Re: [PATCH 2/5] pwm: sun4i: Add support for PWM controller on sun6i SoCs

[Icenowy Zheng <icenowy-ymACFijhrKM@public.gmane.org>]

Hi,

----- 原件 -----
> Hi,
> 
> On Wed, Oct 12, 2016 at 12:20 PM, Icenowy Zheng <icenowy-ymACFijhrKM@public.gmane.org> wrote:
> > The PWM controller in A31 is different with other Allwinner SoCs, with
> > a control register per channel (in other SoCs the control register is
> > shared), and each channel are allocated 16 bytes of address (but only 8
> > bytes are used.). The register map in one channel is just like a
> > single-channel A10 PWM controller, however, A31 have a different
> > prescaler table than other SoCs.
> > 
> > In order to use the driver for all 4 channels, device nodes should be
> > created per channel.
> 
> I think Maxime wants you to support the different register offsets
> in this driver, and have all 4 channels in the same device (node).

I think that will make the code much more complex...
And in hardware there may also be 4 controllers... as the register is aligned at 0x10.

The error I made in my previous patch set is making
a dedicatded pwm-sun6i driver. So I reworked this.
(This also why I do not call the current patchset PATCH v2 -- it's a new patchset)

Icenowy Zheng

> 
> ChenYu
> 
> 
> > Signed-off-by: Icenowy Zheng <icenowy-ymACFijhrKM@public.gmane.org>
> > ---
> > drivers/pwm/pwm-sun4i.c | 37 ++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 36 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
> > index 03a99a5..3e93bdf 100644
> > --- a/drivers/pwm/pwm-sun4i.c
> > +++ b/drivers/pwm/pwm-sun4i.c
> > @@ -46,7 +46,7 @@
> > 
> > #define BIT_CH(bit, chan)           ((bit) << ((chan) * PWMCH_OFFSET))
> > 
> > -static const u32 prescaler_table[] = {
> > +static const u32 prescaler_table_a10[] = {
> > 120,
> > 180,
> > 240,
> > @@ -65,10 +65,30 @@ static const u32 prescaler_table[] = {
> > 0, /* Actually 1 but tested separately */
> > };
> > 
> > +static const u32 prescaler_table_a31[] = {
> > +             1,
> > +             2,
> > +             4,
> > +             8,
> > +             16,
> > +             32,
> > +             64,
> > +             0,
> > +             0,
> > +             0,
> > +             0,
> > +             0,
> > +             0,
> > +             0,
> > +             0,
> > +             0,
> > +};
> > +
> > struct sun4i_pwm_data {
> > bool has_prescaler_bypass;
> > bool has_rdy;
> > unsigned int npwm;
> > +             const u32 *prescaler_table;
> > };
> > 
> > struct sun4i_pwm_chip {
> > @@ -100,6 +120,7 @@ static int sun4i_pwm_config(struct pwm_chip *chip,
> > struct pwm_device *pwm, int duty_ns, int period_ns)
> > {
> > struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
> > +             const u32 *prescaler_table = sun4i_pwm->data->prescaler_table;
> > u32 prd, dty, val, clk_gate;
> > u64 clk_rate, div = 0;
> > unsigned int prescaler = 0;
> > @@ -264,24 +285,35 @@ static const struct sun4i_pwm_data
> > sun4i_pwm_data_a10 = { .has_prescaler_bypass = false,
> > .has_rdy = false,
> > .npwm = 2,
> > +             .prescaler_table = prescaler_table_a10,
> > };
> > 
> > static const struct sun4i_pwm_data sun4i_pwm_data_a10s = {
> > .has_prescaler_bypass = true,
> > .has_rdy = true,
> > .npwm = 2,
> > +             .prescaler_table = prescaler_table_a10,
> > };
> > 
> > static const struct sun4i_pwm_data sun4i_pwm_data_a13 = {
> > .has_prescaler_bypass = true,
> > .has_rdy = true,
> > .npwm = 1,
> > +             .prescaler_table = prescaler_table_a10,
> > };
> > 
> > static const struct sun4i_pwm_data sun4i_pwm_data_a20 = {
> > .has_prescaler_bypass = true,
> > .has_rdy = true,
> > .npwm = 2,
> > +             .prescaler_table = prescaler_table_a10,
> > +};
> > +
> > +static const struct sun4i_pwm_data sun4i_pwm_data_a31 = {
> > +             .has_prescaler_bypass = false,
> > +             .has_rdy = true,
> > +             .npwm = 1,
> > +             .prescaler_table = prescaler_table_a31,
> > };
> > 
> > static const struct of_device_id sun4i_pwm_dt_ids[] = {
> > @@ -298,6 +330,9 @@ static const struct of_device_id
> > sun4i_pwm_dt_ids[] = { .compatible = "allwinner,sun7i-a20-pwm",
> > .data = &sun4i_pwm_data_a20,
> > }, {
> > +                             .compatible = "allwinner,sun6i-a31-pwm",
> > +                             .data = &sun4i_pwm_data_a31
> > +             }, {
> > /* sentinel */
> > },
> > };
> > --
> > 2.10.1
> > 
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