[PATCH 1/2] clk: bcm2835: Fix setting of PLL divider clock rates

[PATCH 1/2] clk: bcm2835: Fix setting of PLL divider clock rates

[Eric Anholt]

Our dividers weren't being set successfully because CM_PASSWORD wasn't
included in the register write.  It looks easier to just compute the
divider to write ourselves than to update clk-divider for the ability
to OR in some arbitrary bits on write.

Fixes about half of the video modes on my HDMI monitor (everything
except 720x400).

Cc: stable@vger.kernel.org
Signed-off-by: Eric Anholt <eric@anholt.net>
---
 drivers/clk/bcm/clk-bcm2835.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index 015e687..9f4df8f 100644
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1107,13 +1107,15 @@ static int bcm2835_pll_divider_set_rate(struct clk_hw *hw,
 	struct bcm2835_pll_divider *divider = bcm2835_pll_divider_from_hw(hw);
 	struct bcm2835_cprman *cprman = divider->cprman;
 	const struct bcm2835_pll_divider_data *data = divider->data;
-	u32 cm;
-	int ret;
+	u32 cm, div, max_div = 1 << A2W_PLL_DIV_BITS;
 
-	ret = clk_divider_ops.set_rate(hw, rate, parent_rate);
-	if (ret)
-		return ret;
+	div = DIV_ROUND_UP_ULL(parent_rate, rate);
+
+	div = min(div, max_div);
+	if (div == max_div)
+		div = 0;
 
+	cprman_write(cprman, data->a2w_reg, div);
 	cm = cprman_read(cprman, data->cm_reg);
 	cprman_write(cprman, data->cm_reg, cm | data->load_mask);
 	cprman_write(cprman, data->cm_reg, cm & ~data->load_mask);
-- 
2.7.0

[PATCH 2/2] clk: bcm2835: Reuse CLK_DIVIDER_MAX_AT_ZERO for recalc_rate()

[Eric Anholt]

We were rolling this ourselves, but clk-divider can do it now.

Signed-off-by: Eric Anholt <eric@anholt.net>
---
 drivers/clk/bcm/clk-bcm2835.c | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index 9f4df8f..353e438 100644
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1060,16 +1060,7 @@ static long bcm2835_pll_divider_round_rate(struct clk_hw *hw,
 static unsigned long bcm2835_pll_divider_get_rate(struct clk_hw *hw,
 						  unsigned long parent_rate)
 {
-	struct bcm2835_pll_divider *divider = bcm2835_pll_divider_from_hw(hw);
-	struct bcm2835_cprman *cprman = divider->cprman;
-	const struct bcm2835_pll_divider_data *data = divider->data;
-	u32 div = cprman_read(cprman, data->a2w_reg);
-
-	div &= (1 << A2W_PLL_DIV_BITS) - 1;
-	if (div == 0)
-		div = 256;
-
-	return parent_rate / div;
+	return clk_divider_ops.recalc_rate(hw, parent_rate);
 }
 
 static void bcm2835_pll_divider_off(struct clk_hw *hw)
@@ -1430,7 +1421,7 @@ bcm2835_register_pll_divider(struct bcm2835_cprman *cprman,
 	divider->div.reg = cprman->regs + data->a2w_reg;
 	divider->div.shift = A2W_PLL_DIV_SHIFT;
 	divider->div.width = A2W_PLL_DIV_BITS;
-	divider->div.flags = 0;
+	divider->div.flags = CLK_DIVIDER_MAX_AT_ZERO;
 	divider->div.lock = &cprman->regs_lock;
 	divider->div.hw.init = &init;
 	divider->div.table = NULL;
-- 
2.7.0

Re: [PATCH 1/2] clk: bcm2835: Fix setting of PLL divider clock rates

[Michael Turquette]

Quoting Eric Anholt (2016-02-15 19:03:57)
> Our dividers weren't being set successfully because CM_PASSWORD wasn't
> included in the register write.  It looks easier to just compute the
> divider to write ourselves than to update clk-divider for the ability
> to OR in some arbitrary bits on write.
> =

> Fixes about half of the video modes on my HDMI monitor (everything
> except 720x400).
> =

> Cc: stable@vger.kernel.org
> Signed-off-by: Eric Anholt <eric@anholt.net>

Applied to clk-next.

Regards,
Mike

> ---
>  drivers/clk/bcm/clk-bcm2835.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
> =

> diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
> index 015e687..9f4df8f 100644
> --- a/drivers/clk/bcm/clk-bcm2835.c
> +++ b/drivers/clk/bcm/clk-bcm2835.c
> @@ -1107,13 +1107,15 @@ static int bcm2835_pll_divider_set_rate(struct cl=
k_hw *hw,
>         struct bcm2835_pll_divider *divider =3D bcm2835_pll_divider_from_=
hw(hw);
>         struct bcm2835_cprman *cprman =3D divider->cprman;
>         const struct bcm2835_pll_divider_data *data =3D divider->data;
> -       u32 cm;
> -       int ret;
> +       u32 cm, div, max_div =3D 1 << A2W_PLL_DIV_BITS;
>  =

