From patchwork Thu Jul 30 08:12:20 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 6900261 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 1F6B4C05AC for ; Thu, 30 Jul 2015 08:15:50 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id A80A82053E for ; Thu, 30 Jul 2015 08:15:48 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3E7BF2053D for ; Thu, 30 Jul 2015 08:15:47 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZKiyH-0008II-0h; Thu, 30 Jul 2015 08:13:45 +0000 Received: from conuserg011.nifty.com ([202.248.44.37] helo=conuserg011-v.nifty.com) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZKixr-000843-0H for linux-arm-kernel@lists.infradead.org; Thu, 30 Jul 2015 08:13:22 +0000 Received: from beagle.diag.org (KD036010086095.au-net.ne.jp [36.10.86.95]) (authenticated) by conuserg011-v.nifty.com with ESMTP id t6U8CXx5028452; Thu, 30 Jul 2015 17:12:42 +0900 X-Nifty-SrcIP: [36.10.86.95] From: Masahiro Yamada To: linux-i2c@vger.kernel.org Subject: [PATCH 1/3] i2c: uniphier: add UniPhier FIFO-less I2C driver Date: Thu, 30 Jul 2015 17:12:20 +0900 Message-Id: <1438243942-26401-2-git-send-email-yamada.masahiro@socionext.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1438243942-26401-1-git-send-email-yamada.masahiro@socionext.com> References: <1438243942-26401-1-git-send-email-yamada.masahiro@socionext.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150730_011319_408743_FEB571D6 X-CRM114-Status: GOOD ( 24.21 ) X-Spam-Score: -1.2 (-) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Laurentiu Palcu , Xudong Chen , Baruch Siach , Zubair Lutfullah Kakakhel , Masahiro Yamada , Andrew Bresticker , Lee Jones , Max Schwarz , linux-kernel@vger.kernel.org, Ray Jui , Sachin Kamat , Wei Yan , Anders Berg , Geert Uytterhoeven , Kamal Dasu , David Box , Wolfram Sang , Neelesh Gupta , Mika Westerberg , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-5.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add support for on-chip I2C controller used on old UniPhier SoCs such as PH1-LD4, PH1-sLD8, etc.. This adapter is so simple that it has no FIFO in it. Signed-off-by: Masahiro Yamada --- drivers/i2c/busses/Kconfig | 8 + drivers/i2c/busses/Makefile | 1 + drivers/i2c/busses/i2c-uniphier.c | 446 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 455 insertions(+) create mode 100644 drivers/i2c/busses/i2c-uniphier.c diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 577d58d..7073a19 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -885,6 +885,14 @@ config I2C_TEGRA If you say yes to this option, support will be included for the I2C controller embedded in NVIDIA Tegra SOCs +config I2C_UNIPHIER + tristate "UniPhier FIFO-less I2C controller" + depends on ARCH_UNIPHIER + help + If you say yes to this option, support will be included for + the UniPhier FIFO-less I2C interface embedded in PH1-LD4, PH1-sLD8, + or older UniPhier SoCs. + config I2C_VERSATILE tristate "ARM Versatile/Realview I2C bus support" depends on ARCH_VERSATILE || ARCH_REALVIEW || ARCH_VEXPRESS diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index e5f537c..e89969c 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -85,6 +85,7 @@ obj-$(CONFIG_I2C_ST) += i2c-st.o obj-$(CONFIG_I2C_STU300) += i2c-stu300.o obj-$(CONFIG_I2C_SUN6I_P2WI) += i2c-sun6i-p2wi.o obj-$(CONFIG_I2C_TEGRA) += i2c-tegra.o +obj-$(CONFIG_I2C_UNIPHIER) += i2c-uniphier.o obj-$(CONFIG_I2C_VERSATILE) += i2c-versatile.o obj-$(CONFIG_I2C_WMT) += i2c-wmt.o obj-$(CONFIG_I2C_OCTEON) += i2c-octeon.o diff --git a/drivers/i2c/busses/i2c-uniphier.c b/drivers/i2c/busses/i2c-uniphier.c new file mode 100644 index 0000000..bd9877f --- /dev/null +++ b/drivers/i2c/busses/i2c-uniphier.c @@ -0,0 +1,446 @@ +/* + * Copyright (C) 2015 Masahiro Yamada + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include +#include +#include +#include +#include +#include + +#define UNIPHIER_I2C_DTRM 0x00 /* TX register */ +#define UNIPHIER_I2C_DTRM_IRQEN BIT(11) /* enable interrupt */ +#define UNIPHIER_I2C_DTRM_STA BIT(10) /* start condition */ +#define UNIPHIER_I2C_DTRM_STO BIT(9) /* stop condition */ +#define UNIPHIER_I2C_DTRM_NACK BIT(8) /* do not return ACK */ +#define UNIPHIER_I2C_DTRM_RD BIT(0) /* read transaction */ +#define UNIPHIER_I2C_DREC 0x04 /* RX register */ +#define UNIPHIER_I2C_DREC_MST BIT(14) /* 1 = master, 0 = slave */ +#define UNIPHIER_I2C_DREC_TX BIT(13) /* 1 = transmit, 0 = receive */ +#define UNIPHIER_I2C_DREC_STS BIT(12) /* stop condition detected */ +#define UNIPHIER_I2C_DREC_LRB BIT(11) /* no ACK */ +#define UNIPHIER_I2C_DREC_LAB BIT(9) /* arbitration lost */ +#define UNIPHIER_I2C_DREC_BBN BIT(8) /* bus not busy */ +#define UNIPHIER_I2C_MYAD 0x08 /* slave address */ +#define UNIPHIER_I2C_CLK 0x0c /* clock frequency control */ +#define UNIPHIER_I2C_BRST 0x10 /* bus reset */ +#define UNIPHIER_I2C_BRST_FOEN BIT(1) /* normal operation */ +#define UNIPHIER_I2C_BRST_RSCL BIT(0) /* release SCL */ +#define UNIPHIER_I2C_HOLD 0x14 /* hold time control */ +#define UNIPHIER_I2C_BSTS 0x18 /* bus status monitor */ +#define UNIPHIER_I2C_BSTS_SDA BIT(1) /* readback of SDA line */ +#define UNIPHIER_I2C_BSTS_SCL BIT(0) /* readback of SCL line */ +#define UNIPHIER_I2C_NOISE 0x1c /* noise filter control */ +#define UNIPHIER_I2C_SETUP 0x20 /* setup time control */ + +#define UNIPHIER_I2C_DEFAULT_SPEED 100000 +#define UNIPHIER_I2C_MAX_SPEED 400000 + +struct uniphier_i2c_priv { + struct completion comp; + struct i2c_adapter adap; + void __iomem *membase; + struct clk *clk; + unsigned int busy_cnt; +}; + +static irqreturn_t uniphier_i2c_interrupt(int irq, void *dev_id) +{ + struct uniphier_i2c_priv *priv = dev_id; + + /* + * This hardware uses edge triggered interrupt. Do not touch the + * hardware registers in this handler to make sure to catch the next + * interrupt edge. Just send a complete signal and return. + */ + complete(&priv->comp); + + return IRQ_HANDLED; +} + +static int uniphier_i2c_xfer_byte(struct i2c_adapter *adap, u32 txdata, + u32 *rxdatap) +{ + struct uniphier_i2c_priv *priv = i2c_get_adapdata(adap); + unsigned long time_left; + u32 rxdata; + + reinit_completion(&priv->comp); + + txdata |= UNIPHIER_I2C_DTRM_IRQEN; + dev_dbg(&adap->dev, "write data: 0x%04x\n", txdata); + writel(txdata, priv->membase + UNIPHIER_I2C_DTRM); + + time_left = wait_for_completion_timeout(&priv->comp, adap->timeout); + if (unlikely(!time_left)) { + dev_err(&adap->dev, "transaction timeout\n"); + return -ETIMEDOUT; + } + + rxdata = readl(priv->membase + UNIPHIER_I2C_DREC); + dev_dbg(&adap->dev, "read data: 0x%04x\n", rxdata); + + if (rxdatap) + *rxdatap = rxdata; + + return 0; +} + +static int uniphier_i2c_send_byte(struct i2c_adapter *adap, u32 txdata) +{ + u32 rxdata; + int ret; + + ret = uniphier_i2c_xfer_byte(adap, txdata, &rxdata); + if (ret) + return ret; + + if (unlikely(rxdata & UNIPHIER_I2C_DREC_LAB)) { + dev_dbg(&adap->dev, "arbitration lost\n"); + return -EAGAIN; + } + if (unlikely(rxdata & UNIPHIER_I2C_DREC_LRB)) { + dev_dbg(&adap->dev, "could not get ACK\n"); + return -ENXIO; + } + + return 0; +} + +static int uniphier_i2c_tx(struct i2c_adapter *adap, u16 addr, u16 len, + const u8 *buf) +{ + int ret; + + dev_dbg(&adap->dev, "start condition\n"); + ret = uniphier_i2c_send_byte(adap, addr << 1 | + UNIPHIER_I2C_DTRM_STA | + UNIPHIER_I2C_DTRM_NACK); + if (ret) + return ret; + + while (len--) { + ret = uniphier_i2c_send_byte(adap, + UNIPHIER_I2C_DTRM_NACK | *buf++); + if (ret) + return ret; + } + + return 0; +} + +static int uniphier_i2c_rx(struct i2c_adapter *adap, u16 addr, u16 len, + u8 *buf) +{ + int ret; + + dev_dbg(&adap->dev, "start condition\n"); + ret = uniphier_i2c_send_byte(adap, addr << 1 | + UNIPHIER_I2C_DTRM_STA | + UNIPHIER_I2C_DTRM_NACK | + UNIPHIER_I2C_DTRM_RD); + if (ret) + return ret; + + while (len--) { + u32 rxdata; + + ret = uniphier_i2c_xfer_byte(adap, + len ? 0 : UNIPHIER_I2C_DTRM_NACK, + &rxdata); + if (ret) + return ret; + *buf++ = rxdata; + } + + return 0; +} + +static int uniphier_i2c_stop(struct i2c_adapter *adap) +{ + dev_dbg(&adap->dev, "stop condition\n"); + return uniphier_i2c_send_byte(adap, UNIPHIER_I2C_DTRM_STO | + UNIPHIER_I2C_DTRM_NACK); +} + +static int uniphier_i2c_master_xfer_one(struct i2c_adapter *adap, + struct i2c_msg *msg, bool stop) +{ + bool is_read = msg->flags & I2C_M_RD; + bool recovery = false; + int ret; + + dev_dbg(&adap->dev, "%s: addr=0x%02x, len=%d, stop=%d\n", + is_read ? "receive" : "transmit", msg->addr, msg->len, stop); + + if (is_read) + ret = uniphier_i2c_rx(adap, msg->addr, msg->len, msg->buf); + else + ret = uniphier_i2c_tx(adap, msg->addr, msg->len, msg->buf); + + if (ret == -EAGAIN) /* could not acquire bus. bail out without STOP */ + return ret; + + if (ret == -ETIMEDOUT) { + /* This error is fatal. Needs recovery. */ + stop = false; + recovery = true; + } + + if (stop) { + int ret2 = uniphier_i2c_stop(adap); + + if (ret2) { + /* Failed to issue STOP. The bus needs recovery. */ + recovery = true; + ret = ret ?: ret2; + } + } + + if (recovery) + i2c_recover_bus(adap); + + return ret; +} + +static int uniphier_i2c_check_bus_busy(struct i2c_adapter *adap) +{ + struct uniphier_i2c_priv *priv = i2c_get_adapdata(adap); + + if (!(readl(priv->membase + UNIPHIER_I2C_DREC) & + UNIPHIER_I2C_DREC_BBN)) { + if (priv->busy_cnt++ > 3) { + /* + * If bus busy continues too long, it is probably + * in a wrong state. Try bus recovery. + */ + i2c_recover_bus(adap); + priv->busy_cnt = 0; + } + + return -EAGAIN; + } + + priv->busy_cnt = 0; + return 0; +} + +static int uniphier_i2c_master_xfer(struct i2c_adapter *adap, + struct i2c_msg *msgs, int num) +{ + struct i2c_msg *msg, *emsg = msgs + num; + int ret; + + ret = uniphier_i2c_check_bus_busy(adap); + if (ret) + return ret; + + for (msg = msgs; msg < emsg; msg++) { + /* If next message is read, skip the stop condition */ + bool stop = !(msg + 1 < emsg && msg[1].flags & I2C_M_RD); + /* but, force it if I2C_M_STOP is set */ + if (msg->flags & I2C_M_STOP) + stop = true; + + ret = uniphier_i2c_master_xfer_one(adap, msg, stop); + if (ret) + return ret; + } + + return num; +} + +static u32 uniphier_i2c_functionality(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C; +} + +static const struct i2c_algorithm uniphier_i2c_algo = { + .master_xfer = uniphier_i2c_master_xfer, + .functionality = uniphier_i2c_functionality, +}; + +static void uniphier_i2c_reset(struct uniphier_i2c_priv *priv, bool reset_on) +{ + u32 val = UNIPHIER_I2C_BRST_RSCL; + + val |= reset_on ? 0 : UNIPHIER_I2C_BRST_FOEN; + writel(val, priv->membase + UNIPHIER_I2C_BRST); +} + +static int uniphier_i2c_get_scl(struct i2c_adapter *adap) +{ + struct uniphier_i2c_priv *priv = i2c_get_adapdata(adap); + + return !!(readl(priv->membase + UNIPHIER_I2C_BSTS) & + UNIPHIER_I2C_BSTS_SCL); +} + +static void uniphier_i2c_set_scl(struct i2c_adapter *adap, int val) +{ + struct uniphier_i2c_priv *priv = i2c_get_adapdata(adap); + + writel(val ? UNIPHIER_I2C_BRST_RSCL : 0, + priv->membase + UNIPHIER_I2C_BRST); +} + +static int uniphier_i2c_get_sda(struct i2c_adapter *adap) +{ + struct uniphier_i2c_priv *priv = i2c_get_adapdata(adap); + + return !!