summaryrefslogtreecommitdiffstats
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.c319
1 files changed, 144 insertions, 175 deletions
diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 599c0d7bd906..1abeadc8ab79 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -1,7 +1,8 @@
/*
* Driver for the Renesas RCar I2C unit
*
- * Copyright (C) 2014 Wolfram Sang <wsa@sang-engineering.com>
+ * Copyright (C) 2014-15 Wolfram Sang <wsa@sang-engineering.com>
+ * Copyright (C) 2011-2015 Renesas Electronics Corporation
*
* Copyright (C) 2012-14 Renesas Solutions Corp.
* Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
@@ -9,9 +10,6 @@
* 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; version 2 of the License.
@@ -33,7 +31,6 @@
#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 */
@@ -84,6 +81,7 @@
#define RCAR_BUS_PHASE_START (MDBS | MIE | ESG)
#define RCAR_BUS_PHASE_DATA (MDBS | MIE)
+#define RCAR_BUS_MASK_DATA (~(ESG | FSB) & 0xFF)
#define RCAR_BUS_PHASE_STOP (MDBS | MIE | FSB)
#define RCAR_IRQ_SEND (MNR | MAL | MST | MAT | MDE)
@@ -94,10 +92,13 @@
#define RCAR_IRQ_ACK_RECV (~(MAT | MDR) & 0xFF)
#define ID_LAST_MSG (1 << 0)
-#define ID_IOERROR (1 << 1)
+#define ID_FIRST_MSG (1 << 1)
#define ID_DONE (1 << 2)
#define ID_ARBLOST (1 << 3)
#define ID_NACK (1 << 4)
+/* persistent flags */
+#define ID_P_PM_BLOCKED (1 << 31)
+#define ID_P_MASK ID_P_PM_BLOCKED
enum rcar_i2c_type {
I2C_RCAR_GEN1,
@@ -108,10 +109,10 @@ enum rcar_i2c_type {
struct rcar_i2c_priv {
void __iomem *io;
struct i2c_adapter adap;
- struct i2c_msg *msg;
+ struct i2c_msg *msg;
+ int msgs_left;
struct clk *clk;
- spinlock_t lock;
wait_queue_head_t wait;
int pos;
@@ -124,9 +125,6 @@ struct rcar_i2c_priv {
#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
@@ -144,9 +142,10 @@ static void rcar_i2c_init(struct rcar_i2c_priv *priv)
{
/* reset master mode */
rcar_i2c_write(priv, ICMIER, 0);
- rcar_i2c_write(priv, ICMCR, 0);
+ rcar_i2c_write(priv, ICMCR, MDBS);
rcar_i2c_write(priv, ICMSR, 0);
- rcar_i2c_write(priv, ICMAR, 0);
+ /* start clock */
+ rcar_i2c_write(priv, ICCCR, priv->icccr);
}
static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv)
@@ -163,15 +162,17 @@ static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv)
return -EBUSY;
}
-static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv,
- u32 bus_speed,
- struct device *dev)
+static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv, struct i2c_timings *t)
{
- u32 scgd, cdf;
- u32 round, ick;
- u32 scl;
- u32 cdf_width;
+ u32 scgd, cdf, round, ick, sum, scl, cdf_width;
unsigned long rate;
+ struct device *dev = rcar_i2c_priv_to_dev(priv);
+
+ /* Fall back to previously used values if not supplied */
+ t->bus_freq_hz = t->bus_freq_hz ?: 100000;
+ t->scl_fall_ns = t->scl_fall_ns ?: 35;
+ t->scl_rise_ns = t->scl_rise_ns ?: 200;
+ t->scl_int_delay_ns = t->scl_int_delay_ns ?: 50;
switch (priv->devtype) {
case I2C_RCAR_GEN1:
@@ -195,9 +196,9 @@ static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv,
* 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
+ * ticf : I2C SCL falling time
+ * tr : I2C SCL rising time
+ * intd : LSI internal delay
* clkp : peripheral_clk
* F[] : integer up-valuation
*/
@@ -213,12 +214,12 @@ static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv,
* 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]
+ * F[(ticf + tr + intd) * ick] with sum = (ticf + tr + intd)
+ * = F[sum * ick / 1000000000]
+ * = F[(ick / 1000000) * sum / 1000]
*/
- round = (ick + 500000) / 1000000 * 285;
+ sum = t->scl_fall_ns + t->scl_rise_ns + t->scl_int_delay_ns;
