On Sun, 26 Jul 2015, Uma Shankar <uma.shankar@xxxxxxxxx> wrote:
> From: Shashank Sharma <shashank.sharma@xxxxxxxxx>
>
> BXT DSI clocks are different than previous platforms. So adding a
> new function to program following clocks and dividers:
> 1. Program variable divider to generate input to Tx clock divider
> (Output value must be < 39.5Mhz)
> 2. Select divide by 2 option to get < 20Mhz for Tx clock
> 3. Program 8by3 divider to generate Rx clock
>
> v2: Fixed Jani's review comments. Adjusted the Macro defintion as
> per convention. Simplified the logic for bit definitions for
> MIPI PORT A and PORT C in same registers.
>
> Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxxxx>
> Signed-off-by: Uma Shankar <uma.shankar@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_reg.h | 40 +++++++++++++++++++++++++++++++++
> drivers/gpu/drm/i915/intel_dsi_pll.c | 41 ++++++++++++++++++++++++++++++++++
> 2 files changed, 81 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 7559062..310afd4 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -7445,6 +7445,46 @@ enum skl_disp_power_wells {
>
> #define _MIPI_PORT(port, a, c) _PORT3(port, a, 0, c) /* ports A and C only */
>
> +/* BXT MIPI clock controls */
> +#define BXT_MAX_VAR_OUTPUT_KHZ 39500
> +
> +#define BXT_MIPI_CLOCK_CTL 0x46090
> +#define BXT_MIPI_DIV_SHIFT 16
> +/* Var clock divider to generate TX source. Result must be < 39.5 M */
> +#define BXT_MIPI1_ESCLK_VAR_DIV_MASK (0x3F << 26)
> +#define BXT_MIPI2_ESCLK_VAR_DIV_MASK (0x3F << 10)
> +#define BXT_MIPI_ESCLK_VAR_DIV_MASK(port) \
> + (0x3F << ((port == PORT_A) * BXT_MIPI_DIV_SHIFT + 10))
> +#define BXT_MIPI_ESCLK_VAR_DIV(port, val) \
> + (val << ((port == PORT_A) * BXT_MIPI_DIV_SHIFT + 10))
> +/* TX control divider to select actual TX clock output from (8x/var) */
> +#define BXT_MIPI1_TX_ESCLK_FIXDIV_MASK (3 << 21)
> +#define BXT_MIPI2_TX_ESCLK_FIXDIV_MASK (3 << 5)
> +#define BXT_MIPI_TX_ESCLK_FIXDIV_MASK(port) \
> + (3 << ((port == PORT_A) * BXT_MIPI_DIV_SHIFT + 5))
> +#define BXT_MIPI_TX_ESCLK_8XDIV_BY2(port) \
> + (0x0 << ((port == PORT_A) * BXT_MIPI_DIV_SHIFT + 5))
> +#define BXT_MIPI_TX_ESCLK_8XDIV_BY4(port) \
> + (0x1 << ((port == PORT_A) * BXT_MIPI_DIV_SHIFT + 5))
> +#define BXT_MIPI_TX_ESCLK_8XDIV_BY8(port) \
> + (0x2 << ((port == PORT_A) * BXT_MIPI_DIV_SHIFT + 5))
> +/* RX control divider to select actual RX clock output from 8x*/
> +#define BXT_MIPI1_RX_ESCLK_FIXDIV_MASK (3 << 19)
> +#define BXT_MIPI2_RX_ESCLK_FIXDIV_MASK (3 << 3)
> +#define BXT_MIPI_RX_ESCLK_FIXDIV_MASK(port) \
> + (3 << ((port == PORT_A) * BXT_MIPI_DIV_SHIFT + 3))
> +#define BXT_MIPI_RX_ESCLK_8X_BY2(port) \
> + (1 << ((port == PORT_A) * BXT_MIPI_DIV_SHIFT + 3))
> +#define BXT_MIPI_RX_ESCLK_8X_BY3(port) \
> + (2 << ((port == PORT_A) * BXT_MIPI_DIV_SHIFT + 3))
> +#define BXT_MIPI_RX_ESCLK_8X_BY4(port) \
> + (3 << ((port == PORT_A) * BXT_MIPI_DIV_SHIFT + 3))
> +/* BXT: Always prog DPHY dividers to 00 */
> +#define BXT_MIPI_1_DPHY_DIVIDER_MASK (3 << 16)
> +#define BXT_MIPI_2_DPHY_DIVIDER_MASK (3 << 0)
> +#define BXT_MIPI_DPHY_DIVIDER_MASK(port) \
> + (3 << ((port == PORT_A) * BXT_MIPI_DIV_SHIFT))
Meh. Please define the shifts and masks for all fields, and if you want
to have macros with port argument, please use _MIPI_PORT for defining
them.
For example,
#define _BXT_MIPI1_TX_ESCLK_FIXDIV_MASK (3 << 21)
#define _BXT_MIPI2_TX_ESCLK_FIXDIV_MASK (3 << 5)
#define BXT_MIPI_TX_ESCLK_FIXDIV_MASK(port) \
_MIPI_PORT(port, _BXT_MIPI1_TX_ESCLK_FIXDIV_MASK, _BXT_MIPI2_TX_ESCLK_FIXDIV_MASK)
> +
> /* BXT MIPI mode configure */
> #define _BXT_MIPIA_TRANS_HACTIVE 0x6B0F8
> #define _BXT_MIPIC_TRANS_HACTIVE 0x6B8F8
> diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c
> index f335e6c..0b74399 100644
> --- a/drivers/gpu/drm/i915/intel_dsi_pll.c
> +++ b/drivers/gpu/drm/i915/intel_dsi_pll.c
> @@ -384,6 +384,41 @@ u32 vlv_get_dsi_pclk(struct intel_encoder *encoder, int pipe_bpp)
> return pclk;
> }
>
> +/* Program BXT Mipi clocks and dividers */
> +static void bxt_dsi_program_clocks(struct drm_device *dev, enum port port)
> +{
> + u32 tmp;
> + u32 divider;
> + u32 dsi_rate;
> + u32 pll_ratio;
> + struct drm_i915_private *dev_priv = dev->dev_private;
> +
> + /* Clear old configurations */
> + tmp = I915_READ(BXT_MIPI_CLOCK_CTL);
> + tmp &= ~(BXT_MIPI_TX_ESCLK_FIXDIV_MASK(port));
> + tmp &= ~(BXT_MIPI_RX_ESCLK_FIXDIV_MASK(port));
> + tmp &= ~(BXT_MIPI_ESCLK_VAR_DIV_MASK(port));
> + tmp &= ~(BXT_MIPI_DPHY_DIVIDER_MASK(port));
> +
> + /* Get the current DSI rate(actual) */
> + pll_ratio = I915_READ(BXT_DSI_PLL_CTL) &
> + BXT_DSI_PLL_RATIO_MASK;
Please do not use registers as temp storage. Pass the information into
this function instead.
> + dsi_rate = (BXT_REF_CLOCK_KHZ * pll_ratio) / 2;
> +
> + /* Max possible output of clock is 39.5 MHz, program value -1 */
> + divider = (dsi_rate / BXT_MAX_VAR_OUTPUT_KHZ) - 1;
> + tmp |= BXT_MIPI_ESCLK_VAR_DIV(port, divider);
> +
> + /* Tx escape clock should be >=20MHz, so select divide by 2 */
Here the comment is useful as it contains rationale...
> + tmp |= BXT_MIPI_TX_ESCLK_8XDIV_BY2(port);
> +
> + /* Rx escape clock, select fix divide by 3 clock */
...however this just describes what should be obvious from the code.
> + tmp |= BXT_MIPI_RX_ESCLK_8X_BY3(port);
> +
> + /* Do the honors */
Useless comment.
> + I915_WRITE(BXT_MIPI_CLOCK_CTL, tmp);
> +}
> +
> static bool bxt_configure_dsi_pll(struct intel_encoder *encoder)
> {
> struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
> @@ -435,6 +470,8 @@ static bool bxt_configure_dsi_pll(struct intel_encoder *encoder)
> static void bxt_enable_dsi_pll(struct intel_encoder *encoder)
> {
> struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
> + struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
> + enum port port;
> u32 val;
>
> DRM_DEBUG_KMS("\n");
> @@ -453,6 +490,10 @@ static void bxt_enable_dsi_pll(struct intel_encoder *encoder)
> return;
> }
>
> + /* Now program TX, RX, Dphy clocks */
> + for_each_dsi_port(port, intel_dsi->ports)
> + bxt_dsi_program_clocks(encoder->base.dev, port);
> +
> /* Enable DSI PLL */
> val = I915_READ(BXT_DSI_PLL_ENABLE);
> val |= BXT_DSI_PLL_DO_ENABLE;
> --
> 1.7.9.5
>
--
Jani Nikula, Intel Open Source Technology Center
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