[PATCH v2 1/2] lib/string_helpers: Add str_read_write() helper

[PATCH v2 1/2] lib/string_helpers: Add str_read_write() helper

[Andy Shevchenko]

Add str_read_write() helper to retun 'read' or 'write' string literal.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
v2: no changes
 include/linux/string_helpers.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index 4d72258d42fd..9e22cd78f3b8 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -126,4 +126,9 @@ static inline const char *str_enabled_disabled(bool v)
 	return v ? "enabled" : "disabled";
 }
 
+static inline const char *str_read_write(bool v)
+{
+	return v ? "read" : "write";
+}
+
 #endif
-- 
2.35.1

[PATCH v2 2/2] i2c: Introduce i2c_str_read_write() and make use of it

[Andy Shevchenko]

str_read_write() returns a string literal "read" or "write" based
on the value. It also allows to unify usage of a such in the kernel.

For i2c case introduce a wrapper that takes struct i2c_msg as parameter.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
v2: fixed typo in exynos5 (LKP)
 drivers/i2c/algos/i2c-algo-pca.c     | 3 +--
 drivers/i2c/algos/i2c-algo-pcf.c     | 3 +--
 drivers/i2c/busses/i2c-at91-master.c | 3 +--
 drivers/i2c/busses/i2c-exynos5.c     | 3 +--
 drivers/i2c/busses/i2c-hix5hd2.c     | 3 +--
 drivers/i2c/busses/i2c-img-scb.c     | 5 ++---
 drivers/i2c/busses/i2c-sh_mobile.c   | 3 +--
 drivers/i2c/busses/i2c-tiny-usb.c    | 6 ++----
 drivers/i2c/busses/i2c-viperboard.c  | 6 ++----
 drivers/i2c/i2c-core-base.c          | 3 +--
 include/linux/i2c.h                  | 7 +++++++
 11 files changed, 20 insertions(+), 25 deletions(-)

diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c
index 384af88e58ad..e5ac3eee7a99 100644
--- a/drivers/i2c/algos/i2c-algo-pca.c
+++ b/drivers/i2c/algos/i2c-algo-pca.c
@@ -119,8 +119,7 @@ static int pca_address(struct i2c_algo_pca_data *adap,
 	int sta = pca_get_con(adap);
 	int addr = i2c_8bit_addr_from_msg(msg);
 
-	DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n",
-	     msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr);
+	DEB2("=== SLAVE ADDRESS %#04x+%s=%#04x\n", msg->addr, i2c_str_read_write(msg), addr);
 
 	pca_outw(adap, I2C_PCA_DAT, addr);
 
diff --git a/drivers/i2c/algos/i2c-algo-pcf.c b/drivers/i2c/algos/i2c-algo-pcf.c
index 7a01f2687b4c..232224bbd670 100644
--- a/drivers/i2c/algos/i2c-algo-pcf.c
+++ b/drivers/i2c/algos/i2c-algo-pcf.c
@@ -316,8 +316,7 @@ static int pcf_xfer(struct i2c_adapter *i2c_adap,
 		pmsg = &msgs[i];
 
 		DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: Doing %s %d bytes to 0x%02x - %d of %d messages\n",
-		     pmsg->flags & I2C_M_RD ? "read" : "write",
-		     pmsg->len, pmsg->addr, i + 1, num);)
+		     i2c_str_read_write(pmsg), pmsg->len, pmsg->addr, i + 1, num);)
 
 		ret = pcf_doAddress(adap, pmsg);
 
diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c
index c0c35785a0dc..3761a6cb320f 100644
--- a/drivers/i2c/busses/i2c-at91-master.c
+++ b/drivers/i2c/busses/i2c-at91-master.c
@@ -523,8 +523,7 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev)
 	 * writing the corresponding bit into the Control Register.
 	 */
 
-	dev_dbg(dev->dev, "transfer: %s %zu bytes.\n",
-		(dev->msg->flags & I2C_M_RD) ? "read" : "write", dev->buf_len);
+	dev_dbg(dev->dev, "transfer: %s %zu bytes.\n", i2c_str_read_write(dev->msg), dev->buf_len);
 
 	reinit_completion(&dev->cmd_complete);
 	dev->transfer_status = 0;
diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c
index b812d1090c0f..4d3fe3cea688 100644
--- a/drivers/i2c/busses/i2c-exynos5.c
+++ b/drivers/i2c/busses/i2c-exynos5.c
@@ -744,8 +744,7 @@ static int exynos5_i2c_xfer_msg(struct exynos5_i2c *i2c,
 	if (ret < 0) {
 		exynos5_i2c_reset(i2c);
 		if (ret == -ETIMEDOUT)
-			dev_warn(i2c->dev, "%s timeout\n",
-				 (msgs->flags & I2C_M_RD) ? "rx" : "tx");
+			dev_warn(i2c->dev, "%s timeout\n", i2c_str_read_write(msgs));
 	}
 
