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

[Matthias Kaehlcke]

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@xxxxxxxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: Akash Asthana <akashast@xxxxxxxxxxxxxx>
> Cc: linux-serial@xxxxxxxxxxxxxxx
> ---
>  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@xxxxxxxxxxxx>