Re: [PATCH v2 4/9] arm: imx: imx8mm: add enable_pwm_clk function

[Tommaso Merciai <tommaso.merciai@amarulasolutions.com>]

On Thu, Mar 17, 2022 at 04:31:15PM +0100, Marek Vasut wrote:
> On 3/17/22 16:13, Tommaso Merciai wrote:
> > On Thu, Mar 17, 2022 at 01:38:18PM +0100, Tommaso Merciai wrote:
> > > On Thu, Mar 17, 2022 at 12:58:31PM +0100, Marek Vasut wrote:
> > > > On 3/17/22 08:39, Tommaso Merciai wrote:
> > > > > On Wed, Mar 16, 2022 at 09:54:34PM +0100, Marek Vasut wrote:
> > > > > > On 3/16/22 16:27, Tommaso Merciai wrote:
> > > > > > > Add function enable_pwm_clk into in clock_imx8mm.c. This
> > > > > > > function first configure, then enable pwm clock from clock control
> > > > > > > register. The following configuration is used:
> > > > > > > 
> > > > > > > source(0) -> 24 MHz ref clock
> > > > > > > div(0)    -> no division for this clock
> > > > > > > 
> > > > > > > References:
> > > > > > >     - iMX8MMRM.pdf p 303
> > > > > > > 
> > > > > > > Signed-off-by: Tommaso Merciai <tommaso.merciai@amarulasolutions.com>
> > > > > > > ---
> > > > > > > Changes since v1:
> > > > > > >     - Fix enable_pwm_clk function implementation. Now is generic for all pwm clks
> > > > > > > 
> > > > > > >     arch/arm/mach-imx/imx8m/clock_imx8mm.c | 53 ++++++++++++++++++++++++++
> > > > > > >     1 file changed, 53 insertions(+)
> > > > > > 
> > > > > > Why is this not in drivers/clk/imx/ DM driver ?
> > > > > 
> > > > > Hi Marek,
> > > > > All function that enable/configure clk from CCGR are in arch/arm/mach-imx/imx8m/clock_imx8mm.c.
> > > > 
> > > > These seems to be CCGR:
> > > > 
> > > > $ grep -C 2 '0x4[0-9a-f]\{3\}' drivers/clk/imx/clk-imx8mm.c | sed "s@^.@@"
> > > > 
> > > > clk_dm(IMX8MM_CLK_ECSPI1_ROOT,
> > > >         imx_clk_gate4("ecspi1_root_clk", "ecspi1", base + 0x4070, 0));
> > > > clk_dm(IMX8MM_CLK_ECSPI2_ROOT,
> > > >         imx_clk_gate4("ecspi2_root_clk", "ecspi2", base + 0x4080, 0));
> > > > clk_dm(IMX8MM_CLK_ECSPI3_ROOT,
> > > >         imx_clk_gate4("ecspi3_root_clk", "ecspi3", base + 0x4090, 0));
> > > > clk_dm(IMX8MM_CLK_I2C1_ROOT,
> > > >         imx_clk_gate4("i2c1_root_clk", "i2c1", base + 0x4170, 0));
> > > > clk_dm(IMX8MM_CLK_I2C2_ROOT,
> > > >         imx_clk_gate4("i2c2_root_clk", "i2c2", base + 0x4180, 0));
> > > > clk_dm(IMX8MM_CLK_I2C3_ROOT,
> > > >         imx_clk_gate4("i2c3_root_clk", "i2c3", base + 0x4190, 0));
> > > > clk_dm(IMX8MM_CLK_I2C4_ROOT,
> > > >         imx_clk_gate4("i2c4_root_clk", "i2c4", base + 0x41a0, 0));
> > > > clk_dm(IMX8MM_CLK_OCOTP_ROOT,
> > > >         imx_clk_gate4("ocotp_root_clk", "ipg_root", base + 0x4220, 0));
> > > > clk_dm(IMX8MM_CLK_USDHC1_ROOT,
> > > >         imx_clk_gate4("usdhc1_root_clk", "usdhc1", base + 0x4510, 0));
> > > > clk_dm(IMX8MM_CLK_USDHC2_ROOT,
> > > >         imx_clk_gate4("usdhc2_root_clk", "usdhc2", base + 0x4520, 0));
> > > > clk_dm(IMX8MM_CLK_WDOG1_ROOT,
> > > >         imx_clk_gate4("wdog1_root_clk", "wdog", base + 0x4530, 0));
> > > > clk_dm(IMX8MM_CLK_WDOG2_ROOT,
> > > >         imx_clk_gate4("wdog2_root_clk", "wdog", base + 0x4540, 0));
> > > > clk_dm(IMX8MM_CLK_WDOG3_ROOT,
> > > >         imx_clk_gate4("wdog3_root_clk", "wdog", base + 0x4550, 0));
> > > > clk_dm(IMX8MM_CLK_USDHC3_ROOT,
> > > >         imx_clk_gate4("usdhc3_root_clk", "usdhc3", base + 0x45e0, 0));
> > > > clk_dm(IMX8MM_CLK_QSPI_ROOT,
> > > >         imx_clk_gate4("qspi_root_clk", "qspi", base + 0x42f0, 0));
> > > > clk_dm(IMX8MM_CLK_USB1_CTRL_ROOT,
> > > >          imx_clk_gate4("usb1_ctrl_root_clk", "usb_bus", base + 0x44d0, 0));
> > > > 
> > > > /* clks not needed in SPL stage */
> > > > -
> > > > clk_dm(IMX8MM_CLK_ENET1_ROOT,
> > > >         imx_clk_gate4("enet1_root_clk", "enet_axi",
> > > >         base + 0x40a0, 0));
> > > > endif
> > > > 
> > > > > For that I continue to put here the implementation. After we can port
> > > > > the clk dm part to manipulate clock in drivers/clk/imx/ DM driver.
> > > > > What do you think about? Let me know.
> > > > 
> > > > Seems like the clk_dm part is already in place and all you have to do is
> > > > extend it.
> > 
> > Hi Marek,
> > I test the solution using DM model, it work:
> > 
> > u-boot=> clk dump
> > 
> >   24000000             2        |   |-- pwm1
> >   24000000             3        |   |   `-- pwm1_root_clk
> >   24000000             0        |   |-- pwm2
> >   24000000             0        |   |   `-- pwm2_root_clk
> >   24000000             0        |   |-- pwm3
> >   24000000             0        |   |   `-- pwm3_root_clk
> >   24000000             0        |   |-- pwm4
> >   24000000             0        |   |   `-- pwm4_root_clk
> > 
> > 
> > I test it using the following call on a dummy driver:
> > 
> > ret = uclass_get_device_by_name(UCLASS_PWM, "pwm@30660000", &pwm);
> > if (ret)
> > 	printk("Failed to get pwm dev\n");
> > 
> > ret = clk_get_by_name(pwm, "per", &per_clk);
> > if (ret) {
> > 	printf("Failed to get per_clk\n");
> > 	return ret;
> > }
> > ret = clk_enable(&per_clk);
> > if (ret) {
> > 	printf("Failed to enable per_clk\n");
> > 	return ret;
> > }
> > 
> > ret = clk_get_by_name(pwm, "ipg", &ipg_clk);
> > if (ret) {
> > 	printf("Failed to get ipg_clk\n");
> > 	return ret;
> > }
> > ret = clk_enable(&ipg_clk);
> > if (ret) {
> > 	printf("Failed to enable ipg_clk\n");
> > 	return ret;
> > }
> > 
> > It's better to keep both the solutions or only
> > based on DM model? I think we can put this initialization into
> > drivers/pwm/pwm-imx.c imx_pwm_of_to_plat function.
> > What do you think about?
> > Let me know.
> 
> DM is the preferred way, non-DM is fading away.

