From e2474541032db65d02bf88b6a8c2f954654b443f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
Date: Mon, 3 Oct 2016 22:06:08 +0200
Subject: [PATCH 31155/39886] i2c: bcm2835: Fix hang for writing messages
larger than 16 bytes
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Writing messages larger than the FIFO size results in a hang, rendering
the machine unusable. This is because the RXD status flag is set on the
first interrupt which results in bcm2835_drain_rxfifo() stealing bytes
from the buffer. The controller continues to trigger interrupts waiting
for the missing bytes, but bcm2835_fill_txfifo() has none to give.
In this situation wait_for_completion_timeout() apparently is unable to
stop the madness.
The BCM2835 ARM Peripherals datasheet has this to say about the flags:
TXD: is set when the FIFO has space for at least one byte of data.
RXD: is set when the FIFO contains at least one byte of data.
TXW: is set during a write transfer and the FIFO is less than full.
RXR: is set during a read transfer and the FIFO is or more full.
Implementing the logic from the downstream i2c-bcm2708 driver solved
the hang problem.
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
---
drivers/i2c/busses/i2c-bcm2835.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
index d4f3239..f283b71 100644
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -64,6 +64,7 @@ struct bcm2835_i2c_dev {
int irq;
struct i2c_adapter adapter;
struct completion completion;
+ struct i2c_msg *curr_msg;
u32 msg_err;
u8 *msg_buf;
size_t msg_buf_remaining;
@@ -126,14 +127,13 @@ static irqreturn_t bcm2835_i2c_isr(int this_irq, void *data)
return IRQ_HANDLED;
}
- if (val & BCM2835_I2C_S_RXD) {
- bcm2835_drain_rxfifo(i2c_dev);
- if (!(val & BCM2835_I2C_S_DONE))
- return IRQ_HANDLED;
- }
-
if (val & BCM2835_I2C_S_DONE) {
- if (i2c_dev->msg_buf_remaining)
+ if (i2c_dev->curr_msg->flags & I2C_M_RD) {
+ bcm2835_drain_rxfifo(i2c_dev);
+ val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S);
+ }
+
+ if ((val & BCM2835_I2C_S_RXD) || i2c_dev->msg_buf_remaining)
i2c_dev->msg_err = BCM2835_I2C_S_LEN;
else
i2c_dev->msg_err = 0;
@@ -141,11 +141,16 @@ static irqreturn_t bcm2835_i2c_isr(int this_irq, void *data)
return IRQ_HANDLED;
}
- if (val & BCM2835_I2C_S_TXD) {
+ if (val & BCM2835_I2C_S_TXW) {
bcm2835_fill_txfifo(i2c_dev);
return IRQ_HANDLED;
}
+ if (val & BCM2835_I2C_S_RXR) {
+ bcm2835_drain_rxfifo(i2c_dev);
+ return IRQ_HANDLED;
+ }
+
return IRQ_NONE;
}
@@ -155,6 +160,7 @@ static int bcm2835_i2c_xfer_msg(struct bcm2835_i2c_dev *i2c_dev,
u32 c;
unsigned long time_left;
+ i2c_dev->curr_msg = msg;
i2c_dev->msg_buf = msg->buf;
i2c_dev->msg_buf_remaining = msg->len;
reinit_completion(&i2c_dev->completion);
--
2.9.3
From d4030d75c7cbb434b2a3e5f6af5065879d2615a5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
Date: Mon, 3 Oct 2016 22:06:09 +0200
Subject: [PATCH 31156/39886] i2c: bcm2835: Protect against unexpected TXW/RXR
interrupts
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
If an unexpected TXW or RXR interrupt occurs (msg_buf_remaining == 0),
the driver has no way to fill/drain the FIFO to stop the interrupts.
In this case the controller has to be disabled and the transfer
completed to avoid hang.
(CLKT | ERR) and DONE interrupts are completed in their own paths, and
the controller is disabled in the transfer function after completion.
Unite the code paths and do disabling inside the interrupt routine.
Clear interrupt status bits in the united completion path instead of
trying to do it on every interrupt which isn't necessary.
Only CLKT, ERR and DONE can be cleared that way.
