From patchwork Fri Oct 16 08:24:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Biwen Li \(OSS\)" X-Patchwork-Id: 293595 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=-9.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, UNWANTED_LANGUAGE_BODY, URIBL_BLOCKED, 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 1F819C433DF for ; Fri, 16 Oct 2020 08:35:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D0B820848 for ; Fri, 16 Oct 2020 08:35:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394635AbgJPIfI (ORCPT ); Fri, 16 Oct 2020 04:35:08 -0400 Received: from inva021.nxp.com ([92.121.34.21]:33664 "EHLO inva021.nxp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394633AbgJPIfI (ORCPT ); Fri, 16 Oct 2020 04:35:08 -0400 Received: from inva021.nxp.com (localhost [127.0.0.1]) by inva021.eu-rdc02.nxp.com (Postfix) with ESMTP id ABB8720181D; Fri, 16 Oct 2020 10:35:04 +0200 (CEST) Received: from invc005.ap-rdc01.nxp.com (invc005.ap-rdc01.nxp.com [165.114.16.14]) by inva021.eu-rdc02.nxp.com (Postfix) with ESMTP id 66BAE2000FB; Fri, 16 Oct 2020 10:34:58 +0200 (CEST) Received: from localhost.localdomain (mega.ap.freescale.net [10.192.208.232]) by invc005.ap-rdc01.nxp.com (Postfix) with ESMTP id 71014402A7; Fri, 16 Oct 2020 10:34:50 +0200 (CEST) From: Biwen Li To: leoyang.li@nxp.com, linux@rempel-privat.de, kernel@pengutronix.de, wsa@the-dreams.de, shawnguo@kernel.org, s.hauer@pengutronix.de, festevam@gmail.com, aisheng.dong@nxp.com, xiaoning.wang@nxp.com, o.rempel@pengutronix.de Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, jiafei.pan@nxp.com, xiaobo.xie@nxp.com, linux-arm-kernel@lists.infradead.org, Biwen Li Subject: [v7] i2c: imx: support slave mode for imx I2C driver Date: Fri, 16 Oct 2020 16:24:35 +0800 Message-Id: <20201016082435.11593-1-biwen.li@oss.nxp.com> X-Mailer: git-send-email 2.17.1 X-Virus-Scanned: ClamAV using ClamSMTP Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Biwen Li The patch supports slave mode for imx I2C driver Signed-off-by: Biwen Li --- Change in v7: - support auto switch mode between master and slave - enable interrupt when idle in slave mode - remove #ifdef Change in v6: - delete robust logs and comments - not read status register again in master isr. Change in v5: - fix a bug that cannot determine in what mode(master mode or slave mode) Change in v4: - add MACRO CONFIG_I2C_SLAVE to fix compilation issue Change in v3: - support layerscape and i.mx platform Change in v2: - remove MACRO CONFIG_I2C_SLAVE drivers/i2c/busses/i2c-imx.c | 213 ++++++++++++++++++++++++++++++++--- 1 file changed, 199 insertions(+), 14 deletions(-) diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index 0ab5381aa012..0d62b09ee967 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -17,6 +17,7 @@ * Copyright (C) 2008 Darius Augulis * * Copyright 2013 Freescale Semiconductor, Inc. + * Copyright 2020 NXP * */ @@ -72,6 +73,7 @@ #define IMX_I2C_I2CR 0x02 /* i2c control */ #define IMX_I2C_I2SR 0x03 /* i2c status */ #define IMX_I2C_I2DR 0x04 /* i2c transfer data */ +#define IMX_I2C_IBIC 0x05 /* i2c transfer data */ #define IMX_I2C_REGSHIFT 2 #define VF610_I2C_REGSHIFT 0 @@ -91,6 +93,7 @@ #define I2CR_MSTA 0x20 #define I2CR_IIEN 0x40 #define I2CR_IEN 0x80 +#define IBIC_BIIE 0x80 // Bus idle interrupt enable /* register bits different operating codes definition: * 1) I2SR: Interrupt flags clear operation differ between SoCs: @@ -201,6 +204,7 @@ struct imx_i2c_struct { struct pinctrl_state *pinctrl_pins_gpio; struct imx_i2c_dma *dma; + struct i2c_client *slave; }; static const struct imx_i2c_hwdata imx1_i2c_hwdata = { @@ -277,6 +281,14 @@ static inline unsigned char imx_i2c_read_reg(struct imx_i2c_struct *i2c_imx, return readb(i2c_imx->base + (reg << i2c_imx->hwdata->regshift)); } +/* Set up i2c controller register and i2c status register to