| Message ID | 1597211328-23500-1-git-send-email-skakit@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | tty: serial: qcom_geni_serial: Remove the UART frequency table | expand |
Quoting satya priya (2020-08-11 22:48:48) > diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c > index 3aa29d2..312daa24 100644 > --- a/drivers/tty/serial/qcom_geni_serial.c > +++ b/drivers/tty/serial/qcom_geni_serial.c > @@ -941,30 +935,22 @@ static int qcom_geni_serial_startup(struct uart_port *uport) > return 0; > } > > -static unsigned long get_clk_cfg(unsigned long clk_freq) > -{ > - int i; > - > - for (i = 0; i < ARRAY_SIZE(root_freq); i++) { > - if (!(root_freq[i] % clk_freq)) > - return root_freq[i]; > - } > - return 0; > -} > - > -static unsigned long get_clk_div_rate(unsigned int baud, > - unsigned int sampling_rate, unsigned int *clk_div) > +static unsigned long get_clk_div_rate(const struct geni_se *se, > + unsigned int baud, unsigned int sampling_rate, > + unsigned int *clk_div) > { > unsigned long ser_clk; > unsigned long desired_clk; > + long actual_clk; > > desired_clk = baud * sampling_rate; > - ser_clk = get_clk_cfg(desired_clk); > - if (!ser_clk) { > + actual_clk = clk_round_rate(se->clk, desired_clk); > + if (actual_clk % desired_clk != 0) { The logic isn't the same. Is that a concern? Before we would loop through all the frequencies this driver knew about and try to find a frequency that evenly divides by the 'desired_clk'. With this patch we'll do that calculation exactly once, and ask the clk driver what rate can be achieved if we call clk_set_rate() with 'desired_clk' as the argument. Maybe we need to loop and call clk_round_rate() with 'desired_clk <<= 1' until it overflows or reaches some limit? > pr_err("%s: Can't find matching DFS entry for baud %d\n", > __func__, baud); > - return ser_clk; > + return 0; > } > + ser_clk = actual_clk; > > *clk_div = ser_clk / desired_clk; > return ser_clk;
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 3aa29d2..312daa24 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -149,12 +149,6 @@ static unsigned int qcom_geni_serial_tx_empty(struct uart_port *port); static void qcom_geni_serial_stop_rx(struct uart_port *uport); static void qcom_geni_serial_handle_rx(struct uart_port *uport, bool drop); -static const unsigned long root_freq[] = {7372800, 14745600, 19200000, 29491200, - 32000000, 48000000, 51200000, 64000000, - 80000000, 96000000, 100000000, - 102400000, 112000000, 120000000, - 128000000}; - #define to_dev_port(ptr, member) \ container_of(ptr, struct qcom_geni_serial_port, member) @@ -941,30 +935,22 @@ static int qcom_geni_serial_startup(struct uart_port *uport) return 0; } -static unsigned long get_clk_cfg(unsigned long clk_freq) -{ - int i; - - for (i = 0; i < ARRAY_SIZE(root_freq); i++) { - if (!(root_freq[i] % clk_freq)) - return root_freq[i]; - } - return 0; -} - -static unsigned long get_clk_div_rate(unsigned int baud, - unsigned int sampling_rate, unsigned int *clk_div) +static unsigned long get_clk_div_rate(const struct geni_se *se, + unsigned int baud, unsigned int sampling_rate, + unsigned int *clk_div) { unsigned long ser_clk; unsigned long desired_clk; + long actual_clk; desired_clk = baud * sampling_rate; - ser_clk = get_clk_cfg(desired_clk); - if (!ser_clk) { + actual_clk = clk_round_rate(se->clk, desired_clk); + if (actual_clk % desired_clk != 0) { pr_err("%s: Can't find matching DFS entry for baud %d\n", __func__, baud); - return ser_clk; + return 0; } + ser_clk = actual_clk; *clk_div = ser_clk / desired_clk; return ser_clk; @@ -998,7 +984,7 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport, if (GENI_SE_VERSION_MAJOR(ver) >= 2 && GENI_SE_VERSION_MINOR(ver) >= 5) sampling_rate /= 2; - clk_rate = get_clk_div_rate(baud, sampling_rate, &clk_div); + clk_rate = get_clk_div_rate(&port->se, baud, sampling_rate, &clk_div); if (!clk_rate) goto out_restart_rx;
Use clk_round_rate() API to find a frequency that will work with the requested baud rate. With this we can avoid updating the table each time we add a new frquency to the table. We can just call clk_round_rate() and make sure it is evenly divisible by the requested rate and then it will be the same as before. Signed-off-by: satya priya <skakit@codeaurora.org> --- drivers/tty/serial/qcom_geni_serial.c | 32 +++++++++----------------------- 1 file changed, 9 insertions(+), 23 deletions(-)