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Message-ID: <7284cad0-b71b-49dc-bb09-cd9f1ff00028@ideasonboard.com>
Date: Thu, 21 Aug 2025 12:28:32 +0300
From: Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>
To: Prabhakar <prabhakar.csengg@...il.com>
Cc: dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
linux-clk@...r.kernel.org, Fabrizio Castro <fabrizio.castro.jz@...esas.com>,
Tommaso Merciai <tommaso.merciai.xr@...renesas.com>,
Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
Geert Uytterhoeven <geert+renesas@...der.be>,
Andrzej Hajda <andrzej.hajda@...el.com>,
Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>,
David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>,
Michael Turquette <mturquette@...libre.com>, Stephen Boyd
<sboyd@...nel.org>, Biju Das <biju.das.jz@...renesas.com>,
Magnus Damm <magnus.damm@...il.com>
Subject: Re: [PATCH v7 6/6] drm: renesas: rz-du: mipi_dsi: Add support for
RZ/V2H(P) SoC
Hi,
On 28/07/2025 23:14, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
>
> Add DSI support for Renesas RZ/V2H(P) SoC.
I think a bit longer desc would be in order, as this is not just a "add
a new compatible string" patch, but we have new registers and functions.
> Co-developed-by: Fabrizio Castro <fabrizio.castro.jz@...esas.com>
> Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@...esas.com>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> ---
> v6->v7:
> - Used the new apis for calculating the PLLDSI
> parameters in the DSI driver.
>
> v5->v6:
> - Made use of GENMASK() macro for PLLCLKSET0R_PLL_*,
> PHYTCLKSETR_* and PHYTHSSETR_* macros.
> - Replaced 10000000UL with 10 * MEGA
> - Renamed mode_freq_hz to mode_freq_khz in rzv2h_dsi_mode_calc
> - Replaced `i -= 1;` with `i--;`
> - Renamed RZV2H_MIPI_DPHY_FOUT_MIN_IN_MEGA to
> RZV2H_MIPI_DPHY_FOUT_MIN_IN_MHZ and
> RZV2H_MIPI_DPHY_FOUT_MAX_IN_MEGA to
> RZV2H_MIPI_DPHY_FOUT_MAX_IN_MHZ.
>
> v4->v5:
> - No changes
>
> v3->v4
> - In rzv2h_dphy_find_ulpsexit() made the array static const.
>
> v2->v3:
> - Simplifed V2H DSI timings array to save space
> - Switched to use fsleep() instead of udelay()
>
> v1->v2:
> - Dropped unused macros
> - Added missing LPCLK flag to rzv2h info
> ---
> .../gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c | 345 ++++++++++++++++++
> .../drm/renesas/rz-du/rzg2l_mipi_dsi_regs.h | 34 ++
> 2 files changed, 379 insertions(+)
>
> diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> index 893a90c7a886..3b2f77665309 100644
> --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> @@ -7,6 +7,7 @@
>
> #include <linux/bitfield.h>
> #include <linux/clk.h>
> +#include <linux/clk/renesas-rzv2h-cpg-pll.h>
> #include <linux/delay.h>
> #include <linux/dma-mapping.h>
> #include <linux/io.h>
