[PATCH 4/4] i2c: sun8i_rsb: Add support for DM clocks and resets

[Samuel Holland]

Hi Andre,

On 4/4/22 12:30 PM, Andre Przywara wrote:
> On Thu, 17 Mar 2022 23:52:36 -0500
> Samuel Holland <samuel at sholland.org> wrote:
> 
>> Currently, clock/reset setup for this device is handled by a
>> platform-specific function and is intermixed with non-DM pinctrl
>> setup. Use the devicetree to get clocks/resets, which disentagles
>> it from the pinctrl setup in preparation for moving to DM_PINCTRL.
>>
>> This also has the added benefit of picking the right clock/reset
>> bits for H6 and new SoCs that have a rearranged PRCM MMIO space.
> 
> So does this actually work right now with the A23/A33? They have specific
> clocks for the RSB gates/resets, and I don't see support for that in the
> tree right now? Or this is just fine because those clocks are treated
> optional and their enabling is actually redundant, in practice?

Yes, A23/A33 work right now because the clocks are already enabled in SPL. So
this change does nothing (positive or negative) on those SoCs, because as you
note we are missing the A23/A33 DM clock driver.

For 64-bit SoCs, where RSB is not used in SPL, this change is not redundant.
With this series plus the pinctrl series, you should now have working RSB in
U-Boot proper on A64/H6/H616. I have been testing this with the `i2c` and `pmic`
commands.

Regards,
Samuel

> Cheers,
> Andre
> 
>>
>> Signed-off-by: Samuel Holland <samuel at sholland.org>
>> ---
>>
>>  drivers/i2c/sun8i_rsb.c | 12 ++++++++++++
>>  1 file changed, 12 insertions(+)
>>
>> diff --git a/drivers/i2c/sun8i_rsb.c b/drivers/i2c/sun8i_rsb.c
>> index 0681e398f7..e3a44e6a1b 100644
>> --- a/drivers/i2c/sun8i_rsb.c
>> +++ b/drivers/i2c/sun8i_rsb.c
>> @@ -9,10 +9,12 @@
>>   */
>>  
>>  #include <axp_pmic.h>
>> +#include <clk.h>
>>  #include <common.h>
>>  #include <dm.h>
>>  #include <errno.h>
>>  #include <i2c.h>
>> +#include <reset.h>
>>  #include <time.h>
>>  #include <asm/arch/cpu.h>
>>  #include <asm/arch/gpio.h>
>> @@ -243,9 +245,19 @@ static int sun8i_rsb_probe_chip(struct udevice *bus, uint chip_addr,
>>  static int sun8i_rsb_probe(struct udevice *bus)
>>  {
>>  	struct sun8i_rsb_priv *priv = dev_get_priv(bus);
>> +	struct reset_ctl *reset;
>> +	struct clk *clk;
>>  
>>  	priv->base = dev_read_addr_ptr(bus);
>>  
>> +	reset = devm_reset_control_get(bus, NULL);
>> +	if (!IS_ERR(reset))
>> +		reset_deassert(reset);
>> +
>> +	clk = devm_clk_get(bus, NULL);
>> +	if (!IS_ERR(clk))
>> +		clk_enable(clk);
>> +
>>  	return sun8i_rsb_init(priv->base);
>>  }
>>  
>