Add the status value to the error value in case of TXW/RXR errors to
distinguish them from the other S_LEN error.
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
---
drivers/i2c/busses/i2c-bcm2835.c | 40 +++++++++++++++++++++++++++++++---------
1 file changed, 31 insertions(+), 9 deletions(-)
diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
index f283b71..d2ba1a4 100644
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -50,8 +50,6 @@
#define BCM2835_I2C_S_CLKT BIT(9)
#define BCM2835_I2C_S_LEN BIT(10) /* Fake bit for SW error reporting */
-#define BCM2835_I2C_BITMSK_S 0x03FF
-
#define BCM2835_I2C_CDIV_MIN 0x0002
#define BCM2835_I2C_CDIV_MAX 0xFFFE
@@ -111,20 +109,26 @@ static void bcm2835_drain_rxfifo(struct bcm2835_i2c_dev *i2c_dev)
}
}
+/*
+ * Note about I2C_C_CLEAR on error:
+ * The I2C_C_CLEAR on errors will take some time to resolve -- if you were in
+ * non-idle state and I2C_C_READ, it sets an abort_rx flag and runs through
+ * the state machine to send a NACK and a STOP. Since we're setting CLEAR
+ * without I2CEN, that NACK will be hanging around queued up for next time
+ * we start the engine.
+ */
+
static irqreturn_t bcm2835_i2c_isr(int this_irq, void *data)
{
struct bcm2835_i2c_dev *i2c_dev = data;
u32 val, err;
val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S);
- val &= BCM2835_I2C_BITMSK_S;
- bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_S, val);
err = val & (BCM2835_I2C_S_CLKT | BCM2835_I2C_S_ERR);
if (err) {
i2c_dev->msg_err = err;
- complete(&i2c_dev->completion);
- return IRQ_HANDLED;
+ goto complete;
}
if (val & BCM2835_I2C_S_DONE) {
@@ -137,21 +141,38 @@ static irqreturn_t bcm2835_i2c_isr(int this_irq, void *data)
i2c_dev->msg_err = BCM2835_I2C_S_LEN;
else
i2c_dev->msg_err = 0;
- complete(&i2c_dev->completion);
- return IRQ_HANDLED;
+ goto complete;
}
if (val & BCM2835_I2C_S_TXW) {
+ if (!i2c_dev->msg_buf_remaining) {
+ i2c_dev->msg_err = val | BCM2835_I2C_S_LEN;
+ goto complete;
+ }
+
bcm2835_fill_txfifo(i2c_dev);
return IRQ_HANDLED;
}
if (val & BCM2835_I2C_S_RXR) {
+ if (!i2c_dev->msg_buf_remaining) {
+ i2c_dev->msg_err = val | BCM2835_I2C_S_LEN;
+ goto complete;
+ }
+
bcm2835_drain_rxfifo(i2c_dev);
return IRQ_HANDLED;
}
return IRQ_NONE;
+
+complete:
+ bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, BCM2835_I2C_C_CLEAR);
+ bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_S, BCM2835_I2C_S_CLKT |
+ BCM2835_I2C_S_ERR | BCM2835_I2C_S_DONE);
+ complete(&i2c_dev->completion);
+
+ return IRQ_HANDLED;
}
static int bcm2835_i2c_xfer_msg(struct bcm2835_i2c_dev *i2c_dev,
@@ -181,8 +202,9 @@ static int bcm2835_i2c_xfer_msg(struct bcm2835_i2c_dev *i2c_dev,
time_left = wait_for_completion_timeout(&i2c_dev->completion,
BCM2835_I2C_TIMEOUT);
- bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, BCM2835_I2C_C_CLEAR);
if (!time_left) {
+ bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C,
+ BCM2835_I2C_C_CLEAR);
dev_err(i2c_dev->dev, "i2c transfer timed out\n");
return -ETIMEDOUT;
}
--
2.9.3
From 23c9540b3ad1d7473fe40df80074d0fb0bf04869 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
Date: Mon, 3 Oct 2016 22:06:10 +0200
Subject: [PATCH 31157/39886] i2c: bcm2835: Use dev_dbg logging on transfer
errors
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Writing to an AT24C32 generates on average 2x i2c transfer errors per
32-byte page write. Which amounts to a lot for a 4k write. This is due
to the fact that the chip doesn't respond during it's internal write
cycle when the at24 driver tries and retries the next write.