> @@ -46,6 +47,11 @@ struct rzg2l_mipi_dsi_hw_info {
> u64 *hsfreq_millihz);
> unsigned int (*dphy_mode_clk_check)(struct rzg2l_mipi_dsi *dsi,
> unsigned long mode_freq);
> + struct {
> + const struct rzv2h_pll_limits **limits;
> + const u8 *table;
> + const u8 table_size;
> + } cpg_plldsi;
> u32 phy_reg_offset;
> u32 link_reg_offset;
> unsigned long min_dclk;
> @@ -53,6 +59,11 @@ struct rzg2l_mipi_dsi_hw_info {
> u8 features;
> };
>
> +struct rzv2h_dsi_mode_calc {
> + unsigned long mode_freq_khz;
> + struct rzv2h_pll_pars dsi_parameters;
> +};
> +
> struct rzg2l_mipi_dsi {
> struct device *dev;
> void __iomem *mmio;
> @@ -75,11 +86,22 @@ struct rzg2l_mipi_dsi {
> unsigned int lanes;
> unsigned long mode_flags;
>
> + struct rzv2h_dsi_mode_calc mode_calc;
> +
> /* DCS buffer pointers when using external memory. */
> dma_addr_t dcs_buf_phys;
> u8 *dcs_buf_virt;
> };
>
> +static const struct rzv2h_pll_limits rzv2h_plldsi_div_limits = {
> + .fout = { .min = 80 * MEGA, .max = 1500 * MEGA },
> + .fvco = { .min = 1050 * MEGA, .max = 2100 * MEGA },
> + .m = { .min = 64, .max = 1023 },
> + .p = { .min = 1, .max = 4 },
> + .s = { .min = 0, .max = 5 },
> + .k = { .min = -32768, .max = 32767 },
> +};
> +
> static inline struct rzg2l_mipi_dsi *
> bridge_to_rzg2l_mipi_dsi(struct drm_bridge *bridge)
> {
> @@ -194,6 +216,155 @@ static const struct rzg2l_mipi_dsi_timings rzg2l_mipi_dsi_global_timings[] = {
> },
> };
>
> +struct rzv2h_mipi_dsi_timings {
> + const u8 *hsfreq;
> + u8 len;
> + u8 start_index;
> +};
> +
> +enum {
> + TCLKPRPRCTL,
> + TCLKZEROCTL,
> + TCLKPOSTCTL,
> + TCLKTRAILCTL,
> + THSPRPRCTL,
> + THSZEROCTL,
> + THSTRAILCTL,
> + TLPXCTL,
> + THSEXITCTL,
> +};
> +
> +static const u8 tclkprprctl[] = {
> + 15, 26, 37, 47, 58, 69, 79, 90, 101, 111, 122, 133, 143, 150,
> +};
> +
> +static const u8 tclkzeroctl[] = {
> + 9, 11, 13, 15, 18, 21, 23, 24, 25, 27, 29, 31, 34, 36, 38,
> + 41, 43, 45, 47, 50, 52, 54, 57, 59, 61, 63, 66, 68, 70, 73,
> + 75, 77, 79, 82, 84, 86, 89, 91, 93, 95, 98, 100, 102, 105,
> + 107, 109, 111, 114, 116, 118, 121, 123, 125, 127, 130, 132,
> + 134, 137, 139, 141, 143, 146, 148, 150,
> +};
> +
> +static const u8 tclkpostctl[] = {
> + 8, 21, 34, 48, 61, 74, 88, 101, 114, 128, 141, 150,
> +};
> +
> +static const u8 tclktrailctl[] = {
> + 14, 25, 37, 48, 59, 71, 82, 94, 105, 117, 128, 139, 150,
> +};
> +
> +static const u8 thsprprctl[] = {
> + 11, 19, 29, 40, 50, 61, 72, 82, 93, 103, 114, 125, 135, 146, 150,
> +};
> +
> +static const u8 thszeroctl[] = {
> + 18, 24, 29, 35, 40, 46, 51, 57, 62, 68, 73, 79, 84, 90,
> + 95, 101, 106, 112, 117, 123, 128, 134, 139, 145, 150,
> +};
> +
> +static const u8 thstrailctl[] = {
> + 10, 21, 32, 42, 53, 64, 75, 85, 96, 107, 118, 128, 139, 150,
