media: ccs-pll: Begin calculation from OP system clock frequency

The OP system clock frequency defines the CSI-2 bus clock frequency, not
the PLL output clock frequency. Both values were overwritten in the end,
but the wrong limit value was used for the OP system clock frequency,
possibly leading to too high frequencies being used.

Also remove now duplicated calculation of OP system clock frequency later
in the PLL calculator.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/i2c/ccs-pll.c

@@ -247,10 +247,6 @@ __ccs_pll_calculate(struct device *dev, const struct ccs_pll_limits *lim,
 	op_pll_fr->pll_op_clk_freq_hz = op_pll_fr->pll_ip_clk_freq_hz
 		* op_pll_fr->pll_multiplier;
 
-	/* Derive pll_op_clk_freq_hz. */
-	op_pll_bk->sys_clk_freq_hz =
-		op_pll_fr->pll_op_clk_freq_hz / op_pll_bk->sys_clk_div;
-
 	op_pll_bk->pix_clk_div = pll->bits_per_pixel;
 	dev_dbg(dev, "op_pix_clk_div: %u\n", op_pll_bk->pix_clk_div);
 
@@ -432,7 +428,7 @@ int ccs_pll_calculate(struct device *dev, const struct ccs_pll_limits *lim,
 	switch (pll->bus_type) {
 	case CCS_PLL_BUS_TYPE_CSI2_DPHY:
 		/* CSI transfers 2 bits per clock per lane; thus times 2 */
-		op_pll_fr->pll_op_clk_freq_hz = pll->link_freq * 2
+		op_pll_bk->sys_clk_freq_hz = pll->link_freq * 2
 			* (pll->csi2.lanes / lane_op_clock_ratio);
 		break;
 	default:
@@ -454,8 +450,8 @@ int ccs_pll_calculate(struct device *dev, const struct ccs_pll_limits *lim,
 	dev_dbg(dev, "pre-pll check: min / max op_pre_pll_clk_div: %u / %u\n",
 		min_op_pre_pll_clk_div, max_op_pre_pll_clk_div);
 
-	i = gcd(op_pll_fr->pll_op_clk_freq_hz, pll->ext_clk_freq_hz);
-	mul = op_pll_fr->pll_op_clk_freq_hz / i;
+	i = gcd(op_pll_bk->sys_clk_freq_hz, pll->ext_clk_freq_hz);
+	mul = op_pll_bk->sys_clk_freq_hz / i;
 	div = pll->ext_clk_freq_hz / i;
 	dev_dbg(dev, "mul %u / div %u\n", mul, div);
 
@@ -463,7 +459,7 @@ int ccs_pll_calculate(struct device *dev, const struct ccs_pll_limits *lim,
 		max_t(uint16_t, min_op_pre_pll_clk_div,
 		      clk_div_even_up(
 			      DIV_ROUND_UP(mul * pll->ext_clk_freq_hz,
-					   op_lim_fr->max_pll_op_clk_freq_hz)));
+					   op_lim_bk->max_sys_clk_freq_hz)));
 	dev_dbg(dev, "pll_op check: min / max op_pre_pll_clk_div: %u / %u\n",
 		min_op_pre_pll_clk_div, max_op_pre_pll_clk_div);