+ round = (ick + 500000) / 1000000 * sum;
round = (round + 500) / 1000;
/*
@@ -235,7 +236,7 @@ static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv,
*/
for (scgd = 0; scgd < 0x40; scgd++) {
scl = ick / (20 + (scgd * 8) + round);
- if (scl <= bus_speed)
+ if (scl <= t->bus_freq_hz)
goto scgd_find;
}
dev_err(dev, "it is impossible to calculate best SCL\n");
@@ -243,11 +244,9 @@ static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv,
scgd_find:
dev_dbg(dev, "clk %d/%d(%lu), round %u, CDF:0x%x, SCGD: 0x%x\n",
- scl, bus_speed, clk_get_rate(priv->clk), round, cdf, scgd);
+ scl, t->bus_freq_hz, clk_get_rate(priv->clk), round, cdf, scgd);
- /*
- * keep icccr value
- */
+ /* keep icccr value */
priv->icccr = scgd << cdf_width | cdf;
return 0;
@@ -257,33 +256,44 @@ static void rcar_i2c_prepare_msg(struct rcar_i2c_priv *priv)
{
int read = !!rcar_i2c_is_recv(priv);
+ priv->pos = 0;
+ if (priv->msgs_left == 1)
+ priv->flags |= ID_LAST_MSG;
+
rcar_i2c_write(priv, ICMAR, (priv->msg->addr << 1) | read);
- rcar_i2c_write(priv, ICMSR, 0);
- rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
+ /*
+ * We don't have a testcase but the HW engineers say that the write order
+ * of ICMSR and ICMCR depends on whether we issue START or REP_START. Since
+ * it didn't cause a drawback for me, let's rather be safe than sorry.
+ */
+ if (priv->flags & ID_FIRST_MSG) {
+ rcar_i2c_write(priv, ICMSR, 0);
+ rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
+ } else {
+ rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
+ rcar_i2c_write(priv, ICMSR, 0);
+ }
rcar_i2c_write(priv, ICMIER, read ? RCAR_IRQ_RECV : RCAR_IRQ_SEND);
}
+static void rcar_i2c_next_msg(struct rcar_i2c_priv *priv)
+{
+ priv->msg++;
+ priv->msgs_left--;
+ priv->flags &= ID_P_MASK;
+ rcar_i2c_prepare_msg(priv);
+}
+
/*
* interrupt functions
*/
-static int rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr)
+static void rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr)
{
struct i2c_msg *msg = priv->msg;
- /*
- * FIXME
- * sometimes, unknown interrupt happened.
- * Do nothing
- */
+ /* 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_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
+ return;
if (priv->pos < msg->len) {
/*
@@ -305,67 +315,50 @@ static int rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr)
* [ICRXTX] -> [SHIFT] -> [I2C bus]
*/
- if (priv->flags & ID_LAST_MSG)
+ 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_write(priv, ICMCR, 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;
+ } else {
+ rcar_i2c_next_msg(priv);
+ return;
+ }
}
rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_SEND);
-
- return 0;
}
-static int rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr)
+static void rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr)
{
struct i2c_msg *msg = priv->msg;
- /*
- * FIXME
- * sometimes, unknown interrupt happened.
- * Do nothing
- */
+ /* FIXME: sometimes, unknown interrupt happened. Do nothing */
if (!(msr & MDR))
- return 0;
+ return;
if (msr & MAT) {
- /*
- * Address transfer phase finished,
- * but, there is no data at this point.
- * Do nothing.
- */
+ /* Address transfer phase finished, but no data at this point. */
} else if (priv->pos < msg->len) {
- /*
- * get received data
- */
+ /* 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 next received data is the _LAST_, go to STOP phase. Might be
+ * overwritten by REP START when setting up a new msg. Not elegant
+ * but the only stable sequence for REP START I have found so far.
