[PATCH 6.17 707/849] clk: at91: clk-sam9x60-pll: force write to PLL_UPDT register

6.17-stable review patch. If anyone has any objections, please let me know.

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From: Nicolas Ferre nicolas.ferre@microchip.com

[ Upstream commit af98caeaa7b6ad11eb7b7c8bfaddc769df2889f3 ]

This register is important for sequencing the commands to PLLs, so actually write the update bits with regmap_write_bits() instead of relying on a read/modify/write regmap command that could skip the actual hardware write if the value is identical to the one read.

It's changed when modification is needed to the PLL, when read-only operation is done, we could keep the call to regmap_update_bits().

Add a comment to the sam9x60_div_pll_set_div() function that uses this PLL_UPDT register so that it's used consistently, according to the product's datasheet.

Signed-off-by: Nicolas Ferre nicolas.ferre@microchip.com Tested-by: Ryan Wanner ryan.wanner@microchip.com # on sama7d65 and sam9x75 Link: https://lore.kernel.org/r/20250827150811.82496-1-nicolas.ferre@microchip.com [claudiu.beznea: fix "Alignment should match open parenthesis" checkpatch.pl check] Signed-off-by: Claudiu Beznea claudiu.beznea@tuxon.dev Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/clk/at91/clk-sam9x60-pll.c | 75 ++++++++++++++++-------------- 1 file changed, 39 insertions(+), 36 deletions(-)

diff --git a/drivers/clk/at91/clk-sam9x60-pll.c b/drivers/clk/at91/clk-sam9x60-pll.c index cefd9948e1039..a035dc15454b0 100644 --- a/drivers/clk/at91/clk-sam9x60-pll.c +++ b/drivers/clk/at91/clk-sam9x60-pll.c @@ -93,8 +93,8 @@ static int sam9x60_frac_pll_set(struct sam9x60_pll_core *core)

spin_lock_irqsave(core->lock, flags);

- regmap_update_bits(regmap, AT91_PMC_PLL_UPDT, - AT91_PMC_PLL_UPDT_ID_MSK, core->id); + regmap_write_bits(regmap, AT91_PMC_PLL_UPDT, + AT91_PMC_PLL_UPDT_ID_MSK, core->id); regmap_read(regmap, AT91_PMC_PLL_CTRL1, &val); cmul = (val & core->layout->mul_mask) >> core->layout->mul_shift; cfrac = (val & core->layout->frac_mask) >> core->layout->frac_shift; @@ -128,17 +128,17 @@ static int sam9x60_frac_pll_set(struct sam9x60_pll_core *core) udelay(10); }

- regmap_update_bits(regmap, AT91_PMC_PLL_UPDT, - AT91_PMC_PLL_UPDT_UPDATE | AT91_PMC_PLL_UPDT_ID_MSK, - AT91_PMC_PLL_UPDT_UPDATE | core->id); + regmap_write_bits(regmap, AT91_PMC_PLL_UPDT, + AT91_PMC_PLL_UPDT_UPDATE | AT91_PMC_PLL_UPDT_ID_MSK, + AT91_PMC_PLL_UPDT_UPDATE | core->id);

regmap_update_bits(regmap, AT91_PMC_PLL_CTRL0, AT91_PMC_PLL_CTRL0_ENLOCK | AT91_PMC_PLL_CTRL0_ENPLL, AT91_PMC_PLL_CTRL0_ENLOCK | AT91_PMC_PLL_CTRL0_ENPLL);

- regmap_update_bits(regmap, AT91_PMC_PLL_UPDT, - AT91_PMC_PLL_UPDT_UPDATE | AT91_PMC_PLL_UPDT_ID_MSK, - AT91_PMC_PLL_UPDT_UPDATE | core->id); + regmap_write_bits(regmap, AT91_PMC_PLL_UPDT, + AT91_PMC_PLL_UPDT_UPDATE | AT91_PMC_PLL_UPDT_ID_MSK, + AT91_PMC_PLL_UPDT_UPDATE | core->id);

while (!sam9x60_pll_ready(regmap, core->id)) cpu_relax(); @@ -164,8 +164,8 @@ static void sam9x60_frac_pll_unprepare(struct clk_hw *hw)

spin_lock_irqsave(core->lock, flags);

