drivers/media/i2c/smiapp-pll.c - linux - Git at Google

 /*
  * drivers/media/i2c/smiapp-pll.c
  *
  * Generic driver for SMIA/SMIA++ compliant camera modules
  *
  * Copyright (C) 2011--2012 Nokia Corporation
  * Contact: Sakari Ailus <sakari.ailus@iki.fi>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * version 2 as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * General Public License for more details.
  */

 #include <linux/device.h>
 #include <linux/gcd.h>
 #include <linux/lcm.h>
 #include <linux/module.h>

 #include "smiapp-pll.h"

 /* Return an even number or one. */
 static inline uint32_t clk_div_even(uint32_t a)
 {
 	return max_t(uint32_t, 1, a & ~1);
 }

 /* Return an even number or one. */
 static inline uint32_t clk_div_even_up(uint32_t a)
 {
 	if (a == 1)
 		return 1;
 	return (a + 1) & ~1;
 }

 static inline uint32_t is_one_or_even(uint32_t a)
 {
 	if (a == 1)
 		return 1;
 	if (a & 1)
 		return 0;

 	return 1;
 }

 static int bounds_check(struct device *dev, uint32_t val,
 			uint32_t min, uint32_t max, char *str)
 {
 	if (val >= min && val <= max)
 		return 0;

 	dev_dbg(dev, "%s out of bounds: %d (%d--%d)\n", str, val, min, max);

 	return -EINVAL;
 }

 static void print_pll(struct device *dev, struct smiapp_pll *pll)
 {
 	dev_dbg(dev, "pre_pll_clk_div\t%u\n",  pll->pre_pll_clk_div);
 	dev_dbg(dev, "pll_multiplier \t%u\n",  pll->pll_multiplier);
 	if (!(pll->flags & SMIAPP_PLL_FLAG_NO_OP_CLOCKS)) {
 		dev_dbg(dev, "op_sys_clk_div \t%u\n", pll->op.sys_clk_div);
 		dev_dbg(dev, "op_pix_clk_div \t%u\n", pll->op.pix_clk_div);
 	}
 	dev_dbg(dev, "vt_sys_clk_div \t%u\n",  pll->vt.sys_clk_div);
 	dev_dbg(dev, "vt_pix_clk_div \t%u\n",  pll->vt.pix_clk_div);

 	dev_dbg(dev, "ext_clk_freq_hz \t%u\n", pll->ext_clk_freq_hz);
 	dev_dbg(dev, "pll_ip_clk_freq_hz \t%u\n", pll->pll_ip_clk_freq_hz);
 	dev_dbg(dev, "pll_op_clk_freq_hz \t%u\n", pll->pll_op_clk_freq_hz);
 	if (!(pll->flags & SMIAPP_PLL_FLAG_NO_OP_CLOCKS)) {
 		dev_dbg(dev, "op_sys_clk_freq_hz \t%u\n",
 			pll->op.sys_clk_freq_hz);
 		dev_dbg(dev, "op_pix_clk_freq_hz \t%u\n",
 			pll->op.pix_clk_freq_hz);
 	}
 	dev_dbg(dev, "vt_sys_clk_freq_hz \t%u\n", pll->vt.sys_clk_freq_hz);
 	dev_dbg(dev, "vt_pix_clk_freq_hz \t%u\n", pll->vt.pix_clk_freq_hz);
 }

 static int check_all_bounds(struct device *dev,
 			    const struct smiapp_pll_limits *limits,
 			    const struct smiapp_pll_branch_limits *op_limits,
 			    struct smiapp_pll *pll,
 			    struct smiapp_pll_branch *op_pll)
 {
 	int rval;

 	rval = bounds_check(dev, pll->pll_ip_clk_freq_hz,
 			    limits->min_pll_ip_freq_hz,
 			    limits->max_pll_ip_freq_hz,
 			    "pll_ip_clk_freq_hz");
 	if (!rval)
 		rval = bounds_check(
 			dev, pll->pll_multiplier,
 			limits->min_pll_multiplier, limits->max_pll_multiplier,
 			"pll_multiplier");
 	if (!rval)
 		rval = bounds_check(
 			dev, pll->pll_op_clk_freq_hz,
 			limits->min_pll_op_freq_hz, limits->max_pll_op_freq_hz,
 			"pll_op_clk_freq_hz");
 	if (!rval)
 		rval = bounds_check(
 			dev, op_pll->sys_clk_div,
 			op_limits->min_sys_clk_div, op_limits->max_sys_clk_div,
 			"op_sys_clk_div");
 	if (!rval)
 		rval = bounds_check(
 			dev, op_pll->sys_clk_freq_hz,
 			op_limits->min_sys_clk_freq_hz,
 			op_limits->max_sys_clk_freq_hz,
 			"op_sys_clk_freq_hz");
 	if (!rval)
 		rval = bounds_check(
 			dev, op_pll->pix_clk_freq_hz,
 			op_limits->min_pix_clk_freq_hz,
 			op_limits->max_pix_clk_freq_hz,
 			"op_pix_clk_freq_hz");

 	/*
 	 * If there are no OP clocks, the VT clocks are contained in
 	 * the OP clock struct.
 	 */
 	if (pll->flags & SMIAPP_PLL_FLAG_NO_OP_CLOCKS)
 		return rval;

 	if (!rval)
 		rval = bounds_check(
 			dev, pll->vt.sys_clk_freq_hz,
 			limits->vt.min_sys_clk_freq_hz,
 			limits->vt.max_sys_clk_freq_hz,
 			"vt_sys_clk_freq_hz");
 	if (!rval)
 		rval = bounds_check(
 			dev, pll->vt.pix_clk_freq_hz,
 			limits->vt.min_pix_clk_freq_hz,
 			limits->vt.max_pix_clk_freq_hz,
 			"vt_pix_clk_freq_hz");

 	return rval;
 }

 /*
  * Heuristically guess the PLL tree for a given common multiplier and
  * divisor. Begin with the operational timing and continue to video
  * timing once operational timing has been verified.
  *
  * @mul is the PLL multiplier and @div is the common divisor
  * (pre_pll_clk_div and op_sys_clk_div combined). The final PLL
  * multiplier will be a multiple of @mul.
  *
  * @return Zero on success, error code on error.
  */
 static int __smiapp_pll_calculate(
 	struct device *dev, const struct smiapp_pll_limits *limits,
 	const struct smiapp_pll_branch_limits *op_limits,
 	struct smiapp_pll *pll, struct smiapp_pll_branch *op_pll, uint32_t mul,
 	uint32_t div, uint32_t lane_op_clock_ratio)
 {
 	uint32_t sys_div;
 	uint32_t best_pix_div = INT_MAX >> 1;
 	uint32_t vt_op_binning_div;
 	/*
 	 * Higher multipliers (and divisors) are often required than
 	 * necessitated by the external clock and the output clocks.
 	 * There are limits for all values in the clock tree. These
 	 * are the minimum and maximum multiplier for mul.
 	 */
 	uint32_t more_mul_min, more_mul_max;
 	uint32_t more_mul_factor;
 	uint32_t min_vt_div, max_vt_div, vt_div;
 	uint32_t min_sys_div, max_sys_div;
 	unsigned int i;

 	/*
 	 * Get pre_pll_clk_div so that our pll_op_clk_freq_hz won't be
 	 * too high.
 	 */
 	dev_dbg(dev, "pre_pll_clk_div %u\n", pll->pre_pll_clk_div);

 	/* Don't go above max pll multiplier. */
 	more_mul_max = limits->max_pll_multiplier / mul;
 	dev_dbg(dev, "more_mul_max: max_pll_multiplier check: %u\n",
 		more_mul_max);
 	/* Don't go above max pll op frequency. */
 	more_mul_max =
 		min_t(uint32_t,
 		      more_mul_max,
 		      limits->max_pll_op_freq_hz
 		      / (pll->ext_clk_freq_hz / pll->pre_pll_clk_div * mul));
 	dev_dbg(dev, "more_mul_max: max_pll_op_freq_hz check: %u\n",
 		more_mul_max);
 	/* Don't go above the division capability of op sys clock divider. */
 	more_mul_max = min(more_mul_max,
 			   op_limits->max_sys_clk_div * pll->pre_pll_clk_div
 			   / div);
 	dev_dbg(dev, "more_mul_max: max_op_sys_clk_div check: %u\n",
 		more_mul_max);
 	/* Ensure we won't go above min_pll_multiplier. */
 	more_mul_max = min(more_mul_max,
 			   DIV_ROUND_UP(limits->max_pll_multiplier, mul));
 	dev_dbg(dev, "more_mul_max: min_pll_multiplier check: %u\n",
 		more_mul_max);

 	/* Ensure we won't go below min_pll_op_freq_hz. */
 	more_mul_min = DIV_ROUND_UP(limits->min_pll_op_freq_hz,
 				    pll->ext_clk_freq_hz / pll->pre_pll_clk_div
 				    * mul);
 	dev_dbg(dev, "more_mul_min: min_pll_op_freq_hz check: %u\n",
 		more_mul_min);
 	/* Ensure we won't go below min_pll_multiplier. */
 	more_mul_min = max(more_mul_min,
 			   DIV_ROUND_UP(limits->min_pll_multiplier, mul));
 	dev_dbg(dev, "more_mul_min: min_pll_multiplier check: %u\n",
 		more_mul_min);

 	if (more_mul_min > more_mul_max) {
 		dev_dbg(dev,
 			"unable to compute more_mul_min and more_mul_max\n");
 		return -EINVAL;
 	}

 	more_mul_factor = lcm(div, pll->pre_pll_clk_div) / div;
 	dev_dbg(dev, "more_mul_factor: %u\n", more_mul_factor);
 	more_mul_factor = lcm(more_mul_factor, op_limits->min_sys_clk_div);
 	dev_dbg(dev, "more_mul_factor: min_op_sys_clk_div: %d\n",
 		more_mul_factor);
 	i = roundup(more_mul_min, more_mul_factor);
 	if (!is_one_or_even(i))
 		i <<= 1;

 	dev_dbg(dev, "final more_mul: %u\n", i);
 	if (i > more_mul_max) {
 		dev_dbg(dev, "final more_mul is bad, max %u\n", more_mul_max);
 		return -EINVAL;
 	}

 	pll->pll_multiplier = mul * i;
 	op_pll->sys_clk_div = div * i / pll->pre_pll_clk_div;
 	dev_dbg(dev, "op_sys_clk_div: %u\n", op_pll->sys_clk_div);

 	pll->pll_ip_clk_freq_hz = pll->ext_clk_freq_hz
 		/ pll->pre_pll_clk_div;

 	pll->pll_op_clk_freq_hz = pll->pll_ip_clk_freq_hz
 		* pll->pll_multiplier;