Only a handful drivers use dev_err() on transfer error, so switch to
dev_dbg() instead.
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
---
drivers/i2c/busses/i2c-bcm2835.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
index d2ba1a4..54d510a 100644
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -216,7 +216,7 @@ static int bcm2835_i2c_xfer_msg(struct bcm2835_i2c_dev *i2c_dev,
(msg->flags & I2C_M_IGNORE_NAK))
return 0;
- dev_err(i2c_dev->dev, "i2c transfer failed: %x\n", i2c_dev->msg_err);
+ dev_dbg(i2c_dev->dev, "i2c transfer failed: %x\n", i2c_dev->msg_err);
if (i2c_dev->msg_err & BCM2835_I2C_S_ERR)
return -EREMOTEIO;
--
2.9.3
From 8d2cc5cc6ee5c0fc48a96bb29af55fc700f66fdf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
Date: Mon, 3 Oct 2016 22:06:11 +0200
Subject: [PATCH 31158/39886] i2c: bcm2835: Can't support I2C_M_IGNORE_NAK
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
The controller can't support this flag, so remove it.
Documentation/i2c/i2c-protocol states that all of the message is sent:
I2C_M_IGNORE_NAK:
Normally message is interrupted immediately if there is [NA] from the
client. Setting this flag treats any [NA] as [A], and all of
message is sent.
>From the BCM2835 ARM Peripherals datasheet:
The ERR field is set when the slave fails to acknowledge either
its address or a data byte written to it.
So when the controller doesn't receive an ack, it sets ERR and raises
an interrupt. In other words, the whole message is not sent.
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
---
drivers/i2c/busses/i2c-bcm2835.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
index 54d510a..565ef69 100644
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -212,10 +212,6 @@ static int bcm2835_i2c_xfer_msg(struct bcm2835_i2c_dev *i2c_dev,
if (likely(!i2c_dev->msg_err))
return 0;
- if ((i2c_dev->msg_err & BCM2835_I2C_S_ERR) &&
- (msg->flags & I2C_M_IGNORE_NAK))
- return 0;
-
dev_dbg(i2c_dev->dev, "i2c transfer failed: %x\n", i2c_dev->msg_err);
if (i2c_dev->msg_err & BCM2835_I2C_S_ERR)
--
2.9.3
From ee05fea21b017b81a9477569b6a0c2d8e2946ac9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
Date: Mon, 3 Oct 2016 22:06:12 +0200
Subject: [PATCH 31159/39886] i2c: bcm2835: Add support for Repeated Start
Condition
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Documentation/i2c/i2c-protocol states that Combined transactions should
separate messages with a Start bit and end the whole transaction with a
Stop bit. This patch adds support for issuing only a Start between
messages instead of a Stop followed by a Start.
This implementation differs from downstream i2c-bcm2708 in 2 respects:
- it uses an interrupt to detect that the transfer is active instead
of using polling. There is no interrupt for Transfer Active, but by
not prefilling the FIFO it's possible to use the TXW interrupt.
- when resetting/disabling the controller between transfers it writes
CLEAR to the control register instead of just zero.
Using just zero gave many errors. This might be the reason why
downstream had to disable this feature and make it available with a
module parameter.
I have run thousands of transfers to a DS1307 (rtc), MMA8451 (accel)
and AT24C32 (eeprom) in parallel without problems.
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
---
drivers/i2c/busses/i2c-bcm2835.c | 101 ++++++++++++++++++++++++---------------
1 file changed, 63 insertions(+), 38 deletions(-)
diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
index 565ef69..241e08a 100644
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -63,6 +63,7 @@ struct bcm2835_i2c_dev {
struct i2c_adapter adapter;
struct completion completion;
struct i2c_msg *curr_msg;
+ int num_msgs;
u32 msg_err;
u8 *msg_buf;
size_t msg_buf_remaining;
@@ -110,6 +111,45 @@ static void bcm2835_drain_rxfifo(struct bcm2835_i2c_dev *i2c_dev)
}
/*
+ * Repeated Start Condition (Sr)
+ * The BCM2835 ARM Peripherals datasheet mentions a way to trigger a Sr when it
+ * talks about reading from a slave with 10 bit address. This is achieved by
+ * issuing a write, poll the I2CS.TA flag and wait for it to be set, and then
+ * issue a read.
