RE: [PATCH 06/12] i2c: riic: Add suspend/resume support

[Biju Das]

Hi Claudiu,

Thanks for the patch

> -----Original Message-----
> From: Claudiu <claudiu.beznea@xxxxxxxxx>
> Sent: Friday, June 21, 2024 12:23 PM
> Subject: [PATCH 06/12] i2c: riic: Add suspend/resume support
> 
> From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
> 
> Add suspend/resume support for the RIIC driver. This is necessary for the Renesas RZ/G3S SoC which
> support suspend to deep sleep state where power to most of the SoC components is turned off. As a
> result the I2C controller needs to be reconfigured after suspend/resume. For this, the reset line
> was stored in the driver private data structure as well as i2c timings.
> The reset line and I2C timings are necessary to re-initialize the controller after resume.
> 
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
> ---
>  drivers/i2c/busses/i2c-riic.c | 66 +++++++++++++++++++++++++++++------
>  1 file changed, 55 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c index
> 00fb09786e48..f9b9e92570d8 100644
> --- a/drivers/i2c/busses/i2c-riic.c
> +++ b/drivers/i2c/busses/i2c-riic.c
> @@ -105,6 +105,8 @@ struct riic_dev {
>  	struct completion msg_done;
>  	struct i2c_adapter adapter;
>  	struct clk *clk;
> +	struct reset_control *rstc;
> +	struct i2c_timings i2c_t;
>  };
> 
>  struct riic_irq_desc {
> @@ -306,11 +308,12 @@ static const struct i2c_algorithm riic_algo = {
>  	.functionality	= riic_func,
>  };
> 
> -static int riic_init_hw(struct riic_dev *riic, struct i2c_timings *t)
> +static int riic_init_hw(struct riic_dev *riic)
>  {
>  	int ret;
>  	unsigned long rate;
>  	int total_ticks, cks, brl, brh;
> +	struct i2c_timings *t = &riic->i2c_t;
>  	struct device *dev = riic->adapter.dev.parent;
> 
>  	if (t->bus_freq_hz > I2C_MAX_FAST_MODE_FREQ) { @@ -429,8 +432,6 @@ static int
> riic_i2c_probe(struct platform_device *pdev)
>  	struct device *dev = &pdev->dev;
>  	struct riic_dev *riic;
>  	struct i2c_adapter *adap;
> -	struct i2c_timings i2c_t;
> -	struct reset_control *rstc;
>  	int i, ret;
> 
>  	riic = devm_kzalloc(dev, sizeof(*riic), GFP_KERNEL); @@ -447,16 +448,16 @@ static int
> riic_i2c_probe(struct platform_device *pdev)
>  		return PTR_ERR(riic->clk);
>  	}
> 
> -	rstc = devm_reset_control_get_optional_exclusive(dev, NULL);
> -	if (IS_ERR(rstc))
> -		return dev_err_probe(dev, PTR_ERR(rstc),
> +	riic->rstc = devm_reset_control_get_optional_exclusive(dev, NULL);
> +	if (IS_ERR(riic->rstc))
> +		return dev_err_probe(dev, PTR_ERR(riic->rstc),
>  				     "Error: missing reset ctrl\n");
> 
> -	ret = reset_control_deassert(rstc);
> +	ret = reset_control_deassert(riic->rstc);
>  	if (ret)
>  		return ret;
> 
> -	ret = devm_add_action_or_reset(dev, riic_reset_control_assert, rstc);
> +	ret = devm_add_action_or_reset(dev, riic_reset_control_assert,
> +riic->rstc);
>  	if (ret)
>  		return ret;
> 
> @@ -485,13 +486,13 @@ static int riic_i2c_probe(struct platform_device *pdev)
> 
>  	init_completion(&riic->msg_done);
> 
> -	i2c_parse_fw_timings(dev, &i2c_t, true);
> +	i2c_parse_fw_timings(dev, &riic->i2c_t, true);
> 
>  	pm_runtime_set_autosuspend_delay(dev, 0);
>  	pm_runtime_use_autosuspend(dev);
>  	pm_runtime_enable(dev);
> 
> -	ret = riic_init_hw(riic, &i2c_t);
> +	ret = riic_init_hw(riic);
>  	if (ret)
>  		goto out;
> 
> @@ -501,7 +502,7 @@ static int riic_i2c_probe(struct platform_device *pdev)
> 
>  	platform_set_drvdata(pdev, riic);
> 
> -	dev_info(dev, "registered with %dHz bus speed\n", i2c_t.bus_freq_hz);
> +	dev_info(dev, "registered with %dHz bus speed\n",
> +riic->i2c_t.bus_freq_hz);
>  	return 0;
> 
>  out:
> @@ -561,6 +562,48 @@ static const struct riic_of_data riic_rz_v2h_info = {
>  	},
>  };
> 
> +static int riic_i2c_suspend(struct device *dev) {
> +	struct riic_dev *riic = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = pm_runtime_resume_and_get(dev);
> +	if (ret)
> +		return ret;
> +
> +	i2c_mark_adapter_suspended(&riic->adapter);
> +
> +	/* Disable output on SDA, SCL pins. */
> +	riic_clear_set_bit(riic, ICCR1_ICE, 0, RIIC_ICCR1);
> +
> +	pm_runtime_mark_last_busy(dev);
> +	pm_runtime_put_sync(dev);
> +
> +	return reset_control_assert(riic->rstc); }
> +
> +static int riic_i2c_resume(struct device *dev) {
> +	struct riic_dev *riic = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = reset_control_deassert(riic->rstc);
> +	if (ret)
> +		return ret;
> +
> +	ret = riic_init_hw(riic);
> +	if (ret)
> +		return ret;

On error case we need to assert back??

Cheers,
Biju

> +
> +	i2c_mark_adapter_resumed(&riic->adapter);
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops riic_i2c_pm_ops = {
> +	SYSTEM_SLEEP_PM_OPS(riic_i2c_suspend, riic_i2c_resume) };
> +
>  static const struct of_device_id riic_i2c_dt_ids[] = {
>  	{ .compatible = "renesas,riic-rz", .data = &riic_rz_a_info },
>  	{ .compatible = "renesas,riic-r9a09g057", .data = &riic_rz_v2h_info }, @@ -573,6 +616,7 @@
> static struct platform_driver riic_i2c_driver = {
>  	.driver		= {
>  		.name	= "i2c-riic",
>  		.of_match_table = riic_i2c_dt_ids,
> +		.pm	= pm_ptr(&riic_i2c_pm_ops),
>  	},
>  };
> 
> --
> 2.39.2
>