On Wed, Sep 30, 2020 at 10:21:58AM +0800, Crystal Guo wrote:
> Introduce ti_syscon_reset() to integrate assert and deassert together.
> If some modules need do serialized assert and deassert operations
> to reset itself, reset_control_reset can be called for convenience.
>
> Such as reset-qcom-aoss.c, it integrates assert and deassert together
> by 'reset' method. MTK Socs also need this method to perform reset.
>
> Signed-off-by: Crystal Guo <crystal....@mediatek.com>
Reviewed-by: Ikjoon Jang <i...@chromium.org>
> ---
> drivers/reset/reset-ti-syscon.c | 40 ++++++++++++++++++++++++++++++++-
> 1 file changed, 39 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/reset/reset-ti-syscon.c b/drivers/reset/reset-ti-syscon.c
> index a2635c21db7f..5d1f8306cd4f 100644
> --- a/drivers/reset/reset-ti-syscon.c
> +++ b/drivers/reset/reset-ti-syscon.c
> @@ -15,15 +15,22 @@
> * GNU General Public License for more details.
> */
>
> +#include <linux/delay.h>
> #include <linux/mfd/syscon.h>
> #include <linux/module.h>
> #include <linux/of.h>
> +#include <linux/of_device.h>
> #include <linux/platform_device.h>
> #include <linux/regmap.h>
> #include <linux/reset-controller.h>
>
> #include <dt-bindings/reset/ti-syscon.h>
>
> +struct mediatek_reset_data {
> + unsigned char *reset_bits;
> + unsigned int reset_duration_us;
> +};
> +
> /**
> * struct ti_syscon_reset_control - reset control structure
> * @assert_offset: reset assert control register offset from syscon base
> @@ -56,6 +63,7 @@ struct ti_syscon_reset_data {
> struct regmap *regmap;
> struct ti_syscon_reset_control *controls;
> unsigned int nr_controls;
> + const struct mediatek_reset_data *reset_data;
> };
>
> #define to_ti_syscon_reset_data(rcdev) \
> @@ -158,9 +166,29 @@ static int ti_syscon_reset_status(struct
> reset_controller_dev *rcdev,
> !(control->flags & STATUS_SET);
> }
>
> +static int ti_syscon_reset(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);
> + int ret;
> +
> + if (data->reset_data) {
> + ret = ti_syscon_reset_assert(rcdev, id);
> + if (ret)
> + return ret;
> + usleep_range(data->reset_data->reset_duration_us,
> + data->reset_data->reset_duration_us * 2);
> +
There are many users using assert() and deassert() seperately
without any delay between them.
If there's a timing requirement between assertion and deassertion,
shouldn't there be a same amount of delay in assert?
> + return ti_syscon_reset_deassert(rcdev, id);
> + } else {
> + return -ENOTSUPP;
> + }
> +}
> +
> static const struct reset_control_ops ti_syscon_reset_ops = {
> .assert = ti_syscon_reset_assert,
> .deassert = ti_syscon_reset_deassert,
> + .reset = ti_syscon_reset,
> .status = ti_syscon_reset_status,
> };
>
> @@ -182,7 +210,11 @@ static int ti_syscon_reset_probe(struct platform_device
> *pdev)
> if (IS_ERR(regmap))
> return PTR_ERR(regmap);
>
> - list = of_get_property(np, "ti,reset-bits", &size);
> + data->reset_data = of_device_get_match_data(&pdev->dev);
> + if (data->reset_data)
> + list = of_get_property(np, data->reset_data->reset_bits, &size);
> + else
> + list = of_get_property(np, "ti,reset-bits", &size);
> if (!list || (size / sizeof(*list)) % 7 != 0) {
> dev_err(dev, "invalid DT reset description\n");
> return -EINVAL;
> @@ -217,8 +249,14 @@ static int ti_syscon_reset_probe(struct platform_device
> *pdev)
> return devm_reset_controller_register(dev, &data->rcdev);
> }
>
> +static const struct mediatek_reset_data mtk_reset_data = {
> + .reset_bits = "mediatek,reset-bits",
> + .reset_duration_us = 10,
> +};
> +
> static const struct of_device_id ti_syscon_reset_of_match[] = {
> { .compatible = "ti,syscon-reset", },
> + { .compatible = "mediatek,syscon-reset", .data = &mtk_reset_data},
> { /* sentinel */ },
> };
> MODULE_DEVICE_TABLE(of, ti_syscon_reset_of_match);
