From 6c957ed73e5bb908c8d33471671290e93b41ebc1 Mon Sep 17 00:00:00 2001 From: Jacopo Mondi Date: Fri, 13 May 2022 15:13:55 +0100 Subject: [PATCH] media: ov5640: Rework CSI-2 clock tree Re-work the ov5640_set_mipi_pclk() function to calculate the PLL configuration using the pixel_rate and link_freq values set at s_fmt time. Rework the DVP clock mode settings to calculate the pixel clock internally and remove the assumption on the 16bpp format. Tested in MIPI CSI-2 mode with 1 and 2 data lanes with: - all the sensor supported resolutions in UYVY, RGB565 and MJPEG formats. - resolutions >= 1280x720 in RAW Bayer format. - resolutions < 1280x720 in RGB888 format. [Rework pclk_period and link_freq computation] Signed-off-by: Jacopo Mondi Reviewed-by: Laurent Pinchart Signed-off-by: Hugues Fruchet Signed-off-by: Sakari Ailus Signed-off-by: Mauro Carvalho Chehab --- drivers/media/i2c/ov5640.c | 196 ++++++++++++++++++++++----------------------- 1 file changed, 96 insertions(+), 100 deletions(-) diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c index 3aac84a..5447820 100644 --- a/drivers/media/i2c/ov5640.c +++ b/drivers/media/i2c/ov5640.c @@ -90,6 +90,7 @@ #define OV5640_REG_POLARITY_CTRL00 0x4740 #define OV5640_REG_MIPI_CTRL00 0x4800 #define OV5640_REG_DEBUG_MODE 0x4814 +#define OV5640_REG_PCLK_PERIOD 0x4837 #define OV5640_REG_ISP_FORMAT_MUX_CTRL 0x501f #define OV5640_REG_PRE_ISP_TEST_SET1 0x503d #define OV5640_REG_SDE_CTRL0 0x5580 @@ -926,20 +927,10 @@ static int ov5640_mod_reg(struct ov5640_dev *sensor, u16 reg, * +-----+-----+ * +------------> PCLK * - * This is deviating from the datasheet at least for the register - * 0x3108, since it's said here that the PCLK would be clocked from - * the PLL. - * - * There seems to be also (unverified) constraints: + * There seems to be also constraints: * - the PLL pre-divider output rate should be in the 4-27MHz range * - the PLL multiplier output rate should be in the 500-1000MHz range * - PCLK >= SCLK * 2 in YUV, >= SCLK in Raw or JPEG - * - * In the two latter cases, these constraints are met since our - * factors are hardcoded. If we were to change that, we would need to - * take this into account. The only varying parts are the PLL - * multiplier and the system clock divider, which are shared between - * all these clocks so won't cause any issue. */ /* @@ -959,13 +950,6 @@ static int ov5640_mod_reg(struct ov5640_dev *sensor, u16 reg, #define OV5640_SYSDIV_MAX 16 /* - * Hardcode these values for scaler and non-scaler modes. - * FIXME: to be re-calcualted for 1 data lanes setups - */ -#define OV5640_MIPI_DIV_PCLK 2 -#define OV5640_MIPI_DIV_SCLK 1 - -/* * This is supposed to be ranging from 1 to 2, but the value is always * set to 2 in the vendor kernels. */ @@ -1074,70 +1058,83 @@ out: /* * ov5640_set_mipi_pclk() - Calculate the clock tree configuration values * for the MIPI CSI-2 output. - * - * @rate: The requested bandwidth per lane in bytes per second. - * 'Bandwidth Per Lane' is calculated as: - * bpl = HTOT * VTOT * FPS * bpp / num_lanes; - * - * This function use the requested bandwidth to calculate: - * - sample_rate = bpl / (bpp / num_lanes); - * = bpl / (PLL_RDIV * BIT_DIV * PCLK_DIV * MIPI_DIV / num_lanes); - * - * - mipi_sclk = bpl / MIPI_DIV / 2; ( / 2 is for CSI-2 DDR) - * - * with these fixed parameters: - * PLL_RDIV = 2; - * BIT_DIVIDER = 2; (MIPI_BIT_MODE == 8 ? 