Hi All,
I'm working on pwm-imx drv, what do you think about move pwm-imx-utils
and put all the 2 function inside pwm-imx.c under an ifndef
CONFIG_DM_PWM. Using DM on pwm-imx make pwm-imx-utils.c no sense to exist. 

Example:

#ifndef CONFIG_DM_PWM
int pwm_imx_get_parms(int period_ns, int duty_ns, unsigned long *period_c,
		      unsigned long *duty_c, unsigned long *prescale){
....

struct pwm_regs *pwm_id_to_reg(int pwm_id)
{
...

+ all non dm implementation

#else 

struct imx_pwm_priv {
	struct pwm_regs *regs;
	bool invert;
	struct clk *per_clk;
	struct clk *ipg_clk;
};

int pwm_dm_imx_get_parms(struct imx_pwm_priv *priv, int period_ns,
		      int duty_ns, unsigned long *period_c, unsigned long *duty_c,
		      unsigned long *prescale)
{
....

+ all dm implementation

#endif

What do you think about?
Let me know.

Thanks
Tommaso


-- 
Tommaso Merciai
Embedded Linux Engineer
tommaso.merciai@amarulasolutions.com
__________________________________

Amarula Solutions SRL
Via Le Canevare 30, 31100 Treviso, Veneto, IT
T. +39 042 243 5310
info@amarulasolutions.com
www.amarulasolutions.com