Re: [PATCH] clk: at91: fix programmable clock for sama5d2

From: Nicolas.Ferre
Date: Mon Mar 04 2019 - 05:04:01 EST

On 25/02/2019 at 18:27, Alexandre Belloni wrote:
> From: Matthias Wieloch <matthias.wieloch@xxxxxxxxxxxx>
>
> The prescaler formula of the programmable clock has changed for sama5d2. Update
> the driver accordingly. A new compatibility string is needed for this driver,
> now.

Actually, with new clk binding, a new compatibility string is not needed
anymore: this last sentence can be removed.

>
> Signed-off-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx>
> [nicolas.ferre@xxxxxxxxxxxxx: adapt the prescaler range,
> fix clk_programmable_recalc_rate, split patch]
> Signed-off-by: Matthias Wieloch <matthias.wieloch@xxxxxxxxxxxx>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>

Fixes: a2038077de9a ("clk: at91: add sama5d2 PMC driver")
Cc: <stable@xxxxxxxxxxxxxxx> # v4.20+

Stephen,
Do you want us to re-post this patch or will you update it yourself?

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 5bc68b9c5498..c3174a6bbd48 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)
> @@ -140,16 +156,23 @@ 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;
> @@ -205,19 +228,25 @@ 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 d69ad96fe988..31d6226b297a 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);
> @@ -248,7 +256,7 @@ static void __init sama5d2_pmc_setup(struct device_node *np)
>
> hw = at91_clk_register_programmable(regmap, name,
> parent_names, 5, i,
> - &at91sam9x5_programmable_layout);
> + &sama5d2_programmable_layout);
> if (IS_ERR(hw))
> goto err_free;
> }
>


--
Nicolas Ferre