10.03.2020 18:19, Thierry Reding пишет:
> From: Joseph Lo <josephl@xxxxxxxxxx>
>
> The EMC clock needs to carefully coordinate with the EMC controller
> programming to make sure external memory can be properly clocked. Do so
> by hooking up the EMC clock with an EMC provider that will specify which
> rates are supported by the EMC and provide a callback to use for setting
> the clock rate at the EMC.
>
> Based on work by Peter De Schrijver <pdeschrijver@xxxxxxxxxx>.
>
> Signed-off-by: Joseph Lo <josephl@xxxxxxxxxx>
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> ---
> Changes in v5:
> - major rework and cleanup
...
> +static u8 tegra210_clk_emc_get_parent(struct clk_hw *hw)
> +{
> + struct tegra210_clk_emc *emc = to_tegra210_clk_emc(hw);
> + u32 value;
> + u8 src;
> +
> + value = readl_relaxed(emc->regs + CLK_SOURCE_EMC);
> + src = (value >> CLK_SOURCE_EMC_2X_CLK_SRC_SHIFT) &
> + CLK_SOURCE_EMC_2X_CLK_SRC_MASK;
What about to use a generic FIELD_GET/PREP()?
> +static int tegra210_clk_emc_set_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long parent_rate)
> +{
> + struct tegra210_clk_emc *emc = to_tegra210_clk_emc(hw);
> + struct tegra210_clk_emc_provider *provider = emc->provider;
> + struct tegra210_clk_emc_config *config;
> + struct device *dev = provider->dev;
> + struct clk_hw *old, *new, *parent;
> + u8 old_idx, new_idx, index;
> + struct clk *clk;
> + unsigned int i;
> + int err;
> +
> + if (!provider || !provider->configs || provider->num_configs == 0)
> + return -EINVAL;
Why all these checks are needed? I don't think it ever could fail,
couldn't it?
> +static int emc_table_lookup(struct tegra_emc *emc, unsigned long rate)
> +{
> + int i;
unsigned int
Same for all other occurrences in the code.