(readl(priv->membase + UNIPHIER_I2C_BSTS) & + UNIPHIER_I2C_BSTS_SDA); +} + +static void uniphier_i2c_unprepare_recovery(struct i2c_adapter *adap) +{ + uniphier_i2c_reset(i2c_get_adapdata(adap), false); +} + +static struct i2c_bus_recovery_info uniphier_i2c_bus_recovery_info = { + .recover_bus = i2c_generic_scl_recovery, + .get_scl = uniphier_i2c_get_scl, + .set_scl = uniphier_i2c_set_scl, + .get_sda = uniphier_i2c_get_sda, + .unprepare_recovery = uniphier_i2c_unprepare_recovery, +}; + +static int uniphier_i2c_clk_init(struct device *dev, + struct uniphier_i2c_priv *priv) +{ + struct device_node *np = dev->of_node; + unsigned long clk_rate; + u32 bus_speed; + int ret; + + if (of_property_read_u32(np, "clock-frequency", &bus_speed)) + bus_speed = UNIPHIER_I2C_DEFAULT_SPEED; + + if (bus_speed > UNIPHIER_I2C_MAX_SPEED) + bus_speed = UNIPHIER_I2C_MAX_SPEED; + + /* Get input clk rate through clk driver */ + priv->clk = devm_clk_get(dev, NULL); + if (IS_ERR(priv->clk)) { + dev_err(dev, "failed to get clock\n"); + return PTR_ERR(priv->clk); + } + + ret = clk_prepare_enable(priv->clk); + if (ret) + return ret; + + clk_rate = clk_get_rate(priv->clk); + + uniphier_i2c_reset(priv, true); + + writel((clk_rate / bus_speed / 2 << 16) | (clk_rate / bus_speed), + priv->membase + UNIPHIER_I2C_CLK); + + uniphier_i2c_reset(priv, false); + + return 0; +} + +static int uniphier_i2c_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct uniphier_i2c_priv *priv; + struct resource *regs; + int irq; + int ret; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!regs) { + dev_err(dev, "failed to get memory resource"); + return -EINVAL; + } + + priv->membase = devm_ioremap_resource(dev, regs); + if (IS_ERR(priv->membase)) + return PTR_ERR(priv->membase); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + dev_err(dev, "failed to get IRQ number"); + return irq; + } + + init_completion(&priv->comp); + priv->adap.owner = THIS_MODULE; + priv->adap.algo = &uniphier_i2c_algo; + priv->adap.dev.parent = dev; + priv->adap.dev.of_node = dev->of_node; + strlcpy(priv->adap.name, "UniPhier I2C", sizeof(priv->adap.name)); + priv->adap.bus_recovery_info = &uniphier_i2c_bus_recovery_info; + i2c_set_adapdata(&priv->adap, priv); + platform_set_drvdata(pdev, priv); + + ret = uniphier_i2c_clk_init(dev, priv); + if (ret) + return ret; + + ret = devm_request_irq(dev, irq, uniphier_i2c_interrupt, 0, pdev->name, + priv); + if (ret) { + dev_err(dev, "failed to request irq %d\n", irq); + goto err; + } + + ret = i2c_add_adapter(&priv->adap); + if (ret) { + dev_err(dev, "failed to add I2C adapter\n"); + goto err; + } + +err: + if (ret) + clk_disable_unprepare(priv->clk); + + return ret; +} + +static int uniphier_i2c_remove(struct platform_device *pdev) +{ + struct uniphier_i2c_priv *priv = platform_get_drvdata(pdev); + + i2c_del_adapter(&priv->adap); + clk_disable_unprepare(priv->clk); + + return 0; +} + +static const struct of_device_id uniphier_i2c_match[] = { + { .compatible = "socionext,uniphier-i2c" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, uniphier_i2c_match); + +static struct platform_driver uniphier_i2c_drv = { + .probe = uniphier_i2c_probe, + .remove = uniphier_i2c_remove, + .driver = { + .name = "uniphier-i2c", + .of_match_table = uniphier_i2c_match, + }, +}; +module_platform_driver(uniphier_i2c_drv); + +MODULE_DESCRIPTION("UniPhier I2C bus driver"); +MODULE_AUTHOR("Masahiro Yamada "); +MODULE_LICENSE("GPL");