Re: [PATCH v4 08/19] soc: tegra: Add support for 32KHz blink clock

[Dmitry Osipenko]

17.12.2019 23:03, Sowjanya Komatineni ÐÐÑÐÑ:
> Tegra PMC has blink control to output 32 Khz clock out to Tegra
> blink pin. Blink pad DPD state and enable controls are part of
> Tegra PMC register space.
> 
> Currently Tegra clock driver registers blink control by passing
> PMC address and register offset to clk_register_gate which performs
> direct PMC access during clk_ops and with this when PMC is in secure
> mode, any access from non-secure world does not go through.
> 
> This patch adds blink control registration to the Tegra PMC driver
> using PMC specific clock gate operations that use tegra_pmc_readl
> and tegra_pmc_writel to support both secure mode and non-secure
> mode PMC register access.
> 
> Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
> ---
>  drivers/soc/tegra/pmc.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 107 insertions(+)
> 
> diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
> index 6d65194a6e71..19996c21c60d 100644
> --- a/drivers/soc/tegra/pmc.c
> +++ b/drivers/soc/tegra/pmc.c
> @@ -61,12 +61,15 @@
>  #define  PMC_CNTRL_SYSCLK_OE		BIT(11) /* system clock enable */
>  #define  PMC_CNTRL_SYSCLK_POLARITY	BIT(10) /* sys clk polarity */
>  #define  PMC_CNTRL_PWRREQ_POLARITY	BIT(8)
> +#define  PMC_CNTRL_BLINK_EN		7
>  #define  PMC_CNTRL_MAIN_RST		BIT(4)
>  
>  #define PMC_WAKE_MASK			0x0c
>  #define PMC_WAKE_LEVEL			0x10
>  #define PMC_WAKE_STATUS			0x14
>  #define PMC_SW_WAKE_STATUS		0x18
> +#define PMC_DPD_PADS_ORIDE		0x1c
> +#define  PMC_DPD_PADS_ORIDE_BLINK	20
>  
>  #define DPD_SAMPLE			0x020
>  #define  DPD_SAMPLE_ENABLE		BIT(0)
> @@ -79,6 +82,7 @@
>  
>  #define PWRGATE_STATUS			0x38
>  
> +#define PMC_BLINK_TIMER			0x40
>  #define PMC_IMPL_E_33V_PWR		0x40
>  
>  #define PMC_PWR_DET			0x48
> @@ -170,6 +174,14 @@ struct pmc_clk {
>  
>  #define to_pmc_clk(_hw) container_of(_hw, struct pmc_clk, hw)
>  
> +struct pmc_clk_gate {
> +	struct clk_hw	hw;
> +	unsigned long	offs;
> +	u32		shift;
> +};
> +
> +#define to_pmc_clk_gate(_hw) container_of(_hw, struct pmc_clk_gate, hw)
> +
>  struct pmc_clk_init_data {
>  	char *name;
>  	const char *const *parents;
> @@ -320,6 +332,7 @@ struct tegra_pmc_soc {
>  
>  	const struct pmc_clk_init_data *pmc_clks_data;
>  	unsigned int num_pmc_clks;
> +	bool has_blink_output;
>  };
>  
>  static const char * const tegra186_reset_sources[] = {
> @@ -2330,6 +2343,60 @@ tegra_pmc_clk_out_register(const struct pmc_clk_init_data *data,
>  	return clk_register(NULL, &pmc_clk->hw);
>  }
>  
> +static int pmc_clk_gate_is_enabled(struct clk_hw *hw)
> +{
> +	struct pmc_clk_gate *gate = to_pmc_clk_gate(hw);
> +
> +	return tegra_pmc_readl(pmc, gate->offs) & BIT(gate->shift) ? 1 : 0;
> +}
> +
> +static int pmc_clk_gate_enable(struct clk_hw *hw)
> +{
> +	struct pmc_clk_gate *gate = to_pmc_clk_gate(hw);
> +
> +	pmc_clk_set_state(gate->offs, gate->shift, 1);
> +
> +	return 0;
> +}
> +
> +static void pmc_clk_gate_disable(struct clk_hw *hw)
> +{
> +	struct pmc_clk_gate *gate = to_pmc_clk_gate(hw);
> +
> +	pmc_clk_set_state(gate->offs, gate->shift, 0);
> +}
> +
> +static const struct clk_ops pmc_clk_gate_ops = {
> +	.is_enabled = pmc_clk_gate_is_enabled,
> +	.enable = pmc_clk_gate_enable,
> +	.disable = pmc_clk_gate_disable,
> +};
> +
> +static struct clk *
> +tegra_pmc_clk_gate_register(const char *name, const char *parent_name,
> +			    unsigned long flags, unsigned long offset,
> +			    u32 shift)
> +{
> +	struct clk_init_data init;
> +	struct pmc_clk_gate *gate;
> +
> +	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
> +	if (!gate)
> +		return ERR_PTR(-ENOMEM);
> +
> +	init.name = name;
> +	init.ops = &pmc_clk_gate_ops;
> +	init.parent_names = &parent_name;
> +	init.num_parents = 1;
> +	init.flags = flags;

What about "init.flags = 0"?