 	/* Derive pll_op_clk_freq_hz. */
 	op_pll->sys_clk_freq_hz =
 		pll->pll_op_clk_freq_hz / op_pll->sys_clk_div;

 	op_pll->pix_clk_div = pll->bits_per_pixel;
 	dev_dbg(dev, "op_pix_clk_div: %u\n", op_pll->pix_clk_div);

 	op_pll->pix_clk_freq_hz =
 		op_pll->sys_clk_freq_hz / op_pll->pix_clk_div;

 	if (pll->flags & SMIAPP_PLL_FLAG_NO_OP_CLOCKS) {
 		/* No OP clocks --- VT clocks are used instead. */
 		goto out_skip_vt_calc;
 	}

 	/*
 	 * Some sensors perform analogue binning and some do this
 	 * digitally. The ones doing this digitally can be roughly be
 	 * found out using this formula. The ones doing this digitally
 	 * should run at higher clock rate, so smaller divisor is used
 	 * on video timing side.
 	 */
 	if (limits->min_line_length_pck_bin > limits->min_line_length_pck
 	    / pll->binning_horizontal)
 		vt_op_binning_div = pll->binning_horizontal;
 	else
 		vt_op_binning_div = 1;
 	dev_dbg(dev, "vt_op_binning_div: %u\n", vt_op_binning_div);

 	/*
 	 * Profile 2 supports vt_pix_clk_div E [4, 10]
 	 *
 	 * Horizontal binning can be used as a base for difference in
 	 * divisors. One must make sure that horizontal blanking is
 	 * enough to accommodate the CSI-2 sync codes.
 	 *
 	 * Take scaling factor into account as well.
 	 *
 	 * Find absolute limits for the factor of vt divider.
 	 */
 	dev_dbg(dev, "scale_m: %u\n", pll->scale_m);
 	min_vt_div = DIV_ROUND_UP(op_pll->pix_clk_div * op_pll->sys_clk_div
 				  * pll->scale_n,
 				  lane_op_clock_ratio * vt_op_binning_div
 				  * pll->scale_m);

 	/* Find smallest and biggest allowed vt divisor. */
 	dev_dbg(dev, "min_vt_div: %u\n", min_vt_div);
 	min_vt_div = max(min_vt_div,
 			 DIV_ROUND_UP(pll->pll_op_clk_freq_hz,
 				      limits->vt.max_pix_clk_freq_hz));
 	dev_dbg(dev, "min_vt_div: max_vt_pix_clk_freq_hz: %u\n",
 		min_vt_div);
 	min_vt_div = max_t(uint32_t, min_vt_div,
 			   limits->vt.min_pix_clk_div
 			   * limits->vt.min_sys_clk_div);
 	dev_dbg(dev, "min_vt_div: min_vt_clk_div: %u\n", min_vt_div);

 	max_vt_div = limits->vt.max_sys_clk_div * limits->vt.max_pix_clk_div;
 	dev_dbg(dev, "max_vt_div: %u\n", max_vt_div);
 	max_vt_div = min(max_vt_div,
 			 DIV_ROUND_UP(pll->pll_op_clk_freq_hz,
 				      limits->vt.min_pix_clk_freq_hz));
 	dev_dbg(dev, "max_vt_div: min_vt_pix_clk_freq_hz: %u\n",
 		max_vt_div);

 	/*
 	 * Find limitsits for sys_clk_div. Not all values are possible
 	 * with all values of pix_clk_div.
 	 */
 	min_sys_div = limits->vt.min_sys_clk_div;
 	dev_dbg(dev, "min_sys_div: %u\n", min_sys_div);
 	min_sys_div = max(min_sys_div,
 			  DIV_ROUND_UP(min_vt_div,
 				       limits->vt.max_pix_clk_div));
 	dev_dbg(dev, "min_sys_div: max_vt_pix_clk_div: %u\n", min_sys_div);
 	min_sys_div = max(min_sys_div,
 			  pll->pll_op_clk_freq_hz
 			  / limits->vt.max_sys_clk_freq_hz);
 	dev_dbg(dev, "min_sys_div: max_pll_op_clk_freq_hz: %u\n", min_sys_div);
 	min_sys_div = clk_div_even_up(min_sys_div);
 	dev_dbg(dev, "min_sys_div: one or even: %u\n", min_sys_div);

 	max_sys_div = limits->vt.max_sys_clk_div;
 	dev_dbg(dev, "max_sys_div: %u\n", max_sys_div);
 	max_sys_div = min(max_sys_div,
 			  DIV_ROUND_UP(max_vt_div,
 				       limits->vt.min_pix_clk_div));
 	dev_dbg(dev, "max_sys_div: min_vt_pix_clk_div: %u\n", max_sys_div);
 	max_sys_div = min(max_sys_div,
 			  DIV_ROUND_UP(pll->pll_op_clk_freq_hz,
 				       limits->vt.min_pix_clk_freq_hz));
 	dev_dbg(dev, "max_sys_div: min_vt_pix_clk_freq_hz: %u\n", max_sys_div);

 	/*
 	 * Find pix_div such that a legal pix_div * sys_div results
 	 * into a value which is not smaller than div, the desired
 	 * divisor.
 	 */
 	for (vt_div = min_vt_div; vt_div <= max_vt_div;
 	     vt_div += 2 - (vt_div & 1)) {
 		for (sys_div = min_sys_div;
 		     sys_div <= max_sys_div;
 		     sys_div += 2 - (sys_div & 1)) {
 			uint16_t pix_div = DIV_ROUND_UP(vt_div, sys_div);

 			if (pix_div < limits->vt.min_pix_clk_div
 			    || pix_div > limits->vt.max_pix_clk_div) {
 				dev_dbg(dev,
 					"pix_div %u too small or too big (%u--%u)\n",
 					pix_div,
 					limits->vt.min_pix_clk_div,
 					limits->vt.max_pix_clk_div);
 				continue;
 			}

