summaryrefslogtreecommitdiff
path: root/drivers/i2c/busses/i2c-rcar.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/i2c/busses/i2c-rcar.c')
-rw-r--r--drivers/i2c/busses/i2c-rcar.c709
1 files changed, 709 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
new file mode 100644
index 000000000000..f9399d163af2
--- /dev/null
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -0,0 +1,709 @@
+/*
+ * drivers/i2c/busses/i2c-rcar.c
+ *
+ * Copyright (C) 2012 Renesas Solutions Corp.
+ * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
+ *
+ * This file is based on the drivers/i2c/busses/i2c-sh7760.c
+ * (c) 2005-2008 MSC Vertriebsges.m.b.H, Manuel Lauss <mlau@msc-ge.com>
+ *
+ * This file used out-of-tree driver i2c-rcar.c
+ * Copyright (C) 2011-2012 Renesas Electronics Corporation
+ *
+ * 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
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/i2c.h>
+#include <linux/i2c/i2c-rcar.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+/* register offsets */
+#define ICSCR 0x00 /* slave ctrl */
+#define ICMCR 0x04 /* master ctrl */
+#define ICSSR 0x08 /* slave status */
+#define ICMSR 0x0C /* master status */
+#define ICSIER 0x10 /* slave irq enable */
+#define ICMIER 0x14 /* master irq enable */
+#define ICCCR 0x18 /* clock dividers */
+#define ICSAR 0x1C /* slave address */
+#define ICMAR 0x20 /* master address */
+#define ICRXTX 0x24 /* data port */
+
+/* ICMCR */
+#define MDBS (1 << 7) /* non-fifo mode switch */
+#define FSCL (1 << 6) /* override SCL pin */
+#define FSDA (1 << 5) /* override SDA pin */
+#define OBPC (1 << 4) /* override pins */
+#define MIE (1 << 3) /* master if enable */
+#define TSBE (1 << 2)
+#define FSB (1 << 1) /* force stop bit */
+#define ESG (1 << 0) /* en startbit gen */
+
+/* ICMSR */
+#define MNR (1 << 6) /* nack received */
+#define MAL (1 << 5) /* arbitration lost */
+#define MST (1 << 4) /* sent a stop */
+#define MDE (1 << 3)
+#define MDT (1 << 2)
+#define MDR (1 << 1)
+#define MAT (1 << 0) /* slave addr xfer done */
+
+/* ICMIE */
+#define MNRE (1 << 6) /* nack irq en */
+#define MALE (1 << 5) /* arblos irq en */
+#define MSTE (1 << 4) /* stop irq en */
+#define MDEE (1 << 3)
+#define MDTE (1 << 2)
+#define MDRE (1 << 1)
+#define MATE (1 << 0) /* address sent irq en */
+
+
+enum {
+ RCAR_BUS_PHASE_ADDR,
+ RCAR_BUS_PHASE_DATA,
+ RCAR_BUS_PHASE_STOP,
+};
+
+enum {
+ RCAR_IRQ_CLOSE,
+ RCAR_IRQ_OPEN_FOR_SEND,
+ RCAR_IRQ_OPEN_FOR_RECV,
+ RCAR_IRQ_OPEN_FOR_STOP,
+};
+
+/*
+ * flags
+ */
+#define ID_LAST_MSG (1 << 0)
+#define ID_IOERROR (1 << 1)
+#define ID_DONE (1 << 2)
+#define ID_ARBLOST (1 << 3)
+#define ID_NACK (1 << 4)
+
+struct rcar_i2c_priv {
+ void __iomem *io;
+ struct i2c_adapter adap;
+ struct i2c_msg *msg;
+
+ spinlock_t lock;
+ wait_queue_head_t wait;
+
+ int pos;
+ int irq;
+ u32 icccr;
+ u32 flags;
+};
+
+#define rcar_i2c_priv_to_dev(p) ((p)->adap.dev.parent)
+#define rcar_i2c_is_recv(p) ((p)->msg->flags & I2C_M_RD)
+
+#define rcar_i2c_flags_set(p, f) ((p)->flags |= (f))
+#define rcar_i2c_flags_has(p, f) ((p)->flags & (f))
+
+#define LOOP_TIMEOUT 1024
+
+/*
+ * basic functions
+ */
+static void rcar_i2c_write(struct rcar_i2c_priv *priv, int reg, u32 val)
+{
+ writel(val, priv->io + reg);
+}
+
+static u32 rcar_i2c_read(struct rcar_i2c_priv *priv, int reg)
+{
+ return readl(priv->io + reg);
+}
+
+static void rcar_i2c_init(struct rcar_i2c_priv *priv)
+{
+ /*
+ * reset slave mode.
