Hi Matthias,
On 4/9/2020 11:15 PM, Matthias Kaehlcke wrote:
Hi Rajendra,
On Wed, Apr 08, 2020 at 07:16:28PM +0530, Rajendra Nayak wrote:
geni serial needs to express a perforamnce state requirement on CX
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);
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_set_clkname() can fail for multiple reasons, it seems an error
check would be warranted.
right, looks like I should put some error check there
Is it actually necessary to save the OPP table in 'struct geni_se'? Both
the serial and the SPI driver save the table, but don't use it later (nor
does the SE driver).
I think I did that initially because I wanted to use that to call into
dev_pm_opp_put_clkname during cleanup. That however never worked since
the way the clk_put is done in dev_pm_opp_put_clkname() and _opp_table_kref_release()
seems buggy. I kind of forgot about fixing it up, I will figure our whats the right
way to do it, and either not call dev_pm_opp_put_clkname() or not store the
opp table returned by it.
thanks for taking time to review.
- Rajendra
--
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