+ * A comment in https://github.com/raspberrypi/linux/issues/254 shows how the
+ * firmware actually does it using polling and says that it's a workaround for
+ * a problem in the state machine.
+ * It turns out that it is possible to use the TXW interrupt to know when the
+ * transfer is active, provided the FIFO has not been prefilled.
+ */
+
+static void bcm2835_i2c_start_transfer(struct bcm2835_i2c_dev *i2c_dev)
+{
+ u32 c = BCM2835_I2C_C_ST | BCM2835_I2C_C_I2CEN;
+ struct i2c_msg *msg = i2c_dev->curr_msg;
+ bool last_msg = (i2c_dev->num_msgs == 1);
+
+ if (!i2c_dev->num_msgs)
+ return;
+
+ i2c_dev->num_msgs--;
+ i2c_dev->msg_buf = msg->buf;
+ i2c_dev->msg_buf_remaining = msg->len;
+
+ if (msg->flags & I2C_M_RD)
+ c |= BCM2835_I2C_C_READ | BCM2835_I2C_C_INTR;
+ else
+ c |= BCM2835_I2C_C_INTT;
+
+ if (last_msg)
+ c |= BCM2835_I2C_C_INTD;
+
+ bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_A, msg->addr);
+ bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_DLEN, msg->len);
+ bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, c);
+}
+
+/*
* Note about I2C_C_CLEAR on error:
* The I2C_C_CLEAR on errors will take some time to resolve -- if you were in
* non-idle state and I2C_C_READ, it sets an abort_rx flag and runs through
@@ -151,6 +191,12 @@ static irqreturn_t bcm2835_i2c_isr(int this_irq, void *data)
}
bcm2835_fill_txfifo(i2c_dev);
+
+ if (i2c_dev->num_msgs && !i2c_dev->msg_buf_remaining) {
+ i2c_dev->curr_msg++;
+ bcm2835_i2c_start_transfer(i2c_dev);
+ }
+
return IRQ_HANDLED;
}
@@ -175,30 +221,25 @@ static irqreturn_t bcm2835_i2c_isr(int this_irq, void *data)
return IRQ_HANDLED;
}
-static int bcm2835_i2c_xfer_msg(struct bcm2835_i2c_dev *i2c_dev,
- struct i2c_msg *msg)
+static int bcm2835_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
+ int num)
{
- u32 c;
+ struct bcm2835_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
unsigned long time_left;
+ int i;
- i2c_dev->curr_msg = msg;
- i2c_dev->msg_buf = msg->buf;
- i2c_dev->msg_buf_remaining = msg->len;
- reinit_completion(&i2c_dev->completion);
-
- bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, BCM2835_I2C_C_CLEAR);
+ for (i = 0; i < (num - 1); i++)
+ if (msgs[i].flags & I2C_M_RD) {
+ dev_warn_once(i2c_dev->dev,
+ "only one read message supported, has to be last\n");
+ return -EOPNOTSUPP;
+ }
- if (msg->flags & I2C_M_RD) {
- c = BCM2835_I2C_C_READ | BCM2835_I2C_C_INTR;
- } else {
- c = BCM2835_I2C_C_INTT;
- bcm2835_fill_txfifo(i2c_dev);
- }
- c |= BCM2835_I2C_C_ST | BCM2835_I2C_C_INTD | BCM2835_I2C_C_I2CEN;
+ i2c_dev->curr_msg = msgs;
+ i2c_dev->num_msgs = num;
+ reinit_completion(&i2c_dev->completion);
- bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_A, msg->addr);
- bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_DLEN, msg->len);
- bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, c);
+ bcm2835_i2c_start_transfer(i2c_dev);
time_left = wait_for_completion_timeout(&i2c_dev->completion,
BCM2835_I2C_TIMEOUT);
@@ -209,31 +250,15 @@ static int bcm2835_i2c_xfer_msg(struct bcm2835_i2c_dev *i2c_dev,
return -ETIMEDOUT;
}
- if (likely(!i2c_dev->msg_err))
- return 0;