2 : 2,5); - * PCLK_DIV = 1; - * - * The MIPI clock generation differs for modes that use the scaler and modes - * that do not. In case the scaler is in use, the MIPI_SCLK generates the MIPI - * BIT CLk, and thus: - * - * - mipi_sclk = bpl / MIPI_DIV / 2; - * MIPI_DIV = 1; - * - * For modes that do not go through the scaler, the MIPI BIT CLOCK is generated - * from the pixel clock, and thus: - * - * - sample_rate = bpl / (bpp / num_lanes); - * = bpl / (2 * 2 * 1 * MIPI_DIV / num_lanes); - * = bpl / (4 * MIPI_DIV / num_lanes); - * - MIPI_DIV = bpp / (4 * num_lanes); - * - * FIXME: this have been tested with 16bpp and 2 lanes setup only. - * MIPI_DIV is fixed to value 2, but it -might- be changed according to the - * above formula for setups with 1 lane or image formats with different bpp. - * - * FIXME: this deviates from the sensor manual documentation which is quite - * thin on the MIPI clock tree generation part. */ -static int ov5640_set_mipi_pclk(struct ov5640_dev *sensor, - unsigned long rate) +static int ov5640_set_mipi_pclk(struct ov5640_dev *sensor) { - const struct ov5640_mode_info *mode = sensor->current_mode; + u8 bit_div, mipi_div, pclk_div, sclk_div, sclk2x_div, root_div; u8 prediv, mult, sysdiv; - u8 mipi_div; + unsigned long link_freq; + unsigned long sysclk; + u8 pclk_period; + u32 sample_rate; + u32 num_lanes; int ret; + /* Use the link freq computed at ov5640_update_pixel_rate() time. */ + link_freq = sensor->current_link_freq; + /* - * 1280x720 is reported to use 'SUBSAMPLING' only, - * but according to the sensor manual it goes through the - * scaler before subsampling. + * - mipi_div - Additional divider for the MIPI lane clock. + * + * Higher link frequencies would make sysclk > 1GHz. + * Keep the sysclk low and do not divide in the MIPI domain. */ - if (mode->dn_mode == SCALING || - (mode->id == OV5640_MODE_720P_1280_720)) - mipi_div = OV5640_MIPI_DIV_SCLK; + if (link_freq > OV5640_LINK_RATE_MAX) + mipi_div = 1; else - mipi_div = OV5640_MIPI_DIV_PCLK; + mipi_div = 2; - ov5640_calc_sys_clk(sensor, rate, &prediv, &mult, &sysdiv); + sysclk = link_freq * mipi_div; + ov5640_calc_sys_clk(sensor, sysclk, &prediv, &mult, &sysdiv); - ret = ov5640_mod_reg(sensor, OV5640_REG_SC_PLL_CTRL0, - 0x0f, OV5640_PLL_CTRL0_MIPI_MODE_8BIT); + /* + * Adjust PLL parameters to maintain the MIPI_SCLK-to-PCLK ratio. + * + * - root_div = 2 (fixed) + * - bit_div : MIPI 8-bit = 2; MIPI 10-bit = 2.5 + * - pclk_div = 1 (fixed) + * - p_div = (2 lanes ? mipi_div : 2 * mipi_div) + * + * This results in the following MIPI_SCLK depending on the number + * of lanes: + * + * - 2 lanes: MIPI_SCLK = (4 or 5) * PCLK + * - 1 lanes: MIPI_SCLK = (8 or 10) * PCLK + */ + root_div = OV5640_PLL_CTRL3_PLL_ROOT_DIV_2; + bit_div = OV5640_PLL_CTRL0_MIPI_MODE_8BIT; + pclk_div = ilog2(OV5640_PCLK_ROOT_DIV); - ret = ov5640_mod_reg(sensor, OV5640_REG_SC_PLL_CTRL1, - 0xff, sysdiv << 4 | mipi_div); + /* + * Scaler clock: + * - YUV: PCLK >= 2 * SCLK + * - RAW or JPEG: PCLK >= SCLK + * - sclk2x_div = sclk_div / 2 + */ + sclk_div = ilog2(OV5640_SCLK_ROOT_DIV); + sclk2x_div = ilog2(OV5640_SCLK2X_ROOT_DIV); + + /* + * Set the pixel clock period expressed in ns with 1-bit decimal + * (0x01=0.5ns). + * + * The register is very briefly documented. In the OV5645 datasheet it + * is described as (2 * pclk period), and from testing it seems the + * actual definition is 2 * 8-bit sample period. + * + * 2 * sample_period = (mipi_clk * 2 * num_lanes / bpp) * (bpp / 8) / 2 + */ + num_lanes = sensor->ep.bus.mipi_csi2.num_data_lanes; + sample_rate = (link_freq * mipi_div * num_lanes * 2) / 16; + pclk_period = 2000000000UL / sample_rate; + + /* Program the clock tree registers. */ + ret = ov5640_mod_reg(sensor, OV5640_REG_SC_PLL_CTRL0, 0x0f, bit_div); + if (ret) + return ret; + + ret = ov5640_mod_reg(sensor, OV5640_REG_SC_PLL_CTRL1, 0xff, + (sysdiv << 4) | mipi_div); if (ret) return ret; @@ -1145,13 +1142,27 @@ static int ov5640_set_mipi_pclk(struct ov5640_dev *sensor, if (ret) return ret; - ret = ov5640_mod_reg(sensor, OV5640_REG_SC_PLL_CTRL3, - 0x1f, OV5640_PLL_CTRL3_PLL_ROOT_DIV_2 | prediv); + ret = ov5640_mod_reg(sensor, OV5640_REG_SC_PLL_CTRL3, 0x1f, + root_div | prediv); if (ret) return ret; - return ov5640_mod_reg(sensor, OV5640_REG_SYS_ROOT_DIVIDER, - 0x30, OV5640_PLL_SYS_ROOT_DIVIDER_BYPASS); + ret = ov5640_mod_reg(sensor, OV5640_REG_SYS_ROOT_DIVIDER, 0x3f, + (pclk_div << 4) | (sclk2x_div << 2) | sclk_div); + if (ret) + return ret; + + return ov5640_write_reg(sensor, OV5640_REG_PCLK_PERIOD, pclk_period); +} + +static u32 ov5640_calc_pixel_rate(struct ov5640_dev *sensor) +{ + u32 rate; + + rate = sensor->current_mode->vtot * sensor->current_mode->htot; + rate *= ov5640_framerates[sensor->current_fr]; + + return rate; } static unsigned long ov5640_calc_pclk(struct ov5640_dev *sensor, @@ -1171,11 +1182,16 @@ static unsigned long ov5640_calc_pclk(struct ov5640_dev *sensor, return _rate / *pll_rdiv / *bit_div / *pclk_div; } -static int ov5640_set_dvp_pclk(struct ov5640_dev *sensor, unsigned long rate) +static int ov5640_set_dvp_pclk(struct ov5640_dev *sensor) { u8 prediv, mult, sysdiv, pll_rdiv, bit_div, pclk_div; + u32 rate; int ret; + rate = ov5640_calc_pixel_rate(sensor); + rate *= ov5640_code_to_bpp(sensor->fmt.code); + rate /= sensor->ep.bus.parallel.bus_width; + ov5640_calc_pclk(sensor, rate, &prediv, &mult, &sysdiv, &pll_rdiv, &bit_div, &pclk_div); @@ -1700,16 +1716,6 @@ ov5640_find_mode(struct ov5640_dev *sensor, enum ov5640_frame_rate fr, return mode; } -static u64 ov5640_calc_pixel_rate(struct ov5640_dev *sensor) -{ - u64 rate; - - rate = sensor->current_mode->vtot * sensor->current_mode->htot; - rate *= ov5640_framerates[sensor->current_fr]; - - return rate; -} - /* * sensor changes between scaling and subsampling, go through * exposure calculation @@ -1891,7 +1897,6 @@ static int ov5640_set_mode(struct ov5640_dev *sensor) enum ov5640_downsize_mode dn_mode, orig_dn_mode; bool auto_gain = sensor->ctrls.auto_gain->val == 1; bool auto_exp = sensor->ctrls.auto_exp->val == V4L2_EXPOSURE_AUTO; - unsigned long rate; int ret; dn_mode = mode->dn_mode; @@ -1910,19 +1915,10 @@ static int ov5640_set_mode(struct ov5640_dev *sensor) goto restore_auto_gain; } - /* - * All the formats we support have 16 bits per pixel, seems to require - * the same rate than YUV, so we can just use 16 bpp all the time. - */ - rate = ov5640_calc_pixel_rate(sensor) * 16; - if (ov5640_is_csi2(sensor)) { - rate = rate / sensor->ep.bus.mipi_csi2.num_data_lanes; - ret = ov5640_set_mipi_pclk(sensor, rate); - } else { - rate = rate / sensor->ep.bus.parallel.bus_width; - ret = ov5640_set_dvp_pclk(sensor, rate); - } - + if (ov5640_is_csi2(sensor)) + ret = ov5640_set_mipi_pclk(sensor); + else + ret = ov5640_set_dvp_pclk(sensor); if (ret < 0) return 0; -- 2.7.4