diff options
Diffstat (limited to 'target/linux/layerscape/patches-5.4/808-i2c-0014-i2c-mux-pca954x-support-property-idle-state.patch')
| -rw-r--r-- | target/linux/layerscape/patches-5.4/808-i2c-0014-i2c-mux-pca954x-support-property-idle-state.patch | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/target/linux/layerscape/patches-5.4/808-i2c-0014-i2c-mux-pca954x-support-property-idle-state.patch b/target/linux/layerscape/patches-5.4/808-i2c-0014-i2c-mux-pca954x-support-property-idle-state.patch new file mode 100644 index 0000000000..4263717f43 --- /dev/null +++ b/target/linux/layerscape/patches-5.4/808-i2c-0014-i2c-mux-pca954x-support-property-idle-state.patch @@ -0,0 +1,165 @@ +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 + |