This is a note to let you know that I've just added the patch titled clk: pistachio: Fix PLL rate calculation in integer mode to the 4.2-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: clk-pistachio-fix-pll-rate-calculation-in-integer-mode.patch and it can be found in the queue-4.2 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 7937c6c57e0da7bffa7b10bac23f230c77523e35 Mon Sep 17 00:00:00 2001 From: Zdenko Pulitika <zdenko.pulitika@xxxxxxxxxx> Date: Wed, 26 Aug 2015 17:11:39 +0100 Subject: clk: pistachio: Fix PLL rate calculation in integer mode From: Zdenko Pulitika <zdenko.pulitika@xxxxxxxxxx> commit 7937c6c57e0da7bffa7b10bac23f230c77523e35 upstream. .recalc_rate callback for the fractional PLL doesn't take operating mode into account when calculating PLL rate. This results in the incorrect PLL rates when PLL is operating in integer mode. Operating mode of fractional PLL is based on the value of the fractional divider. Currently it assumes that the PLL will always be configured in fractional mode which may not be the case. This may result in the wrong output frequency. Also vco was calculated based on the current operating mode which makes no sense because .set_rate is setting operating mode. Instead, vco should be calculated using PLL settings that are about to be set. Fixes: 43049b0c83f17("CLK: Pistachio: Add PLL driver") Reviewed-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx> Signed-off-by: Zdenko Pulitika <zdenko.pulitika@xxxxxxxxxx> Signed-off-by: Govindraj Raja <govindraj.raja@xxxxxxxxxx> Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/clk/pistachio/clk-pll.c | 48 ++++++++++++++++++++++++++++++++++++++-- 1 file changed, 46 insertions(+), 2 deletions(-) --- a/drivers/clk/pistachio/clk-pll.c +++ b/drivers/clk/pistachio/clk-pll.c @@ -65,6 +65,12 @@ #define MIN_OUTPUT_FRAC 12000000UL #define MAX_OUTPUT_FRAC 1600000000UL +/* Fractional PLL operating modes */ +enum pll_mode { + PLL_MODE_FRAC, + PLL_MODE_INT, +}; + struct pistachio_clk_pll { struct clk_hw hw; void __iomem *base; @@ -99,6 +105,29 @@ static inline struct pistachio_clk_pll * return container_of(hw, struct pistachio_clk_pll, hw); } +static inline enum pll_mode pll_frac_get_mode(struct clk_hw *hw) +{ + struct pistachio_clk_pll *pll = to_pistachio_pll(hw); + u32 val; + + val = pll_readl(pll, PLL_CTRL3) & PLL_FRAC_CTRL3_DSMPD; + return val ? PLL_MODE_INT : PLL_MODE_FRAC; +} + +static inline void pll_frac_set_mode(struct clk_hw *hw, enum pll_mode mode) +{ + struct pistachio_clk_pll *pll = to_pistachio_pll(hw); + u32 val; + + val = pll_readl(pll, PLL_CTRL3); + if (mode == PLL_MODE_INT) + val |= PLL_FRAC_CTRL3_DSMPD | PLL_FRAC_CTRL3_DACPD; + else + val &= ~(PLL_FRAC_CTRL3_DSMPD | PLL_FRAC_CTRL3_DACPD); + + pll_writel(pll, val, PLL_CTRL3); +} + static struct pistachio_pll_rate_table * pll_get_params(struct pistachio_clk_pll *pll, unsigned long fref, unsigned long fout) @@ -180,7 +209,11 @@ static int pll_gf40lp_frac_set_rate(stru if (!params || !params->refdiv) return -EINVAL; - vco = div64_u64(params->fref * params->fbdiv, params->refdiv); + /* calculate vco */ + vco = params->fref; + vco *= (params->fbdiv << 24) + params->frac; + vco = div64_u64(vco, params->refdiv << 24); + if (vco < MIN_VCO_FRAC_FRAC || vco > MAX_VCO_FRAC_FRAC) pr_warn("%s: VCO %llu is out of range %lu..%lu\n", name, vco, MIN_VCO_FRAC_FRAC, MAX_VCO_FRAC_FRAC); @@ -224,6 +257,12 @@ static int pll_gf40lp_frac_set_rate(stru (params->postdiv2 << PLL_FRAC_CTRL2_POSTDIV2_SHIFT); pll_writel(pll, val, PLL_CTRL2); + /* set operating mode */ + if (params->frac) + pll_frac_set_mode(hw, PLL_MODE_FRAC); + else + pll_frac_set_mode(hw, PLL_MODE_INT); + if (enabled) pll_lock(pll); @@ -247,8 +286,13 @@ static unsigned long pll_gf40lp_frac_rec PLL_FRAC_CTRL2_POSTDIV2_MASK; frac = (val >> PLL_FRAC_CTRL2_FRAC_SHIFT) & PLL_FRAC_CTRL2_FRAC_MASK; + /* get operating mode (int/frac) and calculate rate accordingly */ rate = parent_rate; - rate *= (fbdiv << 24) + frac; + if (pll_frac_get_mode(hw) == PLL_MODE_FRAC) + rate *= (fbdiv << 24) + frac; + else + rate *= (fbdiv << 24); + rate = do_div_round_closest(rate, (prediv * postdiv1 * postdiv2) << 24); return rate; Patches currently in stable-queue which might be from zdenko.pulitika@xxxxxxxxxx are queue-4.2/clk-pistachio-fix-32bit-integer-overflows.patch queue-4.2/clk-pistachio-fix-override-of-clk-pll-settings-from-boot-loader.patch queue-4.2/clk-pistachio-fix-pll-rate-calculation-in-integer-mode.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html