> +	gate->hw.init = &init;
> +	gate->offs = offset;
> +	gate->shift = shift;
> +
> +	return clk_register(NULL, &gate->hw);
> +}
> +
>  static void tegra_pmc_clock_register(struct tegra_pmc *pmc,
>  				     struct device_node *np)
>  {
> @@ -2339,6 +2406,8 @@ static void tegra_pmc_clock_register(struct tegra_pmc *pmc,
>  	int i, err = -ENOMEM;
>  
>  	num_clks = pmc->soc->num_pmc_clks;
> +	if (pmc->soc->has_blink_output)
> +		num_clks += 1;
>  
>  	if (!num_clks)
>  		return;
> @@ -2380,6 +2449,37 @@ static void tegra_pmc_clock_register(struct tegra_pmc *pmc,
>  		}
>  	}
>  
> +	if (pmc->soc->has_blink_output) {
> +		tegra_pmc_writel(pmc, 0x0, PMC_BLINK_TIMER);
> +		clk = tegra_pmc_clk_gate_register("blink_override",
> +						  "clk_32k", 0,
> +						  PMC_DPD_PADS_ORIDE,
> +						  PMC_DPD_PADS_ORIDE_BLINK);
> +		if (IS_ERR(clk)) {
> +			dev_err(pmc->dev, "unable to register blink_override\n");
> +			err = PTR_ERR(clk);
> +			goto free_clks;
> +		}
> +
> +		clk = tegra_pmc_clk_gate_register("blink",
> +						  "blink_override", 0,
> +						  PMC_CNTRL,
> +						  PMC_CNTRL_BLINK_EN);
> +		if (IS_ERR(clk)) {
> +			dev_err(pmc->dev, "unable to register blink\n");
> +			err = PTR_ERR(clk);
> +			goto free_clks;
> +		}
> +
> +		clk_data->clks[TEGRA_PMC_CLK_BLINK] = clk;
> +		err = clk_register_clkdev(clk, "blink", NULL);
> +		if (err) {
> +			dev_err(pmc->dev,
> +				"unable to register blink clock lookup\n");
> +			goto free_clks;
> +		}
> +	}
> +
>  	err = of_clk_add_provider(np, of_clk_src_onecell_get, clk_data);
>  	if (err) {
>  		dev_err(pmc->dev, "failed to add pmc clk provider\n");
> @@ -2658,6 +2758,7 @@ static const struct tegra_pmc_soc tegra20_pmc_soc = {
>  	.num_reset_levels = 0,
>  	.pmc_clks_data = NULL,
>  	.num_pmc_clks = 0,
> +	.has_blink_output = true,
>  };
>  
>  static const char * const tegra30_powergates[] = {
> @@ -2707,6 +2808,7 @@ static const struct tegra_pmc_soc tegra30_pmc_soc = {
>  	.num_reset_levels = 0,
>  	.pmc_clks_data = tegra_pmc_clks_data,
>  	.num_pmc_clks = ARRAY_SIZE(tegra_pmc_clks_data),
> +	.has_blink_output = true,
>  };
>  
>  static const char * const tegra114_powergates[] = {
> @@ -2760,6 +2862,7 @@ static const struct tegra_pmc_soc tegra114_pmc_soc = {
>  	.num_reset_levels = 0,
>  	.pmc_clks_data = tegra_pmc_clks_data,
>  	.num_pmc_clks = ARRAY_SIZE(tegra_pmc_clks_data),
> +	.has_blink_output = true,
>  };
>  
>  static const char * const tegra124_powergates[] = {
> @@ -2873,6 +2976,7 @@ static const struct tegra_pmc_soc tegra124_pmc_soc = {
>  	.num_reset_levels = 0,
>  	.pmc_clks_data = tegra_pmc_clks_data,
>  	.num_pmc_clks = ARRAY_SIZE(tegra_pmc_clks_data),
> +	.has_blink_output = true,
>  };
>  
>  static const char * const tegra210_powergates[] = {
> @@ -2989,6 +3093,7 @@ static const struct tegra_pmc_soc tegra210_pmc_soc = {
>  	.wake_events = tegra210_wake_events,
>  	.pmc_clks_data = tegra_pmc_clks_data,
>  	.num_pmc_clks = ARRAY_SIZE(tegra_pmc_clks_data),
> +	.has_blink_output = true,
>  };
>  
>  #define TEGRA186_IO_PAD_TABLE(_pad)					     \
> @@ -3120,6 +3225,7 @@ static const struct tegra_pmc_soc tegra186_pmc_soc = {
>  	.wake_events = tegra186_wake_events,
>  	.pmc_clks_data = NULL,
>  	.num_pmc_clks = 0,
> +	.has_blink_output = false,
>  };
>  
>  static const struct tegra_io_pad_soc tegra194_io_pads[] = {
> @@ -3239,6 +3345,7 @@ static const struct tegra_pmc_soc tegra194_pmc_soc = {
>  	.wake_events = tegra194_wake_events,
>  	.pmc_clks_data = NULL,
>  	.num_pmc_clks = 0,
> +	.has_blink_output = false,
>  };
>  
>  static const struct of_device_id tegra_pmc_match[] = {
>