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

[Tommaso Merciai]

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 at 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 at 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.

Thanks,
Tommaso


> 
> Hi Marek,
> I'll try also this way and let you know.
> 
> Thanks,
> Tommaso
> 
> -- 
> Tommaso Merciai
> Embedded Linux Engineer
> tommaso.merciai at amarulasolutions.com
> __________________________________
> 
> Amarula Solutions SRL
> Via Le Canevare 30, 31100 Treviso, Veneto, IT
> T. +39 042 243 5310
> info at amarulasolutions.com
> www.amarulasolutions.com

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

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