On 12/03/2013 04:35 PM, Mauro Carvalho Chehab wrote:
> Em Tue, 15 Oct 2013 17:24:38 +0200
> Dinesh Ram <dinesh.ram@xxxxxxx> escreveu:
>
>> 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@xxxxxxx>
>> ---
>> 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 ac727e3..24ae41d 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);
>
> This could result on an endless loop due to the limited space for jiffies.
> You should, instead, use the proper macros (time_after, time_before, ...).
True. Can this be done as a separate follow-up patch? I'd really like to get this
driver merged, it's been sitting here for ages.
Dinesh, can you have a go at this?
Regards,
Hans
>
>> +
>> + 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)
>
> Same here: use the proper macro to check time after/before.
>
>> + 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;
>
>
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