- regmap_update_bits(regmap, AT91_PMC_PLL_UPDT, - AT91_PMC_PLL_UPDT_ID_MSK, core->id); + regmap_write_bits(regmap, AT91_PMC_PLL_UPDT, + AT91_PMC_PLL_UPDT_ID_MSK, core->id);

regmap_update_bits(regmap, AT91_PMC_PLL_CTRL0, AT91_PMC_PLL_CTRL0_ENPLL, 0);

@@ -173,9 +173,9 @@ static void sam9x60_frac_pll_unprepare(struct clk_hw *hw) regmap_update_bits(regmap, AT91_PMC_PLL_ACR, AT91_PMC_PLL_ACR_UTMIBG | AT91_PMC_PLL_ACR_UTMIVR, 0);

- regmap_update_bits(regmap, AT91_PMC_PLL_UPDT, - AT91_PMC_PLL_UPDT_UPDATE | AT91_PMC_PLL_UPDT_ID_MSK, - AT91_PMC_PLL_UPDT_UPDATE | core->id); + regmap_write_bits(regmap, AT91_PMC_PLL_UPDT, + AT91_PMC_PLL_UPDT_UPDATE | AT91_PMC_PLL_UPDT_ID_MSK, + AT91_PMC_PLL_UPDT_UPDATE | core->id);

spin_unlock_irqrestore(core->lock, flags); } @@ -262,8 +262,8 @@ static int sam9x60_frac_pll_set_rate_chg(struct clk_hw *hw, unsigned long rate,

spin_lock_irqsave(core->lock, irqflags);

- regmap_update_bits(regmap, AT91_PMC_PLL_UPDT, AT91_PMC_PLL_UPDT_ID_MSK, - core->id); + regmap_write_bits(regmap, AT91_PMC_PLL_UPDT, AT91_PMC_PLL_UPDT_ID_MSK, + core->id); regmap_read(regmap, AT91_PMC_PLL_CTRL1, &val); cmul = (val & core->layout->mul_mask) >> core->layout->mul_shift; cfrac = (val & core->layout->frac_mask) >> core->layout->frac_shift; @@ -275,18 +275,18 @@ static int sam9x60_frac_pll_set_rate_chg(struct clk_hw *hw, unsigned long rate, (frac->mul << core->layout->mul_shift) | (frac->frac << core->layout->frac_shift));

- regmap_update_bits(regmap, AT91_PMC_PLL_UPDT, - AT91_PMC_PLL_UPDT_UPDATE | AT91_PMC_PLL_UPDT_ID_MSK, - AT91_PMC_PLL_UPDT_UPDATE | core->id); + regmap_write_bits(regmap, AT91_PMC_PLL_UPDT, + AT91_PMC_PLL_UPDT_UPDATE | AT91_PMC_PLL_UPDT_ID_MSK, + AT91_PMC_PLL_UPDT_UPDATE | core->id);

regmap_update_bits(regmap, AT91_PMC_PLL_CTRL0, AT91_PMC_PLL_CTRL0_ENLOCK | AT91_PMC_PLL_CTRL0_ENPLL, AT91_PMC_PLL_CTRL0_ENLOCK | AT91_PMC_PLL_CTRL0_ENPLL);

- regmap_update_bits(regmap, AT91_PMC_PLL_UPDT, - AT91_PMC_PLL_UPDT_UPDATE | AT91_PMC_PLL_UPDT_ID_MSK, - AT91_PMC_PLL_UPDT_UPDATE | core->id); + regmap_write_bits(regmap, AT91_PMC_PLL_UPDT, + AT91_PMC_PLL_UPDT_UPDATE | AT91_PMC_PLL_UPDT_ID_MSK, + AT91_PMC_PLL_UPDT_UPDATE | core->id);

while (!sam9x60_pll_ready(regmap, core->id)) cpu_relax(); @@ -338,7 +338,10 @@ static const struct clk_ops sam9x60_frac_pll_ops_chg = { .restore_context = sam9x60_frac_pll_restore_context, };

