Re: [PATCHv2 02/11] si4713: Modified i2c driver to handle cases where interrupts are not used

[Mauro Carvalho Chehab <m.chehab@samsung.com>]

Em Fri,  6 Dec 2013 11:17:05 +0100
Hans Verkuil <hverkuil@xs4all.nl> escreveu:

> From: Dinesh Ram <Dinesh.Ram@cern.ch>
> 
> Checks have been introduced at several places in the code to test if an
> interrupt is set or not. For devices which do not use the interrupt, to
> get a valid response, within a specified timeout, the device is polled
> instead.
> 
> Signed-off-by: Dinesh Ram <dinesh.ram@cern.ch>
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> Tested-by: Eduardo Valentin <edubezval@gmail.com>
> Acked-by: Eduardo Valentin <edubezval@gmail.com>
> ---
>  drivers/media/radio/si4713/si4713.c | 108 +++++++++++++++++++++---------------
>  1 file changed, 64 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/media/radio/si4713/si4713.c b/drivers/media/radio/si4713/si4713.c
> index 4f3308f..5d26b9a 100644
> --- a/drivers/media/radio/si4713/si4713.c
> +++ b/drivers/media/radio/si4713/si4713.c
> @@ -27,11 +27,11 @@
>  #include <linux/i2c.h>
>  #include <linux/slab.h>
>  #include <linux/gpio.h>
> -#include <linux/regulator/consumer.h>
>  #include <linux/module.h>
>  #include <media/v4l2-device.h>
>  #include <media/v4l2-ioctl.h>
>  #include <media/v4l2-common.h>
> +#include <linux/regulator/consumer.h>
>  
>  #include "si4713.h"
>  
> @@ -213,6 +213,7 @@ static int si4713_send_command(struct si4713_device *sdev, const u8 command,
>  				u8 response[], const int respn, const int usecs)
>  {
>  	struct i2c_client *client = v4l2_get_subdevdata(&sdev->sd);
> +	unsigned long until_jiffies;
>  	u8 data1[MAX_ARGS + 1];
>  	int err;
>  
> @@ -228,30 +229,39 @@ static int si4713_send_command(struct si4713_device *sdev, const u8 command,
>  	if (err != argn + 1) {
>  		v4l2_err(&sdev->sd, "Error while sending command 0x%02x\n",
>  			command);
> -		return (err > 0) ? -EIO : err;
> +		return err < 0 ? err : -EIO;
>  	}
>  
> +	until_jiffies = jiffies + usecs_to_jiffies(usecs) + 1;
> +
>  	/* Wait response from interrupt */
> -	if (!wait_for_completion_timeout(&sdev->work,
> +	if (client->irq) {
> +		if (!wait_for_completion_timeout(&sdev->work,
>  				usecs_to_jiffies(usecs) + 1))
> -		v4l2_warn(&sdev->sd,
> +			v4l2_warn(&sdev->sd,
>  				"(%s) Device took too much time to answer.\n",
>  				__func__);
> -
> -	/* Then get the response */
> -	err = i2c_master_recv(client, response, respn);
> -	if (err != respn) {
> -		v4l2_err(&sdev->sd,
> -			"Error while reading response for command 0x%02x\n",
> -			command);
> -		return (err > 0) ? -EIO : err;
>  	}
>  
> -	DBG_BUFFER(&sdev->sd, "Response", response, respn);
> -	if (check_command_failed(response[0]))
> -		return -EBUSY;
> +	do {
> +		err = i2c_master_recv(client, response, respn);
> +		if (err != respn) {
> +			v4l2_err(&sdev->sd,
> +				"Error %d while reading response for command 0x%02x\n",
> +				err, command);
> +			return err < 0 ? err : -EIO;
> +		}
> +
> +		DBG_BUFFER(&sdev->sd, "Response", response, respn);
> +		if (!check_command_failed(response[0]))
> +			return 0;
>  
> -	return 0;
> +		if (client->irq)
> +			return -EBUSY;
> +		msleep(1);
> +	} while (jiffies <= until_jiffies);
> +
> +	return -EBUSY;
>  }
>  
>  /*
> @@ -344,14 +354,15 @@ static int si4713_write_property(struct si4713_device *sdev, u16 prop, u16 val)
>   */
>  static int si4713_powerup(struct si4713_device *sdev)
>  {
