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From:   Adam Ford <aford173@gmail.com>
To:     dri-devel@lists.freedesktop.org
Cc:     m.szyprowski@samsung.com, marex@denx.de, aford@beaconembedded.com,
        Adam Ford <aford173@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Inki Dae <inki.dae@samsung.com>,
        Jagan Teki <jagan@amarulasolutions.com>,
        Andrzej Hajda <andrzej.hajda@intel.com>,
        Neil Armstrong <neil.armstrong@linaro.org>,
        Robert Foss <rfoss@kernel.org>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Frieder Schrempf <frieder.schrempf@kontron.de>,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 2/6] drm: bridge: samsung-dsim: Fix PMS Calculator on imx8m[mnp]
Date:   Sat, 15 Apr 2023 05:40:59 -0500
Message-Id: <20230415104104.5537-2-aford173@gmail.com>
In-Reply-To: <20230415104104.5537-1-aford173@gmail.com>
References: <20230415104104.5537-1-aford173@gmail.com>
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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 also appears to be the case for the
imx8mn and imx8mp.

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@gmail.com>
---
 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 1ccbad4ea577..9fec32b44e05 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -406,6 +406,9 @@ 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 = {
@@ -419,6 +422,9 @@ 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 = {
@@ -430,6 +436,9 @@ 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 = {
@@ -442,6 +451,9 @@ 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 = {
@@ -454,6 +466,9 @@ 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 = {
@@ -470,6 +485,9 @@ 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 *
@@ -548,12 +566,12 @@ 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 {
-- 
2.39.2