-/* This function should be called with spinlock acquired. */ +/* This function should be called with spinlock acquired. + * Warning: this function must be called only if the same PLL ID was set in + * PLL_UPDT register previously. + */ static void sam9x60_div_pll_set_div(struct sam9x60_pll_core *core, u32 div, bool enable) { @@ -350,9 +353,9 @@ static void sam9x60_div_pll_set_div(struct sam9x60_pll_core *core, u32 div, core->layout->div_mask | ena_msk, (div << core->layout->div_shift) | ena_val);

- regmap_update_bits(regmap, AT91_PMC_PLL_UPDT, - AT91_PMC_PLL_UPDT_UPDATE | AT91_PMC_PLL_UPDT_ID_MSK, - AT91_PMC_PLL_UPDT_UPDATE | core->id); + regmap_write_bits(regmap, AT91_PMC_PLL_UPDT, + AT91_PMC_PLL_UPDT_UPDATE | AT91_PMC_PLL_UPDT_ID_MSK, + AT91_PMC_PLL_UPDT_UPDATE | core->id);

while (!sam9x60_pll_ready(regmap, core->id)) cpu_relax(); @@ -366,8 +369,8 @@ static int sam9x60_div_pll_set(struct sam9x60_pll_core *core) unsigned int val, cdiv;

spin_lock_irqsave(core->lock, flags); - regmap_update_bits(regmap, AT91_PMC_PLL_UPDT, - AT91_PMC_PLL_UPDT_ID_MSK, core->id); + regmap_write_bits(regmap, AT91_PMC_PLL_UPDT, + AT91_PMC_PLL_UPDT_ID_MSK, core->id); regmap_read(regmap, AT91_PMC_PLL_CTRL0, &val); cdiv = (val & core->layout->div_mask) >> core->layout->div_shift;

@@ -398,15 +401,15 @@ static void sam9x60_div_pll_unprepare(struct clk_hw *hw)

spin_lock_irqsave(core->lock, flags);

- regmap_update_bits(regmap, AT91_PMC_PLL_UPDT, - AT91_PMC_PLL_UPDT_ID_MSK, core->id); + regmap_write_bits(regmap, AT91_PMC_PLL_UPDT, + AT91_PMC_PLL_UPDT_ID_MSK, core->id);

regmap_update_bits(regmap, AT91_PMC_PLL_CTRL0, core->layout->endiv_mask, 0);

- regmap_update_bits(regmap, AT91_PMC_PLL_UPDT, - AT91_PMC_PLL_UPDT_UPDATE | AT91_PMC_PLL_UPDT_ID_MSK, - AT91_PMC_PLL_UPDT_UPDATE | core->id); + regmap_write_bits(regmap, AT91_PMC_PLL_UPDT, + AT91_PMC_PLL_UPDT_UPDATE | AT91_PMC_PLL_UPDT_ID_MSK, + AT91_PMC_PLL_UPDT_UPDATE | core->id);

spin_unlock_irqrestore(core->lock, flags); } @@ -518,8 +521,8 @@ static int sam9x60_div_pll_set_rate_chg(struct clk_hw *hw, unsigned long rate, div->div = DIV_ROUND_CLOSEST(parent_rate, rate) - 1;

spin_lock_irqsave(core->lock, irqflags); - regmap_update_bits(regmap, AT91_PMC_PLL_UPDT, AT91_PMC_PLL_UPDT_ID_MSK, - core->id); + regmap_write_bits(regmap, AT91_PMC_PLL_UPDT, AT91_PMC_PLL_UPDT_ID_MSK, + core->id); regmap_read(regmap, AT91_PMC_PLL_CTRL0, &val); cdiv = (val & core->layout->div_mask) >> core->layout->div_shift;

@@ -574,8 +577,8 @@ static int sam9x60_div_pll_notifier_fn(struct notifier_block *notifier, div->div = div->safe_div;

spin_lock_irqsave(core.lock, irqflags); - regmap_update_bits(regmap, AT91_PMC_PLL_UPDT, AT91_PMC_PLL_UPDT_ID_MSK, - core.id); + regmap_write_bits(regmap, AT91_PMC_PLL_UPDT, AT91_PMC_PLL_UPDT_ID_MSK, + core.id); regmap_read(regmap, AT91_PMC_PLL_CTRL0, &val); cdiv = (val & core.layout->div_mask) >> core.layout->div_shift;