Re: [PATCH 02/21] tty: serial: qcom_geni_serial: Use OPP API to set clk/perf state

Akash Asthana
2020-04-10T06:56:40Z

Hi Rajendra,

On 4/8/2020 7:16 PM, Rajendra Nayak wrote:
> geni serial needs to express a perforamnce state requirement on CX
*performance
> 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);

Is this change not intended for backward compatibility? If I don't pick
DT change for Geni drivers,  dev_pm_opp_set_rate is failing and causing
functionality issues.

> 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_of_add_table(&pdev->dev);
> +
> uport->private_data = drv;
> platform_set_drvdata(pdev, port);
> port->handle_rx = console ? handle_rx_console : handle_rx_uart;
>
> ret = uart_add_one_port(drv, uport);
> if (ret)
> - return ret;
> + goto err;
>
> irq_set_status_flags(uport->irq, IRQ_NOAUTOEN);
> ret = devm_request_irq(uport->dev, uport->irq, qcom_geni_serial_isr,
> @@ -1332,7 +1338,7 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
> if (ret) {
> dev_err(uport->dev, "Failed to get IRQ ret %d\n", ret);
> uart_remove_one_port(drv, uport);
> - return ret;
> + goto err;
> }
>
> /*
> @@ -1349,11 +1355,14 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
> if (ret) {
> device_init_wakeup(&pdev->dev, false);
> uart_remove_one_port(drv, uport);
> - return ret;
> + goto err;
> }
> }
>
> return 0;
> +err:
> + dev_pm_opp_of_remove_table(&pdev->dev);
do we need to call "dev_pm_opp_put_clkname" here and in remove to
release clk resource grabbed by

dev_pm_opp_set_clkname(&pdev->dev, "se");?

Regards,
Akash

> + return ret;
> }
>
> static int qcom_geni_serial_remove(struct platform_device *pdev)
> @@ -1361,6 +1370,7 @@ static int qcom_geni_serial_remove(struct platform_device *pdev)
> struct qcom_geni_serial_port *port = platform_get_drvdata(pdev);
> struct uart_driver *drv = port->uport.private_data;
>
> + dev_pm_opp_of_remove_table(&pdev->dev);
> dev_pm_clear_wake_irq(&pdev->dev);
> device_init_wakeup(&pdev->dev, false);
> uart_remove_one_port(drv, &port->uport);
> diff --git a/include/linux/qcom-geni-se.h b/include/linux/qcom-geni-se.h
> index dd46494..737e713 100644
> --- a/include/linux/qcom-geni-se.h
> +++ b/include/linux/qcom-geni-se.h
> @@ -24,6 +24,7 @@ enum geni_se_protocol_type {
>
> struct geni_wrapper;
> struct clk;
> +struct opp_table;
>
> /**
> * struct geni_se - GENI Serial Engine
> @@ -39,6 +40,7 @@ struct geni_se {
> struct device *dev;
> struct geni_wrapper *wrapper;
> struct clk *clk;
> + struct opp_table *opp;
> unsigned int num_clk_levels;
> unsigned long *clk_perf_tbl;
> };

--
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