*/
if (priv->pos + 1 >= msg->len)
rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
- else
- rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
-
- rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_RECV);
- return 0;
+ if (priv->pos == msg->len && !(priv->flags & ID_LAST_MSG))
+ rcar_i2c_next_msg(priv);
+ else
+ rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_RECV);
}
static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
@@ -426,62 +419,57 @@ static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
{
struct rcar_i2c_priv *priv = ptr;
- irqreturn_t result = IRQ_HANDLED;
- u32 msr;
-
- /*-------------- spin lock -----------------*/
- spin_lock(&priv->lock);
+ u32 msr, val;
- if (rcar_i2c_slave_irq(priv))
- goto exit;
+ /* Clear START or STOP as soon as we can */
+ val = rcar_i2c_read(priv, ICMCR);
+ rcar_i2c_write(priv, ICMCR, val & RCAR_BUS_MASK_DATA);
msr = rcar_i2c_read(priv, ICMSR);
/* Only handle interrupts that are currently enabled */
msr &= rcar_i2c_read(priv, ICMIER);
if (!msr) {
- result = IRQ_NONE;
- goto exit;
+ if (rcar_i2c_slave_irq(priv))
+ return IRQ_HANDLED;
+
+ return IRQ_NONE;
}
/* Arbitration lost */
if (msr & MAL) {
- rcar_i2c_flags_set(priv, (ID_DONE | ID_ARBLOST));
+ priv->flags |= ID_DONE | ID_ARBLOST;
goto out;
}
/* Nack */
if (msr & MNR) {
- /* go to stop phase */
- rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
+ /* HW automatically sends STOP after received NACK */
rcar_i2c_write(priv, ICMIER, RCAR_IRQ_STOP);
- rcar_i2c_flags_set(priv, ID_NACK);
+ priv->flags |= ID_NACK;
goto out;
}
/* Stop */
if (msr & MST) {
- rcar_i2c_flags_set(priv, ID_DONE);
+ priv->msgs_left--; /* The last message also made it */
+ priv->flags |= ID_DONE;
goto out;
}
if (rcar_i2c_is_recv(priv))
- rcar_i2c_flags_set(priv, rcar_i2c_irq_recv(priv, msr));
+ rcar_i2c_irq_recv(priv, msr);
else
- rcar_i2c_flags_set(priv, rcar_i2c_irq_send(priv, msr));
+ rcar_i2c_irq_send(priv, msr);
out:
- if (rcar_i2c_flags_has(priv, ID_DONE)) {
+ if (priv->flags & ID_DONE) {
rcar_i2c_write(priv, ICMIER, 0);
rcar_i2c_write(priv, ICMSR, 0);
wake_up(&priv->wait);
}
-exit:
- spin_unlock(&priv->lock);
- /*-------------- spin unlock -----------------*/
-
- return result;
+ return IRQ_HANDLED;
}
static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
@@ -490,22 +478,11 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
{
struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
struct device *dev = rcar_i2c_priv_to_dev(priv);
- unsigned long flags;
int i, ret;
- long timeout;
+ long time_left;
pm_runtime_get_sync(dev);
- /*-------------- spin lock -----------------*/
- spin_lock_irqsave(&priv->lock, flags);
-
- rcar_i2c_init(priv);
- /* start clock */
- rcar_i2c_write(priv, ICCCR, priv->icccr);
-
- spin_unlock_irqrestore(&priv->lock, flags);
- /*-------------- spin unlock -----------------*/
-
ret = rcar_i2c_bus_barrier(priv);
if (ret < 0)
goto out;
@@ -514,48 +491,27 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
/* This HW can't send STOP after address phase */
if (msgs[i].len == 0) {
ret = -EOPNOTSUPP;
- break;
- }
-
- /*-------------- spin lock -----------------*/
- spin_lock_irqsave(&priv->lock, flags);
-
- /* init each data */
- priv->msg = &msgs[i];
- priv->pos = 0;
- priv->flags = 0;
- if (i == num - 1)
- rcar_i2c_flags_set(priv, ID_LAST_MSG);
-
- rcar_i2c_prepare_msg(priv);
-
- spin_unlock_irqrestore(&priv->lock, flags);
- /*-------------- spin unlock -----------------*/
-
- timeout = wait_event_timeout(priv->wait,