 			/* Check if this one is better. */
 			if (pix_div * sys_div
 			    <= roundup(min_vt_div, best_pix_div))
 				best_pix_div = pix_div;
 		}
 		if (best_pix_div < INT_MAX >> 1)
 			break;
 	}

 	pll->vt.sys_clk_div = DIV_ROUND_UP(min_vt_div, best_pix_div);
 	pll->vt.pix_clk_div = best_pix_div;

 	pll->vt.sys_clk_freq_hz =
 		pll->pll_op_clk_freq_hz / pll->vt.sys_clk_div;
 	pll->vt.pix_clk_freq_hz =
 		pll->vt.sys_clk_freq_hz / pll->vt.pix_clk_div;

 out_skip_vt_calc:
 	pll->pixel_rate_csi =
 		op_pll->pix_clk_freq_hz * lane_op_clock_ratio;
 	pll->pixel_rate_pixel_array = pll->vt.pix_clk_freq_hz;

 	return check_all_bounds(dev, limits, op_limits, pll, op_pll);
 }

 int smiapp_pll_calculate(struct device *dev,
 			 const struct smiapp_pll_limits *limits,
 			 struct smiapp_pll *pll)
 {
 	const struct smiapp_pll_branch_limits *op_limits = &limits->op;
 	struct smiapp_pll_branch *op_pll = &pll->op;
 	uint16_t min_pre_pll_clk_div;
 	uint16_t max_pre_pll_clk_div;
 	uint32_t lane_op_clock_ratio;
 	uint32_t mul, div;
 	unsigned int i;
 	int rval = -EINVAL;

 	if (pll->flags & SMIAPP_PLL_FLAG_NO_OP_CLOCKS) {
 		/*
 		 * If there's no OP PLL at all, use the VT values
 		 * instead. The OP values are ignored for the rest of
 		 * the PLL calculation.
 		 */
 		op_limits = &limits->vt;
 		op_pll = &pll->vt;
 	}

 	if (pll->flags & SMIAPP_PLL_FLAG_OP_PIX_CLOCK_PER_LANE)
 		lane_op_clock_ratio = pll->csi2.lanes;
 	else
 		lane_op_clock_ratio = 1;
 	dev_dbg(dev, "lane_op_clock_ratio: %u\n", lane_op_clock_ratio);

 	dev_dbg(dev, "binning: %ux%u\n", pll->binning_horizontal,
 		pll->binning_vertical);

 	switch (pll->bus_type) {
 	case SMIAPP_PLL_BUS_TYPE_CSI2:
 		/* CSI transfers 2 bits per clock per lane; thus times 2 */
 		pll->pll_op_clk_freq_hz = pll->link_freq * 2
 			* (pll->csi2.lanes / lane_op_clock_ratio);
 		break;
 	case SMIAPP_PLL_BUS_TYPE_PARALLEL:
 		pll->pll_op_clk_freq_hz = pll->link_freq * pll->bits_per_pixel
 			/ DIV_ROUND_UP(pll->bits_per_pixel,
 				       pll->parallel.bus_width);
 		break;
 	default:
 		return -EINVAL;
 	}

 	/* Figure out limits for pre-pll divider based on extclk */
 	dev_dbg(dev, "min / max pre_pll_clk_div: %u / %u\n",
 		limits->min_pre_pll_clk_div, limits->max_pre_pll_clk_div);
 	max_pre_pll_clk_div =
 		min_t(uint16_t, limits->max_pre_pll_clk_div,
 		      clk_div_even(pll->ext_clk_freq_hz /
 				   limits->min_pll_ip_freq_hz));
 	min_pre_pll_clk_div =
 		max_t(uint16_t, limits->min_pre_pll_clk_div,
 		      clk_div_even_up(
 			      DIV_ROUND_UP(pll->ext_clk_freq_hz,
 					   limits->max_pll_ip_freq_hz)));
 	dev_dbg(dev, "pre-pll check: min / max pre_pll_clk_div: %u / %u\n",
 		min_pre_pll_clk_div, max_pre_pll_clk_div);

 	i = gcd(pll->pll_op_clk_freq_hz, pll->ext_clk_freq_hz);
 	mul = div_u64(pll->pll_op_clk_freq_hz, i);
 	div = pll->ext_clk_freq_hz / i;
 	dev_dbg(dev, "mul %u / div %u\n", mul, div);

 	min_pre_pll_clk_div =
 		max_t(uint16_t, min_pre_pll_clk_div,
 		      clk_div_even_up(
 			      DIV_ROUND_UP(mul * pll->ext_clk_freq_hz,
 					   limits->max_pll_op_freq_hz)));
 	dev_dbg(dev, "pll_op check: min / max pre_pll_clk_div: %u / %u\n",
 		min_pre_pll_clk_div, max_pre_pll_clk_div);

 	for (pll->pre_pll_clk_div = min_pre_pll_clk_div;
 	     pll->pre_pll_clk_div <= max_pre_pll_clk_div;
 	     pll->pre_pll_clk_div += 2 - (pll->pre_pll_clk_div & 1)) {
 		rval = __smiapp_pll_calculate(dev, limits, op_limits, pll,
 					      op_pll, mul, div,
 					      lane_op_clock_ratio);
 		if (rval)
 			continue;

 		print_pll(dev, pll);
 		return 0;
 	}

 	dev_dbg(dev, "unable to compute pre_pll divisor\n");

 	return rval;
 }
 EXPORT_SYMBOL_GPL(smiapp_pll_calculate);