 	/* Return the state as in interrupt routine */
diff --git a/drivers/i2c/busses/i2c-hix5hd2.c b/drivers/i2c/busses/i2c-hix5hd2.c
index 61ae58f57047..fefa5db52138 100644
--- a/drivers/i2c/busses/i2c-hix5hd2.c
+++ b/drivers/i2c/busses/i2c-hix5hd2.c
@@ -332,8 +332,7 @@ static int hix5hd2_i2c_xfer_msg(struct hix5hd2_i2c_priv *priv,
 	if (timeout == 0) {
 		priv->state = HIX5I2C_STAT_RW_ERR;
 		priv->err = -ETIMEDOUT;
-		dev_warn(priv->dev, "%s timeout=%d\n",
-			 msgs->flags & I2C_M_RD ? "rx" : "tx",
+		dev_warn(priv->dev, "%s timeout=%d\n", i2c_str_read_write(msgs),
 			 priv->adap.timeout);
 	}
 	ret = priv->state;
diff --git a/drivers/i2c/busses/i2c-img-scb.c b/drivers/i2c/busses/i2c-img-scb.c
index 8e987945ed45..772443059f49 100644
--- a/drivers/i2c/busses/i2c-img-scb.c
+++ b/drivers/i2c/busses/i2c-img-scb.c
@@ -950,9 +950,8 @@ static irqreturn_t img_i2c_isr(int irq, void *dev_id)
 			    INT_FIFO_EMPTY |
 			    INT_FIFO_FULL))) {
 		dev_crit(i2c->adap.dev.parent,
-			 "fatal: clock low timeout occurred %s addr 0x%02x\n",
-			 (i2c->msg.flags & I2C_M_RD) ? "reading" : "writing",
-			 i2c->msg.addr);
+			 "fatal: clock low timeout occurred when %s addr 0x%02x\n",
+			 i2c_str_read_write(&i2c->msg), i2c->msg.addr);
 		hret = ISR_FATAL(EIO);
 		goto out;
 	}
diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index 72f024a0c363..2b569403ce71 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -409,8 +409,7 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
 	pd->sr |= sr; /* remember state */
 
 	dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
-	       (pd->msg->flags & I2C_M_RD) ? "read" : "write",
-	       pd->pos, pd->msg->len);
+		i2c_str_read_write(pd->msg), pd->pos, pd->msg->len);
 
 	/* Kick off TxDMA after preface was done */
 	if (pd->dma_direction == DMA_TO_DEVICE && pd->pos == 0)
diff --git a/drivers/i2c/busses/i2c-tiny-usb.c b/drivers/i2c/busses/i2c-tiny-usb.c
index 7279ca0eaa2d..74a435d7c308 100644
--- a/drivers/i2c/busses/i2c-tiny-usb.c
+++ b/drivers/i2c/busses/i2c-tiny-usb.c
@@ -71,10 +71,8 @@ static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
 
 		pmsg = &msgs[i];
 
-		dev_dbg(&adapter->dev,
-			"  %d: %s (flags %d) %d bytes to 0x%02x\n",
-			i, pmsg->flags & I2C_M_RD ? "read" : "write",
-			pmsg->flags, pmsg->len, pmsg->addr);
+		dev_dbg(&adapter->dev, "  %d: %s (flags %d) %d bytes to 0x%02x\n",
+			i, i2c_str_read_write(pmsg), pmsg->flags, pmsg->len, pmsg->addr);
 
 		/* and directly send the message */
 		if (pmsg->flags & I2C_M_RD) {
diff --git a/drivers/i2c/busses/i2c-viperboard.c b/drivers/i2c/busses/i2c-viperboard.c
index 8b5322c3bce0..dec12e904aca 100644
--- a/drivers/i2c/busses/i2c-viperboard.c
+++ b/drivers/i2c/busses/i2c-viperboard.c
@@ -278,10 +278,8 @@ static int vprbrd_i2c_xfer(struct i2c_adapter *i2c, struct i2c_msg *msgs,
 	for (i = 0 ; i < num ; i++) {
 		pmsg = &msgs[i];
 
-		dev_dbg(&i2c->dev,
-			"  %d: %s (flags %d) %d bytes to 0x%02x\n",
-			i, pmsg->flags & I2C_M_RD ? "read" : "write",
-			pmsg->flags, pmsg->len, pmsg->addr);
+		dev_dbg(&i2c->dev, "  %d: %s (flags %d) %d bytes to 0x%02x\n",
+			i, i2c_str_read_write(pmsg), pmsg->flags, pmsg->len, pmsg->addr);
 
 		mutex_lock(&vb->lock);
 		/* directly send the message */
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 94c0663a39a6..9811bb44a2e0 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -2004,8 +2004,7 @@ module_exit(i2c_exit);
 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
 {
 	dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
-			    err_msg, msg->addr, msg->len,
-			    msg->flags & I2C_M_RD ? "read" : "write");
+			    err_msg, msg->addr, msg->len, i2c_str_read_write(msg));
 	return -EOPNOTSUPP;
 }
 
