Re: [PATCH v3 3/4] clk: tegra: Add quirk for getting CDEV1/2 clocks on Tegra20

[Peter De Schrijver <pdeschrijver@nvidia.com>]

On Tue, May 08, 2018 at 07:26:06PM +0300, Dmitry Osipenko wrote:
> CDEV1 and CDEV2 clocks are a bit special case, their parent clock is
> created by the pinctrl driver. It should be possible for clk user to
> request these clocks before pinctrl driver got probed and hence user will
> get an orphaned clock. That might be undesirable because user may expect
> parent clock to be enabled by the child, so let's return -EPROBE_DEFER
> till parent clock appears.
> 
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>

Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>                                                                                                     


> ---
>  drivers/clk/tegra/clk-tegra114.c |  2 +-
>  drivers/clk/tegra/clk-tegra124.c |  2 +-
>  drivers/clk/tegra/clk-tegra20.c  | 32 +++++++++++++++++++++++++++++++-
>  drivers/clk/tegra/clk-tegra210.c |  2 +-
>  drivers/clk/tegra/clk-tegra30.c  |  2 +-
>  drivers/clk/tegra/clk.c          |  5 +++--
>  drivers/clk/tegra/clk.h          |  2 +-
>  7 files changed, 39 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/clk/tegra/clk-tegra114.c b/drivers/clk/tegra/clk-tegra114.c
> index 5d5a22d529f5..1824f014202b 100644
> --- a/drivers/clk/tegra/clk-tegra114.c
> +++ b/drivers/clk/tegra/clk-tegra114.c
> @@ -1367,7 +1367,7 @@ static void __init tegra114_clock_init(struct device_node *np)
>  	tegra_super_clk_gen4_init(clk_base, pmc_base, tegra114_clks,
>  					&pll_x_params);
>  
> -	tegra_add_of_provider(np);
> +	tegra_add_of_provider(np, of_clk_src_onecell_get);
>  	tegra_register_devclks(devclks, ARRAY_SIZE(devclks));
>  
>  	tegra_clk_apply_init_table = tegra114_clock_apply_init_table;
> diff --git a/drivers/clk/tegra/clk-tegra124.c b/drivers/clk/tegra/clk-tegra124.c
> index 50088e976611..0c69c7970950 100644
> --- a/drivers/clk/tegra/clk-tegra124.c
> +++ b/drivers/clk/tegra/clk-tegra124.c
> @@ -1479,7 +1479,7 @@ static void __init tegra124_132_clock_init_post(struct device_node *np)
>  				  &pll_x_params);
>  	tegra_init_special_resets(1, tegra124_reset_assert,
>  				  tegra124_reset_deassert);
> -	tegra_add_of_provider(np);
> +	tegra_add_of_provider(np, of_clk_src_onecell_get);
>  
>  	clks[TEGRA124_CLK_EMC] = tegra_clk_register_emc(clk_base, np,
>  							&emc_lock);
> diff --git a/drivers/clk/tegra/clk-tegra20.c b/drivers/clk/tegra/clk-tegra20.c
> index 636500a98561..cc857d4d4a86 100644
> --- a/drivers/clk/tegra/clk-tegra20.c
> +++ b/drivers/clk/tegra/clk-tegra20.c
> @@ -1089,6 +1089,36 @@ static const struct of_device_id pmc_match[] __initconst = {
>  	{ },
>  };
>  
> +static struct clk *tegra20_clk_src_onecell_get(struct of_phandle_args *clkspec,
> +					       void *data)
> +{
> +	struct clk_hw *parent_hw;
> +	struct clk_hw *hw;
> +	struct clk *clk;
> +
> +	clk = of_clk_src_onecell_get(clkspec, data);
> +	if (IS_ERR(clk))
> +		return clk;
> +
> +	/*
> +	 * Tegra20 CDEV1 and CDEV2 clocks are a bit special case, their parent
> +	 * clock is created by the pinctrl driver. It is possible for clk user
> +	 * to request these clocks before pinctrl driver got probed and hence
> +	 * user will get an orphaned clock. That might be undesirable because
> +	 * user may expect parent clock to be enabled by the child.