 MODULE_AUTHOR("Sakari Ailus <sakari.ailus@iki.fi>");
 MODULE_DESCRIPTION("Generic SMIA/SMIA++ PLL calculator");
 MODULE_LICENSE("GPL");
	/*
	* drivers/media/i2c/smiapp-pll.c
	*
	* Generic driver for SMIA/SMIA++ compliant camera modules
	*
	* Copyright (C) 2011--2012 Nokia Corporation
	* Contact: Sakari Ailus <sakari.ailus@iki.fi>
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* version 2 as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*/

	#include <linux/device.h>
	#include <linux/gcd.h>
	#include <linux/lcm.h>
	#include <linux/module.h>

	#include "smiapp-pll.h"

	/* Return an even number or one. */
	static inline uint32_t clk_div_even(uint32_t a)
	{
	return max_t(uint32_t, 1, a & ~1);
	}

	/* Return an even number or one. */
	static inline uint32_t clk_div_even_up(uint32_t a)
	{
	if (a == 1)
	return 1;
	return (a + 1) & ~1;
	}

	static inline uint32_t is_one_or_even(uint32_t a)
	{
	if (a == 1)
	return 1;
	if (a & 1)
	return 0;

	return 1;
	}

	static int bounds_check(struct device *dev, uint32_t val,
	uint32_t min, uint32_t max, char *str)
	{
	if (val >= min && val <= max)
	return 0;

	dev_dbg(dev, "%s out of bounds: %d (%d--%d)\n", str, val, min, max);

	return -EINVAL;
	}

	static void print_pll(struct device dev, struct smiapp_pll pll)
	{
	dev_dbg(dev, "pre_pll_clk_div\t%u\n", pll->pre_pll_clk_div);
	dev_dbg(dev, "pll_multiplier \t%u\n", pll->pll_multiplier);
	if (!(pll->flags & SMIAPP_PLL_FLAG_NO_OP_CLOCKS)) {
	dev_dbg(dev, "op_sys_clk_div \t%u\n", pll->op.sys_clk_div);
	dev_dbg(dev, "op_pix_clk_div \t%u\n", pll->op.pix_clk_div);
	}
	dev_dbg(dev, "vt_sys_clk_div \t%u\n", pll->vt.sys_clk_div);
	dev_dbg(dev, "vt_pix_clk_div \t%u\n", pll->vt.pix_clk_div);

	dev_dbg(dev, "ext_clk_freq_hz \t%u\n", pll->ext_clk_freq_hz);
	dev_dbg(dev, "pll_ip_clk_freq_hz \t%u\n", pll->pll_ip_clk_freq_hz);
	dev_dbg(dev, "pll_op_clk_freq_hz \t%u\n", pll->pll_op_clk_freq_hz);
	if (!(pll->flags & SMIAPP_PLL_FLAG_NO_OP_CLOCKS)) {
	dev_dbg(dev, "op_sys_clk_freq_hz \t%u\n",
	pll->op.sys_clk_freq_hz);
	dev_dbg(dev, "op_pix_clk_freq_hz \t%u\n",
	pll->op.pix_clk_freq_hz);
	}
	dev_dbg(dev, "vt_sys_clk_freq_hz \t%u\n", pll->vt.sys_clk_freq_hz);
	dev_dbg(dev, "vt_pix_clk_freq_hz \t%u\n", pll->vt.pix_clk_freq_hz);
	}

	static int check_all_bounds(struct device *dev,
	const struct smiapp_pll_limits *limits,
	const struct smiapp_pll_branch_limits *op_limits,
	struct smiapp_pll *pll,
	struct smiapp_pll_branch *op_pll)
	{
	int rval;

	rval = bounds_check(dev, pll->pll_ip_clk_freq_hz,
	limits->min_pll_ip_freq_hz,
	limits->max_pll_ip_freq_hz,
	"pll_ip_clk_freq_hz");
	if (!rval)
	rval = bounds_check(
	dev, pll->pll_multiplier,
	limits->min_pll_multiplier, limits->max_pll_multiplier,
	"pll_multiplier");
	if (!rval)
	rval = bounds_check(
	dev, pll->pll_op_clk_freq_hz,
	limits->min_pll_op_freq_hz, limits->max_pll_op_freq_hz,
	"pll_op_clk_freq_hz");
	if (!rval)
	rval = bounds_check(
	dev, op_pll->sys_clk_div,
	op_limits->min_sys_clk_div, op_limits->max_sys_clk_div,
	"op_sys_clk_div");
	if (!rval)
	rval = bounds_check(
	dev, op_pll->sys_clk_freq_hz,
	op_limits->min_sys_clk_freq_hz,
	op_limits->max_sys_clk_freq_hz,
	"op_sys_clk_freq_hz");
	if (!rval)
	rval = bounds_check(
	dev, op_pll->pix_clk_freq_hz,
	op_limits->min_pix_clk_freq_hz,
	op_limits->max_pix_clk_freq_hz,
	"op_pix_clk_freq_hz");

