Re: [PATCH 01/12] clk: tegra: simplify periph clock data

From: Stephen Warren
Date: Mon Sep 23 2013 - 13:29:41 EST


On 09/18/2013 08:40 AM, Peter De Schrijver wrote:
> This patch determines the register bank for clock enable/disable and reset
> based on the clock ID instead of hardcoding it in the tables describing the
> clocks. This results in less data to be maintained in the tables, making the
> code easier to understand. The full benefit of the change will be realized once
> also other clocktypes will be table based.

> drivers/clk/tegra/clk-tegra114.c | 483 ++++++++++++++++----------------------
> drivers/clk/tegra/clk.c | 105 ++++++++
> drivers/clk/tegra/clk.h | 3 +

Can't this change be applied to the Tegra20/30 diffstat too, for even
more negative diffstat? Similar comments probably apply for other
patches in the series.

> diff --git a/drivers/clk/tegra/clk-tegra114.c b/drivers/clk/tegra/clk-tegra114.c

> #define TEGRA_INIT_DATA_MUX(_name, _con_id, _dev_id, _parents, _offset, \
> - _clk_num, _regs, _gate_flags, _clk_id) \
> + _clk_num, _gate_flags, _clk_id) \
> TEGRA_INIT_DATA_TABLE(_name, _con_id, _dev_id, _parents, _offset,\
> - 30, MASK(2), 0, 0, 8, 1, 0, _regs, _clk_num, \
> - periph_clk_enb_refcnt, _gate_flags, _clk_id, \
> - _parents##_idx, 0)
> + 30, MASK(2), 0, 0, 8, 1, 0, 0,\
> + _clk_num, periph_clk_enb_refcnt, _gate_flags,\
> + _clk_id, _parents##_idx, 0)

Nit: A simple s/_regs/0/ without re-flowing the parameters would have
made that diff smaller, and more similar to all the others...

> @@ -1606,9 +1538,9 @@ static void __init tegra114_audio_clk_init(void __iomem *clk_base)
> clk = tegra_clk_register_divider("audio0_div", "audio0_doubler",
> clk_base + AUDIO_SYNC_DOUBLER, 0, 0, 24, 1,
> 0, &clk_doubler_lock);
> - clk = tegra_clk_register_periph_gate("audio0_2x", "audio0_div",
> + clk = tegra114_periph_gate_helper("audio0_2x", "audio0_div",
> TEGRA_PERIPH_NO_RESET, clk_base,
> - CLK_SET_RATE_PARENT, 113, &periph_v_regs,
> + CLK_SET_RATE_PARENT, 113,
> periph_clk_enb_refcnt);
> clk_register_clkdev(clk, "audio0_2x", NULL);
> clks[TEGRA114_CLK_AUDIO0_2X] = clk;

It sure seems like much of this repetitive code could be driven from a
data table rather than cut/paste code. Perhaps a later patch in this
series cleans this up?

> @@ -2030,21 +1949,10 @@ static __init void tegra114_periph_clk_init(void __iomem *clk_base)
...
> - /* dsib */
> - clk = clk_register_mux(NULL, "dsib_mux", mux_plld_out0_plld2_out0,
> - ARRAY_SIZE(mux_plld_out0_plld2_out0), 0,
> - clk_base + PLLD2_BASE, 25, 1, 0, &pll_d2_lock);
> - clks[TEGRA114_CLK_DSIB_MUX] = clk;
> - clk = tegra_clk_register_periph_gate("dsib", "dsib_mux", 0, clk_base,
> - 0, 82, &periph_u_regs,
> - periph_clk_enb_refcnt);
> - clks[TEGRA114_CLK_DSIB] = clk;
> -

Why delete dsib? I don't think it got added elsewhere in this patch.

> @@ -2077,21 +1982,36 @@ static __init void tegra114_periph_clk_init(void __iomem *clk_base)

> for (i = 0; i < ARRAY_SIZE(tegra_periph_clk_list); i++) {
> + struct tegra_clk_periph_regs *bank;
> +
> data = &tegra_periph_clk_list[i];
> - clk = tegra_clk_register_periph(data->name, data->parent_names,
> - data->num_parents, &data->periph,
> - clk_base, data->offset, data->flags);
> + bank = get_reg_bank(data->periph.gate.clk_num);
> +
> + if (!bank)
> + continue;

Nit: I dislike blank lines between the code that retrieves a value, and
the immediately following error-check of the value. This applies to the
second change to this function too.

> @@ -2337,6 +2257,9 @@ static void __init tegra114_clock_init(struct device_node *np)
> if (tegra114_osc_clk_init(clk_base) < 0)
> return;
>
> + if (tegra_clk_periph_banks(5) < 0)
> + return;

Is that just debugging code? If you intend to keep this as a permanent
run-time check, wouldn't it be better to validate the result of
get_reg_bank(max_tegra114_periph_clock_id)? But, I'm not sure the check
is necessary at all, since the result of get_reg_bank() is checked when
registering each individual clock, so there's already plenty of coverage.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/