Commit ecc8fb54 authored by Vitor Soares's avatar Vitor Soares Committed by Boris Brezillon
Browse files

i3c: fix i2c and i3c scl rate by bus mode 



Currently the I3C framework limits SCL frequency to FM speed when
dealing with a mixed slow bus, even if all I2C devices are FM+ capable.

The core was also not accounting for I3C speed limitations when
operating in mixed slow mode and was erroneously using FM+ speed as the
max I2C speed when operating in mixed fast mode.

Fixes: 3a379bbc ("i3c: Add core I3C infrastructure")
Signed-off-by: default avatarVitor Soares <vitor.soares@synopsys.com>
Cc: Boris Brezillon <bbrezillon@kernel.org>
Cc: <stable@vger.kernel.org>
Cc: <linux-kernel@vger.kernel.org>
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@collabora.com>
parent 5e343fbb

drivers/i3c/master.c

+38 −13
Original line number Diff line number Diff line
@@ -91,6 +91,12 @@ void i3c_bus_normaluse_unlock(struct i3c_bus *bus) 
	up_read(&bus->lock);

}



static struct i3c_master_controller *

i3c_bus_to_i3c_master(struct i3c_bus *i3cbus)

{

	return container_of(i3cbus, struct i3c_master_controller, bus);

}



static struct i3c_master_controller *dev_to_i3cmaster(struct device *dev)

{

	return container_of(dev, struct i3c_master_controller, dev);
@@ -565,20 +571,38 @@ static const struct device_type i3c_masterdev_type = { 
	.groups	= i3c_masterdev_groups,

};



int i3c_bus_set_mode(struct i3c_bus *i3cbus, enum i3c_bus_mode mode)

int i3c_bus_set_mode(struct i3c_bus *i3cbus, enum i3c_bus_mode mode,

		     unsigned long max_i2c_scl_rate)

{

	struct i3c_master_controller *master = i3c_bus_to_i3c_master(i3cbus);



	i3cbus->mode = mode;



	switch (i3cbus->mode) {

	case I3C_BUS_MODE_PURE:

		if (!i3cbus->scl_rate.i3c)

			i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;



	if (!i3cbus->scl_rate.i2c) {

		if (i3cbus->mode == I3C_BUS_MODE_MIXED_SLOW)

			i3cbus->scl_rate.i2c = I3C_BUS_I2C_FM_SCL_RATE;

		else

			i3cbus->scl_rate.i2c = I3C_BUS_I2C_FM_PLUS_SCL_RATE;

		break;

	case I3C_BUS_MODE_MIXED_FAST:

		if (!i3cbus->scl_rate.i3c)

			i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;

		if (!i3cbus->scl_rate.i2c)

			i3cbus->scl_rate.i2c = max_i2c_scl_rate;

		break;

	case I3C_BUS_MODE_MIXED_SLOW:

		if (!i3cbus->scl_rate.i2c)

			i3cbus->scl_rate.i2c = max_i2c_scl_rate;

		if (!i3cbus->scl_rate.i3c ||

		    i3cbus->scl_rate.i3c > i3cbus->scl_rate.i2c)

			i3cbus->scl_rate.i3c = i3cbus->scl_rate.i2c;

		break;

	default:

		return -EINVAL;

	}



	dev_dbg(&master->dev, "i2c-scl = %ld Hz i3c-scl = %ld Hz\n",

		i3cbus->scl_rate.i2c, i3cbus->scl_rate.i3c);



	/*

	 * I3C/I2C frequency may have been overridden, check that user-provided

	 * values are not exceeding max possible frequency.
@@ -1976,9 +2000,6 @@ of_i3c_master_add_i2c_boardinfo(struct i3c_master_controller *master, 
	/* LVR is encoded in reg[2]. */

	boardinfo->lvr = reg[2];



	if (boardinfo->lvr & I3C_LVR_I2C_FM_MODE)

		master->bus.scl_rate.i2c = I3C_BUS_I2C_FM_SCL_RATE;



	list_add_tail(&boardinfo->node, &master->boardinfo.i2c);

	of_node_get(node);
@@ -2424,6 +2445,7 @@ int i3c_master_register(struct i3c_master_controller *master, 
			const struct i3c_master_controller_ops *ops,

			bool secondary)

{

	unsigned long i2c_scl_rate = I3C_BUS_I2C_FM_PLUS_SCL_RATE;

	struct i3c_bus *i3cbus = i3c_master_get_bus(master);

	enum i3c_bus_mode mode = I3C_BUS_MODE_PURE;

	struct i2c_dev_boardinfo *i2cbi;
@@ -2473,9 +2495,12 @@ int i3c_master_register(struct i3c_master_controller *master, 
			ret = -EINVAL;

			goto err_put_dev;

		}



		if (i2cbi->lvr & I3C_LVR_I2C_FM_MODE)

			i2c_scl_rate = I3C_BUS_I2C_FM_SCL_RATE;

	}



	ret = i3c_bus_set_mode(i3cbus, mode);

	ret = i3c_bus_set_mode(i3cbus, mode, i2c_scl_rate);

	if (ret)

		goto err_put_dev;

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