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

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

[Rajendra Nayak]

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 | 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;
 };
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

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

[Matthias Kaehlcke]

Hi Rajendra,

On Fri, Apr 17, 2020 at 07:34:23PM +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 | 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;

The name of the variable suggests that it holds a OPP table, something
like 'has_opp_table' would be clearer.

>  };
>  
>  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))

Even if the OPP table is optional you probably want to fail if the error
is anything other than -ENODEV ("'operating-points' property is not found
or is invalid data in device node.").

> 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;

This name suggests that the variable holds a single OPP ('struct
dev_pm_opp'). Most other code uses the name 'opp_table', which
also seems a good candidate here.

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

[Rajendra Nayak]

On 4/17/2020 11:30 PM, Matthias Kaehlcke wrote:
> Hi Rajendra,

Hey Matthias,

> 
> On Fri, Apr 17, 2020 at 07:34:23PM +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 | 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;
> 
> The name of the variable suggests that it holds a OPP table, something
> like 'has_opp_table' would be clearer.

I agree with your suggestions, I will update the variable names when I respin.

> 
>>   };
>>   
>>   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))
> 
> Even if the OPP table is optional you probably want to fail if the error
> is anything other than -ENODEV ("'operating-points' property is not found
> or is invalid data in device node.").

sounds valid. I will fix it up and respin. Will just wait a few days to see if
I get any more reviews and feedback.

> 
>> 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;
> 
> This name suggests that the variable holds a single OPP ('struct
> dev_pm_opp'). Most other code uses the name 'opp_table', which
> also seems a good candidate here.

Agree, thanks again for taking time to review.

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

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

[Rajendra Nayak]

Hey Bjorn,

> 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;

I just realized this is going to cause merge issues across geni serial and geni spi
driver (PATCH 02/17 in this series) unless all of this goes via your tree.
I see this is also an issue with the ongoing ICC patch series [1]

Do you or Greg have any thoughts on how this common header across various drivers
issue should be resolved to avoid conflicts while merging?

- Rajendra

[1] https://patchwork.kernel.org/patch/11491015/

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

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

[Greg Kroah-Hartman]

On Wed, Apr 22, 2020 at 02:52:21PM +0530, Rajendra Nayak wrote:
> Hey Bjorn,
> 
> > 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;
> 
> I just realized this is going to cause merge issues across geni serial and geni spi
> driver (PATCH 02/17 in this series) unless all of this goes via your tree.
> I see this is also an issue with the ongoing ICC patch series [1]
> 
> Do you or Greg have any thoughts on how this common header across various drivers
> issue should be resolved to avoid conflicts while merging?

I can ack it and you can take it through a different tree as part of the
whole series to prevent that.

thanks,

greg k-h