> -       ret =3D clk_divider_ops.set_rate(hw, rate, parent_rate);
> -       if (ret)
> -               return ret;
> +       div =3D DIV_ROUND_UP_ULL(parent_rate, rate);
> +
> +       div =3D min(div, max_div);
> +       if (div =3D=3D max_div)
> +               div =3D 0;
>  =

> +       cprman_write(cprman, data->a2w_reg, div);
>         cm =3D cprman_read(cprman, data->cm_reg);
>         cprman_write(cprman, data->cm_reg, cm | data->load_mask);
>         cprman_write(cprman, data->cm_reg, cm & ~data->load_mask);
> -- =

> 2.7.0
>=20

Re: [PATCH 2/2] clk: bcm2835: Reuse CLK_DIVIDER_MAX_AT_ZERO for recalc_rate()

[Michael Turquette]

Quoting Eric Anholt (2016-02-15 19:03:58)
> We were rolling this ourselves, but clk-divider can do it now.
> =

> Signed-off-by: Eric Anholt <eric@anholt.net>

Applied to clk-next.

Regards,
Mike

> ---
>  drivers/clk/bcm/clk-bcm2835.c | 13 ++-----------
>  1 file changed, 2 insertions(+), 11 deletions(-)
> =

> diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
> index 9f4df8f..353e438 100644
> --- a/drivers/clk/bcm/clk-bcm2835.c
> +++ b/drivers/clk/bcm/clk-bcm2835.c
> @@ -1060,16 +1060,7 @@ static long bcm2835_pll_divider_round_rate(struct =
clk_hw *hw,
>  static unsigned long bcm2835_pll_divider_get_rate(struct clk_hw *hw,
>                                                   unsigned long parent_ra=
te)
>  {
> -       struct bcm2835_pll_divider *divider =3D bcm2835_pll_divider_from_=
hw(hw);
> -       struct bcm2835_cprman *cprman =3D divider->cprman;
> -       const struct bcm2835_pll_divider_data *data =3D divider->data;
> -       u32 div =3D cprman_read(cprman, data->a2w_reg);
> -
> -       div &=3D (1 << A2W_PLL_DIV_BITS) - 1;
> -       if (div =3D=3D 0)
> -               div =3D 256;
> -
> -       return parent_rate / div;
> +       return clk_divider_ops.recalc_rate(hw, parent_rate);
>  }
>  =

>  static void bcm2835_pll_divider_off(struct clk_hw *hw)
> @@ -1430,7 +1421,7 @@ bcm2835_register_pll_divider(struct bcm2835_cprman =
*cprman,
>         divider->div.reg =3D cprman->regs + data->a2w_reg;
>         divider->div.shift =3D A2W_PLL_DIV_SHIFT;
>         divider->div.width =3D A2W_PLL_DIV_BITS;
> -       divider->div.flags =3D 0;
> +       divider->div.flags =3D CLK_DIVIDER_MAX_AT_ZERO;
>         divider->div.lock =3D &cprman->regs_lock;
>         divider->div.hw.init =3D &init;
>         divider->div.table =3D NULL;
> -- =

> 2.7.0
>=20

Re: [PATCH 1/2] clk: bcm2835: Fix setting of PLL divider clock rates

[Jayson Aguilar]

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Unsubscribe
On Feb 16, 2016 12:42 AM, "Eric Anholt" <eric@anholt.net> wrote:

> Our dividers weren't being set successfully because CM_PASSWORD wasn't
> included in the register write.  It looks easier to just compute the
> divider to write ourselves than to update clk-divider for the ability
> to OR in some arbitrary bits on write.
>
> Fixes about half of the video modes on my HDMI monitor (everything
> except 720x400).
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Eric Anholt <eric@anholt.net>
> ---
>  drivers/clk/bcm/clk-bcm2835.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
> index 015e687..9f4df8f 100644
> --- a/drivers/clk/bcm/clk-bcm2835.c
> +++ b/drivers/clk/bcm/clk-bcm2835.c
> @@ -1107,13 +1107,15 @@ static int bcm2835_pll_divider_set_rate(struct
> clk_hw *hw,
>         struct bcm2835_pll_divider *divider =
> bcm2835_pll_divider_from_hw(hw);
>         struct bcm2835_cprman *cprman = divider->cprman;
>         const struct bcm2835_pll_divider_data *data = divider->data;
> -       u32 cm;
> -       int ret;
> +       u32 cm, div, max_div = 1 << A2W_PLL_DIV_BITS;
>
> -       ret = clk_divider_ops.set_rate(hw, rate, parent_rate);
> -       if (ret)
> -               return ret;
> +       div = DIV_ROUND_UP_ULL(parent_rate, rate);
> +
> +       div = min(div, max_div);
> +       if (div == max_div)
> +               div = 0;
>
> +       cprman_write(cprman, data->a2w_reg, div);
>         cm = cprman_read(cprman, data->cm_reg);
>         cprman_write(cprman, data->cm_reg, cm | data->load_mask);
>         cprman_write(cprman, data->cm_reg, cm & ~data->load_mask);
> --
> 2.7.0
>
>
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> linux-rpi-kernel mailing list
> linux-rpi-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-rpi-kernel
>

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