> +};
> +
> +static const u8 tlpxctl[] = {
> + 13, 26, 39, 53, 66, 79, 93, 106, 119, 133, 146, 150,
> +};
> +
> +static const u8 thsexitctl[] = {
> + 15, 23, 31, 39, 47, 55, 63, 71, 79, 87,
> + 95, 103, 111, 119, 127, 135, 143, 150,
> +};
> +
> +static const struct rzv2h_mipi_dsi_timings rzv2h_dsi_timings_tables[] = {
> + [TCLKPRPRCTL] = {
> + .hsfreq = tclkprprctl,
> + .len = ARRAY_SIZE(tclkprprctl),
> + .start_index = 0,
> + },
> + [TCLKZEROCTL] = {
> + .hsfreq = tclkzeroctl,
> + .len = ARRAY_SIZE(tclkzeroctl),
> + .start_index = 2,
> + },
> + [TCLKPOSTCTL] = {
> + .hsfreq = tclkpostctl,
> + .len = ARRAY_SIZE(tclkpostctl),
> + .start_index = 6,
> + },
> + [TCLKTRAILCTL] = {
> + .hsfreq = tclktrailctl,
> + .len = ARRAY_SIZE(tclktrailctl),
> + .start_index = 1,
> + },
> + [THSPRPRCTL] = {
> + .hsfreq = thsprprctl,
> + .len = ARRAY_SIZE(thsprprctl),
> + .start_index = 0,
> + },
> + [THSZEROCTL] = {
> + .hsfreq = thszeroctl,
> + .len = ARRAY_SIZE(thszeroctl),
> + .start_index = 0,
> + },
> + [THSTRAILCTL] = {
> + .hsfreq = thstrailctl,
> + .len = ARRAY_SIZE(thstrailctl),
> + .start_index = 3,
> + },
> + [TLPXCTL] = {
> + .hsfreq = tlpxctl,
> + .len = ARRAY_SIZE(tlpxctl),
> + .start_index = 0,
> + },
> + [THSEXITCTL] = {
> + .hsfreq = thsexitctl,
> + .len = ARRAY_SIZE(thsexitctl),
> + .start_index = 1,
> + },
> +};
> +
> +static u16 rzv2h_dphy_find_ulpsexit(unsigned long freq)
> +{
> + static const unsigned long hsfreq[] = {
> + 1953125UL,
> + 3906250UL,
> + 7812500UL,
> + 15625000UL,
> + };
> + static const u16 ulpsexit[] = {49, 98, 195, 391};
> + unsigned int i;
> +
> + for (i = 0; i < ARRAY_SIZE(hsfreq); i++) {
> + if (freq <= hsfreq[i])
> + break;
> + }
> +
> + if (i == ARRAY_SIZE(hsfreq))
> + i--;
> +
> + return ulpsexit[i];
> +}
> +
> +static u16 rzv2h_dphy_find_timings_val(unsigned long freq, u8 index)
> +{
> + const struct rzv2h_mipi_dsi_timings *timings;
> + u16 i;
> +
> + timings = &rzv2h_dsi_timings_tables[index];
> + for (i = 0; i < timings->len; i++) {
> + unsigned long hsfreq = timings->hsfreq[i] * 10 * MEGA;
> +
> + if (freq <= hsfreq)
> + break;
> + }
> +
> + if (i == timings->len)
> + i--;
> +
> + return timings->start_index + i;
> +};
I have to say I really don't like this... In the minimum, the method how
this works has to be explained in a comment. These values can't really
be calculated? If we really have to deal with hardcoded values and with
that table from the docs, I would say that just replicate the table in
the driver (i.e. a struct that represents one row of the table), instead
of the method in this driver.
Or was this method added based on earlier feedback, for v3? I see
"Simplifed V2H DSI timings array to save space" in the change log. If
so, at least document it clearly.