	/*
	* If there are no OP clocks, the VT clocks are contained in
	* the OP clock struct.
	*/
	if (pll->flags & SMIAPP_PLL_FLAG_NO_OP_CLOCKS)
	return rval;

	if (!rval)
	rval = bounds_check(
	dev, pll->vt.sys_clk_freq_hz,
	limits->vt.min_sys_clk_freq_hz,
	limits->vt.max_sys_clk_freq_hz,
	"vt_sys_clk_freq_hz");
	if (!rval)
	rval = bounds_check(
	dev, pll->vt.pix_clk_freq_hz,
	limits->vt.min_pix_clk_freq_hz,
	limits->vt.max_pix_clk_freq_hz,
	"vt_pix_clk_freq_hz");

	return rval;
	}

	/*
	* Heuristically guess the PLL tree for a given common multiplier and
	* divisor. Begin with the operational timing and continue to video
	* timing once operational timing has been verified.
	*
	* @mul is the PLL multiplier and @div is the common divisor
	* (pre_pll_clk_div and op_sys_clk_div combined). The final PLL
	* multiplier will be a multiple of @mul.
	*
	* @return Zero on success, error code on error.
	*/
	static int __smiapp_pll_calculate(
	struct device dev, const struct smiapp_pll_limits limits,
	const struct smiapp_pll_branch_limits *op_limits,
	struct smiapp_pll pll, struct smiapp_pll_branch op_pll, uint32_t mul,
	uint32_t div, uint32_t lane_op_clock_ratio)
	{
	uint32_t sys_div;
	uint32_t best_pix_div = INT_MAX >> 1;
	uint32_t vt_op_binning_div;
	/*
	* Higher multipliers (and divisors) are often required than
	* necessitated by the external clock and the output clocks.
	* There are limits for all values in the clock tree. These
	* are the minimum and maximum multiplier for mul.
	*/
	uint32_t more_mul_min, more_mul_max;
	uint32_t more_mul_factor;
	uint32_t min_vt_div, max_vt_div, vt_div;
	uint32_t min_sys_div, max_sys_div;
	unsigned int i;

	/*
	* Get pre_pll_clk_div so that our pll_op_clk_freq_hz won't be
	* too high.
	*/
	dev_dbg(dev, "pre_pll_clk_div %u\n", pll->pre_pll_clk_div);

	/* Don't go above max pll multiplier. */
	more_mul_max = limits->max_pll_multiplier / mul;
	dev_dbg(dev, "more_mul_max: max_pll_multiplier check: %u\n",
	more_mul_max);
	/* Don't go above max pll op frequency. */
	more_mul_max =
	min_t(uint32_t,
	more_mul_max,
	limits->max_pll_op_freq_hz
	/ (pll->ext_clk_freq_hz / pll->pre_pll_clk_div * mul));
	dev_dbg(dev, "more_mul_max: max_pll_op_freq_hz check: %u\n",
	more_mul_max);
	/* Don't go above the division capability of op sys clock divider. */
	more_mul_max = min(more_mul_max,
	op_limits->max_sys_clk_div * pll->pre_pll_clk_div
	/ div);
	dev_dbg(dev, "more_mul_max: max_op_sys_clk_div check: %u\n",
	more_mul_max);
	/* Ensure we won't go above min_pll_multiplier. */
	more_mul_max = min(more_mul_max,
	DIV_ROUND_UP(limits->max_pll_multiplier, mul));
	dev_dbg(dev, "more_mul_max: min_pll_multiplier check: %u\n",
	more_mul_max);

	/* Ensure we won't go below min_pll_op_freq_hz. */
	more_mul_min = DIV_ROUND_UP(limits->min_pll_op_freq_hz,
	pll->ext_clk_freq_hz / pll->pre_pll_clk_div
	* mul);
	dev_dbg(dev, "more_mul_min: min_pll_op_freq_hz check: %u\n",
	more_mul_min);
	/* Ensure we won't go below min_pll_multiplier. */
	more_mul_min = max(more_mul_min,
	DIV_ROUND_UP(limits->min_pll_multiplier, mul));
	dev_dbg(dev, "more_mul_min: min_pll_multiplier check: %u\n",
	more_mul_min);

	if (more_mul_min > more_mul_max) {
	dev_dbg(dev,
	"unable to compute more_mul_min and more_mul_max\n");
	return -EINVAL;
	}

	more_mul_factor = lcm(div, pll->pre_pll_clk_div) / div;
	dev_dbg(dev, "more_mul_factor: %u\n", more_mul_factor);
	more_mul_factor = lcm(more_mul_factor, op_limits->min_sys_clk_div);
	dev_dbg(dev, "more_mul_factor: min_op_sys_clk_div: %d\n",
	more_mul_factor);
	i = roundup(more_mul_min, more_mul_factor);
	if (!is_one_or_even(i))
	i <<= 1;

	dev_dbg(dev, "final more_mul: %u\n", i);
	if (i > more_mul_max) {
	dev_dbg(dev, "final more_mul is bad, max %u\n", more_mul_max);
	return -EINVAL;
	}

	pll->pll_multiplier = mul * i;
	op_pll->sys_clk_div = div * i / pll->pre_pll_clk_div;
	dev_dbg(dev, "op_sys_clk_div: %u\n", op_pll->sys_clk_div);

	pll->pll_ip_clk_freq_hz = pll->ext_clk_freq_hz
	/ pll->pre_pll_clk_div;

	pll->pll_op_clk_freq_hz = pll->pll_ip_clk_freq_hz
	* pll->pll_multiplier;

