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SubjectRe: [PATCH v2 1/8] drm/rockchip/dsi: correct Feedback divider setting
From
Date
Hi,

On 09/26/2017 01:25 PM, Nickey Yang wrote:
> This patch correct Feedback divider setting:
> 1、Set Feedback divider [8:5] when HIGH_PROGRAM_EN
> 2、Due to the use of a "by 2 pre-scaler," the range of the
> feedback multiplication Feedback divider is limited to even
> division numbers, and Feedback divider must be greater than
> 12, less than 1000.
> 3、Make the previously configured Feedback divider(LSB)
> factors effective
> 4、Add the definition of the MIPI PHY register.

Slightly unrelated topic: We now have a generic dw-mipi-dsi bridge
driver. Can we consider moving to that instead of adding new features
within the rockchip kms driver?

Thanks,
Archit

>
> Signed-off-by: Nickey Yang <nickey.yang@rock-chips.com>
> ---
> drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 219 ++++++++++++++++++++++-----------
> 1 file changed, 146 insertions(+), 73 deletions(-)
>
> diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> index 9a20b9d..c933a3a 100644
> --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> @@ -228,7 +228,7 @@
> #define LOW_PROGRAM_EN 0
> #define HIGH_PROGRAM_EN BIT(7)
> #define LOOP_DIV_LOW_SEL(val) (((val) - 1) & 0x1f)
> -#define LOOP_DIV_HIGH_SEL(val) ((((val) - 1) >> 5) & 0x1f)
> +#define LOOP_DIV_HIGH_SEL(val) ((((val) - 1) >> 5) & 0xf)
> #define PLL_LOOP_DIV_EN BIT(5)
> #define PLL_INPUT_DIV_EN BIT(4)
>
> @@ -254,6 +254,28 @@
> #define DW_MIPI_NEEDS_PHY_CFG_CLK BIT(0)
> #define DW_MIPI_NEEDS_GRF_CLK BIT(1)
>
> +#define PLL_BIAS_CUR_SEL_CAP_VCO_CONTROL 0x10
> +#define PLL_CP_CONTROL_PLL_LOCK_BYPASS 0x11
> +#define PLL_LPF_AND_CP_CONTROL 0x12
> +#define PLL_INPUT_DIVIDER_RATIO 0x17
> +#define PLL_LOOP_DIVIDER_RATIO 0x18
> +#define PLL_INPUT_AND_LOOP_DIVIDER_RATIOS_CONTROL 0x19
> +#define BANDGAP_AND_BIAS_CONTROL 0x20
> +#define TERMINATION_RESISTER_CONTROL 0x21
> +#define AFE_BIAS_BANDGAP_ANALOG_PROGRAMMABILITY 0x22
> +#define HS_RX_CONTROL_OF_LANE_0 0x44
> +#define HS_TX_CLOCK_LANE_REQUEST_STATE_TIME_CONTROL 0x60
> +#define HS_TX_CLOCK_LANE_PREPARE_STATE_TIME_CONTROL 0x61
> +#define HS_TX_CLOCK_LANE_HS_ZERO_STATE_TIME_CONTROL 0x62
> +#define HS_TX_CLOCK_LANE_TRAIL_STATE_TIME_CONTROL 0x63
> +#define HS_TX_CLOCK_LANE_EXIT_STATE_TIME_CONTROL 0x64
> +#define HS_TX_CLOCK_LANE_POST_TIME_CONTROL 0x65
> +#define HS_TX_DATA_LANE_REQUEST_STATE_TIME_CONTROL 0x70
> +#define HS_TX_DATA_LANE_PREPARE_STATE_TIME_CONTROL 0x71
> +#define HS_TX_DATA_LANE_HS_ZERO_STATE_TIME_CONTROL 0x72
> +#define HS_TX_DATA_LANE_TRAIL_STATE_TIME_CONTROL 0x73
> +#define HS_TX_DATA_LANE_EXIT_STATE_TIME_CONTROL 0x74
> +
> enum {
> BANDGAP_97_07,
> BANDGAP_98_05,
> @@ -447,53 +469,79 @@ static int dw_mipi_dsi_phy_init(struct dw_mipi_dsi *dsi)
> return ret;
> }
>
> - dw_mipi_dsi_phy_write(dsi, 0x10, BYPASS_VCO_RANGE |
> - VCO_RANGE_CON_SEL(vco) |
> - VCO_IN_CAP_CON_LOW |
> - REF_BIAS_CUR_SEL);
> -
> - dw_mipi_dsi_phy_write(dsi, 0x11, CP_CURRENT_3MA);
> - dw_mipi_dsi_phy_write(dsi, 0x12, CP_PROGRAM_EN | LPF_PROGRAM_EN |
> - LPF_RESISTORS_20_KOHM);
> -
> - dw_mipi_dsi_phy_write(dsi, 0x44, HSFREQRANGE_SEL(testdin));
> -
> - dw_mipi_dsi_phy_write(dsi, 0x17, INPUT_DIVIDER(dsi->input_div));
> - dw_mipi_dsi_phy_write(dsi, 0x18, LOOP_DIV_LOW_SEL(dsi->feedback_div) |
> - LOW_PROGRAM_EN);
> - dw_mipi_dsi_phy_write(dsi, 0x18, LOOP_DIV_HIGH_SEL(dsi->feedback_div) |
> - HIGH_PROGRAM_EN);
> - dw_mipi_dsi_phy_write(dsi, 0x19, PLL_LOOP_DIV_EN | PLL_INPUT_DIV_EN);
> -
> - dw_mipi_dsi_phy_write(dsi, 0x22, LOW_PROGRAM_EN |
> - BIASEXTR_SEL(BIASEXTR_127_7));
> - dw_mipi_dsi_phy_write(dsi, 0x22, HIGH_PROGRAM_EN |
> - BANDGAP_SEL(BANDGAP_96_10));
> -
> - dw_mipi_dsi_phy_write(dsi, 0x20, POWER_CONTROL | INTERNAL_REG_CURRENT |
> - BIAS_BLOCK_ON | BANDGAP_ON);
> -
> - dw_mipi_dsi_phy_write(dsi, 0x21, TER_RESISTOR_LOW | TER_CAL_DONE |
> - SETRD_MAX | TER_RESISTORS_ON);
> - dw_mipi_dsi_phy_write(dsi, 0x21, TER_RESISTOR_HIGH | LEVEL_SHIFTERS_ON |
> - SETRD_MAX | POWER_MANAGE |
> - TER_RESISTORS_ON);
> -
> - dw_mipi_dsi_phy_write(dsi, 0x60, TLP_PROGRAM_EN | ns2bc(dsi, 500));
> - dw_mipi_dsi_phy_write(dsi, 0x61, THS_PRE_PROGRAM_EN | ns2ui(dsi, 40));
> - dw_mipi_dsi_phy_write(dsi, 0x62, THS_ZERO_PROGRAM_EN | ns2bc(dsi, 300));
> - dw_mipi_dsi_phy_write(dsi, 0x63, THS_PRE_PROGRAM_EN | ns2ui(dsi, 100));
> - dw_mipi_dsi_phy_write(dsi, 0x64, BIT(5) | ns2bc(dsi, 100));
> - dw_mipi_dsi_phy_write(dsi, 0x65, BIT(5) | (ns2bc(dsi, 60) + 7));
> -
> - dw_mipi_dsi_phy_write(dsi, 0x70, TLP_PROGRAM_EN | ns2bc(dsi, 500));
> - dw_mipi_dsi_phy_write(dsi, 0x71,
> + dw_mipi_dsi_phy_write(dsi, PLL_BIAS_CUR_SEL_CAP_VCO_CONTROL,
> + BYPASS_VCO_RANGE |
> + VCO_RANGE_CON_SEL(vco) |
> + VCO_IN_CAP_CON_LOW |
> + REF_BIAS_CUR_SEL);
> +
> + dw_mipi_dsi_phy_write(dsi, PLL_CP_CONTROL_PLL_LOCK_BYPASS,
> + CP_CURRENT_3MA);
> + dw_mipi_dsi_phy_write(dsi, PLL_LPF_AND_CP_CONTROL,
> + CP_PROGRAM_EN | LPF_PROGRAM_EN |
> + LPF_RESISTORS_20_KOHM);
> +
> + dw_mipi_dsi_phy_write(dsi, HS_RX_CONTROL_OF_LANE_0,
> + HSFREQRANGE_SEL(testdin));
> +
> + dw_mipi_dsi_phy_write(dsi, PLL_INPUT_DIVIDER_RATIO,
> + INPUT_DIVIDER(dsi->input_div));
> + dw_mipi_dsi_phy_write(dsi, PLL_LOOP_DIVIDER_RATIO,
> + LOOP_DIV_LOW_SEL(dsi->feedback_div) |
> + LOW_PROGRAM_EN);
> + /*
> + * we need set 0x19 immediately to make the configrued LSB
> + * effective according to IP simulation and lab test results.
> + * Only in this way can we get correct mipi phy pll frequency.
> + */
> + dw_mipi_dsi_phy_write(dsi, PLL_INPUT_AND_LOOP_DIVIDER_RATIOS_CONTROL,
> + PLL_LOOP_DIV_EN | PLL_INPUT_DIV_EN);
> + dw_mipi_dsi_phy_write(dsi, PLL_LOOP_DIVIDER_RATIO,
> + LOOP_DIV_HIGH_SEL(dsi->feedback_div) |
> + HIGH_PROGRAM_EN);
> + dw_mipi_dsi_phy_write(dsi, PLL_INPUT_AND_LOOP_DIVIDER_RATIOS_CONTROL,
> + PLL_LOOP_DIV_EN | PLL_INPUT_DIV_EN);
> +
> + dw_mipi_dsi_phy_write(dsi, AFE_BIAS_BANDGAP_ANALOG_PROGRAMMABILITY,
> + LOW_PROGRAM_EN | BIASEXTR_SEL(BIASEXTR_127_7));
> + dw_mipi_dsi_phy_write(dsi, AFE_BIAS_BANDGAP_ANALOG_PROGRAMMABILITY,
> + HIGH_PROGRAM_EN | BANDGAP_SEL(BANDGAP_96_10));
> +
> + dw_mipi_dsi_phy_write(dsi, BANDGAP_AND_BIAS_CONTROL,
> + POWER_CONTROL | INTERNAL_REG_CURRENT |
> + BIAS_BLOCK_ON | BANDGAP_ON);
> +
> + dw_mipi_dsi_phy_write(dsi, TERMINATION_RESISTER_CONTROL,
> + TER_RESISTOR_LOW | TER_CAL_DONE |
> + SETRD_MAX | TER_RESISTORS_ON);
> + dw_mipi_dsi_phy_write(dsi, TERMINATION_RESISTER_CONTROL,
> + TER_RESISTOR_HIGH | LEVEL_SHIFTERS_ON |
> + SETRD_MAX | POWER_MANAGE |
> + TER_RESISTORS_ON);
> +
> + dw_mipi_dsi_phy_write(dsi, HS_TX_CLOCK_LANE_REQUEST_STATE_TIME_CONTROL,
> + TLP_PROGRAM_EN | ns2bc(dsi, 500));
> + dw_mipi_dsi_phy_write(dsi, HS_TX_CLOCK_LANE_PREPARE_STATE_TIME_CONTROL,
> + THS_PRE_PROGRAM_EN | ns2ui(dsi, 40));
> + dw_mipi_dsi_phy_write(dsi, HS_TX_CLOCK_LANE_HS_ZERO_STATE_TIME_CONTROL,
> + THS_ZERO_PROGRAM_EN | ns2bc(dsi, 300));
> + dw_mipi_dsi_phy_write(dsi, HS_TX_CLOCK_LANE_TRAIL_STATE_TIME_CONTROL,
> + THS_PRE_PROGRAM_EN | ns2ui(dsi, 100));
> + dw_mipi_dsi_phy_write(dsi, HS_TX_CLOCK_LANE_EXIT_STATE_TIME_CONTROL,
> + BIT(5) | ns2bc(dsi, 100));
> + dw_mipi_dsi_phy_write(dsi, HS_TX_CLOCK_LANE_POST_TIME_CONTROL,
> + BIT(5) | (ns2bc(dsi, 60) + 7));
> +
> + dw_mipi_dsi_phy_write(dsi, HS_TX_DATA_LANE_REQUEST_STATE_TIME_CONTROL,
> + TLP_PROGRAM_EN | ns2bc(dsi, 500));
> + dw_mipi_dsi_phy_write(dsi, HS_TX_DATA_LANE_PREPARE_STATE_TIME_CONTROL,
> THS_PRE_PROGRAM_EN | (ns2ui(dsi, 50) + 5));
> - dw_mipi_dsi_phy_write(dsi, 0x72,
> + dw_mipi_dsi_phy_write(dsi, HS_TX_DATA_LANE_HS_ZERO_STATE_TIME_CONTROL,
> THS_ZERO_PROGRAM_EN | (ns2bc(dsi, 140) + 2));
> - dw_mipi_dsi_phy_write(dsi, 0x73,
> + dw_mipi_dsi_phy_write(dsi, HS_TX_DATA_LANE_TRAIL_STATE_TIME_CONTROL,
> THS_PRE_PROGRAM_EN | (ns2ui(dsi, 60) + 8));
> - dw_mipi_dsi_phy_write(dsi, 0x74, BIT(5) | ns2bc(dsi, 100));
> + dw_mipi_dsi_phy_write(dsi, HS_TX_DATA_LANE_EXIT_STATE_TIME_CONTROL,
> + BIT(5) | ns2bc(dsi, 100));
>
> dsi_write(dsi, DSI_PHY_RSTZ, PHY_ENFORCEPLL | PHY_ENABLECLK |
> PHY_UNRSTZ | PHY_UNSHUTDOWNZ);
> @@ -521,11 +569,16 @@ static int dw_mipi_dsi_phy_init(struct dw_mipi_dsi *dsi)
> static int dw_mipi_dsi_get_lane_bps(struct dw_mipi_dsi *dsi,
> struct drm_display_mode *mode)
> {
> - unsigned int i, pre;
> - unsigned long mpclk, pllref, tmp;
> - unsigned int m = 1, n = 1, target_mbps = 1000;
> + unsigned long mpclk, tmp;
> + unsigned int target_mbps = 1000;
> unsigned int max_mbps = dptdin_map[ARRAY_SIZE(dptdin_map) - 1].max_mbps;
> int bpp;
> + unsigned long best_freq = 0;
> + unsigned long fvco_min, fvco_max, fin, fout;
> + unsigned int min_prediv, max_prediv;
> + unsigned int _prediv, uninitialized_var(best_prediv);
> + unsigned long _fbdiv, uninitialized_var(best_fbdiv);
> + unsigned long min_delta = ULONG_MAX;
>
> bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
> if (bpp < 0) {
> @@ -544,34 +597,54 @@ static int dw_mipi_dsi_get_lane_bps(struct dw_mipi_dsi *dsi,
> dev_err(dsi->dev, "DPHY clock frequency is out of range\n");
> }
>
> - pllref = DIV_ROUND_UP(clk_get_rate(dsi->pllref_clk), USEC_PER_SEC);
> - tmp = pllref;
> -
> - /*
> - * The limits on the PLL divisor are:
> - *
> - * 5MHz <= (pllref / n) <= 40MHz
> - *
> - * we walk over these values in descreasing order so that if we hit
> - * an exact match for target_mbps it is more likely that "m" will be
> - * even.
> - *
> - * TODO: ensure that "m" is even after this loop.
> - */
> - for (i = pllref / 5; i > (pllref / 40); i--) {
> - pre = pllref / i;
> - if ((tmp > (target_mbps % pre)) && (target_mbps / pre < 512)) {
> - tmp = target_mbps % pre;
> - n = i;
> - m = target_mbps / pre;
> + fin = clk_get_rate(dsi->pllref_clk);
> + fout = target_mbps * USEC_PER_SEC;
> +
> + /* constraint: 5Mhz <= Fref / N <= 40MHz */
> + min_prediv = DIV_ROUND_UP(fin, 40 * USEC_PER_SEC);
> + max_prediv = fin / (5 * USEC_PER_SEC);
> +
> + /* constraint: 80MHz <= Fvco <= 1500Mhz */
> + fvco_min = 80 * USEC_PER_SEC;
> + fvco_max = 1500 * USEC_PER_SEC;
> +
> + for (_prediv = min_prediv; _prediv <= max_prediv; _prediv++) {
> + u64 tmp;
> + u32 delta;
> + /* Fvco = Fref * M / N */
> + tmp = (u64)fout * _prediv;
> + do_div(tmp, fin);
> + _fbdiv = tmp;
> + /*
> + * Due to the use of a "by 2 pre-scaler," the range of the
> + * feedback multiplication value M is limited to even division
> + * numbers, and m must be greater than 12, less than 1000.
> + */
> + if (_fbdiv <= 12 || _fbdiv >= 1000)
> + continue;
> +
> + _fbdiv += _fbdiv % 2;
> +
> + tmp = (u64)_fbdiv * fin;
> + do_div(tmp, _prediv);
> + if (tmp < fvco_min || tmp > fvco_max)
> + continue;
> +
> + delta = abs(fout - tmp);
> + if (delta < min_delta) {
> + best_prediv = _prediv;
> + best_fbdiv = _fbdiv;
> + min_delta = delta;
> + best_freq = tmp;
> }
> - if (tmp == 0)
> - break;
> }
>
> - dsi->lane_mbps = pllref / n * m;
> - dsi->input_div = n;
> - dsi->feedback_div = m;
> + if (best_freq) {
> + dsi->lane_mbps = DIV_ROUND_UP(best_freq, USEC_PER_SEC);
> + dsi->input_div = best_prediv;
> + dsi->feedback_div = best_fbdiv;
> + } else
> + dev_err(dsi->dev, "Can not find best_freq for DPHY\n");
>
> return 0;
> }
>

--
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