Re: [PATCH 4/6] clk: actions: Fix AHPPREDIV-H-AHB clock chain on Owl S500 SoC

Manivannan Sadhasivam
2021-03-16T05:46:48Z

On Mon, Mar 08, 2021 at 07:18:29PM +0200, Cristian Ciocaltea wrote:
> There are a few issues with the setup of the Actions Semi Owl S500 SoC's
> clock chain involving AHPPREDIV, H and AHB clocks:
>
> * AHBPREDIV clock is defined as a muxer only, although it also acts as
> a divider.
> * H clock is defined as a standard divider, although the raw value zero
> is not supported.

What do you mean by not supported? The datasheet lists "0" as the valid divisor
value for divide by 1.

Rest looks good to me.

Thanks,
Mani

> * AHB is defined as a multi-rate factor clock, but it is actually just
> a fixed pass clock.
>
> Let's provide the following fixes:
>
> * Change AHBPREDIV clock to an ungated OWL_COMP_DIV definition.
> * Add a clock div table 'h_div_table' for the H clock to drop the
> unsupported 0 rate and use the correct register shift value in the
> OWL_DIVIDER definition.
> * Drop the unneeded 'ahb_factor_table[]' and change AHB clock to an
> ungated OWL_COMP_FIXED_FACTOR definition.
>
> Fixes: ed6b4795ece4 ("clk: actions: Add clock driver for S500 SoC")
> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
> ---
> drivers/clk/actions/owl-s500.c | 20 ++++++++++++++------
> 1 file changed, 14 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/clk/actions/owl-s500.c b/drivers/clk/actions/owl-s500.c
> index abe8874353de..b9e434173b4f 100644
> --- a/drivers/clk/actions/owl-s500.c
> +++ b/drivers/clk/actions/owl-s500.c
> @@ -151,9 +151,9 @@ static struct clk_factor_table hde_factor_table[] = {
> { 0, 0, 0 },
> };
>
> -static struct clk_factor_table ahb_factor_table[] = {
> - { 1, 1, 2 }, { 2, 1, 3 },
> - { 0, 0, 0 },
> +static struct clk_div_table h_div_table[] = {
> + { 1, 2 }, { 2, 3 }, { 3, 4 },
> + { 0, 0 },
> };
>
> static struct clk_div_table rmii_ref_div_table[] = {
> @@ -184,7 +184,6 @@ static struct clk_div_table nand_div_table[] = {
>
> /* mux clock */
> static OWL_MUX(dev_clk, "dev_clk", dev_clk_mux_p, CMU_DEVPLL, 12, 1, CLK_SET_RATE_PARENT);
> -static OWL_MUX(ahbprediv_clk, "ahbprediv_clk", ahbprediv_clk_mux_p, CMU_BUSCLK1, 8, 3, CLK_SET_RATE_PARENT);
>
> /* gate clocks */
> static OWL_GATE(gpio_clk, "gpio_clk", "apb_clk", CMU_DEVCLKEN0, 18, 0, 0);
> @@ -197,16 +196,25 @@ static OWL_GATE(timer_clk, "timer_clk", "hosc", CMU_DEVCLKEN1, 27, 0, 0);
> static OWL_GATE(hdmi_clk, "hdmi_clk", "hosc", CMU_DEVCLKEN1, 3, 0, 0);
>
> /* divider clocks */
> -static OWL_DIVIDER(h_clk, "h_clk", "ahbprediv_clk", CMU_BUSCLK1, 12, 2, NULL, 0, 0);
> +static OWL_DIVIDER(h_clk, "h_clk", "ahbprediv_clk", CMU_BUSCLK1, 2, 2, h_div_table, 0, 0);
> static OWL_DIVIDER(apb_clk, "apb_clk", "ahb_clk", CMU_BUSCLK1, 14, 2, NULL, 0, 0);
> static OWL_DIVIDER(rmii_ref_clk, "rmii_ref_clk", "ethernet_pll_clk", CMU_ETHERNETPLL, 1, 1, rmii_ref_div_table, 0, 0);
>
> /* factor clocks */
> -static OWL_FACTOR(ahb_clk, "ahb_clk", "h_clk", CMU_BUSCLK1, 2, 2, ahb_factor_table, 0, 0);
> static OWL_FACTOR(de1_clk, "de_clk1", "de_clk", CMU_DECLK, 0, 4, de_factor_table, 0, 0);
> static OWL_FACTOR(de2_clk, "de_clk2", "de_clk", CMU_DECLK, 4, 4, de_factor_table, 0, 0);
>
> /* composite clocks */
> +static OWL_COMP_DIV(ahbprediv_clk, "ahbprediv_clk", ahbprediv_clk_mux_p,
> + OWL_MUX_HW(CMU_BUSCLK1, 8, 3),
> + { 0 },
> + OWL_DIVIDER_HW(CMU_BUSCLK1, 12, 2, 0, NULL),
> + 0);
> +
> +static OWL_COMP_FIXED_FACTOR(ahb_clk, "ahb_clk", "h_clk",
> + { 0 },
> + 1, 1, CLK_SET_RATE_PARENT);
> +
> static OWL_COMP_FACTOR(vce_clk, "vce_clk", hde_clk_mux_p,
> OWL_MUX_HW(CMU_VCECLK, 4, 2),
> OWL_GATE_HW(CMU_DEVCLKEN0, 26, 0),
> --
> 2.30.1
>