Unverified Commit faed986d authored by Adlavinitha Reddy's avatar Adlavinitha Reddy Committed by Andi Shyti
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i2c: mediatek: add bus regulator control for power saving 



Add conditional bus regulator enable/disable in mtk_i2c_transfer()
to support I2C bus power gating for platforms that require it.

This implementation:
- Enables bus_regulator before clk_bulk_enable() if vbus-supply is defined
- Disables bus_regulator after clk_bulk_disable()
- Only activates when vbus-supply is provided in device tree
- Has no impact on platforms without vbus-supply defined

This approach provides power savings for platforms with an extra I2C bus
regulator, while avoiding runtime PM complexity.

Tested on MT8188.

Signed-off-by: default avatarAdlavinitha Reddy <adlavinitha.reddy@mediatek.com>
Reviewed-by: default avatarChen-Yu Tsai <wenst@chromium.org>
Signed-off-by: default avatarAndi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20260318084621.4127757-2-adlavinitha.reddy@mediatek.com
parent 60c8a400

drivers/i2c/busses/i2c-mt65xx.c

+12 −1
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/module.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/regulator/consumer.h>

#include <linux/scatterlist.h>

#include <linux/sched.h>

#include <linux/slab.h>
@@ -1244,9 +1245,15 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap, 
	bool write_then_read_en = false;

	struct mtk_i2c *i2c = i2c_get_adapdata(adap);



	ret = clk_bulk_enable(I2C_MT65XX_CLK_MAX, i2c->clocks);

	if (i2c->adap.bus_regulator) {

		ret = regulator_enable(i2c->adap.bus_regulator);

		if (ret)

			return ret;

	}



	ret = clk_bulk_enable(I2C_MT65XX_CLK_MAX, i2c->clocks);

	if (ret)

		goto err_regulator;



	i2c->auto_restart = i2c->dev_comp->auto_restart;
@@ -1301,6 +1308,10 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap, 


err_exit:

	clk_bulk_disable(I2C_MT65XX_CLK_MAX, i2c->clocks);

err_regulator:

	if (i2c->adap.bus_regulator)

		regulator_disable(i2c->adap.bus_regulator);



	return ret;

}