diff options
Diffstat (limited to 'kernel/drivers/media/i2c/smiapp-pll.c')
| -rw-r--r-- | kernel/drivers/media/i2c/smiapp-pll.c | 489 |
1 files changed, 489 insertions, 0 deletions
diff --git a/kernel/drivers/media/i2c/smiapp-pll.c b/kernel/drivers/media/i2c/smiapp-pll.c new file mode 100644 index 000000000..e3348db56 --- /dev/null +++ b/kernel/drivers/media/i2c/smiapp-pll.c @@ -0,0 +1,489 @@ +/* + * 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_info(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"); |