+ if (!i2c_dev->msg_err)
+ return num;
dev_dbg(i2c_dev->dev, "i2c transfer failed: %x\n", i2c_dev->msg_err);
if (i2c_dev->msg_err & BCM2835_I2C_S_ERR)
return -EREMOTEIO;
- else
- return -EIO;
-}
-
-static int bcm2835_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
- int num)
-{
- struct bcm2835_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
- int i;
- int ret = 0;
-
- for (i = 0; i < num; i++) {
- ret = bcm2835_i2c_xfer_msg(i2c_dev, &msgs[i]);
- if (ret)
- break;
- }
- return ret ?: i;
+ return -EIO;
}
static u32 bcm2835_i2c_func(struct i2c_adapter *adap)
--
2.9.3
From e13e19e12f66401ce1e21ab491715835852babe7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
Date: Mon, 3 Oct 2016 22:06:13 +0200
Subject: [PATCH 31160/39886] i2c: bcm2835: Support i2c-dev ioctl I2C_TIMEOUT
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Use i2c_adapter->timeout for the completion timeout value. The core
default is 1 second.
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
---
drivers/i2c/busses/i2c-bcm2835.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
index 241e08a..d2085dd 100644
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -53,8 +53,6 @@
#define BCM2835_I2C_CDIV_MIN 0x0002
#define BCM2835_I2C_CDIV_MAX 0xFFFE
-#define BCM2835_I2C_TIMEOUT (msecs_to_jiffies(1000))
-
struct bcm2835_i2c_dev {
struct device *dev;
void __iomem *regs;
@@ -242,7 +240,7 @@ static int bcm2835_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
bcm2835_i2c_start_transfer(i2c_dev);
time_left = wait_for_completion_timeout(&i2c_dev->completion,
- BCM2835_I2C_TIMEOUT);
+ adap->timeout);
if (!time_left) {
bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C,
BCM2835_I2C_C_CLEAR);
--
2.9.3
From 9446f62e8e18057fceb179d947508df2f7253b26 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
Date: Mon, 3 Oct 2016 22:06:14 +0200
Subject: [PATCH 31161/39886] i2c: bcm2835: Add support for dynamic clock
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Support a dynamic clock by reading the frequency and setting the
divisor in the transfer function instead of during probe.
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
---
drivers/i2c/busses/i2c-bcm2835.c | 51 +++++++++++++++++++++++++---------------
1 file changed, 32 insertions(+), 19 deletions(-)
diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
index d2085dd..c3436f6 100644
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -58,6 +58,7 @@ struct bcm2835_i2c_dev {
void __iomem *regs;
struct clk *clk;
int irq;
+ u32 bus_clk_rate;
struct i2c_adapter adapter;
struct completion completion;
struct i2c_msg *curr_msg;
@@ -78,6 +79,30 @@ static inline u32 bcm2835_i2c_readl(struct bcm2835_i2c_dev *i2c_dev, u32 reg)
return readl(i2c_dev->regs + reg);
}
+static int bcm2835_i2c_set_divider(struct bcm2835_i2c_dev *i2c_dev)
+{
+ u32 divider;
+
+ divider = DIV_ROUND_UP(clk_get_rate(i2c_dev->clk),
+ i2c_dev->bus_clk_rate);
+ /*
+ * Per the datasheet, the register is always interpreted as an even
+ * number, by rounding down. In other words, the LSB is ignored. So,
+ * if the LSB is set, increment the divider to avoid any issue.
