delay_data *ph =
> + meson_clk_get_phase_delay_data(clk);
> + unsigned long period_ps, d = 0, r;
> + u64 p;
> +
> + p = degrees % 360;

We don't allow phase to be larger than 360 so this isn't needed.

> + period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,

Drop the cast?

> + clk_hw_get_rate(hw));
> +
> + /* First compute the phase index (p), the remainder (r) is the

Nitpick: Please leave /* on it's own line.

> + * part we'll try to acheive using the delays (d).
> + */
> + r = do_div(p, 360 / (1 << (ph->phase.width)));

Drop useless parenthesis please.

> + d = DIV_ROUND_CLOSEST(r * period_ps,
> + 360 * ph->delay_step_ps);
> + d = min(d, PMASK(ph->delay.width));
> +
> + meson_parm_write(clk->map, &ph->phase, p);
> + meson_parm_write(clk->map, &ph->delay, d);
> + return 0;
> +}

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