+ * slave mode is not used on this driver
+ */
+ rcar_i2c_write(priv, ICSIER, 0);
+ rcar_i2c_write(priv, ICSAR, 0);
+ rcar_i2c_write(priv, ICSCR, 0);
+ rcar_i2c_write(priv, ICSSR, 0);
+
+ /* reset master mode */
+ rcar_i2c_write(priv, ICMIER, 0);
+ rcar_i2c_write(priv, ICMCR, 0);
+ rcar_i2c_write(priv, ICMSR, 0);
+ rcar_i2c_write(priv, ICMAR, 0);
+}
+
+static void rcar_i2c_irq_mask(struct rcar_i2c_priv *priv, int open)
+{
+ u32 val = MNRE | MALE | MSTE | MATE; /* default */
+
+ switch (open) {
+ case RCAR_IRQ_OPEN_FOR_SEND:
+ val |= MDEE; /* default + send */
+ break;
+ case RCAR_IRQ_OPEN_FOR_RECV:
+ val |= MDRE; /* default + read */
+ break;
+ case RCAR_IRQ_OPEN_FOR_STOP:
+ val = MSTE; /* stop irq only */
+ break;
+ case RCAR_IRQ_CLOSE:
+ default:
+ val = 0; /* all close */
+ break;
+ }
+ rcar_i2c_write(priv, ICMIER, val);
+}
+
+static void rcar_i2c_set_addr(struct rcar_i2c_priv *priv, u32 recv)
+{
+ rcar_i2c_write(priv, ICMAR, (priv->msg->addr << 1) | recv);
+}
+
+/*
+ * bus control functions
+ */
+static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv)
+{
+ int i;
+
+ for (i = 0; i < LOOP_TIMEOUT; i++) {
+ /* make sure that bus is not busy */
+ if (!(rcar_i2c_read(priv, ICMCR) & FSDA))
+ return 0;
+ udelay(1);
+ }
+
+ return -EBUSY;
+}
+
+static void rcar_i2c_bus_phase(struct rcar_i2c_priv *priv, int phase)
+{
+ switch (phase) {
+ case RCAR_BUS_PHASE_ADDR:
+ rcar_i2c_write(priv, ICMCR, MDBS | MIE | ESG);
+ break;
+ case RCAR_BUS_PHASE_DATA:
+ rcar_i2c_write(priv, ICMCR, MDBS | MIE);
+ break;
+ case RCAR_BUS_PHASE_STOP:
+ rcar_i2c_write(priv, ICMCR, MDBS | MIE | FSB);
+ break;
+ }
+}
+
+/*
+ * clock function
+ */
+static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv,
+ u32 bus_speed,
+ struct device *dev)
+{
+ struct clk *clkp = clk_get(NULL, "peripheral_clk");
+ u32 scgd, cdf;
+ u32 round, ick;
+ u32 scl;
+
+ if (!clkp) {
+ dev_err(dev, "there is no peripheral_clk\n");
+ return -EIO;
+ }
+
+ /*
+ * calculate SCL clock
+ * see
+ * ICCCR
+ *
+ * ick = clkp / (1 + CDF)
+ * SCL = ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick])
+ *
+ * ick : I2C internal clock < 20 MHz
+ * ticf : I2C SCL falling time = 35 ns here
+ * tr : I2C SCL rising time = 200 ns here
+ * intd : LSI internal delay = 50 ns here
+ * clkp : peripheral_clk
+ * F[] : integer up-valuation
+ */
+ for (cdf = 0; cdf < 4; cdf++) {
+ ick = clk_get_rate(clkp) / (1 + cdf);
+ if (ick < 20000000)
+ goto ick_find;
+ }
+ dev_err(dev, "there is no best CDF\n");
+ return -EIO;
+
+ick_find:
+ /*
+ * it is impossible to calculate large scale
+ * number on u32. separate it
+ *
+ * F[(ticf + tr + intd) * ick]
+ * = F[(35 + 200 + 50)ns * ick]
+ * = F[285 * ick / 1000000000]
+ * = F[(ick / 1000000) * 285 / 1000]
+ */
+ round = (ick + 500000) / 1000000 * 285;
+ round = (round + 500) / 1000;
+
+ /*
+ * SCL = ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick])
+ *
