On 07/07/2011 05:43 PM, Dmitry Torokhov wrote:
> On Wed, Jul 06, 2011 at 03:12:24PM +0300, Iiro Valkonen wrote:
>> The delay before the chip can be accessed after reset varies between different
>> chips in maXTouch family. Waiting for 200ms and then monitoring the CHG (chip
>> is ready when the line is low) is guaranteed to work with all chips.
>>
>> v3: Add a check for NULL read_chg() function, and add the read_chg() to platform
>> files using this driver (currently only mach-goni.c)
>> v2: At Dmitry's suggestion, add a timeout so we are not stuck looping
>> endlessly in case the CHG is not going low.
>>
>> Signed-off-by: Iiro Valkonen <iiro.valkonen@xxxxxxxxx>
>> ---
>> arch/arm/mach-s5pv210/mach-goni.c | 6 ++++++
>> drivers/input/touchscreen/atmel_mxt_ts.c | 14 +++++++++++++-
>> include/linux/i2c/atmel_mxt_ts.h | 1 +
>> 3 files changed, 20 insertions(+), 1 deletions(-)
>>
>> diff --git a/arch/arm/mach-s5pv210/mach-goni.c b/arch/arm/mach-s5pv210/mach-goni.c
>> index 31d5aa7..196e92c 100644
>> --- a/arch/arm/mach-s5pv210/mach-goni.c
>> +++ b/arch/arm/mach-s5pv210/mach-goni.c
>> @@ -225,6 +225,11 @@ static void __init goni_radio_init(void)
>> gpio_direction_output(gpio, 1);
>> }
>>
>> +static u8 read_chg(void)
>> +{
>> + return gpio_get_value(S5PV210_GPJ0(5));
>> +}
>> +
>> /* TSP */
>> static struct mxt_platform_data qt602240_platform_data = {
>> .x_line = 17,
>> @@ -236,6 +241,7 @@ static struct mxt_platform_data qt602240_platform_data = {
>> .voltage = 2800000, /* 2.8V */
>> .orient = MXT_DIAGONAL,
>> .irqflags = IRQF_TRIGGER_FALLING,
>> + .read_chg = &read_chg,
>> };
>>
>> static struct s3c2410_platform_i2c i2c2_data __initdata = {
>> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
>> index 1e61387..99df3b7 100644
>> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
>> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
>> @@ -170,7 +170,8 @@
>> #define MXT_BOOT_VALUE 0xa5
>> #define MXT_BACKUP_VALUE 0x55
>> #define MXT_BACKUP_TIME 25 /* msec */
>> -#define MXT_RESET_TIME 65 /* msec */
>> +#define MXT_RESET_TIME 200 /* msec */
>
> Can't we really start polling before 200msecs are up? Woudl it be
> possible to leave the initial wait at 65 (or maybe increase it to 100
> msecs)?
>
I'm afraid that on mXT1386, we need 200ms. I'll submit a version where we check the ID
of the chip and adjust the delay based on that.
>> +#define MXT_RESET_NOCHGREAD 400 /* msec */
>>
>> #define MXT_FWRESET_TIME 175 /* msec */
>>
>> @@ -792,6 +793,7 @@ static int mxt_initialize(struct mxt_data *data)
>> struct i2c_client *client = data->client;
>> struct mxt_info *info = &data->info;
>> int error;
>> + int reset_timeout = 0;
>> u8 val;
>>
>> error = mxt_get_info(data);
>> @@ -828,6 +830,16 @@ static int mxt_initialize(struct mxt_data *data)
>> mxt_write_object(data, MXT_GEN_COMMAND,
>> MXT_COMMAND_RESET, 1);
>> msleep(MXT_RESET_TIME);
>> + if (data->pdata->read_chg == NULL) {
>> + msleep(MXT_RESET_NOCHGREAD);
>
> This means that without read_chg we are waiting for 600ms now... It is
> eternity. Can we wait for MXT_RESET_NOCHGREAD total?
>
Yes, 400ms in total should be fine.
>> + } else {
>> + while ((reset_timeout++ <= 100) && data->pdata->read_chg())
>> + msleep(2);
>> + if (reset_timeout >= 100) {
>> + dev_err(&client->dev, "No response after reset!\n");
>> + return -EIO;
>> + }
>> + }
>>
>> /* Update matrix size at info struct */
>> error = mxt_read_reg(client, MXT_MATRIX_X_SIZE, &val);
>> diff --git a/include/linux/i2c/atmel_mxt_ts.h b/include/linux/i2c/atmel_mxt_ts.h
>> index f027f7a..ef59c22 100644
>> --- a/include/linux/i2c/atmel_mxt_ts.h
>> +++ b/include/linux/i2c/atmel_mxt_ts.h
>> @@ -39,6 +39,7 @@ struct mxt_platform_data {
>> unsigned int voltage;
>> unsigned char orient;
>> unsigned long irqflags;
>> + u8(*read_chg) (void);
>> };
>>
>> #endif /* __LINUX_ATMEL_MXT_TS_H */
>> --
>> 1.7.0.4
>
--
Iiro
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