From 5ae51d67aec95f6f9386aa8dd5db424964895575 Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Mon, 11 Feb 2019 14:59:07 -0800 Subject: [PATCH] clk: clk-twl6040: Fix imprecise external abort for pdmclk I noticed that modprobe clk-twl6040 can fail after a cold boot with: abe_cm:clk:0010:0: failed to enable ... Unhandled fault: imprecise external abort (0x1406) at 0xbe896b20 WARNING: CPU: 1 PID: 29 at drivers/clk/clk.c:828 clk_core_disable_lock+0x18/0x24 ... (clk_core_disable_lock) from [] (_disable_clocks+0x18/0x90) (_disable_clocks) from [] (_idle+0x17c/0x244) (_idle) from [] (omap_hwmod_idle+0x24/0x44) (omap_hwmod_idle) from [] (sysc_runtime_suspend+0x48/0x108) (sysc_runtime_suspend) from [] (__rpm_callback+0x144/0x1d8) (__rpm_callback) from [] (rpm_callback+0x20/0x80) (rpm_callback) from [] (rpm_suspend+0x120/0x694) (rpm_suspend) from [] (__pm_runtime_idle+0x60/0x84) (__pm_runtime_idle) from [] (sysc_probe+0x874/0xf2c) (sysc_probe) from [] (platform_drv_probe+0x48/0x98) After searching around for a similar issue, I came across an earlier fix that never got merged upstream in the Android tree for glass-omap-xrr02. There is patch "MFD: twl6040-codec: Implement PDMCLK cold temp errata" by Misael Lopez Cruz . Based on my observations, this fix is also needed when cold booting devices, and not just for deeper idle modes. Since we now have a clock driver for pdmclk, let's fix the issue in twl6040_pdmclk_prepare(). Cc: Misael Lopez Cruz Cc: Peter Ujfalusi Signed-off-by: Tony Lindgren Acked-by: Peter Ujfalusi Cc: Signed-off-by: Stephen Boyd --- drivers/clk/clk-twl6040.c | 53 +++++++++++++++++++++++++++++++++++++-- 1 file changed, 51 insertions(+), 2 deletions(-) diff --git a/drivers/clk/clk-twl6040.c b/drivers/clk/clk-twl6040.c index ea846f77750b..0cad5748bf0e 100644 --- a/drivers/clk/clk-twl6040.c +++ b/drivers/clk/clk-twl6040.c @@ -41,6 +41,43 @@ static int twl6040_pdmclk_is_prepared(struct clk_hw *hw) return pdmclk->enabled; } +static int twl6040_pdmclk_reset_one_clock(struct twl6040_pdmclk *pdmclk, + unsigned int reg) +{ + const u8 reset_mask = TWL6040_HPLLRST; /* Same for HPPLL and LPPLL */ + int ret; + + ret = twl6040_set_bits(pdmclk->twl6040, reg, reset_mask); + if (ret < 0) + return ret; + + ret = twl6040_clear_bits(pdmclk->twl6040, reg, reset_mask); + if (ret < 0) + return ret; + + return 0; +} + +/* + * TWL6040A2 Phoenix Audio IC erratum #6: "PDM Clock Generation Issue At + * Cold Temperature". This affects cold boot and deeper idle states it + * seems. The workaround consists of resetting HPPLL and LPPLL. + */ +static int twl6040_pdmclk_quirk_reset_clocks(struct twl6040_pdmclk *pdmclk) +{ + int ret; + + ret = twl6040_pdmclk_reset_one_clock(pdmclk, TWL6040_REG_HPPLLCTL); + if (ret) + return ret; + + ret = twl6040_pdmclk_reset_one_clock(pdmclk, TWL6040_REG_LPPLLCTL); + if (ret) + return ret; + + return 0; +} + static int twl6040_pdmclk_prepare(struct clk_hw *hw) { struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk, @@ -48,8 +85,20 @@ static int twl6040_pdmclk_prepare(struct clk_hw *hw) int ret; ret = twl6040_power(pdmclk->twl6040, 1); - if (!ret) - pdmclk->enabled = 1; + if (ret) + return ret; + + ret = twl6040_pdmclk_quirk_reset_clocks(pdmclk); + if (ret) + goto out_err; + + pdmclk->enabled = 1; + + return 0; + +out_err: + dev_err(pdmclk->dev, "%s: error %i\n", __func__, ret); + twl6040_power(pdmclk->twl6040, 0); return ret; }