	/* Derive pll_op_clk_freq_hz. */
	op_pll->sys_clk_freq_hz =
	pll->pll_op_clk_freq_hz / op_pll->sys_clk_div;

	op_pll->pix_clk_div = pll->bits_per_pixel;
	dev_dbg(dev, "op_pix_clk_div: %u\n", op_pll->pix_clk_div);

	op_pll->pix_clk_freq_hz =
	op_pll->sys_clk_freq_hz / op_pll->pix_clk_div;

	if (pll->flags & SMIAPP_PLL_FLAG_NO_OP_CLOCKS) {
	/* No OP clocks --- VT clocks are used instead. */
	goto out_skip_vt_calc;
	}

	/*
	* Some sensors perform analogue binning and some do this
	* digitally. The ones doing this digitally can be roughly be
	* found out using this formula. The ones doing this digitally
	* should run at higher clock rate, so smaller divisor is used
	* on video timing side.
	*/
	if (limits->min_line_length_pck_bin > limits->min_line_length_pck
	/ pll->binning_horizontal)
	vt_op_binning_div = pll->binning_horizontal;
	else
	vt_op_binning_div = 1;
	dev_dbg(dev, "vt_op_binning_div: %u\n", vt_op_binning_div);

	/*
	* Profile 2 supports vt_pix_clk_div E [4, 10]
	*
	* Horizontal binning can be used as a base for difference in
	* divisors. One must make sure that horizontal blanking is
	* enough to accommodate the CSI-2 sync codes.
	*
	* Take scaling factor into account as well.
	*
	* Find absolute limits for the factor of vt divider.
	*/
	dev_dbg(dev, "scale_m: %u\n", pll->scale_m);
	min_vt_div = DIV_ROUND_UP(op_pll->pix_clk_div * op_pll->sys_clk_div
	* pll->scale_n,
	lane_op_clock_ratio * vt_op_binning_div
	* pll->scale_m);

	/* Find smallest and biggest allowed vt divisor. */
	dev_dbg(dev, "min_vt_div: %u\n", min_vt_div);
	min_vt_div = max(min_vt_div,
	DIV_ROUND_UP(pll->pll_op_clk_freq_hz,
	limits->vt.max_pix_clk_freq_hz));
	dev_dbg(dev, "min_vt_div: max_vt_pix_clk_freq_hz: %u\n",
	min_vt_div);
	min_vt_div = max_t(uint32_t, min_vt_div,
	limits->vt.min_pix_clk_div
	* limits->vt.min_sys_clk_div);
	dev_dbg(dev, "min_vt_div: min_vt_clk_div: %u\n", min_vt_div);

	max_vt_div = limits->vt.max_sys_clk_div * limits->vt.max_pix_clk_div;
	dev_dbg(dev, "max_vt_div: %u\n", max_vt_div);
	max_vt_div = min(max_vt_div,
	DIV_ROUND_UP(pll->pll_op_clk_freq_hz,
	limits->vt.min_pix_clk_freq_hz));
	dev_dbg(dev, "max_vt_div: min_vt_pix_clk_freq_hz: %u\n",
	max_vt_div);

	/*
	* Find limitsits for sys_clk_div. Not all values are possible
	* with all values of pix_clk_div.
	*/
	min_sys_div = limits->vt.min_sys_clk_div;
	dev_dbg(dev, "min_sys_div: %u\n", min_sys_div);
	min_sys_div = max(min_sys_div,
	DIV_ROUND_UP(min_vt_div,
	limits->vt.max_pix_clk_div));
	dev_dbg(dev, "min_sys_div: max_vt_pix_clk_div: %u\n", min_sys_div);
	min_sys_div = max(min_sys_div,
	pll->pll_op_clk_freq_hz
	/ limits->vt.max_sys_clk_freq_hz);
	dev_dbg(dev, "min_sys_div: max_pll_op_clk_freq_hz: %u\n", min_sys_div);
	min_sys_div = clk_div_even_up(min_sys_div);
	dev_dbg(dev, "min_sys_div: one or even: %u\n", min_sys_div);

	max_sys_div = limits->vt.max_sys_clk_div;
	dev_dbg(dev, "max_sys_div: %u\n", max_sys_div);
	max_sys_div = min(max_sys_div,
	DIV_ROUND_UP(max_vt_div,
	limits->vt.min_pix_clk_div));
	dev_dbg(dev, "max_sys_div: min_vt_pix_clk_div: %u\n", max_sys_div);
	max_sys_div = min(max_sys_div,
	DIV_ROUND_UP(pll->pll_op_clk_freq_hz,
	limits->vt.min_pix_clk_freq_hz));
	dev_dbg(dev, "max_sys_div: min_vt_pix_clk_freq_hz: %u\n", max_sys_div);

	/*
	* Find pix_div such that a legal pix_div * sys_div results
	* into a value which is not smaller than div, the desired
	* divisor.
	*/
	for (vt_div = min_vt_div; vt_div <= max_vt_div;
	vt_div += 2 - (vt_div & 1)) {
	for (sys_div = min_sys_div;
	sys_div <= max_sys_div;
	sys_div += 2 - (sys_div & 1)) {
	uint16_t pix_div = DIV_ROUND_UP(vt_div, sys_div);

	if (pix_div < limits->vt.min_pix_clk_div
	\|\| pix_div > limits->vt.max_pix_clk_div) {
	dev_dbg(dev,
	"pix_div %u too small or too big (%u--%u)\n",
	pix_div,
	limits->vt.min_pix_clk_div,
	limits->vt.max_pix_clk_div);
	continue;
	}