default value. */ +static void i2c_imx_reset_regs(struct imx_i2c_struct *i2c_imx) +{ + imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN, + i2c_imx, IMX_I2C_I2CR); + imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR); +} + /* Functions for DMA support */ static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx, dma_addr_t phy_addr) @@ -614,20 +626,110 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx, bool atomic) imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); } +/* + * Enable bus idle interrupts + * Note: IBIC register will be cleared after disabled i2c module. + */ +static void i2c_imx_enable_bus_idle(struct imx_i2c_struct *i2c_imx) +{ + unsigned int temp; + + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_IBIC); + temp |= IBIC_BIIE; + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_IBIC); +} + +static void i2c_imx_clr_if_bit(unsigned int status, struct imx_i2c_struct *i2c_imx) +{ + status &= ~I2SR_IIF; + status |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF); + imx_i2c_write_reg(status, i2c_imx, IMX_I2C_I2SR); +} + +/* Clear arbitration lost bit */ +static void i2c_imx_clr_al_bit(unsigned int status, struct imx_i2c_struct *i2c_imx) +{ + status &= ~I2SR_IAL; + status |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IAL); + imx_i2c_write_reg(status, i2c_imx, IMX_I2C_I2SR); +} + +static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx, + unsigned int status, unsigned int ctl) +{ + u8 value; + + if (status & I2SR_IAL) { /* Arbitration lost */ + i2c_imx_clr_al_bit(status | I2SR_IIF, i2c_imx); + } else if (status & I2SR_IAAS) { /* Addressed as a slave */ + if (status & I2SR_SRW) { /* Master wants to read from us*/ + dev_dbg(&i2c_imx->adapter.dev, "read requested"); + i2c_slave_event(i2c_imx->slave, I2C_SLAVE_READ_REQUESTED, &value); + + /* Slave transmit */ + ctl |= I2CR_MTX; + imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR); + + /* Send data */ + imx_i2c_write_reg(value, i2c_imx, IMX_I2C_I2DR); + } else { /* Master wants to write to us */ + dev_dbg(&i2c_imx->adapter.dev, "write requested"); + i2c_slave_event(i2c_imx->slave, I2C_SLAVE_WRITE_REQUESTED, &value); + + /* Slave receive */ + ctl &= ~I2CR_MTX; + imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR); + /* Dummy read */ + imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); + } + } else if (!(ctl & I2CR_MTX)) { /* Receive mode */ + if (status & I2SR_IBB) { /* No STOP signal detected */ + value = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); + i2c_slave_event(i2c_imx->slave, I2C_SLAVE_WRITE_RECEIVED, &value); + } else { /* STOP signal is detected */ + dev_dbg(&i2c_imx->adapter.dev, + "STOP signal detected"); + i2c_slave_event(i2c_imx->slave, I2C_SLAVE_STOP, &value); + } + } else if (!(status & I2SR_RXAK)) { /* Transmit mode received ACK */ + ctl |= I2CR_MTX; + imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR); + + i2c_slave_event(i2c_imx->slave, I2C_SLAVE_READ_PROCESSED, &value); + + imx_i2c_write_reg(value, i2c_imx, IMX_I2C_I2DR); + } else { /* Transmit mode received NAK */ + ctl &= ~I2CR_MTX; + imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR); + imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); + } + + return IRQ_HANDLED; +} + +static irqreturn_t i2c_imx_master_isr(struct imx_i2c_struct *i2c_imx, unsigned int status) +{ + /* Save status register */ + i2c_imx->i2csr = status | I2SR_IIF; + wake_up(&i2c_imx->queue); + + return IRQ_HANDLED; +} + static irqreturn_t i2c_imx_isr(int irq, void *dev_id) { struct imx_i2c_struct *i2c_imx = dev_id; - unsigned int temp; + unsigned int ctl, status; + + status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); + ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + + if (status & I2SR_IIF) { + i2c_imx_clr_if_bit(status, i2c_imx); + if (IS_ENABLED(CONFIG_I2C_SLAVE) && i2c_imx->slave && !