Commit 2d74187d authored by Peter Rosin's avatar Peter Rosin
Browse files

i2c: mux: pca954x: verify the device id of the pca984x chips 



Make sure to not disallow the chips on adapters that are not capable
of reading the device id, but also make sure to check the device id
before writing to the chip.

Tested-by: default avatarAdrian Fiergolski <adrian.fiergolski@cern.ch>
Signed-off-by: default avatarPeter Rosin <peda@axentia.se>
parent dde67eb1

drivers/i2c/muxes/i2c-mux-pca954x.c

+49 −6
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ struct chip_desc { 
		pca954x_ismux = 0,

		pca954x_isswi

	} muxtype;

	struct i2c_device_identity id;

};



struct pca954x {
@@ -97,59 +98,83 @@ static const struct chip_desc chips[] = { 
		.nchans = 2,

		.enable = 0x4,

		.muxtype = pca954x_ismux,

		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },

	},

	[pca_9542] = {

		.nchans = 2,

		.enable = 0x4,

		.has_irq = 1,

		.muxtype = pca954x_ismux,

		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },

	},

	[pca_9543] = {

		.nchans = 2,

		.has_irq = 1,

		.muxtype = pca954x_isswi,

		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },

	},

	[pca_9544] = {

		.nchans = 4,

		.enable = 0x4,

		.has_irq = 1,

		.muxtype = pca954x_ismux,

		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },

	},

	[pca_9545] = {

		.nchans = 4,

		.has_irq = 1,

		.muxtype = pca954x_isswi,

		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },

	},

	[pca_9546] = {

		.nchans = 4,

		.muxtype = pca954x_isswi,

		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },

	},

	[pca_9547] = {

		.nchans = 8,

		.enable = 0x8,

		.muxtype = pca954x_ismux,

		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },

	},

	[pca_9548] = {

		.nchans = 8,

		.muxtype = pca954x_isswi,

		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },

	},

	[pca_9846] = {

		.nchans = 4,

		.muxtype = pca954x_isswi,

		.id = {

			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,

			.part_id = 0x10b,

		},

	},

	[pca_9847] = {

		.nchans = 8,

		.enable = 0x8,

		.muxtype = pca954x_ismux,

		.id = {

			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,

			.part_id = 0x108,

		},

	},

	[pca_9848] = {

		.nchans = 8,

		.muxtype = pca954x_isswi,

		.id = {

			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,

			.part_id = 0x10a,

		},

	},

	[pca_9849] = {

		.nchans = 4,

		.enable = 0x4,

		.muxtype = pca954x_ismux,

		.id = {

			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,

			.part_id = 0x109,

		},

	},

};
@@ -369,6 +394,30 @@ static int pca954x_probe(struct i2c_client *client, 
	if (IS_ERR(gpio))

		return PTR_ERR(gpio);



	match = of_match_device(of_match_ptr(pca954x_of_match), &client->dev);

	if (match)

		data->chip = of_device_get_match_data(&client->dev);

	else

		data->chip = &chips[id->driver_data];



	if (data->chip->id.manufacturer_id != I2C_DEVICE_ID_NONE) {

		struct i2c_device_identity id;



		ret = i2c_get_device_id(client, &id);

		if (ret && ret != -EOPNOTSUPP)

			return ret;



		if (!ret &&

		    (id.manufacturer_id != data->chip->id.manufacturer_id ||

		     id.part_id != data->chip->id.part_id)) {

			dev_warn(&client->dev,

				 "unexpected device id %03x-%03x-%x\n",

				 id.manufacturer_id, id.part_id,

				 id.die_revision);

			return -ENODEV;

		}

	}



	/* Write the mux register at addr to verify

	 * that the mux is in fact present. This also

	 * initializes the mux to disconnected state.
@@ -378,12 +427,6 @@ static int pca954x_probe(struct i2c_client *client, 
		return -ENODEV;

	}



	match = of_match_device(of_match_ptr(pca954x_of_match), &client->dev);

	if (match)

		data->chip = of_device_get_match_data(&client->dev);

	else

		data->chip = &chips[id->driver_data];



	data->last_chan = 0;		   /* force the first selection */



	idle_disconnect_dt = of_node &&

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