	/* Check if this one is better. */
	if (pix_div * sys_div
	<= roundup(min_vt_div, best_pix_div))
	best_pix_div = pix_div;
	}
	if (best_pix_div < INT_MAX >> 1)
	break;
	}

	pll->vt.sys_clk_div = DIV_ROUND_UP(min_vt_div, best_pix_div);
	pll->vt.pix_clk_div = best_pix_div;

	pll->vt.sys_clk_freq_hz =
	pll->pll_op_clk_freq_hz / pll->vt.sys_clk_div;
	pll->vt.pix_clk_freq_hz =
	pll->vt.sys_clk_freq_hz / pll->vt.pix_clk_div;

	out_skip_vt_calc:
	pll->pixel_rate_csi =
	op_pll->pix_clk_freq_hz * lane_op_clock_ratio;
	pll->pixel_rate_pixel_array = pll->vt.pix_clk_freq_hz;

	return check_all_bounds(dev, limits, op_limits, pll, op_pll);
	}

	int smiapp_pll_calculate(struct device *dev,
	const struct smiapp_pll_limits *limits,
	struct smiapp_pll *pll)
	{
	const struct smiapp_pll_branch_limits *op_limits = &limits->op;
	struct smiapp_pll_branch *op_pll = &pll->op;
	uint16_t min_pre_pll_clk_div;
	uint16_t max_pre_pll_clk_div;
	uint32_t lane_op_clock_ratio;
	uint32_t mul, div;
	unsigned int i;
	int rval = -EINVAL;

	if (pll->flags & SMIAPP_PLL_FLAG_NO_OP_CLOCKS) {
	/*
	* If there's no OP PLL at all, use the VT values
	* instead. The OP values are ignored for the rest of
	* the PLL calculation.
	*/
	op_limits = &limits->vt;
	op_pll = &pll->vt;
	}

	if (pll->flags & SMIAPP_PLL_FLAG_OP_PIX_CLOCK_PER_LANE)
	lane_op_clock_ratio = pll->csi2.lanes;
	else
	lane_op_clock_ratio = 1;
	dev_dbg(dev, "lane_op_clock_ratio: %u\n", lane_op_clock_ratio);

	dev_dbg(dev, "binning: %ux%u\n", pll->binning_horizontal,
	pll->binning_vertical);

	switch (pll->bus_type) {
	case SMIAPP_PLL_BUS_TYPE_CSI2:
	/* CSI transfers 2 bits per clock per lane; thus times 2 */
	pll->pll_op_clk_freq_hz = pll->link_freq * 2
	* (pll->csi2.lanes / lane_op_clock_ratio);
	break;
	case SMIAPP_PLL_BUS_TYPE_PARALLEL:
	pll->pll_op_clk_freq_hz = pll->link_freq * pll->bits_per_pixel
	/ DIV_ROUND_UP(pll->bits_per_pixel,
	pll->parallel.bus_width);
	break;
	default:
	return -EINVAL;
	}

	/* Figure out limits for pre-pll divider based on extclk */
	dev_dbg(dev, "min / max pre_pll_clk_div: %u / %u\n",
	limits->min_pre_pll_clk_div, limits->max_pre_pll_clk_div);
	max_pre_pll_clk_div =
	min_t(uint16_t, limits->max_pre_pll_clk_div,
	clk_div_even(pll->ext_clk_freq_hz /
	limits->min_pll_ip_freq_hz));
	min_pre_pll_clk_div =
	max_t(uint16_t, limits->min_pre_pll_clk_div,
	clk_div_even_up(
	DIV_ROUND_UP(pll->ext_clk_freq_hz,
	limits->max_pll_ip_freq_hz)));
	dev_dbg(dev, "pre-pll check: min / max pre_pll_clk_div: %u / %u\n",
	min_pre_pll_clk_div, max_pre_pll_clk_div);

	i = gcd(pll->pll_op_clk_freq_hz, pll->ext_clk_freq_hz);
	mul = div_u64(pll->pll_op_clk_freq_hz, i);
	div = pll->ext_clk_freq_hz / i;
	dev_dbg(dev, "mul %u / div %u\n", mul, div);

	min_pre_pll_clk_div =
	max_t(uint16_t, min_pre_pll_clk_div,
	clk_div_even_up(
	DIV_ROUND_UP(mul * pll->ext_clk_freq_hz,
	limits->max_pll_op_freq_hz)));
	dev_dbg(dev, "pll_op check: min / max pre_pll_clk_div: %u / %u\n",
	min_pre_pll_clk_div, max_pre_pll_clk_div);

	for (pll->pre_pll_clk_div = min_pre_pll_clk_div;
	pll->pre_pll_clk_div <= max_pre_pll_clk_div;
	pll->pre_pll_clk_div += 2 - (pll->pre_pll_clk_div & 1)) {
	rval = __smiapp_pll_calculate(dev, limits, op_limits, pll,
	op_pll, mul, div,
	lane_op_clock_ratio);
	if (rval)
	continue;

	print_pll(dev, pll);
	return 0;
	}

	dev_dbg(dev, "unable to compute pre_pll divisor\n");

	return rval;
	}
	EXPORT_SYMBOL_GPL(smiapp_pll_calculate);

	MODULE_AUTHOR("Sakari Ailus <sakari.ailus@iki.fi>");
	MODULE_DESCRIPTION("Generic SMIA/SMIA++ PLL calculator");
	MODULE_LICENSE("GPL");