On Tue, Jul 17, 2018 at 08:16:25PM +0200, Paweł Chmiel wrote:
> This patch adds optional regulators, which can be used to power
> up touchscreen. After enabling regulators, we need to wait 150msec.
> This value is taken from official driver.
>
> It was tested on Samsung Galaxy i9000 (based on Samsung S5PV210 SOC).
>
> Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@xxxxxxxxx>
> ---
> Changes from v1:
> - Enable regulators only if reset_gpio is present.
> - Switch from devm_regulator_get_optional to devm_regulator_get
> ---
> drivers/input/touchscreen/atmel_mxt_ts.c | 46 ++++++++++++++++++++++++++++++--
> 1 file changed, 44 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
> index 54fe190fd4bc..005f0fee9fc8 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -27,6 +27,7 @@
> #include <linux/interrupt.h>
> #include <linux/of.h>
> #include <linux/property.h>
> +#include <linux/regulator/consumer.h>
> #include <linux/slab.h>
> #include <linux/gpio/consumer.h>
> #include <linux/property.h>
> @@ -194,10 +195,10 @@ enum t100_type {
>
> /* Delay times */
> #define MXT_BACKUP_TIME 50 /* msec */
> -#define MXT_RESET_GPIO_TIME 20 /* msec */
> #define MXT_RESET_INVALID_CHG 100 /* msec */
> #define MXT_RESET_TIME 200 /* msec */
> #define MXT_RESET_TIMEOUT 3000 /* msec */
> +#define MXT_REGULATOR_DELAY 150 /* msec */
> #define MXT_CRC_TIMEOUT 1000 /* msec */
> #define MXT_FW_RESET_TIME 3000 /* msec */
> #define MXT_FW_CHG_TIMEOUT 300 /* msec */
> @@ -310,6 +311,8 @@ struct mxt_data {
> struct t7_config t7_cfg;
> struct mxt_dbg dbg;
> struct gpio_desc *reset_gpio;
> + struct regulator *vdd_reg;
> + struct regulator *avdd_reg;
>
> /* Cached parameters from object table */
> u16 T5_address;
> @@ -3076,6 +3079,22 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
> return error;
> }
>
> + data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
> + if (IS_ERR(data->vdd_reg)) {
> + error = PTR_ERR(data->vdd_reg);
> + dev_err(&client->dev, "Failed to get vdd regulator: %d\n",
> + error);
> + return error;
> + }
> +
> + data->avdd_reg = devm_regulator_get(&client->dev, "avdd");
> + if (IS_ERR(data->avdd_reg)) {
> + error = PTR_ERR(data->avdd_reg);
> + dev_err(&client->dev, "Failed to get avdd regulator: %d\n",
> + error);
> + return error;
> + }
> +
> error = devm_request_threaded_irq(&client->dev, client->irq,
> NULL, mxt_interrupt, IRQF_ONESHOT,
> client->name, data);
> @@ -3087,7 +3106,26 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
> disable_irq(client->irq);
>
> if (data->reset_gpio) {
> - msleep(MXT_RESET_GPIO_TIME);
> + error = regulator_enable(data->vdd_reg);
> + if (error) {
> + dev_err(&client->dev, "Failed to enable vdd regulator: %d\n",
> + error);
> + return error;
> + }
> +
> + error = regulator_enable(data->avdd_reg);
> + if (error) {
> + dev_err(&client->dev, "Failed to enable avdd regulator: %d\n",
> + error);
> + return error;
> + }
> +
> + /*
> + * According to maXTouch power sequencing specification, RESET line
> + * must be kept low until some time after regulators come up to
> + * voltage
> + */
> + msleep(MXT_REGULATOR_DELAY);
> gpiod_set_value(data->reset_gpio, 1);
> msleep(MXT_RESET_INVALID_CHG);
Hi Pawel-
I see you've borrowed some of the logic from the patch I wrote a while
back (see https://github.com/ndyer/linux/commit/8e9687e41ed062 )
The correct behaviour according to Atmel should be:
* Make RESET zero
* Bring up regulators
* Wait for a period to settle (150 msec)
* Release RESET
* Wait for 100 msec whilst device gets through bootloader
* Wait for CHG line assert before reading info block
I can't see the first and last steps in your patch at present.
The only downside with this approach is that there are a lot of
delays during driver probe, but I believe the asynchronous probe stuff
that's landed since I wrote the original patch should address that.
cheers
Nick
> }
> @@ -3116,6 +3154,10 @@ static int mxt_remove(struct i2c_client *client)
> struct mxt_data *data = i2c_get_clientdata(client);
>
> disable_irq(data->irq);
> + if (data->reset_gpio) {
> + regulator_disable(data->avdd_reg);
> + regulator_disable(data->vdd_reg);
> + }
> sysfs_remove_group(&client->dev.kobj, &mxt_attr_group);
> mxt_free_input_device(data);
> mxt_free_object_table(data);
> --
> 2.7.4
>
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