+++ /dev/null
-From 5b51284db77e6383ff438b1dd21ee83bb6eaa895 Mon Sep 17 00:00:00 2001
-From: Biwen Li <biwen.li@nxp.com>
-Date: Tue, 22 Oct 2019 12:11:51 +0800
-Subject: [PATCH] i2c: mux: pca954x: support property idle-state
-
-This supports property idle-state,if present,
-overrides i2c-mux-idle-disconnect.
-
-My use cases:
- - Use the property idle-state to fix
- an errata on LS2085ARDB and LS2088ARDB.
- - Errata id: E-00013(board LS2085ARDB and
- LS2088ARDB revision on Rev.B, Rev.C and Rev.D).
- - About E-00013:
- - Description: I2C1 and I2C3 buses
- are missing pull-up.
- - Impact: When the PCA954x device is tri-stated, the I2C bus
- will float. This makes the I2C bus and its associated
- downstream devices inaccessible.
- - Hardware fix: Populate resistors R189 and R190 for I2C1
- and resistors R228 and R229 for I2C3.
- - Software fix: Remove the tri-state option from the PCA954x
- driver(PCA954x always on enable status, specify a
- channel zero in dts to fix the errata E-00013).
-
-Tested-by: Ioana Ciornei <ioana.ciornei@nxp.com>
-Signed-off-by: Biwen Li <biwen.li@nxp.com>
----
- drivers/i2c/muxes/i2c-mux-pca954x.c | 69 ++++++++++++++++++++++++-------------
- 1 file changed, 46 insertions(+), 23 deletions(-)
-
---- a/drivers/i2c/muxes/i2c-mux-pca954x.c
-+++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
-@@ -87,7 +87,7 @@ struct pca954x {
-
- u8 last_chan; /* last register value */
- /* MUX_IDLE_AS_IS, MUX_IDLE_DISCONNECT or >= 0 for channel */
-- s8 idle_state;
-+ s32 idle_state;
-
- struct i2c_client *client;
-
-@@ -237,20 +237,23 @@ static int pca954x_reg_write(struct i2c_
- I2C_SMBUS_BYTE, &dummy);
- }
-
-+static u8 pca954x_regval(struct pca954x *data, u8 chan)
-+{
-+ /* We make switches look like muxes, not sure how to be smarter. */
-+ if (data->chip->muxtype == pca954x_ismux)
-+ return chan | data->chip->enable;
-+ else
-+ return 1 << chan;
-+}
-+
- static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
- {
- struct pca954x *data = i2c_mux_priv(muxc);
- struct i2c_client *client = data->client;
-- const struct chip_desc *chip = data->chip;
- u8 regval;
- int ret = 0;
-
-- /* we make switches look like muxes, not sure how to be smarter */
-- if (chip->muxtype == pca954x_ismux)
-- regval = chan | chip->enable;
-- else
-- regval = 1 << chan;
--
-+ regval = pca954x_regval(data, chan);
- /* Only select the channel if its different from the last channel */
- if (data->last_chan != regval) {
- ret = pca954x_reg_write(muxc->parent, client, regval);
-@@ -264,7 +267,7 @@ static int pca954x_deselect_mux(struct i
- {
- struct pca954x *data = i2c_mux_priv(muxc);
- struct i2c_client *client = data->client;
-- s8 idle_state;
-+ s32 idle_state;
-
- idle_state = READ_ONCE(data->idle_state);
- if (idle_state >= 0)
-@@ -410,6 +413,22 @@ static void pca954x_cleanup(struct i2c_m
- i2c_mux_del_adapters(muxc);
- }
-
-+static int pca954x_init(struct i2c_client *client, struct pca954x *data)
-+{
-+ int ret;
-+ if (data->idle_state >= 0) {
-+ data->last_chan = pca954x_regval(data, data->idle_state);
-+ } else {
-+ /* Disconnect multiplexer */
-+ data->last_chan = 0;
-+ }
-+ ret = i2c_smbus_write_byte(client, data->last_chan);
-+ if (ret < 0)
-+ data->last_chan = 0;
-+
-+ return ret;
-+}
-+
- /*
- * I2C init/probing/exit functions
- */
-@@ -419,7 +438,6 @@ static int pca954x_probe(struct i2c_clie
- struct i2c_adapter *adap = client->adapter;
- struct device *dev = &client->dev;
- struct device_node *np = dev->of_node;
-- bool idle_disconnect_dt;
- struct gpio_desc *gpio;
- struct i2c_mux_core *muxc;
- struct pca954x *data;
-@@ -470,23 +488,24 @@ static int pca954x_probe(struct i2c_clie
- }
- }
-
-- /* Write the mux register at addr to verify
-+ data->idle_state = MUX_IDLE_AS_IS;
-+ if (of_property_read_u32(np, "idle-state", &data->idle_state)) {
-+ if (np && of_property_read_bool(np, "i2c-mux-idle-disconnect"))
-+ data->idle_state = MUX_IDLE_DISCONNECT;
-+ }
-+
-+ /*
-+ * Write the mux register at addr to verify
- * that the mux is in fact present. This also
-- * initializes the mux to disconnected state.
-+ * initializes the mux to a channel
-+ * or disconnected state.
- */
-- if (i2c_smbus_write_byte(client, 0) < 0) {
-+ ret = pca954x_init(client, data);
-+ if (ret < 0) {
- dev_warn(dev, "probe failed\n");
- return -ENODEV;
- }
-
-- data->last_chan = 0; /* force the first selection */
-- data->idle_state = MUX_IDLE_AS_IS;
--
-- idle_disconnect_dt = np &&
-- of_property_read_bool(np, "i2c-mux-idle-disconnect");
-- if (idle_disconnect_dt)
-- data->idle_state = MUX_IDLE_DISCONNECT;
--
- ret = pca954x_irq_setup(muxc);
- if (ret)
- goto fail_cleanup;
-@@ -538,9 +557,13 @@ static int pca954x_resume(struct device
- struct i2c_client *client = to_i2c_client(dev);
- struct i2c_mux_core *muxc = i2c_get_clientdata(client);
- struct pca954x *data = i2c_mux_priv(muxc);
-+ int ret;
-
-- data->last_chan = 0;
-- return i2c_smbus_write_byte(client, 0);
-+ ret = pca954x_init(client, data);
-+ if (ret < 0)
-+ dev_err(&client->dev, "failed to verify the mux, the mux maybe not present in fact\n");
-+
-+ return ret;
- }
- #endif
-
projects / openwrt / staging / chunkeey.git / blobdiff