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

From: Akash Asthana
Date: Fri Apr 10 2020 - 08:53:16 EST


Hi Rajendra,

On 4/10/2020 12:26 PM, Akash Asthana wrote:
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,
ÂÂÂÂÂÂÂÂÂ goto out_restart_rx;
 Â uport->uartclk = clk_rate;
-ÂÂÂ clk_set_rate(port->se.clk, clk_rate);
+ÂÂÂ 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.

oops Sorry, 1st patch is intended for backward compatibility. Which I missed earlier.

Regards,

Akash


ÂÂÂÂÂ ser_clk_cfg = SER_CLK_EN;
ÂÂÂÂÂ ser_clk_cfg |= clk_div << CLK_DIV_SHFT;
 @@ -1198,8 +1199,10 @@ static void qcom_geni_serial_pm(struct uart_port *uport,
ÂÂÂÂÂ if (new_state == UART_PM_STATE_ON && old_state == UART_PM_STATE_OFF)
ÂÂÂÂÂÂÂÂÂ geni_se_resources_on(&port->se);
ÂÂÂÂÂ else if (new_state == UART_PM_STATE_OFF &&
-ÂÂÂÂÂÂÂÂÂÂÂ old_state == UART_PM_STATE_ON)
+ÂÂÂÂÂÂÂÂÂÂÂ old_state == UART_PM_STATE_ON) {
+ÂÂÂÂÂÂÂ dev_pm_opp_set_rate(uport->dev, 0);
ÂÂÂÂÂÂÂÂÂ geni_se_resources_off(&port->se);
+ÂÂÂ }
 }
  static const struct uart_ops qcom_geni_console_pops = {
@@ -1318,13 +1321,16 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
ÂÂÂÂÂ if (of_property_read_bool(pdev->dev.of_node, "cts-rts-swap"))
ÂÂÂÂÂÂÂÂÂ port->cts_rts_swap = true;
 + port->se.opp = dev_pm_opp_set_clkname(&pdev->dev, "se");
+ÂÂÂ dev_pm_opp_of_add_table(&pdev->dev);
+
ÂÂÂÂÂ uport->private_data = drv;
ÂÂÂÂÂ platform_set_drvdata(pdev, port);
ÂÂÂÂÂ port->handle_rx = console ? handle_rx_console : handle_rx_uart;
 Â ret = uart_add_one_port(drv, uport);
ÂÂÂÂÂ if (ret)
-ÂÂÂÂÂÂÂ return ret;
+ÂÂÂÂÂÂÂ goto err;
 Â irq_set_status_flags(uport->irq, IRQ_NOAUTOEN);
ÂÂÂÂÂ 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)
ÂÂÂÂÂ if (ret) {
ÂÂÂÂÂÂÂÂÂ dev_err(uport->dev, "Failed to get IRQ ret %d\n", ret);
ÂÂÂÂÂÂÂÂÂ uart_remove_one_port(drv, uport);
-ÂÂÂÂÂÂÂ return ret;
+ÂÂÂÂÂÂÂ goto err;
ÂÂÂÂÂ }
 Â /*
@@ -1349,11 +1355,14 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
ÂÂÂÂÂÂÂÂÂ if (ret) {
ÂÂÂÂÂÂÂÂÂÂÂÂÂ device_init_wakeup(&pdev->dev, false);
ÂÂÂÂÂÂÂÂÂÂÂÂÂ uart_remove_one_port(drv, uport);
-ÂÂÂÂÂÂÂÂÂÂÂ return ret;
+ÂÂÂÂÂÂÂÂÂÂÂ goto err;
ÂÂÂÂÂÂÂÂÂ }
ÂÂÂÂÂ }
 Â return 0;
+err:
+ÂÂÂ 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

+ÂÂÂ 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)
ÂÂÂÂÂ struct qcom_geni_serial_port *port = platform_get_drvdata(pdev);
ÂÂÂÂÂ struct uart_driver *drv = port->uport.private_data;
 + dev_pm_opp_of_remove_table(&pdev->dev);
ÂÂÂÂÂ dev_pm_clear_wake_irq(&pdev->dev);
ÂÂÂÂÂ device_init_wakeup(&pdev->dev, false);
ÂÂÂÂÂ 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;
  /**
ÂÂ * struct geni_se - GENI Serial Engine
@@ -39,6 +40,7 @@ struct geni_se {
ÂÂÂÂÂ struct device *dev;
ÂÂÂÂÂ struct geni_wrapper *wrapper;
ÂÂÂÂÂ struct clk *clk;
+ÂÂÂ struct opp_table *opp;
ÂÂÂÂÂ unsigned int num_clk_levels;
ÂÂÂÂÂ unsigned long *clk_perf_tbl;
 };

--
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