Re: [PATCH v2] input: synaptics-rmi4 - use snprintf instead of sprintf in rmi_i2c.c

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Wed, Jan 08, 2014 at 05:18:39PM -0800, Christopher Heiny wrote:
> This is a trivial change to replace the sprintf loop with snprintf using
> up-to-date format capability.

Hmm, how about we do this instead:

Input: synaptics-rmi4 - clean up debug handling in rmi_i2c

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Kernel now has standard facility to format and print binary buffers, let's
use it. By doing so we no longer need to allocate memory for debug buffers
and we can let debugfs code go as well.

We have a new limitation however - output is limited to the first 64 bytes
of the buffer. However if we really need to capture larger messages dumping
them in dmesg is not right interface anyway.

Also clean up extra includes, while we are at it.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/rmi4/rmi_i2c.c |  131 +++++-------------------------------------
 1 file changed, 15 insertions(+), 116 deletions(-)

diff --git a/drivers/input/rmi4/rmi_i2c.c b/drivers/input/rmi4/rmi_i2c.c
index b33074c..c2ad1aa 100644
--- a/drivers/input/rmi4/rmi_i2c.c
+++ b/drivers/input/rmi4/rmi_i2c.c
@@ -8,16 +8,10 @@
  */
 
 #include <linux/kernel.h>
-#include <linux/delay.h>
 #include <linux/i2c.h>
-#include <linux/interrupt.h>
-#include <linux/kconfig.h>
-#include <linux/lockdep.h>
 #include <linux/module.h>
-#include <linux/pm.h>
 #include <linux/rmi.h>
 #include <linux/slab.h>
-#include <linux/uaccess.h>
 #include "rmi_driver.h"
 
 #define BUFFER_SIZE_INCREMENT 32
@@ -31,11 +25,6 @@
  *
  * @tx_buf: Buffer used for transmitting data to the sensor over i2c.
  * @tx_buf_size: Size of the buffer
- * @debug_buf: Buffer used for exposing buffer contents using dev_dbg
- * @debug_buf_size: Size of the debug buffer.
- *
- * @comms_debug: Latest data read/written for debugging I2C communications
- * @debugfs_comms: Debugfs file for debugging I2C communications
  */
 struct rmi_i2c_data {
 	struct mutex page_mutex;
@@ -44,56 +33,8 @@ struct rmi_i2c_data {
 
 	u8 *tx_buf;
 	int tx_buf_size;
-	u8 *debug_buf;
-	int debug_buf_size;
-
-	u32 comms_debug;
-#ifdef CONFIG_RMI4_DEBUG
-	struct dentry *debugfs_comms;
-#endif
 };
 
-#ifdef CONFIG_RMI4_DEBUG
-
-static int setup_debugfs(struct rmi_device *rmi_dev, struct rmi_i2c_data *data)
-{
-	if (!rmi_dev->debugfs_root)
-		return -ENODEV;
-
-	data->debugfs_comms = debugfs_create_bool("comms_debug",
-			(S_IRUGO | S_IWUGO), rmi_dev->debugfs_root,
-			&data->comms_debug);
-	if (!data->debugfs_comms || IS_ERR(data->debugfs_comms)) {
-		dev_warn(&rmi_dev->dev,
-			 "Failed to create debugfs comms_debug.\n");
-		data->debugfs_comms = NULL;
-	}
-
-	return 0;
-}
-
-static void teardown_debugfs(struct rmi_i2c_data *data)
-{
-	if (data->debugfs_comms)
-		debugfs_remove(data->debugfs_comms);
-}
-
-#else
-
-static inline int setup_debugfs(struct rmi_device *rmi_dev,
-				struct rmi_i2c_data *data)
-{
-	return 0;
-}
-
-static inline void teardown_debugfs(struct rmi_i2c_data *data)
-{
-}
-
-#endif
-
-#define COMMS_DEBUG(data) (IS_ENABLED(CONFIG_RMI4_DEBUG) && data->comms_debug)
-
 #define RMI_PAGE_SELECT_REGISTER 0xff
 #define RMI_I2C_PAGE(addr) (((addr) >> 8) & 0xff)
 
@@ -120,8 +61,7 @@ static int rmi_set_page(struct rmi_transport_dev *xport, u8 page)
 	u8 txbuf[2] = {RMI_PAGE_SELECT_REGISTER, page};
 	int retval;
 
-	if (COMMS_DEBUG(data))
-		dev_dbg(&client->dev, "writes 3 bytes: %02x %02x\n",
+	dev_dbg(&client->dev, "writes 3 bytes: %02x %02x\n",
 			txbuf[0], txbuf[1]);
 	xport->info.tx_count++;
 	xport->info.tx_bytes += sizeof(txbuf);
@@ -136,34 +76,6 @@ static int rmi_set_page(struct rmi_transport_dev *xport, u8 page)
 	return 0;
 }
 
