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

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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@xxxxxxxxxxxxxx>
Cc: Akash Asthana <akashast@xxxxxxxxxxxxxx>
Cc: linux-serial@xxxxxxxxxxxxxxx
---
  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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