+ */
+ if (divider & 1)
+ divider++;
+ if ((divider < BCM2835_I2C_CDIV_MIN) ||
+ (divider > BCM2835_I2C_CDIV_MAX)) {
+ dev_err_ratelimited(i2c_dev->dev, "Invalid clock-frequency\n");
+ return -EINVAL;
+ }
+
+ bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_DIV, divider);
+
+ return 0;
+}
+
static void bcm2835_fill_txfifo(struct bcm2835_i2c_dev *i2c_dev)
{
u32 val;
@@ -224,7 +249,7 @@ static int bcm2835_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
{
struct bcm2835_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
unsigned long time_left;
- int i;
+ int i, ret;
for (i = 0; i < (num - 1); i++)
if (msgs[i].flags & I2C_M_RD) {
@@ -233,6 +258,10 @@ static int bcm2835_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
return -EOPNOTSUPP;
}
+ ret = bcm2835_i2c_set_divider(i2c_dev);
+ if (ret)
+ return ret;
+
i2c_dev->curr_msg = msgs;
i2c_dev->num_msgs = num;
reinit_completion(&i2c_dev->completion);
@@ -282,7 +311,6 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
{
struct bcm2835_i2c_dev *i2c_dev;
struct resource *mem, *irq;
- u32 bus_clk_rate, divider;
int ret;
struct i2c_adapter *adap;
@@ -306,27 +334,12 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
}
ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
- &bus_clk_rate);
+ &i2c_dev->bus_clk_rate);
if (ret < 0) {
dev_warn(&pdev->dev,
"Could not read clock-frequency property\n");
- bus_clk_rate = 100000;
- }
-
- divider = DIV_ROUND_UP(clk_get_rate(i2c_dev->clk), bus_clk_rate);
- /*
- * Per the datasheet, the register is always interpreted as an even
- * number, by rounding down. In other words, the LSB is ignored. So,
- * if the LSB is set, increment the divider to avoid any issue.
- */
- if (divider & 1)
- divider++;
- if ((divider < BCM2835_I2C_CDIV_MIN) ||
- (divider > BCM2835_I2C_CDIV_MAX)) {
- dev_err(&pdev->dev, "Invalid clock-frequency\n");
- return -ENODEV;
+ i2c_dev->bus_clk_rate = 100000;
}
- bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_DIV, divider);
irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (!irq) {
--
2.9.3
From f2a46926aba1f0c33944901d2420a6a887455ddc Mon Sep 17 00:00:00 2001
From: Boris Brezillon <boris.brezillon@free-electrons.com>
Date: Tue, 22 Nov 2016 12:45:28 -0800
Subject: [PATCH 08819/13183] clk: bcm2835: Fix ->fixed_divider of pllh_aux
There is no fixed divider on pllh_aux.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
drivers/clk/bcm/clk-bcm2835.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index 8c7763f..836d075 100644
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1596,7 +1596,7 @@ static const struct bcm2835_clk_desc clk_desc_array[] = {
.a2w_reg = A2W_PLLH_AUX,
.load_mask = CM_PLLH_LOADAUX,
.hold_mask = 0,
- .fixed_divider = 10),
+ .fixed_divider = 1),
[BCM2835_PLLH_PIX] = REGISTER_PLL_DIV(
.name = "pllh_pix",
.source_pll = "pllh",
--
2.9.3
commit 84c39b8b7d46883f7a7514c7d55909831aa846fd
Author: Arvind Yadav <arvind.yadav.cs@gmail.com>
Date: Wed Sep 21 23:03:57 2016 +0530
clocksource/drivers/bcm2835_timer: Unmap region obtained by of_iomap
Free memory mapping, if bcm2835_timer_init is not successful.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
diff --git a/drivers/clocksource/bcm2835_timer.c b/drivers/clocksource/bcm2835_timer.c
index e71acf2..f2f29d2 100644
--- a/drivers/clocksource/bcm2835_timer.c
+++ b/drivers/clocksource/bcm2835_timer.c
@@ -96,7 +96,7 @@ static int __init bcm2835_timer_init(struct device_node *node)
ret = of_property_read_u32(node, "clock-frequency", &freq);
if (ret) {
pr_err("Can't read clock-frequency");
- return ret;
+ goto err_iounmap;
}
system_clock = base + REG_COUNTER_LO;
