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)?
> +#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?
> + } 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
--
Dmitry
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