Commit 53326135 authored by Claudiu Beznea's avatar Claudiu Beznea Committed by Andi Shyti
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i2c: riic: Add suspend/resume support 



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.

Reviewed-by: default avatarAndi Shyti <andi.shyti@kernel.org>
Signed-off-by: default avatarClaudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Signed-off-by: default avatarAndi Shyti <andi.shyti@kernel.org>
parent 10d5c884

drivers/i2c/busses/i2c-riic.c

+62 −11
Original line number Diff line number Diff line
@@ -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 {
@@ -302,11 +304,12 @@ 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) {
@@ -423,8 +426,6 @@ 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);
@@ -441,16 +442,16 @@ 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;
@@ -479,14 +480,14 @@ 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);



	/* Default 0 to save power. Can be overridden via sysfs for lower latency. */

	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;
@@ -496,7 +497,7 @@ 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:
@@ -553,6 +554,55 @@ 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) {

		/*

		 * In case this happens there is no way to recover from this

		 * state. The driver will remain loaded. We want to avoid

		 * keeping the reset line de-asserted for no reason.

		 */

		reset_control_assert(riic->rstc);

		return ret;

	}



	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 },
@@ -565,6 +615,7 @@ 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),

	},

};