+ * Calculation result (= SCL) should be less than
+ * bus_speed for hardware safety
+ */
+ for (scgd = 0; scgd < 0x40; scgd++) {
+ scl = ick / (20 + (scgd * 8) + round);
+ if (scl <= bus_speed)
+ goto scgd_find;
+ }
+ dev_err(dev, "it is impossible to calculate best SCL\n");
+ return -EIO;
+
+scgd_find:
+ dev_dbg(dev, "clk %d/%d(%lu), round %u, CDF:0x%x, SCGD: 0x%x\n",
+ scl, bus_speed, clk_get_rate(clkp), round, cdf, scgd);
+
+ /*
+ * keep icccr value
+ */
+ priv->icccr = (scgd << 2 | cdf);
+
+ return 0;
+}
+
+static void rcar_i2c_clock_start(struct rcar_i2c_priv *priv)
+{
+ rcar_i2c_write(priv, ICCCR, priv->icccr);
+}
+
+/*
+ * status functions
+ */
+static u32 rcar_i2c_status_get(struct rcar_i2c_priv *priv)
+{
+ return rcar_i2c_read(priv, ICMSR);
+}
+
+#define rcar_i2c_status_clear(priv) rcar_i2c_status_bit_clear(priv, 0xffffffff)
+static void rcar_i2c_status_bit_clear(struct rcar_i2c_priv *priv, u32 bit)
+{
+ rcar_i2c_write(priv, ICMSR, ~bit);
+}
+
+/*
+ * recv/send functions
+ */
+static int rcar_i2c_recv(struct rcar_i2c_priv *priv)
+{
+ rcar_i2c_set_addr(priv, 1);
+ rcar_i2c_status_clear(priv);
+ rcar_i2c_bus_phase(priv, RCAR_BUS_PHASE_ADDR);
+ rcar_i2c_irq_mask(priv, RCAR_IRQ_OPEN_FOR_RECV);
+
+ return 0;
+}
+
+static int rcar_i2c_send(struct rcar_i2c_priv *priv)
+{
+ int ret;
+
+ /*
+ * It should check bus status when send case
+ */
+ ret = rcar_i2c_bus_barrier(priv);
+ if (ret < 0)
+ return ret;
+
+ rcar_i2c_set_addr(priv, 0);
+ rcar_i2c_status_clear(priv);
+ rcar_i2c_bus_phase(priv, RCAR_BUS_PHASE_ADDR);
+ rcar_i2c_irq_mask(priv, RCAR_IRQ_OPEN_FOR_SEND);
+
+ return 0;
+}
+
+#define rcar_i2c_send_restart(priv) rcar_i2c_status_bit_clear(priv, (MAT | MDE))
+#define rcar_i2c_recv_restart(priv) rcar_i2c_status_bit_clear(priv, (MAT | MDR))
+
+/*
+ * interrupt functions
+ */
+static int rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr)
+{
+ struct i2c_msg *msg = priv->msg;
+
+ /*
+ * FIXME
+ * sometimes, unknown interrupt happened.
+ * Do nothing
+ */
+ if (!(msr & MDE))
+ return 0;
+
+ /*
+ * If address transfer phase finished,
+ * goto data phase.
+ */
+ if (msr & MAT)
+ rcar_i2c_bus_phase(priv, RCAR_BUS_PHASE_DATA);
+
+ if (priv->pos < msg->len) {
+ /*
+ * Prepare next data to ICRXTX register.
+ * This data will go to _SHIFT_ register.
+ *
+ * *
+ * [ICRXTX] -> [SHIFT] -> [I2C bus]
+ */
+ rcar_i2c_write(priv, ICRXTX, msg->buf[priv->pos]);
+ priv->pos++;
+
+ } else {
+ /*
+ * The last data was pushed to ICRXTX on _PREV_ empty irq.
+ * It is on _SHIFT_ register, and will sent to I2C bus.
+ *
+ * *
+ * [ICRXTX] -> [SHIFT] -> [I2C bus]
+ */
+
+ if (priv->flags & ID_LAST_MSG)
+ /*
+ * If current msg is the _LAST_ msg,
+ * prepare stop condition here.
+ * ID_DONE will be set on STOP irq.
+ */
+ rcar_i2c_bus_phase(priv, RCAR_BUS_PHASE_STOP);
+ else
+ /*
+ * If current msg is _NOT_ last msg,
+ * it doesn't call stop phase.
+ * thus, there is no STOP irq.
+ * return ID_DONE here.