> +
> static void rzg2l_mipi_dsi_phy_write(struct rzg2l_mipi_dsi *dsi, u32 reg, u32 data)
> {
> iowrite32(data, dsi->mmio + dsi->info->phy_reg_offset + reg);
> @@ -318,6 +489,150 @@ static int rzg2l_dphy_conf_clks(struct rzg2l_mipi_dsi *dsi, unsigned long mode_f
> return 0;
> }
>
> +static unsigned int rzv2h_dphy_mode_clk_check(struct rzg2l_mipi_dsi *dsi,
> + unsigned long mode_freq)
> +{
> + u64 hsfreq_millihz, mode_freq_hz, mode_freq_millihz;
> + struct rzv2h_pll_div_pars cpg_dsi_parameters;
> + struct rzv2h_pll_pars dsi_parameters;
> + bool parameters_found;
> + unsigned int bpp;
> +
> + bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
> + mode_freq_hz = mul_u32_u32(mode_freq, KILO);
> + mode_freq_millihz = mode_freq_hz * MILLI;
> + parameters_found =
> + rzv2h_get_pll_divs_pars(dsi->info->cpg_plldsi.limits[0],
> + &cpg_dsi_parameters,
> + dsi->info->cpg_plldsi.table,
> + dsi->info->cpg_plldsi.table_size,
> + mode_freq_millihz);
> + if (!parameters_found)
> + return MODE_CLOCK_RANGE;
> +
> + hsfreq_millihz = DIV_ROUND_CLOSEST_ULL(cpg_dsi_parameters.div.freq_millihz * bpp,
> + dsi->lanes);
> + parameters_found = rzv2h_get_pll_pars(&rzv2h_plldsi_div_limits,
> + &dsi_parameters, hsfreq_millihz);
> + if (!parameters_found)
> + return MODE_CLOCK_RANGE;
> +
> + if (abs(dsi_parameters.error_millihz) >= 500)
> + return MODE_CLOCK_RANGE;
> +
> + memcpy(&dsi->mode_calc.dsi_parameters, &dsi_parameters, sizeof(dsi_parameters));
> + dsi->mode_calc.mode_freq_khz = mode_freq;
> +
> + return MODE_OK;
> +}
> +
> +static int rzv2h_dphy_conf_clks(struct rzg2l_mipi_dsi *dsi, unsigned long mode_freq,
> + u64 *hsfreq_millihz)
> +{
> + struct rzv2h_pll_pars *dsi_parameters = &dsi->mode_calc.dsi_parameters;
> + unsigned long status;
> +
> + if (dsi->mode_calc.mode_freq_khz != mode_freq) {
> + status = rzv2h_dphy_mode_clk_check(dsi, mode_freq);
> + if (status != MODE_OK) {
> + dev_err(dsi->dev, "No PLL parameters found for mode clk %lu\n",
> + mode_freq);
> + return -EINVAL;
> + }
> + }
> +
> + *hsfreq_millihz = dsi_parameters->freq_millihz;
> +
> + return 0;
> +}
> +
> +static int rzv2h_mipi_dsi_dphy_init(struct rzg2l_mipi_dsi *dsi,
> + u64 hsfreq_millihz)
> +{
> + struct rzv2h_pll_pars *dsi_parameters = &dsi->mode_calc.dsi_parameters;
> + unsigned long lpclk_rate = clk_get_rate(dsi->lpclk);
> + u32 phytclksetr, phythssetr, phytlpxsetr, phycr;
> + struct rzg2l_mipi_dsi_timings dphy_timings;
> + u16 ulpsexit;
> + u64 hsfreq;
> +
> + hsfreq = DIV_ROUND_CLOSEST_ULL(hsfreq_millihz, MILLI);
> +
> + if (dsi_parameters->freq_millihz == hsfreq_millihz)
> + goto parameters_found;
> +
> + if (rzv2h_get_pll_pars(&rzv2h_plldsi_div_limits,
> + dsi_parameters, hsfreq_millihz))
> + goto parameters_found;
> +
> + dev_err(dsi->dev, "No PLL parameters found for HSFREQ %lluHz\n", hsfreq);
> + return -EINVAL;
> +
> +parameters_found:
Maybe:
if (dsi_parameters->freq_millihz != hsfreq_millihz &&
!rzv2h_get_pll_pars(&rzv2h_plldsi_div_limits, dsi_parameters,
hsfreq_millihz)) {
dev_err(dsi->dev, "No PLL parameters found for HSFREQ %lluHz\n",
hsfreq);
return -EINVAL;
}
keeps the flow a bit cleaner.
