diff options
Diffstat (limited to 'target/linux/layerscape/patches-4.4/8233-i2c-pca954x-Add-option-to-skip-disabling-PCA954x-Mux.patch')
| -rw-r--r-- | target/linux/layerscape/patches-4.4/8233-i2c-pca954x-Add-option-to-skip-disabling-PCA954x-Mux.patch | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/target/linux/layerscape/patches-4.4/8233-i2c-pca954x-Add-option-to-skip-disabling-PCA954x-Mux.patch b/target/linux/layerscape/patches-4.4/8233-i2c-pca954x-Add-option-to-skip-disabling-PCA954x-Mux.patch new file mode 100644 index 0000000000..0967aeb698 --- /dev/null +++ b/target/linux/layerscape/patches-4.4/8233-i2c-pca954x-Add-option-to-skip-disabling-PCA954x-Mux.patch @@ -0,0 +1,110 @@ +From a4be9046c3a3fc39a06089553df8cc19a2abd814 Mon Sep 17 00:00:00 2001 +From: Priyanka Jain <Priyanka.Jain@freescale.com> +Date: Tue, 3 Nov 2015 11:25:24 +0530 +Subject: [PATCH 233/238] i2c: pca954x: Add option to skip disabling PCA954x + Mux device + +On some Layerscape boards like LS2085ARDB/LS2080ARDB, +input pull-up resistors on PCA954x Mux device are +missing on board. So, if mux are disabled after powered-on, +input lines will float leading to incorrect functionality. + +Hence, PCA954x Mux device should never be turned-off after +power-on. + +Add option to skip disabling PCA954x Mux device +if device tree contians "i2c-mux-never-disable" property +for pca954x device node. + +Signed-off-by: Priyanka Jain <Priyanka.Jain@freescale.com> +--- + drivers/i2c/muxes/i2c-mux-pca954x.c | 38 +++++++++++++++++++++++++++++++++++ + 1 file changed, 38 insertions(+) + +diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c +index acfcef3..386f86f 100644 +--- a/drivers/i2c/muxes/i2c-mux-pca954x.c ++++ b/drivers/i2c/muxes/i2c-mux-pca954x.c +@@ -63,6 +63,7 @@ struct pca954x { + struct i2c_adapter *virt_adaps[PCA954X_MAX_NCHANS]; + + u8 last_chan; /* last register value */ ++ u8 disable_mux; /* do not disable mux if val not 0 */ + }; + + struct chip_desc { +@@ -174,6 +175,13 @@ static int pca954x_deselect_mux(struct i2c_adapter *adap, + { + struct pca954x *data = i2c_get_clientdata(client); + ++#ifdef CONFIG_ARCH_LAYERSCAPE ++ if (data->disable_mux != 0) ++ data->last_chan = chips[data->type].nchans; ++ else ++ data->last_chan = 0; ++ return pca954x_reg_write(adap, client, data->disable_mux); ++#endif + /* Deselect active channel */ + data->last_chan = 0; + return pca954x_reg_write(adap, client, data->last_chan); +@@ -201,6 +209,23 @@ static int pca954x_probe(struct i2c_client *client, + if (!data) + return -ENOMEM; + ++#ifdef CONFIG_ARCH_LAYERSCAPE ++ /* The point here is that you must not disable a mux if there ++ * are no pullups on the input or you mess up the I2C. This ++ * needs to be put into the DTS really as the kernel cannot ++ * know this otherwise. ++ */ ++ data->type = id->driver_data; ++ data->disable_mux = of_node && ++ of_property_read_bool(of_node, "i2c-mux-never-disable") && ++ chips[data->type].muxtype == pca954x_ismux ? ++ chips[data->type].enable : 0; ++ /* force the first selection */ ++ if (data->disable_mux != 0) ++ data->last_chan = chips[data->type].nchans; ++ else ++ data->last_chan = 0; ++#endif + i2c_set_clientdata(client, data); + + /* Get the mux out of reset if a reset GPIO is specified. */ +@@ -212,13 +237,19 @@ static int pca954x_probe(struct i2c_client *client, + * that the mux is in fact present. This also + * initializes the mux to disconnected state. + */ ++#ifdef CONFIG_ARCH_LAYERSCAPE ++ if (i2c_smbus_write_byte(client, data->disable_mux) < 0) { ++#else + if (i2c_smbus_write_byte(client, 0) < 0) { ++#endif + dev_warn(&client->dev, "probe failed\n"); + return -ENODEV; + } + ++#ifndef CONFIG_ARCH_LAYERSCAPE + data->type = id->driver_data; + data->last_chan = 0; /* force the first selection */ ++#endif + + idle_disconnect_dt = of_node && + of_property_read_bool(of_node, "i2c-mux-idle-disconnect"); +@@ -289,6 +320,13 @@ static int pca954x_resume(struct device *dev) + struct i2c_client *client = to_i2c_client(dev); + struct pca954x *data = i2c_get_clientdata(client); + ++#ifdef CONFIG_ARCH_LAYERSCAPE ++ if (data->disable_mux != 0) ++ data->last_chan = chips[data->type].nchans; ++ else ++ data->last_chan = 0; ++ return i2c_smbus_write_byte(client, data->disable_mux); ++#endif + data->last_chan = 0; + return i2c_smbus_write_byte(client, 0); + } +-- +1.7.9.5 + |