> +	struct i2c_client *client = v4l2_get_subdevdata(&sdev->sd);
>  	int err;
>  	u8 resp[SI4713_PWUP_NRESP];
>  	/*
>  	 * 	.First byte = Enabled interrupts and boot function
>  	 * 	.Second byte = Input operation mode
>  	 */
> -	const u8 args[SI4713_PWUP_NARGS] = {
> -		SI4713_PWUP_CTSIEN | SI4713_PWUP_GPO2OEN | SI4713_PWUP_FUNC_TX,
> +	u8 args[SI4713_PWUP_NARGS] = {
> +		SI4713_PWUP_GPO2OEN | SI4713_PWUP_FUNC_TX,
>  		SI4713_PWUP_OPMOD_ANALOG,
>  	};
>  
> @@ -369,6 +380,9 @@ static int si4713_powerup(struct si4713_device *sdev)
>  		gpio_set_value(sdev->gpio_reset, 1);
>  	}
>  
> +	if (client->irq)
> +		args[0] |= SI4713_PWUP_CTSIEN;
> +
>  	err = si4713_send_command(sdev, SI4713_CMD_POWER_UP,
>  					args, ARRAY_SIZE(args),
>  					resp, ARRAY_SIZE(resp),
> @@ -380,7 +394,8 @@ static int si4713_powerup(struct si4713_device *sdev)
>  		v4l2_dbg(1, debug, &sdev->sd, "Device in power up mode\n");
>  		sdev->power_state = POWER_ON;
>  
> -		err = si4713_write_property(sdev, SI4713_GPO_IEN,
> +		if (client->irq)
> +			err = si4713_write_property(sdev, SI4713_GPO_IEN,
>  						SI4713_STC_INT | SI4713_CTS);
>  	} else {
>  		if (gpio_is_valid(sdev->gpio_reset))
> @@ -465,33 +480,39 @@ static int si4713_checkrev(struct si4713_device *sdev)
>   */
>  static int si4713_wait_stc(struct si4713_device *sdev, const int usecs)
>  {
> -	int err;
> +	struct i2c_client *client = v4l2_get_subdevdata(&sdev->sd);
>  	u8 resp[SI4713_GET_STATUS_NRESP];
> +	unsigned long start_jiffies = jiffies;
> +	int err;
>  
> -	/* Wait response from STC interrupt */
> -	if (!wait_for_completion_timeout(&sdev->work,
> -			usecs_to_jiffies(usecs) + 1))
> +	if (client->irq &&
> +	    !wait_for_completion_timeout(&sdev->work, usecs_to_jiffies(usecs) + 1))
>  		v4l2_warn(&sdev->sd,
> -			"%s: device took too much time to answer (%d usec).\n",
> -				__func__, usecs);
> -
> -	/* Clear status bits */
> -	err = si4713_send_command(sdev, SI4713_CMD_GET_INT_STATUS,
> -					NULL, 0,
> -					resp, ARRAY_SIZE(resp),
> -					DEFAULT_TIMEOUT);
> -
> -	if (err < 0)
> -		goto exit;
> -
> -	v4l2_dbg(1, debug, &sdev->sd,
> -			"%s: status bits: 0x%02x\n", __func__, resp[0]);
> -
> -	if (!(resp[0] & SI4713_STC_INT))
> -		err = -EIO;
> -
> -exit:
> -	return err;
> +			"(%s) Device took too much time to answer.\n", __func__);
> +
> +	for (;;) {
> +		/* Clear status bits */
> +		err = si4713_send_command(sdev, SI4713_CMD_GET_INT_STATUS,
> +				NULL, 0,
> +				resp, ARRAY_SIZE(resp),
> +				DEFAULT_TIMEOUT);
> +		/* The USB device returns errors when it waits for the
> +		 * STC bit to be set. Hence polling */
> +		if (err >= 0) {
> +			v4l2_dbg(1, debug, &sdev->sd,
> +				"%s: status bits: 0x%02x\n", __func__, resp[0]);
> +
> +			if (resp[0] & SI4713_STC_INT)
> +				return 0;
> +		}
> +		if (jiffies_to_usecs(jiffies - start_jiffies) > usecs)

Please use time_is_after_jiffies() here too.

> +			return err < 0 ? err : -EIO;
> +		/* We sleep here for 3 ms in order to avoid flooding the device
> +		 * with USB requests. The si4713 USB driver was developed
> +		 * by reverse engineering the Windows USB driver. The windows
> +		 * driver also has a ~2.5 ms delay between responses. */
> +		msleep(3);
> +	}
>  }
>  
>  /*
> @@ -1024,7 +1045,6 @@ static int si4713_initialize(struct si4713_device *sdev)
>  	if (rval < 0)
>  		return rval;
>  
> -
>  	sdev->frequency = DEFAULT_FREQUENCY;
>  	sdev->stereo = 1;
>  	sdev->tune_rnl = DEFAULT_TUNE_RNL;


-- 

Cheers,
Mauro