> +	 */
> +	if (clkspec->args[0] == TEGRA20_CLK_CDEV1 ||
> +	    clkspec->args[0] == TEGRA20_CLK_CDEV2) {
> +		hw = __clk_get_hw(clk);
> +
> +		parent_hw = clk_hw_get_parent(hw);
> +		if (!parent_hw)
> +			return ERR_PTR(-EPROBE_DEFER);
> +	}
> +
> +	return clk;
> +}
> +
>  static void __init tegra20_clock_init(struct device_node *np)
>  {
>  	struct device_node *node;
> @@ -1127,7 +1157,7 @@ static void __init tegra20_clock_init(struct device_node *np)
>  
>  	tegra_init_dup_clks(tegra_clk_duplicates, clks, TEGRA20_CLK_CLK_MAX);
>  
> -	tegra_add_of_provider(np);
> +	tegra_add_of_provider(np, tegra20_clk_src_onecell_get);
>  	tegra_register_devclks(devclks, ARRAY_SIZE(devclks));
>  
>  	tegra_clk_apply_init_table = tegra20_clock_apply_init_table;
> diff --git a/drivers/clk/tegra/clk-tegra210.c b/drivers/clk/tegra/clk-tegra210.c
> index 9fb5d51ccce4..5435d01c636a 100644
> --- a/drivers/clk/tegra/clk-tegra210.c
> +++ b/drivers/clk/tegra/clk-tegra210.c
> @@ -3567,7 +3567,7 @@ static void __init tegra210_clock_init(struct device_node *np)
>  	tegra_init_special_resets(2, tegra210_reset_assert,
>  				  tegra210_reset_deassert);
>  
> -	tegra_add_of_provider(np);
> +	tegra_add_of_provider(np, of_clk_src_onecell_get);
>  	tegra_register_devclks(devclks, ARRAY_SIZE(devclks));
>  
>  	tegra210_mbist_clk_init();
> diff --git a/drivers/clk/tegra/clk-tegra30.c b/drivers/clk/tegra/clk-tegra30.c
> index b316dfb6f6c7..acfe661b2ae7 100644
> --- a/drivers/clk/tegra/clk-tegra30.c
> +++ b/drivers/clk/tegra/clk-tegra30.c
> @@ -1349,7 +1349,7 @@ static void __init tegra30_clock_init(struct device_node *np)
>  
>  	tegra_init_dup_clks(tegra_clk_duplicates, clks, TEGRA30_CLK_CLK_MAX);
>  
> -	tegra_add_of_provider(np);
> +	tegra_add_of_provider(np, of_clk_src_onecell_get);
>  	tegra_register_devclks(devclks, ARRAY_SIZE(devclks));
>  
>  	tegra_clk_apply_init_table = tegra30_clock_apply_init_table;
> diff --git a/drivers/clk/tegra/clk.c b/drivers/clk/tegra/clk.c
> index ba923f0d5953..593d76a114f9 100644
> --- a/drivers/clk/tegra/clk.c
> +++ b/drivers/clk/tegra/clk.c
> @@ -298,7 +298,8 @@ static struct reset_controller_dev rst_ctlr = {
>  	.of_reset_n_cells = 1,
>  };
>  
> -void __init tegra_add_of_provider(struct device_node *np)
> +void __init tegra_add_of_provider(struct device_node *np,
> +				  void *clk_src_onecell_get)
>  {
>  	int i;
>  
> @@ -314,7 +315,7 @@ void __init tegra_add_of_provider(struct device_node *np)
>  
>  	clk_data.clks = clks;
>  	clk_data.clk_num = clk_num;
> -	of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
> +	of_clk_add_provider(np, clk_src_onecell_get, &clk_data);
>  
>  	rst_ctlr.of_node = np;
>  	rst_ctlr.nr_resets = periph_banks * 32 + num_special_reset;
> diff --git a/drivers/clk/tegra/clk.h b/drivers/clk/tegra/clk.h
> index ba7e20e6a82b..e1f88463b600 100644
> --- a/drivers/clk/tegra/clk.h
> +++ b/drivers/clk/tegra/clk.h
> @@ -763,7 +763,7 @@ struct clk **tegra_clk_init(void __iomem *clk_base, int num, int periph_banks);
>  
>  struct clk **tegra_lookup_dt_id(int clk_id, struct tegra_clk *tegra_clk);
>  
> -void tegra_add_of_provider(struct device_node *np);
> +void tegra_add_of_provider(struct device_node *np, void *clk_src_onecell_get);
>  void tegra_register_devclks(struct tegra_devclk *dev_clks, int num);
>  
>  void tegra_audio_clk_init(void __iomem *clk_base,
> -- 
> 2.17.0
>