@@ -108,13 +108,15 @@ static int __init bcm2835_timer_init(struct device_node *node)
irq = irq_of_parse_and_map(node, DEFAULT_TIMER);
if (irq <= 0) {
pr_err("Can't parse IRQ");
- return -EINVAL;
+ ret = -EINVAL;
+ goto err_iounmap;
}
timer = kzalloc(sizeof(*timer), GFP_KERNEL);
if (!timer) {
pr_err("Can't allocate timer struct\n");
- return -ENOMEM;
+ ret = -ENOMEM;
+ goto err_iounmap;
}
timer->control = base + REG_CONTROL;
@@ -133,7 +135,7 @@ static int __init bcm2835_timer_init(struct device_node *node)
ret = setup_irq(irq, &timer->act);
if (ret) {
pr_err("Can't set up timer IRQ\n");
- return ret;
+ goto err_iounmap;
}
clockevents_config_and_register(&timer->evt, freq, 0xf, 0xffffffff);
@@ -141,6 +143,10 @@ static int __init bcm2835_timer_init(struct device_node *node)
pr_info("bcm2835: system timer (irq = %d)\n", irq);
return 0;
+
+err_iounmap:
+ iounmap(base);
+ return ret;
}
CLOCKSOURCE_OF_DECLARE(bcm2835, "brcm,bcm2835-system-timer",
bcm2835_timer_init);
From 155e8b3b0ee320ae866b97dd31eba8a1f080a772 Mon Sep 17 00:00:00 2001
From: Boris Brezillon <boris.brezillon@free-electrons.com>
Date: Thu, 1 Dec 2016 22:00:19 +0100
Subject: [PATCH 11733/13183] clk: bcm: Support rate change propagation on
bcm2835 clocks
Some peripheral clocks, like the VEC (Video EnCoder) clock need to be set
to a precise rate (in our case 108MHz). With the current implementation,
where peripheral clocks are not allowed to forward rate change requests
to their parents, it is impossible to match this requirement unless the
bootloader has configured things correctly, or a specific rate has been
assigned through the DT (with the assigned-clk-rates property).
Add a new field to struct bcm2835_clock_data to specify which parent
clocks accept rate change propagation, and support set rate propagation
in bcm2835_clock_determine_rate().
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
drivers/clk/bcm/clk-bcm2835.c | 67 ++++++++++++++++++++++++++++++++++++++++---
1 file changed, 63 insertions(+), 4 deletions(-)
diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index 2acaa77..df96fe6 100644
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -436,6 +436,9 @@ struct bcm2835_clock_data {
const char *const *parents;
int num_mux_parents;
+ /* Bitmap encoding which parents accept rate change propagation. */
+ unsigned int set_rate_parent;
+
u32 ctl_reg;
u32 div_reg;
@@ -1017,10 +1020,60 @@ bcm2835_clk_is_pllc(struct clk_hw *hw)
return strncmp(clk_hw_get_name(hw), "pllc", 4) == 0;
}
+static unsigned long bcm2835_clock_choose_div_and_prate(struct clk_hw *hw,
+ int parent_idx,
+ unsigned long rate,
+ u32 *div,
+ unsigned long *prate)
+{
+ struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw);
+ struct bcm2835_cprman *cprman = clock->cprman;
+ const struct bcm2835_clock_data *data = clock->data;
+ unsigned long best_rate;
+ u32 curdiv, mindiv, maxdiv;
+ struct clk_hw *parent;
+
+ parent = clk_hw_get_parent_by_index(hw, parent_idx);
+
+ if (!(BIT(parent_idx) & data->set_rate_parent)) {
+ *prate = clk_hw_get_rate(parent);
+ *div = bcm2835_clock_choose_div(hw, rate, *prate, true);
+
+ return bcm2835_clock_rate_from_divisor(clock, *prate,
+ *div);
+ }
+
+ if (data->frac_bits)
+ dev_warn(cprman->dev,
+ "frac bits are not used when propagating rate change");
+
+ /* clamp to min divider of 2 if we're dealing with a mash clock */
+ mindiv = data->is_mash_clock ? 2 : 1;
+ maxdiv = BIT(data->int_bits) - 1;
+
+ /* TODO: Be smart, and only test a subset of the available divisors. */
+ for (curdiv = mindiv; curdiv <= maxdiv; curdiv++) {
+ unsigned long tmp_rate;
+
+ tmp_rate = clk_hw_round_rate(parent, rate * curdiv);
