[PATCH v3 3/6] clk: ti: Remove AM33xx dependency

[Bastien Curutchet]

Hi Tom,

On 6/8/26 3:11 PM, Bastien Curutchet wrote:
> The clock controller driven by this driver exists on other OMAP platforms
> than the AM33xx. Yet, it uses functions provided by
> arch/arm/mach-omap2/am33xx/clock.c making it unusable by other OMAPs.
> 
> Replace am33xx-specific do_{enable/disable}_clocks() with new static
> functions implemented locally.
> Replace the am33xx-specific clock header with the one shared by all OMAP
> platforms.
> 
> Signed-off-by: Bastien Curutchet <bastien.curutchet at bootlin.com>
> ---
>   drivers/clk/ti/clk-ctrl.c | 48 ++++++++++++++++++++++++++++++++++++-----------
>   1 file changed, 37 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/clk/ti/clk-ctrl.c b/drivers/clk/ti/clk-ctrl.c
> index c5c97dc35c4..08f7410edce 100644
> --- a/drivers/clk/ti/clk-ctrl.c
> +++ b/drivers/clk/ti/clk-ctrl.c
> @@ -8,7 +8,11 @@
>   #include <dm.h>
>   #include <dm/device_compat.h>
>   #include <clk-uclass.h>
> -#include <asm/arch-am33xx/clock.h>
> +#include <asm/ti-common/omap_clock.h>
> +#include <asm/io.h>
> +#include <linux/iopoll.h>
> +
> +#define TRANSITION_TIMEOUT_US	10000
>   
>   struct clk_ti_ctrl_offs {
>   	fdt_addr_t start;
> @@ -33,10 +37,37 @@ static int clk_ti_ctrl_check_offs(struct clk *clk, fdt_addr_t offs)
>   	return -EFAULT;
>   }
>   
> +#define IDLEST_DISABLED		(MODULE_CLKCTRL_IDLEST_DISABLED << MODULE_CLKCTRL_IDLEST_SHIFT)
> +#define IDLEST_TRANSITION	(MODULE_CLKCTRL_IDLEST_TRANSITIONING << MODULE_CLKCTRL_IDLEST_SHIFT)
> +static int clk_ti_ctrl_disable_clock_module(u32 addr)
> +{
> +	int val;
> +
> +	clrsetbits_le32(addr, MODULE_CLKCTRL_MODULEMODE_MASK,
> +			MODULE_CLKCTRL_MODULEMODE_SW_DISABLE <<
> +			MODULE_CLKCTRL_MODULEMODE_SHIFT);
> +
> +	return readl_relaxed_poll_timeout(addr, val,
> +					  (val & MODULE_CLKCTRL_IDLEST_MASK) == IDLEST_DISABLED,
> +					  TRANSITION_TIMEOUT_US);
> +}
> +
> +static int clk_ti_ctrl_enable_clock_module(u32 addr)
> +{
> +	int val;
> +
> +	clrsetbits_le32(addr, MODULE_CLKCTRL_MODULEMODE_MASK,
> +			MODULE_CLKCTRL_MODULEMODE_SW_EXPLICIT_EN <<
> +			MODULE_CLKCTRL_MODULEMODE_SHIFT);
> +	return readl_relaxed_poll_timeout(addr, val,
> +					  ((val & MODULE_CLKCTRL_IDLEST_MASK) != IDLEST_DISABLED) &&
> +					  ((val & MODULE_CLKCTRL_IDLEST_MASK) != IDLEST_TRANSITION),
> +					  TRANSITION_TIMEOUT_US);

This is the culprit. In arch/arm/mach-omap2/am333x/clock.c, the timeout 
is computed using CPU ticks. Here, readl_relaxed_poll_timeout() relies 
on a timer. On the beaglebone, this timer dependency creates a sort of 
circular dependency during initialization (enable clock -> init timer -> 
enable clock -> init timer) which leads to a division-by-0 during the 
second timer initialization. This division triggers the hang() 
outputting the "### ERROR ### Please RESET the board ###".

I'm going to send a new series for the OMAP4 support that uses a 
CPU-based loop in this driver instead of readl_relaxed_poll_timeout().


Best regards,
Bastien