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    SubjectRe: [PATCH 02/21] tty: serial: qcom_geni_serial: Use OPP API to set clk/perf state
    Hi Rajendra,

    On Wed, Apr 08, 2020 at 07:16:28PM +0530, Rajendra Nayak wrote:
    > geni serial needs to express a perforamnce state requirement on CX
    > depending on the frequency of the clock rates. Use OPP table from
    > DT to register with OPP framework and use dev_pm_opp_set_rate() to
    > set the clk/perf state.
    >
    > Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
    > Cc: Akash Asthana <akashast@codeaurora.org>
    > Cc: linux-serial@vger.kernel.org
    > ---
    > drivers/tty/serial/qcom_geni_serial.c | 20 +++++++++++++++-----
    > include/linux/qcom-geni-se.h | 2 ++
    > 2 files changed, 17 insertions(+), 5 deletions(-)
    >
    > diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
    > index 6119090..754eaf6 100644
    > --- a/drivers/tty/serial/qcom_geni_serial.c
    > +++ b/drivers/tty/serial/qcom_geni_serial.c
    > @@ -9,6 +9,7 @@
    > #include <linux/module.h>
    > #include <linux/of.h>
    > #include <linux/of_device.h>
    > +#include <linux/pm_opp.h>
    > #include <linux/platform_device.h>
    > #include <linux/pm_runtime.h>
    > #include <linux/pm_wakeirq.h>
    > @@ -961,7 +962,7 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport,
    > goto out_restart_rx;
    >
    > uport->uartclk = clk_rate;
    > - clk_set_rate(port->se.clk, clk_rate);
    > + dev_pm_opp_set_rate(uport->dev, clk_rate);
    > ser_clk_cfg = SER_CLK_EN;
    > ser_clk_cfg |= clk_div << CLK_DIV_SHFT;
    >
    > @@ -1198,8 +1199,10 @@ static void qcom_geni_serial_pm(struct uart_port *uport,
    > if (new_state == UART_PM_STATE_ON && old_state == UART_PM_STATE_OFF)
    > geni_se_resources_on(&port->se);
    > else if (new_state == UART_PM_STATE_OFF &&
    > - old_state == UART_PM_STATE_ON)
    > + old_state == UART_PM_STATE_ON) {
    > + dev_pm_opp_set_rate(uport->dev, 0);
    > geni_se_resources_off(&port->se);
    > + }
    > }
    >
    > static const struct uart_ops qcom_geni_console_pops = {
    > @@ -1318,13 +1321,16 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
    > if (of_property_read_bool(pdev->dev.of_node, "cts-rts-swap"))
    > port->cts_rts_swap = true;
    >
    > + port->se.opp = dev_pm_opp_set_clkname(&pdev->dev, "se");

    dev_pm_opp_set_clkname() can fail for multiple reasons, it seems an error
    check would be warranted.

    Is it actually necessary to save the OPP table in 'struct geni_se'? Both
    the serial and the SPI driver save the table, but don't use it later (nor
    does the SE driver).

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