+ */
+ return ID_DONE;
+ }
+
+ rcar_i2c_send_restart(priv);
+
+ return 0;
+}
+
+static int rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr)
+{
+ struct i2c_msg *msg = priv->msg;
+
+ /*
+ * FIXME
+ * sometimes, unknown interrupt happened.
+ * Do nothing
+ */
+ if (!(msr & MDR))
+ return 0;
+
+ if (msr & MAT) {
+ /*
+ * Address transfer phase finished,
+ * but, there is no data at this point.
+ * Do nothing.
+ */
+ } else if (priv->pos < msg->len) {
+ /*
+ * get received data
+ */
+ msg->buf[priv->pos] = rcar_i2c_read(priv, ICRXTX);
+ priv->pos++;
+ }
+
+ /*
+ * If next received data is the _LAST_,
+ * go to STOP phase,
+ * otherwise, go to DATA phase.
+ */
+ if (priv->pos + 1 >= msg->len)
+ rcar_i2c_bus_phase(priv, RCAR_BUS_PHASE_STOP);
+ else
+ rcar_i2c_bus_phase(priv, RCAR_BUS_PHASE_DATA);
+
+ rcar_i2c_recv_restart(priv);
+
+ return 0;
+}
+
+static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
+{
+ struct rcar_i2c_priv *priv = ptr;
+ struct device *dev = rcar_i2c_priv_to_dev(priv);
+ u32 msr;
+
+ /*-------------- spin lock -----------------*/
+ spin_lock(&priv->lock);
+
+ msr = rcar_i2c_status_get(priv);
+
+ /*
+ * Arbitration lost
+ */
+ if (msr & MAL) {
+ /*
+ * CAUTION
+ *
+ * When arbitration lost, device become _slave_ mode.
+ */
+ dev_dbg(dev, "Arbitration Lost\n");
+ rcar_i2c_flags_set(priv, (ID_DONE | ID_ARBLOST));
+ goto out;
+ }
+
+ /*
+ * Stop
+ */
+ if (msr & MST) {
+ dev_dbg(dev, "Stop\n");
+ rcar_i2c_flags_set(priv, ID_DONE);
+ goto out;
+ }
+
+ /*
+ * Nack
+ */
+ if (msr & MNR) {
+ dev_dbg(dev, "Nack\n");
+
+ /* go to stop phase */
+ rcar_i2c_bus_phase(priv, RCAR_BUS_PHASE_STOP);
+ rcar_i2c_irq_mask(priv, RCAR_IRQ_OPEN_FOR_STOP);
+ rcar_i2c_flags_set(priv, ID_NACK);
+ goto out;
+ }
+
+ /*
+ * recv/send
+ */
+ if (rcar_i2c_is_recv(priv))
+ rcar_i2c_flags_set(priv, rcar_i2c_irq_recv(priv, msr));
+ else
+ rcar_i2c_flags_set(priv, rcar_i2c_irq_send(priv, msr));
+
+out:
+ if (rcar_i2c_flags_has(priv, ID_DONE)) {
+ rcar_i2c_irq_mask(priv, RCAR_IRQ_CLOSE);
+ rcar_i2c_status_clear(priv);
+ wake_up(&priv->wait);
+ }
+
+ spin_unlock(&priv->lock);
+ /*-------------- spin unlock -----------------*/
+
+ return IRQ_HANDLED;
+}
+
+static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
+ struct i2c_msg *msgs,
+ int num)
+{
+ struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
+ struct device *dev = rcar_i2c_priv_to_dev(priv);
+ unsigned long flags;
+ int i, ret, timeout;
+
+ pm_runtime_get_sync(dev);
+
+ /*-------------- spin lock -----------------*/
+ spin_lock_irqsave(&priv->lock, flags);
+
+ rcar_i2c_init(priv);
+ rcar_i2c_clock_start(priv);
+
+ spin_unlock_irqrestore(&priv->lock, flags);
+ /*-------------- spin unlock -----------------*/
+
+ ret = -EINVAL;
+ for (i = 0; i < num; i++) {
+ /*-------------- spin lock -----------------*/
+ spin_lock_irqsave(&priv->lock, flags);
+
+ /* init each data */
+ priv->msg = &msgs[i];
+ priv->pos = 0;
+ priv->flags = 0;
+ if (priv->msg == &msgs[num - 1])
+ rcar_i2c_flags_set(priv, ID_LAST_MSG);
+
+ /* start send/recv */
+ if (rcar_i2c_is_recv(priv))
+ ret = rcar_i2c_recv(priv);
+ else
+ ret = rcar_i2c_send(priv);
+
+ spin_unlock_irqrestore(&priv->lock, flags);
+ /*-------------- spin unlock -----------------*/
+
+ if (ret < 0)
+ break;
+
+ /*
+ * wait result
+ */
+ timeout = wait_event_timeout(priv->wait,
+ rcar_i2c_flags_has(priv, ID_DONE),
+ 5 * HZ);
+ if (!timeout) {
+ ret = -ETIMEDOUT;
+ break;
+ }
+
+ /*
+ * error handling
+ */
+ if (rcar_i2c_flags_has(priv, ID_NACK)) {
+ ret = -EREMOTEIO;
+ break;
+ }
+
+ if (rcar_i2c_flags_has(priv, ID_ARBLOST)) {
+ ret = -EAGAIN;
+ break;
+ }
+
+ if (rcar_i2c_flags_has(priv, ID_IOERROR)) {
+ ret = -EIO;
+ break;
+ }
+
+ ret = i + 1; /* The number of transfer */
+ }
+
+ pm_runtime_put(dev);
+
+ if (ret < 0)
+ dev_err(dev, "error %d : %x\n", ret, priv->flags);
+
+ return ret;
+}
+
+static u32 rcar_i2c_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm rcar_i2c_algo = {
+ .master_xfer = rcar_i2c_master_xfer,
+ .functionality = rcar_i2c_func,
+};
+
+static int __devinit rcar_i2c_probe(struct platform_device *pdev)
+{
+ struct i2c_rcar_platform_data *pdata = pdev->dev.platform_data;
+ struct rcar_i2c_priv *priv;
+ struct i2c_adapter *adap;
+ struct resource *res;
+ struct device *dev = &pdev->dev;
+ u32 bus_speed;
+ int ret;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(dev, "no mmio resources\n");
+ return -ENODEV;
+ }
+
+ priv = devm_kzalloc(dev, sizeof(struct rcar_i2c_priv), GFP_KERNEL);
+ if (!priv) {
+ dev_err(dev, "no mem for private data\n");
+ return -ENOMEM;
+ }
+
+ bus_speed = 100000; /* default 100 kHz */
+ if (pdata && pdata->bus_speed)
+ bus_speed = pdata->bus_speed;
+ ret = rcar_i2c_clock_calculate(priv, bus_speed, dev);
+ if (ret < 0)
+ return ret;
+
+ priv->io = devm_ioremap(dev, res->start, resource_size(res));
+ if (!priv->io) {
+ dev_err(dev, "cannot ioremap\n");
+ return -ENODEV;
+ }
+
+ priv->irq = platform_get_irq(pdev, 0);
+ init_waitqueue_head(&priv->wait);
+ spin_lock_init(&priv->lock);
+
+ adap = &priv->adap;
+ adap->nr = pdev->id;
+ adap->algo = &rcar_i2c_algo;
+ adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+ adap->retries = 3;
+ adap->dev.parent = dev;
+ i2c_set_adapdata(adap, priv);
+ strlcpy(adap->name, pdev->name, sizeof(adap->name));
+
+ ret = devm_request_irq(dev, priv->irq, rcar_i2c_irq, 0,
+ dev_name(dev), priv);
+ if (ret < 0) {
+ dev_err(dev, "cannot get irq %d\n", priv->irq);
+ return ret;
+ }
+
+ ret = i2c_add_numbered_adapter(adap);
+ if (ret < 0) {
+ dev_err(dev, "reg adap failed: %d\n", ret);
+ return ret;
+ }
+
+ pm_runtime_enable(dev);
+ platform_set_drvdata(pdev, priv);
+
+ dev_info(dev, "probed\n");
+
+ return 0;
+}
+
+static int __devexit rcar_i2c_remove(struct platform_device *pdev)
+{
+ struct rcar_i2c_priv *priv = platform_get_drvdata(pdev);
+ struct device *dev = &pdev->dev;
+
+ i2c_del_adapter(&priv->adap);
+ pm_runtime_disable(dev);
+
+ return 0;
+}
+
+static struct platform_driver rcar_i2c_drv = {
+ .driver = {
+ .name = "i2c-rcar",
+ .owner = THIS_MODULE,
+ },
+ .probe = rcar_i2c_probe,
+ .remove = __devexit_p(rcar_i2c_remove),
+};
+
+module_platform_driver(rcar_i2c_drv);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Renesas R-Car I2C bus driver");
+MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");
generated by cgit v1.2.3 (git 2.0.4) at 2024-11-02 00:27:16 +0000