Currently, in rcar_mipi_dsi_parameters_calc(), the VCLK divider is stored in setup_info structure as BIT(divider). The rcar_mipi_dsi_parameters_calc() is called at the early beginning of rcar_mipi_dsi_startup() function. Later, in the same rcar_mipi_dsi_startup() function, the stored BIT(divider) value is passed to __ffs() to calculate back the divider out of the value again.
Factor out VCLK divider calculation into rcar_mipi_dsi_vclk_divider() function and call the function from both rcar_mipi_dsi_parameters_calc() and rcar_mipi_dsi_startup() to avoid this back and forth BIT() and _ffs() and avoid unnecessarily storing the divider value in setup_info at all. This rework has a slight side-effect, in that it should allow the compiler to better evaluate the code and avoid compiler warnings about variable value overflows, which can never happen. Reported-by: kernel test robot <[email protected]> Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/ Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/ Signed-off-by: Marek Vasut <[email protected]> --- Cc: David Airlie <[email protected]> Cc: Geert Uytterhoeven <[email protected]> Cc: Kieran Bingham <[email protected]> Cc: Laurent Pinchart <[email protected]> Cc: Maarten Lankhorst <[email protected]> Cc: Magnus Damm <[email protected]> Cc: Maxime Ripard <[email protected]> Cc: Simona Vetter <[email protected]> Cc: Thomas Zimmermann <[email protected]> Cc: Tomi Valkeinen <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] --- .../gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c | 35 ++++++++++++++----- 1 file changed, 26 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c index 4ef2e3c129ed7..875945bf8255b 100644 --- a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c +++ b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c @@ -84,7 +84,6 @@ struct dsi_setup_info { unsigned long fout; u16 m; u16 n; - u16 vclk_divider; const struct dsi_clk_config *clkset; }; @@ -335,10 +334,24 @@ rcar_mipi_dsi_post_init_phtw_v4h(struct rcar_mipi_dsi *dsi, * Hardware Setup */ +static unsigned int rcar_mipi_dsi_vclk_divider(struct rcar_mipi_dsi *dsi, + struct dsi_setup_info *setup_info) +{ + switch (dsi->info->model) { + case RCAR_DSI_V3U: + default: + return (setup_info->clkset->vco_cntrl >> 4) & 0x3; + + case RCAR_DSI_V4H: + return (setup_info->clkset->vco_cntrl >> 3) & 0x7; + } +} + static void rcar_mipi_dsi_pll_calc(struct rcar_mipi_dsi *dsi, unsigned long fin_rate, unsigned long fout_target, - struct dsi_setup_info *setup_info) + struct dsi_setup_info *setup_info, + u16 vclk_divider) { unsigned int best_err = -1; const struct rcar_mipi_dsi_device_info *info = dsi->info; @@ -360,7 +373,7 @@ static void rcar_mipi_dsi_pll_calc(struct rcar_mipi_dsi *dsi, if (fout < info->fout_min || fout > info->fout_max) continue; - fout = div64_u64(fout, setup_info->vclk_divider); + fout = div64_u64(fout, vclk_divider); if (fout < setup_info->clkset->min_freq || fout > setup_info->clkset->max_freq) @@ -390,7 +403,9 @@ static void rcar_mipi_dsi_parameters_calc(struct rcar_mipi_dsi *dsi, unsigned long fout_target; unsigned long fin_rate; unsigned int i; + unsigned int div; unsigned int err; + u16 vclk_divider; /* * Calculate Fout = dot clock * ColorDepth / (2 * Lane Count) @@ -412,18 +427,20 @@ static void rcar_mipi_dsi_parameters_calc(struct rcar_mipi_dsi *dsi, fin_rate = clk_get_rate(clk); + div = rcar_mipi_dsi_vclk_divider(dsi, setup_info); + switch (dsi->info->model) { case RCAR_DSI_V3U: default: - setup_info->vclk_divider = 1 << ((clk_cfg->vco_cntrl >> 4) & 0x3); + vclk_divider = BIT_U32(div); break; case RCAR_DSI_V4H: - setup_info->vclk_divider = 1 << (((clk_cfg->vco_cntrl >> 3) & 0x7) + 1); + vclk_divider = BIT_U32(div + 1); break; } - rcar_mipi_dsi_pll_calc(dsi, fin_rate, fout_target, setup_info); + rcar_mipi_dsi_pll_calc(dsi, fin_rate, fout_target, setup_info, vclk_divider); /* Find hsfreqrange */ setup_info->hsfreq = setup_info->fout * 2; @@ -439,7 +456,7 @@ static void rcar_mipi_dsi_parameters_calc(struct rcar_mipi_dsi *dsi, dev_dbg(dsi->dev, "Fout = %u * %lu / (%u * %u * %u) = %lu (target %lu Hz, error %d.%02u%%)\n", setup_info->m, fin_rate, dsi->info->n_mul, setup_info->n, - setup_info->vclk_divider, setup_info->fout, fout_target, + vclk_divider, setup_info->fout, fout_target, err / 100, err % 100); dev_dbg(dsi->dev, @@ -653,11 +670,11 @@ static int rcar_mipi_dsi_startup(struct rcar_mipi_dsi *dsi, switch (dsi->info->model) { case RCAR_DSI_V3U: default: - vclkset |= VCLKSET_DIV_V3U(__ffs(setup_info.vclk_divider)); + vclkset |= VCLKSET_DIV_V3U(rcar_mipi_dsi_vclk_divider(dsi, &setup_info)); break; case RCAR_DSI_V4H: - vclkset |= VCLKSET_DIV_V4H(__ffs(setup_info.vclk_divider) - 1); + vclkset |= VCLKSET_DIV_V4H(rcar_mipi_dsi_vclk_divider(dsi, &setup_info)); break; } -- 2.51.0
