From: Matthias Wieloch matthias.wieloch@few-bauer.de

The prescaler formula of the programmable clock has changed for sama5d2. Update the driver accordingly.

Fixes: a2038077de9a ("clk: at91: add sama5d2 PMC driver") Cc: stable@vger.kernel.org # v4.20+ Signed-off-by: Nicolas Ferre nicolas.ferre@microchip.com [nicolas.ferre@microchip.com: adapt the prescaler range, fix clk_programmable_recalc_rate, split patch] Signed-off-by: Matthias Wieloch matthias.wieloch@few-bauer.de Signed-off-by: Alexandre Belloni alexandre.belloni@bootlin.com --- v2: adapt to v5.1-rc1 remove unneeded sentence about DT in commit message

Stephen,

I think it would be good to see this fix going upstream during v5.1-rc phase.

Best regards, Nicolas

drivers/clk/at91/clk-programmable.c | 57 ++++++++++++++++++++++------- drivers/clk/at91/pmc.h | 2 + drivers/clk/at91/sama5d2.c | 10 ++++- 3 files changed, 54 insertions(+), 15 deletions(-)

diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c index 89d6f3736dbf..f8edbb65eda3 100644 --- a/drivers/clk/at91/clk-programmable.c +++ b/drivers/clk/at91/clk-programmable.c @@ -20,8 +20,7 @@ #define PROG_ID_MAX 7

#define PROG_STATUS_MASK(id) (1 << ((id) + 8)) -#define PROG_PRES_MASK 0x7 -#define PROG_PRES(layout, pckr) ((pckr >> layout->pres_shift) & PROG_PRES_MASK) +#define PROG_PRES(layout, pckr) ((pckr >> layout->pres_shift) & layout->pres_mask) #define PROG_MAX_RM9200_CSS 3

struct clk_programmable { @@ -37,20 +36,29 @@ static unsigned long clk_programmable_recalc_rate(struct clk_hw *hw, unsigned long parent_rate) { struct clk_programmable *prog = to_clk_programmable(hw); + const struct clk_programmable_layout *layout = prog->layout; unsigned int pckr; + unsigned long rate;

regmap_read(prog->regmap, AT91_PMC_PCKR(prog->id), &pckr);

- return parent_rate >> PROG_PRES(prog->layout, pckr); + if (layout->is_pres_direct) + rate = parent_rate / (PROG_PRES(layout, pckr) + 1); + else + rate = parent_rate >> PROG_PRES(layout, pckr); + + return rate; }

static int clk_programmable_determine_rate(struct clk_hw *hw, struct clk_rate_request *req) { + struct clk_programmable *prog = to_clk_programmable(hw); + const struct clk_programmable_layout *layout = prog->layout; struct clk_hw *parent; long best_rate = -EINVAL; unsigned long parent_rate; - unsigned long tmp_rate; + unsigned long tmp_rate = 0; int shift; int i;

@@ -60,10 +68,18 @@ static int clk_programmable_determine_rate(struct clk_hw *hw, continue;

parent_rate = clk_hw_get_rate(parent); - for (shift = 0; shift < PROG_PRES_MASK; shift++) { - tmp_rate = parent_rate >> shift; - if (tmp_rate <= req->rate) - break; + if (layout->is_pres_direct) { + for (shift = 0; shift <= layout->pres_mask; shift++) { + tmp_rate = parent_rate / (shift + 1); + if (tmp_rate <= req->rate) + break; + } + } else { + for (shift = 0; shift < layout->pres_mask; shift++) { + tmp_rate = parent_rate >> shift; + if (tmp_rate <= req->rate) + break; + } }

if (tmp_rate > req->rate) @@ -137,16 +153,23 @@ static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate, if (!div) return -EINVAL;

- shift = fls(div) - 1; + if (layout->is_pres_direct) { + shift = div - 1;

- if (div != (1 << shift)) - return -EINVAL; + if (shift > layout->pres_mask) + return -EINVAL; + } else { + shift = fls(div) - 1;

- if (shift >= PROG_PRES_MASK) - return -EINVAL; + if (div != (1 << shift)) + return -EINVAL; + + if (shift >= layout->pres_mask) + return -EINVAL; + }

regmap_update_bits(prog->regmap, AT91_PMC_PCKR(prog->id), - PROG_PRES_MASK << layout->pres_shift, + layout->pres_mask << layout->pres_shift, shift << layout->pres_shift);

return 0; @@ -202,19 +225,25 @@ at91_clk_register_programmable(struct regmap *regmap, }

const struct clk_programmable_layout at91rm9200_programmable_layout = { + .pres_mask = 0x7, .pres_shift = 2, .css_mask = 0x3, .have_slck_mck = 0, + .is_pres_direct = 0, };

const struct clk_programmable_layout at91sam9g45_programmable_layout = { + .pres_mask = 0x7, .pres_shift = 2, .css_mask = 0x3, .have_slck_mck = 1, + .is_pres_direct = 0, };

const struct clk_programmable_layout at91sam9x5_programmable_layout = { + .pres_mask = 0x7, .pres_shift = 4, .css_mask = 0x7, .have_slck_mck = 0, + .is_pres_direct = 0, }; diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h index 672a79bda88c..a0e5ce9c9b9e 100644 --- a/drivers/clk/at91/pmc.h +++ b/drivers/clk/at91/pmc.h @@ -71,9 +71,11 @@ struct clk_pll_characteristics { };

struct clk_programmable_layout { + u8 pres_mask; u8 pres_shift; u8 css_mask; u8 have_slck_mck; + u8 is_pres_direct; };

extern const struct clk_programmable_layout at91rm9200_programmable_layout; diff --git a/drivers/clk/at91/sama5d2.c b/drivers/clk/at91/sama5d2.c index 1f70cb164b06..81943fac4537 100644 --- a/drivers/clk/at91/sama5d2.c +++ b/drivers/clk/at91/sama5d2.c @@ -125,6 +125,14 @@ static const struct { .pll = true }, };

+static const struct clk_programmable_layout sama5d2_programmable_layout = { + .pres_mask = 0xff, + .pres_shift = 4, + .css_mask = 0x7, + .have_slck_mck = 0, + .is_pres_direct = 1, +}; + static void __init sama5d2_pmc_setup(struct device_node *np) { struct clk_range range = CLK_RANGE(0, 0); @@ -249,7 +257,7 @@ static void __init sama5d2_pmc_setup(struct device_node *np)

hw = at91_clk_register_programmable(regmap, name, parent_names, 6, i, - &at91sam9x5_programmable_layout); + &sama5d2_programmable_layout); if (IS_ERR(hw)) goto err_free; }