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index fbda5ada2afc..3cfaad39cc24 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -20,7 +20,9 @@
 #include <linux/rtmutex.h>
 #include <linux/irqdomain.h>		/* for Host Notify IRQ */
 #include <linux/of.h>		/* for struct device_node */
+#include <linux/string_helpers.h>	/* for str_read_write() */
 #include <linux/swab.h>		/* for swab16 */
+
 #include <uapi/linux/i2c.h>
 
 extern struct bus_type i2c_bus_type;
@@ -934,6 +936,11 @@ static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg)
 	return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0);
 }
 
+static inline const char *i2c_str_read_write(const struct i2c_msg *msg)
+{
+	return str_read_write(msg->flags & I2C_M_RD);
+}
+
 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold);
 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred);
 
-- 
2.35.1

Re: [PATCH v2 2/2] i2c: Introduce i2c_str_read_write() and make use of it

[Wolfram Sang]

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Hi Andy,

On Sun, Jul 03, 2022 at 06:42:32PM +0300, Andy Shevchenko wrote:
> str_read_write() returns a string literal "read" or "write" based
> on the value. It also allows to unify usage of a such in the kernel.
> 
> For i2c case introduce a wrapper that takes struct i2c_msg as parameter.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

To be honest, I don't think this series is very useful. Most of the
converted strings here are debug printouts which could rather be removed
because we have a tracepoint for i2c_transfer (which is the preferred
unification). The warnings printed on timeouts are plain wrong, because
timeouts can happen and need to be handled by the client driver. And the
change in the I2C core is not worth the hazzle IMHO.

Happy hacking,

   Wolfram

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Re: [PATCH v2 2/2] i2c: Introduce i2c_str_read_write() and make use of it

[Andy Shevchenko]

On Wed, Jul 06, 2022 at 03:06:42PM +0200, Wolfram Sang wrote:
> On Sun, Jul 03, 2022 at 06:42:32PM +0300, Andy Shevchenko wrote:
> > str_read_write() returns a string literal "read" or "write" based
> > on the value. It also allows to unify usage of a such in the kernel.
> > 
> > For i2c case introduce a wrapper that takes struct i2c_msg as parameter.
> > 
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> 
> To be honest, I don't think this series is very useful. Most of the
> converted strings here are debug printouts which could rather be removed
> because we have a tracepoint for i2c_transfer (which is the preferred
> unification). 

OK.

> The warnings printed on timeouts are plain wrong, because
> timeouts can happen and need to be handled by the client driver.

OK

> And the
> change in the I2C core is not worth the hazzle IMHO.

OK

Just noticed yet another (but not in the category of the above) debug message
[1]. Would it be acceptable to use patch 1 from this series and its use in (a
completely new) patch 2?

[1]: i2c-scmi.c:

	dev_dbg(&adap->dev, "access size: %d %s\n", size,
                (read_write) ? "READ" : "WRITE");

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 2/2] i2c: Introduce i2c_str_read_write() and make use of it

[Wolfram Sang]

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> Just noticed yet another (but not in the category of the above) debug message
> [1]. Would it be acceptable to use patch 1 from this series and its use in (a
> completely new) patch 2?

Well, it falls into the first category because we also have a tracepoint
for smbus_xfer :)


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Re: [PATCH v2 2/2] i2c: Introduce i2c_str_read_write() and make use of it

[Andy Shevchenko]

On Fri, Jul 8, 2022 at 2:07 PM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
>
>
> > Just noticed yet another (but not in the category of the above) debug message
> > [1]. Would it be acceptable to use patch 1 from this series and its use in (a
> > completely new) patch 2?
>
> Well, it falls into the first category because we also have a tracepoint
> for smbus_xfer :)

Ah, indeed.

Okay, let me find another subsystem where this will be more useful. Do
yuo have any wiki page about TODO in i2c subsys for kernel newbies (it
would be good task to add)?


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 2/2] i2c: Introduce i2c_str_read_write() and make use of it

[Wolfram Sang]

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> Okay, let me find another subsystem where this will be more useful. Do

Yes :)

> yuo have any wiki page about TODO in i2c subsys for kernel newbies (it
> would be good task to add)?

There is https://i2c.wiki.kernel.org/index.php/Main_Page but it is not
kept up to date. Do you mean "cleaning drivers from dbg messages"?


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Re: [PATCH v2 2/2] i2c: Introduce i2c_str_read_write() and make use of it

[Andy Shevchenko]

On Sat, Jul 9, 2022 at 6:06 PM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
>
> > Okay, let me find another subsystem where this will be more useful. Do
>
> Yes :)
>
> > yuo have any wiki page about TODO in i2c subsys for kernel newbies (it
> > would be good task to add)?
>
> There is https://i2c.wiki.kernel.org/index.php/Main_Page but it is not
> kept up to date. Do you mean "cleaning drivers from dbg messages"?

Yes.


-- 
With Best Regards,
Andy Shevchenko