(ctl & I2CR_MSTA)) + return i2c_imx_slave_isr(i2c_imx, status, ctl); - temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); - if (temp & I2SR_IIF) { - /* save status register */ - i2c_imx->i2csr = temp; - temp &= ~I2SR_IIF; - temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF); - imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR); - wake_up(&i2c_imx->queue); - return IRQ_HANDLED; + return i2c_imx_master_isr(i2c_imx, status); } return IRQ_NONE; @@ -918,6 +1020,38 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, return 0; } +static int i2c_imx_slave_init(struct imx_i2c_struct *i2c_imx) +{ + int temp; + + /* Resume */ + temp = pm_runtime_get_sync(i2c_imx->adapter.dev.parent); + if (temp < 0) { + dev_err(&i2c_imx->adapter.dev, "failed to resume i2c controller"); + return temp; + } + + /* Set slave addr. */ + imx_i2c_write_reg((i2c_imx->slave->addr << 1), i2c_imx, IMX_I2C_IADR); + + i2c_imx_reset_regs(i2c_imx); + + /* Enable module */ + temp = i2c_imx->hwdata->i2cr_ien_opcode; + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); + + /* Enable interrupt from i2c module */ + temp |= I2CR_IIEN; + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); + + i2c_imx_enable_bus_idle(i2c_imx); + + /* Wait controller to be stable */ + usleep_range(50, 150); + + return 0; +} + static int i2c_imx_xfer_common(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num, bool atomic) { @@ -999,6 +1133,12 @@ static int i2c_imx_xfer_common(struct i2c_adapter *adapter, dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__, (result < 0) ? "error" : "success msg", (result < 0) ? result : num); + /* After data is transferred, switch to slave mode(as a receiver) */ + if (IS_ENABLED(CONFIG_I2C_SLAVE) && i2c_imx->slave) { + if (i2c_imx_slave_init(i2c_imx) < 0) + dev_err(&i2c_imx->adapter.dev, "failed to switch to slave mode"); + } + return (result < 0) ? result : num; } @@ -1108,10 +1248,58 @@ static u32 i2c_imx_func(struct i2c_adapter *adapter) | I2C_FUNC_SMBUS_READ_BLOCK_DATA; } +static int i2c_imx_reg_slave(struct i2c_client *client) +{ + struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(client->adapter); + int ret; + + if (!IS_ENABLED(CONFIG_I2C_SLAVE)) + return -EINVAL; + + if (i2c_imx->slave) + return -EBUSY; + + i2c_imx->slave = client; + + ret = i2c_imx_slave_init(i2c_imx); + if (ret < 0) + dev_err(&i2c_imx->adapter.dev, "failed to switch to slave mode"); + + return ret; +} + +static int i2c_imx_unreg_slave(struct i2c_client *client) +{ + struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(client->adapter); + int ret; + + if (!IS_ENABLED(CONFIG_I2C_SLAVE)) + return -EINVAL; + + if (!i2c_imx->slave) + return -EINVAL; + + /* Reset slave address. */ + imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IADR); + + i2c_imx_reset_regs(i2c_imx); + + i2c_imx->slave = NULL; + + /* Suspend */ + ret = pm_runtime_put_sync(i2c_imx->adapter.dev.parent); + if (ret < 0) + dev_err(&i2c_imx->adapter.dev, "failed to suspend i2c controller"); + + return ret; +} + static const struct i2c_algorithm i2c_imx_algo = { .master_xfer = i2c_imx_xfer, .master_xfer_atomic = i2c_imx_xfer_atomic, .functionality = i2c_imx_func, + .reg_slave = i2c_imx_reg_slave, + .unreg_slave = i2c_imx_unreg_slave, }; static int i2c_imx_probe(struct platform_device *pdev) @@ -1207,10 +1395,7 @@ static int i2c_imx_probe(struct platform_device *pdev) clk_notifier_register(i2c_imx->clk, &i2c_imx->clk_change_nb); i2c_imx_set_clk(i2c_imx, clk_get_rate(i2c_imx->clk)); - /* Set up chip registers to defaults */ - imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN, - i2c_imx, IMX_I2C_I2CR); - imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR); + i2c_imx_reset_regs(i2c_imx); /* Init optional bus recovery function */ ret = i2c_imx_init_recovery_info(i2c_imx, pdev);