- rcar_i2c_flags_has(priv, ID_DONE),
- adap->timeout);
- if (!timeout) {
- ret = -ETIMEDOUT;
- break;
- }
-
- if (rcar_i2c_flags_has(priv, ID_NACK)) {
- ret = -ENXIO;
- break;
- }
-
- if (rcar_i2c_flags_has(priv, ID_ARBLOST)) {
- ret = -EAGAIN;
- break;
- }
-
- if (rcar_i2c_flags_has(priv, ID_IOERROR)) {
- ret = -EIO;
- break;
+ goto out;
}
+ }
- ret = i + 1; /* The number of transfer */
+ /* init first message */
+ priv->msg = msgs;
+ priv->msgs_left = num;
+ priv->flags = (priv->flags & ID_P_MASK) | ID_FIRST_MSG;
+ rcar_i2c_prepare_msg(priv);
+
+ time_left = wait_event_timeout(priv->wait, priv->flags & ID_DONE,
+ num * adap->timeout);
+ if (!time_left) {
+ rcar_i2c_init(priv);
+ ret = -ETIMEDOUT;
+ } else if (priv->flags & ID_NACK) {
+ ret = -ENXIO;
+ } else if (priv->flags & ID_ARBLOST) {
+ ret = -EAGAIN;
+ } else {
+ ret = num - priv->msgs_left; /* The number of transfer */
}
out:
pm_runtime_put(dev);
@@ -637,7 +593,7 @@ static int rcar_i2c_probe(struct platform_device *pdev)
struct i2c_adapter *adap;
struct resource *res;
struct device *dev = &pdev->dev;
- u32 bus_speed;
+ struct i2c_timings i2c_t;
int irq, ret;
priv = devm_kzalloc(dev, sizeof(struct rcar_i2c_priv), GFP_KERNEL);
@@ -650,23 +606,13 @@ static int rcar_i2c_probe(struct platform_device *pdev)
return PTR_ERR(priv->clk);
}
- bus_speed = 100000; /* default 100 kHz */
- of_property_read_u32(dev->of_node, "clock-frequency", &bus_speed);
-
- priv->devtype = (enum rcar_i2c_type)of_match_device(rcar_i2c_dt_ids, dev)->data;
-
- ret = rcar_i2c_clock_calculate(priv, bus_speed, dev);
- if (ret < 0)
- return ret;
-
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->io = devm_ioremap_resource(dev, res);
if (IS_ERR(priv->io))
return PTR_ERR(priv->io);
- irq = platform_get_irq(pdev, 0);
+ priv->devtype = (enum rcar_i2c_type)of_match_device(rcar_i2c_dt_ids, dev)->data;
init_waitqueue_head(&priv->wait);
- spin_lock_init(&priv->lock);
adap = &priv->adap;
adap->nr = pdev->id;
@@ -678,26 +624,47 @@ static int rcar_i2c_probe(struct platform_device *pdev)
i2c_set_adapdata(adap, priv);
strlcpy(adap->name, pdev->name, sizeof(adap->name));
- ret = devm_request_irq(dev, irq, rcar_i2c_irq, 0,
- dev_name(dev), priv);
+ i2c_parse_fw_timings(dev, &i2c_t, false);
+
+ pm_runtime_enable(dev);
+ pm_runtime_get_sync(dev);
+ ret = rcar_i2c_clock_calculate(priv, &i2c_t);
+ if (ret < 0)
+ goto out_pm_put;
+
+ rcar_i2c_init(priv);
+
+ /* Don't suspend when multi-master to keep arbitration working */
+ if (of_property_read_bool(dev->of_node, "multi-master"))
+ priv->flags |= ID_P_PM_BLOCKED;
+ else
+ pm_runtime_put(dev);
+
+
+ irq = platform_get_irq(pdev, 0);
+ ret = devm_request_irq(dev, irq, rcar_i2c_irq, 0, dev_name(dev), priv);
if (ret < 0) {
dev_err(dev, "cannot get irq %d\n", irq);
- return ret;
+ goto out_pm_disable;
}
- pm_runtime_enable(dev);
platform_set_drvdata(pdev, priv);
ret = i2c_add_numbered_adapter(adap);
if (ret < 0) {
dev_err(dev, "reg adap failed: %d\n", ret);
- pm_runtime_disable(dev);
- return ret;
+ goto out_pm_disable;
}
dev_info(dev, "probed\n");
return 0;
+
+ out_pm_put:
+ pm_runtime_put(dev);
+ out_pm_disable:
+ pm_runtime_disable(dev);
+ return ret;
}
static int rcar_i2c_remove(struct platform_device *pdev)
@@ -706,6 +673,8 @@ static int rcar_i2c_remove(struct platform_device *pdev)
struct device *dev = &pdev->dev;
i2c_del_adapter(&priv->adap);
+ if (priv->flags & ID_P_PM_BLOCKED)
+ pm_runtime_put(dev);
pm_runtime_disable(dev);
return 0;
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-18 06:40:01 +0100