linux-kernel - [PATCH v2 01/17] tty: serial: qcom_geni_serial: Use OPP API to set clk/perf state

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Date:   Fri, 17 Apr 2020 19:34:23 +0530
From:   Rajendra Nayak <rnayak@...eaurora.org>
To:     viresh.kumar@...aro.org, sboyd@...nel.org,
        bjorn.andersson@...aro.org, agross@...nel.org
Cc:     linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, mka@...omium.org,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Akash Asthana <akashast@...eaurora.org>,
        linux-serial@...r.kernel.org
Subject: [PATCH v2 01/17] tty: serial: qcom_geni_serial: Use OPP API to set clk/perf state

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@...eaurora.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Akash Asthana <akashast@...eaurora.org>
Cc: linux-serial@...r.kernel.org
---
 drivers/tty/serial/qcom_geni_serial.c | 30 +++++++++++++++++++++++++-----
 include/linux/qcom-geni-se.h          |  2 ++
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 6119090..151012c 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>
@@ -128,6 +129,7 @@ struct qcom_geni_serial_port {
 	int wakeup_irq;
 	bool rx_tx_swap;
 	bool cts_rts_swap;
+	bool opp_table;
 };
 
 static const struct uart_ops qcom_geni_console_pops;
@@ -961,7 +963,7 @@ 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 +1200,11 @@ 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 +1323,20 @@ 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");
+	if (IS_ERR(port->se.opp))
+		return PTR_ERR(port->se.opp);
+	/* OPP table is optional */
+	if (!dev_pm_opp_of_add_table(&pdev->dev))
+		port->opp_table = true;
+
 	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 +1344,7 @@ 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 +1361,16 @@ 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->opp_table)
+		dev_pm_opp_of_remove_table(&pdev->dev);
+	dev_pm_opp_put_clkname(port->se.opp);
+	return ret;
 }
 
 static int qcom_geni_serial_remove(struct platform_device *pdev)
@@ -1361,6 +1378,9 @@ 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->opp_table)
+		dev_pm_opp_of_remove_table(&pdev->dev);
+	dev_pm_opp_put_clkname(port->se.opp);
 	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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