Am Sonntag, dem 23.04.2023 um 07:12 -0500 schrieb Adam Ford:
> According to Table 13-45 of the i.MX8M Mini Reference Manual, the min
> and max values for M and the frequency range for the VCO_out
> calculator were incorrect. This information was contradicted in other
> parts of the mini, nano and plus manuals. After reaching out to my
> NXP Rep, when confronting him about discrepencies in the Nano manual,
> he responded with:
> "Yes it is definitely wrong, the one that is part
> of the NOTE in MIPI_DPHY_M_PLLPMS register table against PMS_P,
> PMS_M and PMS_S is not correct. I will report this to Doc team,
> the one customer should be take into account is the Table 13-40
> DPHY PLL Parameters and the Note above."
>
> These updated values also match what is used in the NXP downstream
> kernel.
>
> To fix this, make new variables to hold the min and max values of m
> and the minimum value of VCO_out, and update the PMS calculator to
> use these new variables instead of using hard-coded values to keep
> the backwards compatibility with other parts using this driver.
>
> Fixes: 4d562c70c4dc ("drm: bridge: samsung-dsim: Add i.MX8M Mini/Nano support")
> Signed-off-by: Adam Ford <aford173@xxxxxxxxx>
Reviewed-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/bridge/samsung-dsim.c | 22 ++++++++++++++++++++--
> include/drm/bridge/samsung-dsim.h | 3 +++
> 2 files changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
> index 2be3b58624c3..adb9c13c5f7f 100644
> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> @@ -405,6 +405,9 @@ static const struct samsung_dsim_driver_data exynos3_dsi_driver_data = {
> .num_bits_resol = 11,
> .pll_p_offset = 13,
> .reg_values = reg_values,
> + .m_min = 41,
> + .m_max = 125,
> + .vco_min = 500,
> };
>
> static const struct samsung_dsim_driver_data exynos4_dsi_driver_data = {
> @@ -418,6 +421,9 @@ static const struct samsung_dsim_driver_data exynos4_dsi_driver_data = {
> .num_bits_resol = 11,
> .pll_p_offset = 13,
> .reg_values = reg_values,
> + .m_min = 41,
> + .m_max = 125,
> + .vco_min = 500,
> };
>
> static const struct samsung_dsim_driver_data exynos5_dsi_driver_data = {
> @@ -429,6 +435,9 @@ static const struct samsung_dsim_driver_data exynos5_dsi_driver_data = {
> .num_bits_resol = 11,
> .pll_p_offset = 13,
> .reg_values = reg_values,
> + .m_min = 41,
> + .m_max = 125,
> + .vco_min = 500,
> };
>
> static const struct samsung_dsim_driver_data exynos5433_dsi_driver_data = {
> @@ -441,6 +450,9 @@ static const struct samsung_dsim_driver_data exynos5433_dsi_driver_data = {
> .num_bits_resol = 12,
> .pll_p_offset = 13,
> .reg_values = exynos5433_reg_values,
> + .m_min = 41,
> + .m_max = 125,
> + .vco_min = 500,
> };
>
> static const struct samsung_dsim_driver_data exynos5422_dsi_driver_data = {
> @@ -453,6 +465,9 @@ static const struct samsung_dsim_driver_data exynos5422_dsi_driver_data = {
> .num_bits_resol = 12,
> .pll_p_offset = 13,
> .reg_values = exynos5422_reg_values,
> + .m_min = 41,
> + .m_max = 125,
> + .vco_min = 500,
> };
>
> static const struct samsung_dsim_driver_data imx8mm_dsi_driver_data = {
> @@ -469,6 +484,9 @@ static const struct samsung_dsim_driver_data imx8mm_dsi_driver_data = {
> */
> .pll_p_offset = 14,
> .reg_values = imx8mm_dsim_reg_values,
> + .m_min = 64,
> + .m_max = 1023,
> + .vco_min = 1050,
> };
>
> static const struct samsung_dsim_driver_data *
> @@ -547,12 +565,12 @@ static unsigned long samsung_dsim_pll_find_pms(struct samsung_dsim *dsi,
> tmp = (u64)fout * (_p << _s);
> do_div(tmp, fin);
> _m = tmp;
> - if (_m < 41 || _m > 125)
> + if (_m < driver_data->m_min || _m > driver_data->m_max)
> continue;
>
> tmp = (u64)_m * fin;
> do_div(tmp, _p);
> - if (tmp < 500 * MHZ ||
> + if (tmp < driver_data->vco_min * MHZ ||
> tmp > driver_data->max_freq * MHZ)
> continue;
>
> diff --git a/include/drm/bridge/samsung-dsim.h b/include/drm/bridge/samsung-dsim.h
> index ba5484de2b30..a088d84579bc 100644
> --- a/include/drm/bridge/samsung-dsim.h
> +++ b/include/drm/bridge/samsung-dsim.h
> @@ -59,6 +59,9 @@ struct samsung_dsim_driver_data {
> unsigned int num_bits_resol;
> unsigned int pll_p_offset;
> const unsigned int *reg_values;
> + u16 m_min;
> + u16 m_max;
> + u64 vco_min;
> };
>
> struct samsung_dsim_host_ops {
