i2c: riic: remove fixed clock restriction

Message ID 20170929153259.105408-1-chris.brandt@renesas.com
State Superseded
Headers show
Series
  • i2c: riic: remove fixed clock restriction
Related show

Commit Message

Chris Brandt Sept. 29, 2017, 3:32 p.m.
Most systems with this i2c are going to have a clock of either 33.3MHz or
32MHz. That 4% difference is not reason enough to warrant that the driver
to completely fail.

Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
---
 drivers/i2c/busses/i2c-riic.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

Comments

Geert Uytterhoeven Sept. 29, 2017, 4:26 p.m. | #1
Hi Chris,

On Fri, Sep 29, 2017 at 5:32 PM, Chris Brandt <chris.brandt@renesas.com> wrote:
> Most systems with this i2c are going to have a clock of either 33.3MHz or
> 32MHz. That 4% difference is not reason enough to warrant that the driver
> to completely fail.
>
> Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
> ---
>  drivers/i2c/busses/i2c-riic.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c
> index c811af4c8d81..0a61beeb384a 100644
> --- a/drivers/i2c/busses/i2c-riic.c
> +++ b/drivers/i2c/busses/i2c-riic.c
> @@ -299,12 +299,13 @@ static int riic_init_hw(struct riic_dev *riic, u32 spd)
>
>         /*
>          * TODO: Implement formula to calculate the timing values depending on
> -        * variable parent clock rate and arbitrary bus speed
> +        * variable parent clock rate and arbitrary bus speed.
> +        * For now, just use calculations based on a 33325000Hz clock.
>          */
>         rate = clk_get_rate(riic->clk);
> -       if (rate != 33325000) {
> +       if (!rate) {
>                 dev_err(&riic->adapter.dev,
> -                       "invalid parent clk (%lu). Must be 33325000Hz\n", rate);
> +                       "invalid parent clk (%lu)\n", rate);

The printed rate is always zero here.

>                 clk_disable_unprepare(riic->clk);
>                 return -EINVAL;
>         }

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Chris Brandt Sept. 29, 2017, 5:07 p.m. | #2
Hi Geert,

On Friday, September 29, 2017 1, Geert Uytterhoeven wrote:
> > -       if (rate != 33325000) {

> > +       if (!rate) {

> >                 dev_err(&riic->adapter.dev,

> > -                       "invalid parent clk (%lu). Must be 33325000Hz\n",

> rate);

> > +                       "invalid parent clk (%lu)\n", rate);

> 

> The printed rate is always zero here.


OK, I will change to just:

"invalid parent clock rate of 0\n"

Chris

Patch

diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c
index c811af4c8d81..0a61beeb384a 100644
--- a/drivers/i2c/busses/i2c-riic.c
+++ b/drivers/i2c/busses/i2c-riic.c
@@ -299,12 +299,13 @@  static int riic_init_hw(struct riic_dev *riic, u32 spd)
 
 	/*
 	 * TODO: Implement formula to calculate the timing values depending on
-	 * variable parent clock rate and arbitrary bus speed
+	 * variable parent clock rate and arbitrary bus speed.
+	 * For now, just use calculations based on a 33325000Hz clock.
 	 */
 	rate = clk_get_rate(riic->clk);
-	if (rate != 33325000) {
+	if (!rate) {
 		dev_err(&riic->adapter.dev,
-			"invalid parent clk (%lu). Must be 33325000Hz\n", rate);
+			"invalid parent clk (%lu)\n", rate);
 		clk_disable_unprepare(riic->clk);
 		return -EINVAL;
 	}