-static int copy_to_debug_buf(struct device *dev, struct rmi_i2c_data *data,
-			     const u8 *buf, const int len) {
-	int i;
-	int n = 0;
-	char *temp;
-	int dbg_size = 3 * len + 1;
-
-	if (!data->debug_buf || data->debug_buf_size < dbg_size) {
-		if (data->debug_buf)
-			devm_kfree(dev, data->debug_buf);
-		data->debug_buf_size = dbg_size + BUFFER_SIZE_INCREMENT;
-		data->debug_buf = devm_kzalloc(dev, data->debug_buf_size,
-					       GFP_KERNEL);
-		if (!data->debug_buf) {
-			data->debug_buf_size = 0;
-			return -ENOMEM;
-		}
-	}
-	temp = data->debug_buf;
-
-	for (i = 0; i < len; i++) {
-		n = sprintf(temp, " %02x", buf[i]);
-		temp += n;
-	}
-
-	return 0;
-}
-
 static int rmi_i2c_write_block(struct rmi_transport_dev *xport, u16 addr,
 			       const void *buf, const int len)
 {
@@ -195,12 +107,8 @@ static int rmi_i2c_write_block(struct rmi_transport_dev *xport, u16 addr,
 			goto exit;
 	}
 
-	if (COMMS_DEBUG(data)) {
-		int rc = copy_to_debug_buf(&client->dev, data, (u8 *) buf, len);
-		if (!rc)
-			dev_dbg(&client->dev, "writes %d bytes at %#06x:%s\n",
-				len, addr, data->debug_buf);
-	}
+	dev_dbg(&client->dev,
+		"writes %d bytes at %#06x: %*ph\n", len, addr, len, buf);
 
 	xport->info.tx_count++;
 	xport->info.tx_bytes += tx_size;
@@ -232,8 +140,7 @@ static int rmi_i2c_read_block(struct rmi_transport_dev *xport, u16 addr,
 			goto exit;
 	}
 
-	if (COMMS_DEBUG(data))
-		dev_dbg(&client->dev, "writes 1 bytes: %02x\n", txbuf[0]);
+	dev_dbg(&client->dev, "writes 1 bytes: %02x\n", txbuf[0]);
 
 	xport->info.tx_count++;
 	xport->info.tx_bytes += sizeof(txbuf);
@@ -244,18 +151,16 @@ static int rmi_i2c_read_block(struct rmi_transport_dev *xport, u16 addr,
 		goto exit;
 	}
 
-	retval = i2c_master_recv(client, (u8 *) buf, len);
+	retval = i2c_master_recv(client, buf, len);
 
 	xport->info.rx_count++;
 	xport->info.rx_bytes += len;
 	if (retval < 0)
 		xport->info.rx_errs++;
-	else if (COMMS_DEBUG(data)) {
-		int rc = copy_to_debug_buf(&client->dev, data, (u8 *) buf, len);
-		if (!rc)
-			dev_dbg(&client->dev, "read %d bytes at %#06x:%s\n",
-				len, addr, data->debug_buf);
-	}
+	else
+		dev_dbg(&client->dev,
+			"read %d bytes at %#06x: %*ph\n",
+			len, addr, len, buf);
 
 exit:
 	mutex_unlock(&data->page_mutex);
@@ -265,9 +170,9 @@ exit:
 static int rmi_i2c_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
+	const struct rmi_device_platform_data *pdata = dev_get_platdata(&client->dev);
 	struct rmi_transport_dev *xport;
 	struct rmi_i2c_data *data;
-	struct rmi_device_platform_data *pdata = client->dev.platform_data;
 	int retval;
 
 	if (!pdata) {
@@ -318,7 +223,8 @@ static int rmi_i2c_probe(struct i2c_client *client,
 
 	mutex_init(&data->page_mutex);
 
-	/* Setting the page to zero will (a) make sure the PSR is in a
+	/*
+	 * Setting the page to zero will (a) make sure the PSR is in a
 	 * known state, and (b) make sure we can talk to the device.
 	 */
 	retval = rmi_set_page(xport, 0);
@@ -335,11 +241,6 @@ static int rmi_i2c_probe(struct i2c_client *client,
 	}
 	i2c_set_clientdata(client, xport);
 
-	retval = setup_debugfs(xport->rmi_dev, data);
-	if (retval < 0)
-		dev_warn(&client->dev, "Failed to setup debugfs. Code: %d.\n",
-			 retval);
-
 	dev_info(&client->dev, "registered rmi i2c driver at %#04x.\n",
 			client->addr);
 	return 0;
@@ -353,14 +254,12 @@ err_gpio:
 static int rmi_i2c_remove(struct i2c_client *client)
 {
 	struct rmi_transport_dev *xport = i2c_get_clientdata(client);
-	struct rmi_device_platform_data *pd = client->dev.platform_data;
-
-	teardown_debugfs(xport->data);
+	struct rmi_device_platform_data *pdata = dev_get_platdata(&client->dev);
 
 	rmi_unregister_transport_device(xport);
 
-	if (pd->gpio_config)
-		pd->gpio_config(&pd->gpio_data, false);
+	if (pdata->gpio_config)
+		pdata->gpio_config(&pdata->gpio_data, false);
 
 	return 0;
 }

-- 
Dmitry