> + dphy_timings.tclk_trail =
> + rzv2h_dphy_find_timings_val(hsfreq, TCLKTRAILCTL);
> + dphy_timings.tclk_post =
> + rzv2h_dphy_find_timings_val(hsfreq, TCLKPOSTCTL);
> + dphy_timings.tclk_zero =
> + rzv2h_dphy_find_timings_val(hsfreq, TCLKZEROCTL);
> + dphy_timings.tclk_prepare =
> + rzv2h_dphy_find_timings_val(hsfreq, TCLKPRPRCTL);
> + dphy_timings.ths_exit =
> + rzv2h_dphy_find_timings_val(hsfreq, THSEXITCTL);
> + dphy_timings.ths_trail =
> + rzv2h_dphy_find_timings_val(hsfreq, THSTRAILCTL);
> + dphy_timings.ths_zero =
> + rzv2h_dphy_find_timings_val(hsfreq, THSZEROCTL);
> + dphy_timings.ths_prepare =
> + rzv2h_dphy_find_timings_val(hsfreq, THSPRPRCTL);
> + dphy_timings.tlpx =
> + rzv2h_dphy_find_timings_val(hsfreq, TLPXCTL);
> + ulpsexit = rzv2h_dphy_find_ulpsexit(lpclk_rate);
> +
> + phytclksetr = FIELD_PREP(PHYTCLKSETR_TCLKTRAILCTL, dphy_timings.tclk_trail) |
> + FIELD_PREP(PHYTCLKSETR_TCLKPOSTCTL, dphy_timings.tclk_post) |
> + FIELD_PREP(PHYTCLKSETR_TCLKZEROCTL, dphy_timings.tclk_zero) |
> + FIELD_PREP(PHYTCLKSETR_TCLKPRPRCTL, dphy_timings.tclk_prepare);
> + phythssetr = FIELD_PREP(PHYTHSSETR_THSEXITCTL, dphy_timings.ths_exit) |
> + FIELD_PREP(PHYTHSSETR_THSTRAILCTL, dphy_timings.ths_trail) |
> + FIELD_PREP(PHYTHSSETR_THSZEROCTL, dphy_timings.ths_zero) |
> + FIELD_PREP(PHYTHSSETR_THSPRPRCTL, dphy_timings.ths_prepare);
> + phytlpxsetr = rzg2l_mipi_dsi_phy_read(dsi, PHYTLPXSETR) & ~PHYTLPXSETR_TLPXCTL;
> + phytlpxsetr |= FIELD_PREP(PHYTLPXSETR_TLPXCTL, dphy_timings.tlpx);
> + phycr = rzg2l_mipi_dsi_phy_read(dsi, PHYCR) & ~GENMASK(9, 0);
> + phycr |= FIELD_PREP(PHYCR_ULPSEXIT, ulpsexit);
> +
> + /* Setting all D-PHY Timings Registers */
> + rzg2l_mipi_dsi_phy_write(dsi, PHYTCLKSETR, phytclksetr);
> + rzg2l_mipi_dsi_phy_write(dsi, PHYTHSSETR, phythssetr);
> + rzg2l_mipi_dsi_phy_write(dsi, PHYTLPXSETR, phytlpxsetr);
> + rzg2l_mipi_dsi_phy_write(dsi, PHYCR, phycr);
> +
> + rzg2l_mipi_dsi_phy_write(dsi, PLLCLKSET0R,
> + FIELD_PREP(PLLCLKSET0R_PLL_S, dsi_parameters->s) |
> + FIELD_PREP(PLLCLKSET0R_PLL_P, dsi_parameters->p) |
> + FIELD_PREP(PLLCLKSET0R_PLL_M, dsi_parameters->m));
> + rzg2l_mipi_dsi_phy_write(dsi, PLLCLKSET1R,
> + FIELD_PREP(PLLCLKSET1R_PLL_K, dsi_parameters->k));
> + fsleep(20);
Why sleep? Sleeps should (almost) always have a comment, explaining what
it is waiting for.
> +
> + rzg2l_mipi_dsi_phy_write(dsi, PLLENR, PLLENR_PLLEN);
> + fsleep(500);
> +
> + return 0;
> +}
> +
> +static void rzv2h_mipi_dsi_dphy_startup_late_init(struct rzg2l_mipi_dsi *dsi)
> +{
> + fsleep(220);
Especially sleeps like this, where the upper side is "open ended".
> + rzg2l_mipi_dsi_phy_write(dsi, PHYRSTR, PHYRSTR_PHYMRSTN);
> +}
> +
Tomi
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