Re: [PATCH v3 01/17] tty: serial: qcom_geni_serial: Use OPP API to set clk/perf state

Matthias Kaehlcke
2020-04-28T22:49:33Z

On Tue, Apr 28, 2020 at 07:02:49PM +0530, Rajendra Nayak wrote:
> geni serial needs to express a perforamnce state requirement on CX
> powerdomain 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Akash Asthana <akashast@codeaurora.org>
> Cc: linux-serial@vger.kernel.org
> ---
> drivers/tty/serial/qcom_geni_serial.c | 34 +++++++++++++++++++++++++++++-----
> include/linux/qcom-geni-se.h | 4 ++++
> 2 files changed, 33 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
> index 6119090..c4de3ff 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 +1199,11 @@ 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) {
> + /* Drop the performance state vote */
> + 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 +1322,25 @@ 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_table = dev_pm_opp_set_clkname(&pdev->dev, "se");
> + if (IS_ERR(port->se.opp_table))
> + return PTR_ERR(port->se.opp_table);
> + /* OPP table is optional */
> + ret = dev_pm_opp_of_add_table(&pdev->dev);
> + if (!ret) {
> + port->se.has_opp_table = true;
> + } else if (ret != -ENODEV) {
> + dev_err(&pdev->dev, "Invalid OPP table in Device tree\n");
> + return ret;
> + }
> +
> 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 +1348,7 @@ 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 +1365,16 @@ 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:
> + if (port->se.has_opp_table)
> + dev_pm_opp_of_remove_table(&pdev->dev);
> + dev_pm_opp_put_clkname(port->se.opp_table);
> + return ret;
> }
>
> static int qcom_geni_serial_remove(struct platform_device *pdev)
> @@ -1361,6 +1382,9 @@ 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;
>
> + if (port->se.has_opp_table)
> + dev_pm_opp_of_remove_table(&pdev->dev);
> + dev_pm_opp_put_clkname(port->se.opp_table);
> 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..cce71f3 100644
> --- a/include/linux/qcom-geni-se.h
> +++ b/include/linux/qcom-geni-se.h
> @@ -33,6 +33,8 @@ struct clk;
> * @clk: Handle to the core serial engine clock
> * @num_clk_levels: Number of valid clock levels in clk_perf_tbl
> * @clk_perf_tbl: Table of clock frequency input to serial engine clock
> + * @opp_table: Pointer to the OPP table
> + * @has_opp_table: Specifies if the SE has an OPP table
> */
> struct geni_se {
> void __iomem *base;
> @@ -41,6 +43,8 @@ struct geni_se {
> struct clk *clk;
> unsigned int num_clk_levels;
> unsigned long *clk_perf_tbl;
> + struct opp_table *opp_table;
> + bool has_opp_table;
> };
>
> /* Common SE registers */
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>