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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 2A892C432C0 for ; Mon, 2 Dec 2019 09:55:23 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id F171A2146E for ; Mon, 2 Dec 2019 09:55:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ts9n1hmX" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F171A2146E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=3hyUH3J0VrvbJFpLHcWpVM3TQLvtF9nbl+E5obLKWsU=; b=ts9n1hmXQK09oA P8r55u/R39JCl6stJvxMM1CRdLNzc/8k5ydaZP4tvBH97EUt1k1KEg98HbdplyK4ds0g784o2OHSb /oTYGVonj3oJuG0P704uOjaUbznElu/OZ9LEHIenzTNn3szA+n1yLxrV9rY2TYNCBxUuaCrt0R+U1 uJOfbMiQWdLlNX5nSetKUiSHxZ96Ia8E0E4eF0UVFt9FNzo4+tGkt23GNiz3BpS86w/x6bvgcfL4E p4zqgibWzAvcoESC9d+tnmGdl1VZ9tFrh0ihQ02mYptRRAiGbVk9j6BAzxGNioCOUDYqVcgIjBMCS UMOQ+YOPD1sXSHo+6S0A==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1ibiQH-0000rQ-1g; Mon, 02 Dec 2019 09:55:17 +0000 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1ibiQD-0000qb-NG for linux-arm-kernel@lists.infradead.org; Mon, 02 Dec 2019 09:55:15 +0000 Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1ibiQ9-00037w-Qs; Mon, 02 Dec 2019 10:55:09 +0100 Received: from sha by ptx.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1ibiQ9-0002FL-5L; Mon, 02 Dec 2019 10:55:09 +0100 Date: Mon, 2 Dec 2019 10:55:09 +0100 From: Sascha Hauer To: Biwen Li Subject: Re: [v5] i2c: imx: support slave mode for imx I2C driver Message-ID: <20191202095509.ynxq2dyri36i2fwk@pengutronix.de> References: <20191129090513.2150-1-biwen.li@nxp.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191129090513.2150-1-biwen.li@nxp.com> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 10:17:41 up 147 days, 15:27, 130 users, load average: 0.08, 0.17, 0.24 User-Agent: NeoMutt/20170113 (1.7.2) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-arm-kernel@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191202_015513_920911_B4C44C98 X-CRM114-Status: GOOD ( 26.87 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: aisheng.dong@nxp.com, linux-arm-kernel@lists.infradead.org, wsa@the-dreams.de, shawnguo@kernel.org, xiaobo.xie@nxp.com, leoyang.li@nxp.com, o.rempel@pengutronix.de, xiaoning.wang@nxp.com, linux-imx@nxp.com, kernel@pengutronix.de, jiafei.pan@nxp.com, laurentiu.tudor@nxp.com, festevam@gmail.com, linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, Some more comments inline. On Fri, Nov 29, 2019 at 05:05:13PM +0800, Biwen Li wrote: > The patch supports slave mode for imx I2C driver > > Signed-off-by: Biwen Li > --- > 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 | 216 ++++++++++++++++++++++++++++++++--- > 1 file changed, 198 insertions(+), 18 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c > index a3b61336fe55..52f70de16900 100644 > --- a/drivers/i2c/busses/i2c-imx.c > +++ b/drivers/i2c/busses/i2c-imx.c > @@ -203,6 +203,9 @@ struct imx_i2c_struct { > struct pinctrl_state *pinctrl_pins_gpio; > > struct imx_i2c_dma *dma; > +#if IS_ENABLED(CONFIG_I2C_SLAVE) > + struct i2c_client *slave; > +#endif > }; > > static const struct imx_i2c_hwdata imx1_i2c_hwdata = { > @@ -279,6 +282,14 @@ 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) > @@ -588,23 +599,33 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx) > imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > } > > -static irqreturn_t i2c_imx_isr(int irq, void *dev_id) > +/* Clear interrupt flag bit */ > +static void i2c_imx_clr_if_bit(unsigned int status, struct imx_i2c_struct *i2c_imx) > { > - struct imx_i2c_struct *i2c_imx = dev_id; > - unsigned int temp; > + status &= ~I2SR_IIF; > + status |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF); > + imx_i2c_write_reg(status, i2c_imx, IMX_I2C_I2SR); > +} > > - 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; > - } > +/* Clear arbitration lost bit */ > +static void i2c_imx_clr_al_bit(unsigned int status, struct imx_i2c_struct *i2c_imx) > +{ Can you please remove some of the really obvious comments? When a function is named clr_al_bit, then it doesn't need a comment which says that this function really does this. There are more comments like this in the patch. > + status &= ~I2SR_IAL; > + status |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IAL); > + imx_i2c_write_reg(status, i2c_imx, IMX_I2C_I2SR); > +} > > - return IRQ_NONE; > +static irqreturn_t i2c_imx_master_isr(struct imx_i2c_struct *i2c_imx) > +{ > + unsigned int status; > + > + /* Save status register */ > + status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); > + i2c_imx->i2csr = status | I2SR_IIF; Instead of reading the status register again you could set i2c_imx->i2csr in the caller. > + > + wake_up(&i2c_imx->queue); > + > + return IRQ_HANDLED; > } > > static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx, > @@ -900,6 +921,13 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter, > > dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); > > +#if IS_ENABLED(CONFIG_I2C_SLAVE) > + if (i2c_imx->slave) { > + dev_err(&i2c_imx->adapter.dev, "Please not do operations of master mode in slave mode"); > + return -EBUSY; > + } > +#endif > + > result = pm_runtime_get_sync(i2c_imx->adapter.dev.parent); > if (result < 0) > goto out; > @@ -1048,11 +1076,166 @@ static u32 i2c_imx_func(struct i2c_adapter *adapter) > | I2C_FUNC_SMBUS_READ_BLOCK_DATA; > } > > +#if IS_ENABLED(CONFIG_I2C_SLAVE) > +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); Do these have to be two register accesses? > + > + /* Wait controller to be stable */ > + usleep_range(50, 150); > + return 0; > +} > + > +static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx) > +{ > + unsigned int status, ctl; > + u8 value; > + > + if (!i2c_imx->slave) { > + dev_err(&i2c_imx->adapter.dev, "cannot deal with slave irq,i2c_imx->slave is null"); > + return IRQ_NONE; > + } This function is never called with !i2c_imx->slave. > + > + status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); > + ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > + if (status & I2SR_IAL) { /* Arbitration lost */ > + i2c_imx_clr_al_bit(status, 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 */ > + ctl &= ~I2CR_MTX; > + imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR); > + > + 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 int i2c_imx_reg_slave(struct i2c_client *client) > +{ > + struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(client->adapter); > + int ret; > + 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"); The caller already reports an error. No need to do it here again. > + > + 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 (!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"); I doubt this message is useful. Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel