From 0899431f95a7a695f342527548b24ffd902c68ab Mon Sep 17 00:00:00 2001 From: Dario Binacchi Date: Sun, 6 Jun 2021 22:22:53 +0200 Subject: clk: ti: add am33xx/am43xx spread spectrum clock support The patch enables spread spectrum clocking (SSC) for MPU and LCD PLLs. As reported by the TI spruh73x/spruhl7x RM, SSC is only supported for the DISP/LCD and MPU PLLs on am33xx/am43xx. SSC is not supported for DDR, PER, and CORE PLLs. Calculating the required values and setting the registers accordingly was taken from the set_mpu_spreadspectrum routine contained in the arch/arm/mach-omap2/am33xx/clock_am33xx.c file of the u-boot project. In locked condition, DPLL output clock = CLKINP *[M/N]. In case of SSC enabled, the reference manual explains that there is a restriction of range of M values. Since the omap2_dpll_round_rate routine attempts to select the minimum possible N, the value of M obtained is not guaranteed to be within the range required. With the new "ti,min-div" parameter it is possible to increase N and consequently M to satisfy the constraint imposed by SSC. Signed-off-by: Dario Binacchi Reviewed-by: Tero Kristo Link: https://lore.kernel.org/r/20210606202253.31649-6-dariobin@libero.it Signed-off-by: Stephen Boyd --- include/linux/clk/ti.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'include/linux/clk') diff --git a/include/linux/clk/ti.h b/include/linux/clk/ti.h index c62f6fa6763d..3486f20a3753 100644 --- a/include/linux/clk/ti.h +++ b/include/linux/clk/ti.h @@ -63,6 +63,17 @@ struct clk_omap_reg { * @auto_recal_bit: bitshift of the driftguard enable bit in @control_reg * @recal_en_bit: bitshift of the PRM_IRQENABLE_* bit for recalibration IRQs * @recal_st_bit: bitshift of the PRM_IRQSTATUS_* bit for recalibration IRQs + * @ssc_deltam_reg: register containing the DPLL SSC frequency spreading + * @ssc_modfreq_reg: register containing the DPLL SSC modulation frequency + * @ssc_modfreq_mant_mask: mask of the mantissa component in @ssc_modfreq_reg + * @ssc_modfreq_exp_mask: mask of the exponent component in @ssc_modfreq_reg + * @ssc_enable_mask: mask of the DPLL SSC enable bit in @control_reg + * @ssc_downspread_mask: mask of the DPLL SSC low frequency only bit in + * @control_reg + * @ssc_modfreq: the DPLL SSC frequency modulation in kHz + * @ssc_deltam: the DPLL SSC frequency spreading in permille (10th of percent) + * @ssc_downspread: require the only low frequency spread of the DPLL in SSC + * mode * @flags: DPLL type/features (see below) * * Possible values for @flags: @@ -110,6 +121,17 @@ struct dpll_data { u8 auto_recal_bit; u8 recal_en_bit; u8 recal_st_bit; + struct clk_omap_reg ssc_deltam_reg; + struct clk_omap_reg ssc_modfreq_reg; + u32 ssc_deltam_int_mask; + u32 ssc_deltam_frac_mask; + u32 ssc_modfreq_mant_mask; + u32 ssc_modfreq_exp_mask; + u32 ssc_enable_mask; + u32 ssc_downspread_mask; + u32 ssc_modfreq; + u32 ssc_deltam; + bool ssc_downspread; u8 flags; }; -- cgit v1.2.3