From 7411cdf0e20f3e7028a3ba5be956875b32933cad Mon Sep 17 00:00:00 2001 From: Marek Vasut Date: Sun, 28 Apr 2013 09:20:01 +0000 Subject: arm: mxs: Add LCDIF clock configuration function This function turns on the LCDIF clock and configures it's frequency. The dividers settings are calculated within the function and the current implementation should be fast and accurate. Signed-off-by: Marek Vasut Cc: Fabio Estevam Cc: Otavio Salvador Cc: Stefano Babic --- arch/arm/cpu/arm926ejs/mxs/clock.c | 93 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) (limited to 'arch/arm/cpu/arm926ejs') diff --git a/arch/arm/cpu/arm926ejs/mxs/clock.c b/arch/arm/cpu/arm926ejs/mxs/clock.c index 43e7663..f94107f 100644 --- a/arch/arm/cpu/arm926ejs/mxs/clock.c +++ b/arch/arm/cpu/arm926ejs/mxs/clock.c @@ -325,6 +325,99 @@ void mxs_set_ssp_busclock(unsigned int bus, uint32_t freq) bus, tgtclk, freq); } +void mxs_set_lcdclk(uint32_t freq) +{ + struct mxs_clkctrl_regs *clkctrl_regs = + (struct mxs_clkctrl_regs *)MXS_CLKCTRL_BASE; + uint32_t fp, x, k_rest, k_best, x_best, tk; + int32_t k_best_l = 999, k_best_t = 0, x_best_l = 0xff, x_best_t = 0xff; + + if (freq == 0) + return; + +#if defined(CONFIG_MX23) + writel(CLKCTRL_CLKSEQ_BYPASS_PIX, &clkctrl_regs->hw_clkctrl_clkseq_clr); +#elif defined(CONFIG_MX28) + writel(CLKCTRL_CLKSEQ_BYPASS_DIS_LCDIF, &clkctrl_regs->hw_clkctrl_clkseq_clr); +#endif + + /* + * / 18 \ 1 1 + * freq kHz = | 480000000 Hz * -- | * --- * ------ + * \ x / k 1000 + * + * 480000000 Hz 18 + * ------------ * -- + * freq kHz x + * k = ------------------- + * 1000 + */ + + fp = ((PLL_FREQ_KHZ * 1000) / freq) * 18; + + for (x = 18; x <= 35; x++) { + tk = fp / x; + if ((tk / 1000 == 0) || (tk / 1000 > 255)) + continue; + + k_rest = tk % 1000; + + if (k_rest < (k_best_l % 1000)) { + k_best_l = tk; + x_best_l = x; + } + + if (k_rest > (k_best_t % 1000)) { + k_best_t = tk; + x_best_t = x; + } + } + + if (1000 - (k_best_t % 1000) > (k_best_l % 1000)) { + k_best = k_best_l; + x_best = x_best_l; + } else { + k_best = k_best_t; + x_best = x_best_t; + } + + k_best /= 1000; + +#if defined(CONFIG_MX23) + writeb(CLKCTRL_FRAC_CLKGATE, + &clkctrl_regs->hw_clkctrl_frac0_set[CLKCTRL_FRAC0_PIX]); + writeb(CLKCTRL_FRAC_CLKGATE | (x_best & CLKCTRL_FRAC_FRAC_MASK), + &clkctrl_regs->hw_clkctrl_frac0[CLKCTRL_FRAC0_PIX]); + writeb(CLKCTRL_FRAC_CLKGATE, + &clkctrl_regs->hw_clkctrl_frac0_clr[CLKCTRL_FRAC0_PIX]); + + writel(CLKCTRL_PIX_CLKGATE, + &clkctrl_regs->hw_clkctrl_pix_set); + clrsetbits_le32(&clkctrl_regs->hw_clkctrl_pix, + CLKCTRL_PIX_DIV_MASK | CLKCTRL_PIX_CLKGATE, + k_best << CLKCTRL_PIX_DIV_OFFSET); + + while (readl(&clkctrl_regs->hw_clkctrl_pix) & CLKCTRL_PIX_BUSY) + ; +#elif defined(CONFIG_MX28) + writeb(CLKCTRL_FRAC_CLKGATE, + &clkctrl_regs->hw_clkctrl_frac1_set[CLKCTRL_FRAC1_PIX]); + writeb(CLKCTRL_FRAC_CLKGATE | (x_best & CLKCTRL_FRAC_FRAC_MASK), + &clkctrl_regs->hw_clkctrl_frac1[CLKCTRL_FRAC1_PIX]); + writeb(CLKCTRL_FRAC_CLKGATE, + &clkctrl_regs->hw_clkctrl_frac1_clr[CLKCTRL_FRAC1_PIX]); + + writel(CLKCTRL_DIS_LCDIF_CLKGATE, + &clkctrl_regs->hw_clkctrl_lcdif_set); + clrsetbits_le32(&clkctrl_regs->hw_clkctrl_lcdif, + CLKCTRL_DIS_LCDIF_DIV_MASK | CLKCTRL_DIS_LCDIF_CLKGATE, + k_best << CLKCTRL_DIS_LCDIF_DIV_OFFSET); + + while (readl(&clkctrl_regs->hw_clkctrl_lcdif) & CLKCTRL_DIS_LCDIF_BUSY) + ; +#endif +} + uint32_t mxc_get_clock(enum mxc_clock clk) { switch (clk) { -- cgit v1.1