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phy: freescale: fsl-samsung-hdmi: Clean up fld_tg_code calculation

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Currently, the calcuation for fld_tg_code is based on a lookup table,
but there are gaps in the lookup table, and frequencies in these
gaps may not properly use the correct divider.  Based on the description
of FLD_CK_DIV, the internal PLL frequency should be less than 50 MHz,
so directly calcuate the value of FLD_CK_DIV from pixclk.
This allow for proper calcuation of any pixel clock and eliminates a
few gaps in the LUT.

Since the value of the int_pllclk is in Hz, do the fixed-point
math in Hz to achieve a more accurate value and reduces the complexity
of the caluation to 24MHz * (256 / int_pllclk).

Fixes: 6ad082bee9 ("phy: freescale: add Samsung HDMI PHY")
Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Link: https://lore.kernel.org/r/20241026132014.73050-3-aford173@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Adam Ford 2024-10-26 08:19:59 -05:00 committed by Vinod Koul
parent 1b9b8b1596
commit d567679f2b
1 changed files with 10 additions and 20 deletions
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28
drivers/phy/freescale/phy-fsl-samsung-hdmi.c
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@ -331,25 +331,17 @@ fsl_samsung_hdmi_phy_configure_pll_lock_det(struct fsl_samsung_hdmi_phy *phy,
{
u32 pclk = cfg->pixclk;
u32 fld_tg_code;
u32 pclk_khz;
u8 div = 1;
u32 int_pllclk;
u8 div;
switch (cfg->pixclk) {
case 22250000 ... 47500000:
div = 1;
break;
case 50349650 ... 99000000:
div = 2;
break;
case 100699300 ... 198000000:
div = 4;
break;
case 205000000 ... 297000000:
div = 8;
/* Find int_pllclk speed */
for (div = 0; div < 4; div++) {
int_pllclk = pclk / (1 << div);
if (int_pllclk < (50 * MHZ))
break;
}
writeb(FIELD_PREP(REG12_CK_DIV_MASK, ilog2(div)), phy->regs + PHY_REG(12));
writeb(FIELD_PREP(REG12_CK_DIV_MASK, div), phy->regs + PHY_REG(12));
/*
* Calculation for the frequency lock detector target code (fld_tg_code)
@ -362,10 +354,8 @@ fsl_samsung_hdmi_phy_configure_pll_lock_det(struct fsl_samsung_hdmi_phy *phy,
* settings rounding up always too. TODO: Check if that is
* correct.
*/
pclk /= div;
pclk_khz = pclk / 1000;
fld_tg_code = 256 * 1000 * 1000 / pclk_khz * 24;
fld_tg_code = DIV_ROUND_UP(fld_tg_code, 1000);
fld_tg_code = DIV_ROUND_UP(24 * MHZ * 256, int_pllclk);
/* FLD_TOL and FLD_RP_CODE taken from downstream driver */
writeb(FIELD_PREP(REG13_TG_CODE_LOW_MASK, fld_tg_code),