lkml.org 
[lkml]   [2019]   [Jun]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 04/14] pwm: meson: change MISC_CLK_SEL_WIDTH to MISC_CLK_SEL_MASK
Hello,

[added clk-people to recipients]

On Sat, Jun 08, 2019 at 08:06:16PM +0200, Martin Blumenstingl wrote:
> MISC_CLK_SEL_WIDTH is only used in one place where it's converted into
> a bit-mask. Rename and change the macro to be a bit-mask so that
> conversion is not needed anymore. No functional changes intended.
>
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
> ---
> drivers/pwm/pwm-meson.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
> index c62a3ac924d0..84b28ba0f903 100644
> --- a/drivers/pwm/pwm-meson.c
> +++ b/drivers/pwm/pwm-meson.c
> @@ -33,7 +33,7 @@
> #define MISC_A_CLK_DIV_SHIFT 8
> #define MISC_B_CLK_SEL_SHIFT 6
> #define MISC_A_CLK_SEL_SHIFT 4
> -#define MISC_CLK_SEL_WIDTH 2
> +#define MISC_CLK_SEL_MASK 0x3
> #define MISC_B_EN BIT(1)
> #define MISC_A_EN BIT(0)
>
> @@ -463,7 +463,7 @@ static int meson_pwm_init_channels(struct meson_pwm *meson,
>
> channel->mux.reg = meson->base + REG_MISC_AB;
> channel->mux.shift = mux_reg_shifts[i];
> - channel->mux.mask = BIT(MISC_CLK_SEL_WIDTH) - 1;
> + channel->mux.mask = MISC_CLK_SEL_MASK;
> channel->mux.flags = 0;
> channel->mux.lock = &meson->lock;
> channel->mux.table = NULL;

IMHO clk_mux is ugly here. It could easily just take

.mask = 3 << mux_reg_shifts[i],

as input parameter instead of

.mask = 3,
.shift = mux_reg_shifts[i],

. Then the usage would be (IMHO) a bit more natural, the clock mask
could then be defined as:

#define MISC_CLK_SEL_MASK(i) GENMASK(5 + 2 * (i), 4 + 2 * (i))

and this value could just be passed to the clk_mux.

(OK, this could be done already now, and then we'd do

channel->mux.shift = ffs(MISC_CLK_SEL_MASK(i)) - 1;
channel->mux.mask = MISC_CLK_SEL_MASK(i) >> channel->mux.shift;

.)

Apart from that, I wonder if the pwm-meson driver should better use
clk_register_mux instead of open coding it. (Though there doesn't seem
to exists a devm_ variant of it.)

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |

\
 
 \ /
  Last update: 2019-06-11 18:33    [W:0.104 / U:36.712 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site