Re: [PATCH v6 4/4] clk: qcom: add clock controller driver for qca8386/qca8084

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]


On 9/15/2023 12:30 AM, Stephen Boyd wrote:
Quoting Jie Luo (2023-09-12 20:27:25)

On 9/13/2023 1:18 AM, Stephen Boyd wrote:
Quoting Jie Luo (2023-09-12 05:07:02)

and freq_tbl are necessary to this clock.

I still don't see why the freq_tbl is necessary.

Hi Stephen,
For clk_rcg2_ops, freq_tbl is used to find the closest rate to decided
the parent clock, the configuration of clock source and clock divider
are saved in the freq_tbl to configure the RCG hardware register, the
mapping of parent clock and hardware register value is decided by the
freq_tbl for the RCG clock.

The divider is always 1. The frequency is the frequency of the parent.
The two pieces of information are already known without the frequency
table. Why is it needed?

Hi Stephen,
For mac0 and mac5 RCG clock, it is true with divider 1, since these two MACs are connected with CPU port, which is always the fix link speed, the clock rate is always 312.5M or 125M, in this case with multiple parent clocks and divider 1, it seems there is no special RCG clock ops for it currently, so we leverage the clock ops clk_rcg2_ops.

For other MACs(1-4), which are connected with physical port, the link speed is dynamically changed, and the divider is different for the different link speed, such as the mac1 clock freq table as below.

static const struct freq_tbl ftbl_nss_cc_mac1_tx_clk_src[] = { F(25000000, P_UNIPHY1_TX312P5M, 12.5, 0, 0), F(25000000, P_UNIPHY1_RX312P5M, 12.5, 0, 0), F(50000000, P_XO, 1, 0, 0), F(125000000, P_UNIPHY1_TX312P5M, 2.5, 0, 0), F(125000000, P_UNIPHY1_RX312P5M, 2.5, 0, 0), F(312500000, P_UNIPHY1_TX312P5M, 1, 0, 0), F(312500000, P_UNIPHY1_RX312P5M, 1, 0, 0), { }


[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [Linux for Sparc]     [IETF Annouce]     [Security]     [Bugtraq]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux