From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C548EC47E49 for ; Tue, 22 Oct 2019 04:23:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A60E421783 for ; Tue, 22 Oct 2019 04:23:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731000AbfJVEXF (ORCPT ); Tue, 22 Oct 2019 00:23:05 -0400 Received: from inva020.nxp.com ([92.121.34.13]:56018 "EHLO inva020.nxp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730893AbfJVEXE (ORCPT ); Tue, 22 Oct 2019 00:23:04 -0400 Received: from inva020.nxp.com (localhost [127.0.0.1]) by inva020.eu-rdc02.nxp.com (Postfix) with ESMTP id DC1CD1A05CF; Tue, 22 Oct 2019 06:23:01 +0200 (CEST) Received: from invc005.ap-rdc01.nxp.com (invc005.ap-rdc01.nxp.com [165.114.16.14]) by inva020.eu-rdc02.nxp.com (Postfix) with ESMTP id EB8BD1A0009; Tue, 22 Oct 2019 06:22:57 +0200 (CEST) Received: from titan.ap.freescale.net (TITAN.ap.freescale.net [10.192.208.233]) by invc005.ap-rdc01.nxp.com (Postfix) with ESMTP id 0C7C5402D3; Tue, 22 Oct 2019 12:22:52 +0800 (SGT) From: Biwen Li To: peda@axentia.se, leoyang.li@nxp.com, robh+dt@kernel.org, mark.rutland@arm.com Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Biwen Li Subject: [v5,2/3] i2c: mux: pca954x: support property idle-state Date: Tue, 22 Oct 2019 12:11:51 +0800 Message-Id: <20191022041152.3663-2-biwen.li@nxp.com> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20191022041152.3663-1-biwen.li@nxp.com> References: <20191022041152.3663-1-biwen.li@nxp.com> X-Virus-Scanned: ClamAV using ClamSMTP Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org 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). Signed-off-by: Biwen Li --- Change in v5: - add extra precaution for pca954x_init Change in v4: - rename function pca954x_calculate_chan -> pca954x_regval Change in v3: - update subject and description - add a helper function pca954x_calculate_chan() Change in v2: - update subject and description - add property idle-state drivers/i2c/muxes/i2c-mux-pca954x.c | 67 +++++++++++++++++++---------- 1 file changed, 44 insertions(+), 23 deletions(-) diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c index 923aa3a5a3dc..218ba1a5ed7e 100644 --- a/drivers/i2c/muxes/i2c-mux-pca954x.c +++ b/drivers/i2c/muxes/i2c-mux-pca954x.c @@ -86,7 +86,7 @@ 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; @@ -229,20 +229,23 @@ static int pca954x_reg_write(struct i2c_adapter *adap, 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); @@ -256,7 +259,7 @@ static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan) { 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) @@ -402,6 +405,25 @@ static void pca954x_cleanup(struct i2c_mux_core *muxc) 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; + dev_err(&client->dev, "failed to verify the mux, \ + the mux maybe not present in fact\n"); + } + + return ret; +} + /* * I2C init/probing/exit functions */ @@ -411,7 +433,6 @@ static int pca954x_probe(struct i2c_client *client, 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; @@ -462,23 +483,24 @@ static int pca954x_probe(struct i2c_client *client, } } - /* 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; @@ -531,8 +553,7 @@ static int pca954x_resume(struct device *dev) struct i2c_mux_core *muxc = i2c_get_clientdata(client); struct pca954x *data = i2c_mux_priv(muxc); - data->last_chan = 0; - return i2c_smbus_write_byte(client, 0); + return pca954x_init(client, data); } #endif -- 2.17.1