+ tmp_rate /= curdiv;
+ if (curdiv == mindiv ||
+ (tmp_rate > best_rate && tmp_rate <= rate))
+ best_rate = tmp_rate;
+
+ if (best_rate == rate)
+ break;
+ }
+
+ *div = curdiv << CM_DIV_FRAC_BITS;
+ *prate = curdiv * best_rate;
+
+ return best_rate;
+}
+
static int bcm2835_clock_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
- struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw);
struct clk_hw *parent, *best_parent = NULL;
bool current_parent_is_pllc;
unsigned long rate, best_rate = 0;
@@ -1048,9 +1101,8 @@ static int bcm2835_clock_determine_rate(struct clk_hw *hw,
if (bcm2835_clk_is_pllc(parent) && !current_parent_is_pllc)
continue;
- prate = clk_hw_get_rate(parent);
- div = bcm2835_clock_choose_div(hw, req->rate, prate, true);
- rate = bcm2835_clock_rate_from_divisor(clock, prate, div);
+ rate = bcm2835_clock_choose_div_and_prate(hw, i, req->rate,
+ &div, &prate);
if (rate > best_rate && rate <= req->rate) {
best_parent = parent;
best_prate = prate;
@@ -1262,6 +1314,13 @@ static struct clk_hw *bcm2835_register_clock(struct bcm2835_cprman *cprman,
init.name = data->name;
init.flags = data->flags | CLK_IGNORE_UNUSED;
+ /*
+ * Pass the CLK_SET_RATE_PARENT flag if we are allowed to propagate
+ * rate changes on at least of the parents.
+ */
+ if (data->set_rate_parent)
+ init.flags |= CLK_SET_RATE_PARENT;
+
if (data->is_vpu_clock) {
init.ops = &bcm2835_vpu_clock_clk_ops;
} else {
--
2.9.3
From d86d46af84855403c00018be1c3e7bc190f2a6cd Mon Sep 17 00:00:00 2001
From: Boris Brezillon <boris.brezillon@free-electrons.com>
Date: Thu, 1 Dec 2016 22:00:20 +0100
Subject: [PATCH 11734/13183] clk: bcm: Allow rate change propagation to
PLLH_AUX on VEC clock
The VEC clock requires needs to be set at exactly 108MHz. Allow rate
change propagation on PLLH_AUX to match this requirement wihtout
impacting other IPs (PLLH is currently only used by the HDMI encoder,
which cannot be enabled when the VEC encoder is enabled).
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
drivers/clk/bcm/clk-bcm2835.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index df96fe6..eaf82f4 100644
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1861,7 +1861,12 @@ static const struct bcm2835_clk_desc clk_desc_array[] = {
.ctl_reg = CM_VECCTL,
.div_reg = CM_VECDIV,
.int_bits = 4,
- .frac_bits = 0),
+ .frac_bits = 0,
+ /*
+ * Allow rate change propagation only on PLLH_AUX which is
+ * assigned index 7 in the parent array.
+ */
+ .set_rate_parent = BIT(7)),
/* dsi clocks */
[BCM2835_CLOCK_DSI0E] = REGISTER_PER_CLK(
--
2.9.3
From 2aab7a2055a1705c9e30920d95a596226999eb21 Mon Sep 17 00:00:00 2001
From: Boris Brezillon <boris.brezillon@free-electrons.com>
Date: Mon, 12 Dec 2016 09:00:53 +0100
Subject: [PATCH 12092/13183] clk: bcm: Fix 'maybe-uninitialized' warning in
bcm2835_clock_choose_div_and_prate()
best_rate is reported as potentially uninitialized by gcc.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Fixes: 155e8b3b0ee3 ("clk: bcm: Support rate change propagation on bcm2835 clocks")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
drivers/clk/bcm/clk-bcm2835.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index eaf82f4..0d14409 100644
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1029,7 +1029,7 @@ static unsigned long bcm2835_clock_choose_div_and_prate(struct clk_hw *hw,
struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw);
struct bcm2835_cprman *cprman = clock->cprman;
const struct bcm2835_clock_data *data = clock->data;
- unsigned long best_rate;
+ unsigned long best_rate = 0;
u32 curdiv, mindiv, maxdiv;
struct clk_hw *parent;
--
2.9.3