From patchwork Mon Oct 22 09:46:56 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Felipe Balbi X-Patchwork-Id: 1624971 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork2.kernel.org (Postfix) with ESMTP id C0678DF2F5 for ; Mon, 22 Oct 2012 09:56:35 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TQEiO-0002MA-5u; Mon, 22 Oct 2012 09:54:32 +0000 Received: from bear.ext.ti.com ([192.94.94.41]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1TQEgv-0001mL-6M for linux-arm-kernel@lists.infradead.org; Mon, 22 Oct 2012 09:53:02 +0000 Received: from dlelxv30.itg.ti.com ([172.17.2.17]) by bear.ext.ti.com (8.13.7/8.13.7) with ESMTP id q9M9qjEg032204; Mon, 22 Oct 2012 04:52:45 -0500 Received: from DFLE73.ent.ti.com (dfle73.ent.ti.com [128.247.5.110]) by dlelxv30.itg.ti.com (8.13.8/8.13.8) with ESMTP id q9M9qjmT028505; Mon, 22 Oct 2012 04:52:45 -0500 Received: from dlelxv22.itg.ti.com (172.17.1.197) by dfle73.ent.ti.com (128.247.5.110) with Microsoft SMTP Server id 14.1.323.3; Mon, 22 Oct 2012 04:52:45 -0500 Received: from localhost (h64-14.vpn.ti.com [172.24.64.14]) by dlelxv22.itg.ti.com (8.13.8/8.13.8) with ESMTP id q9M9qik3026814; Mon, 22 Oct 2012 04:52:44 -0500 From: Felipe Balbi To: Subject: [PATCH 6/8] i2c: omap: wait for transfer completion before sending STP bit Date: Mon, 22 Oct 2012 12:46:56 +0300 Message-ID: <1350899218-13624-7-git-send-email-balbi@ti.com> X-Mailer: git-send-email 1.8.0.rc0 In-Reply-To: <1350899218-13624-1-git-send-email-balbi@ti.com> References: <1350899218-13624-1-git-send-email-balbi@ti.com> MIME-Version: 1.0 X-Spam-Note: CRM114 invocation failed X-Spam-Score: -7.6 (-------) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-7.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at http://www.dnswl.org/, high trust [192.94.94.41 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -0.7 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Benoit Cousson , Tony Lindgren , w.sang@pengutronix.de, Felipe Balbi , Santosh Shilimkar , ben-linux@fluff.org, Linux OMAP Mailing List , Shubhrajyoti Datta , Linux ARM Kernel Mailing List X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Later patches will come adding support for reporting amount of bytes transferred so that client drivers can count how many bytes are left to transfer. This is useful mostly in case of NACKs when client driver wants to know exactly which byte got NACKed so it doesn't have to resend all bytes again. In order to make that work with OMAP's I2C controller, we need to prevent sending STP bit until message is transferred. The reason behind that is because OMAP_I2C_CNT_REG gets reset to original value after STP bit is shifted through I2C_SDA line and that would prevent us from reading the correct number of bytes left to transfer. The full programming model suggested by IP owner was the following: - start I2C transfer (without STP bit) - upon completion or NACK, read I2C_CNT register - write STP bit to I2C_CON register - wait for ARDY bit With this patch we're implementing all steps except step #2 which will come in a later patch adding such support. Signed-off-by: Felipe Balbi --- drivers/i2c/busses/i2c-omap.c | 101 ++++++++++++++++-------------------------- 1 file changed, 39 insertions(+), 62 deletions(-) diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c index c65d526..8104aa2 100644 --- a/drivers/i2c/busses/i2c-omap.c +++ b/drivers/i2c/busses/i2c-omap.c @@ -438,9 +438,9 @@ static int omap_i2c_init(struct omap_i2c_dev *dev) /* Enable interrupts */ dev->iestate = (OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY | - OMAP_I2C_IE_ARDY | OMAP_I2C_IE_NACK | - OMAP_I2C_IE_AL) | ((dev->fifo_size) ? - (OMAP_I2C_IE_RDR | OMAP_I2C_IE_XDR) : 0); + OMAP_I2C_IE_NACK | OMAP_I2C_IE_AL) | + ((dev->fifo_size) ? (OMAP_I2C_IE_RDR | + OMAP_I2C_IE_XDR) : 0); omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate); if (dev->flags & OMAP_I2C_FLAG_RESET_REGS_POSTIDLE) { dev->pscstate = psc; @@ -470,6 +476,22 @@ static int omap_i2c_wait_for_bb(struct omap_i2c_dev *dev) return 0; } +static int omap_i2c_wait_for_ardy(struct omap_i2c_dev *dev) +{ + unsigned long timeout; + + timeout = jiffies + OMAP_I2C_TIMEOUT; + while (!(omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG) & OMAP_I2C_STAT_ARDY)) { + if (time_after(jiffies, timeout)) { + dev_warn(dev->dev, "timeout waiting for access ready\n"); + return -ETIMEDOUT; + } + usleep_range(800, 1200); + } + + return 0; +} + static void omap_i2c_resize_fifo(struct omap_i2c_dev *dev, u8 size, bool is_rx) { u16 buf; @@ -515,7 +537,7 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap, { struct omap_i2c_dev *dev = i2c_get_adapdata(adap); unsigned long timeout; - int ret; + int ret = 0; u16 w; dev_dbg(dev->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n", @@ -556,35 +578,9 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap, if (!(msg->flags & I2C_M_RD)) w |= OMAP_I2C_CON_TRX; - if (!dev->b_hw && stop) - w |= OMAP_I2C_CON_STP; - omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w); /* - * Don't write stt and stp together on some hardware. - */ - if (dev->b_hw && stop) { - unsigned long delay = jiffies + OMAP_I2C_TIMEOUT; - u16 con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG); - while (con & OMAP_I2C_CON_STT) { - con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG); - - /* Let the user know if i2c is in a bad state */ - if (time_after(jiffies, delay)) { - dev_err(dev->dev, "controller timed out " - "waiting for start condition to finish\n"); - return -ETIMEDOUT; - } - cpu_relax(); - } - - w |= OMAP_I2C_CON_STP; - w &= ~OMAP_I2C_CON_STT; - omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w); - } - - /* * REVISIT: We should abort the transfer on signals, but the bus goes * into arbitration and we're currently unable to recover from it. */ @@ -594,36 +590,36 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap, if (timeout == 0) { dev_err(dev->dev, "controller timed out\n"); ret = -ETIMEDOUT; - goto err_i2c_init; + omap_i2c_init(dev); + goto out; } if ((dev->cmd_err & OMAP_I2C_STAT_AL) || (dev->cmd_err & OMAP_I2C_STAT_ROVR) || (dev->cmd_err & OMAP_I2C_STAT_XUDF)) { ret = -EIO; - goto err_i2c_init; + omap_i2c_init(dev); + goto out; } if (dev->cmd_err & OMAP_I2C_STAT_NACK) { if (msg->flags & I2C_M_IGNORE_NAK) return 0; - if (stop) { - w = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG); - w |= OMAP_I2C_CON_STP; - omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w); - } - ret = -EREMOTEIO; - goto err; + omap_i2c_init(dev); } - return 0; +out: -err_i2c_init: - omap_i2c_init(dev); + if (stop) { + w = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG); + w |= OMAP_I2C_CON_STP; + omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w); + + ret = omap_i2c_wait_for_ardy(dev); + } -err: return ret; } @@ -947,19 +937,6 @@ omap_i2c_isr_thread(int this_irq, void *dev_id) break; } - /* - * ProDB0017052: Clear ARDY bit twice - */ - if (stat & (OMAP_I2C_STAT_ARDY | OMAP_I2C_STAT_NACK | - OMAP_I2C_STAT_AL)) { - omap_i2c_ack_stat(dev, (OMAP_I2C_STAT_RRDY | - OMAP_I2C_STAT_RDR | - OMAP_I2C_STAT_XRDY | - OMAP_I2C_STAT_XDR | - OMAP_I2C_STAT_ARDY)); - break; - } - if (stat & OMAP_I2C_STAT_RDR) { u8 num_bytes = 1;