Messages in this thread | | | Date | Thu, 2 Jun 2022 11:29:12 +0200 | Subject | Re: [PATCH 2/3] tty: serial: atmel: improve clock management | From | Richard Genoud <> |
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Hi,
Le 25/05/2022 à 15:37, Claudiu Beznea a écrit : > atmel_port->clk was requested in atmel_init_port() (which is called only > on probe path) only if atmel_port->clk was NULL. But atmel_port->clk is > NULL on probing path. Thus don't check this. Along with this the clock is > now requested with devm_clk_get() and the clock request has been moved in > atmel_serial_probe() function to avoid disabling/re-enabling it on probe > path for multiple times. All the checks of atmel_port->clk were removed > along with clk_put() and atmel_port->clk = NULL. Now, on probing time the > clock is enabled at the beginning and disabled at the end of probe. As > atmel_console_setup() is called in the middle of probe and clock is > already enabled at that time the clk_prepare_enable() in > atmel_console_setup() has also been removed. Could you split this patch into smaller steps ? I think it will be easier to read and review.
> > Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> > --- > drivers/tty/serial/atmel_serial.c | 65 +++++++------------------------ > 1 file changed, 15 insertions(+), 50 deletions(-) > > diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c > index 5c793a23dc54..2955b1012014 100644 > --- a/drivers/tty/serial/atmel_serial.c > +++ b/drivers/tty/serial/atmel_serial.c > @@ -2501,24 +2501,7 @@ static int atmel_init_port(struct atmel_uart_port *atmel_port, > if (ret) > return ret; > > - /* for console, the clock could already be configured */ > - if (!atmel_port->clk) { > - atmel_port->clk = clk_get(&mpdev->dev, "usart"); > - if (IS_ERR(atmel_port->clk)) { > - ret = PTR_ERR(atmel_port->clk); > - atmel_port->clk = NULL; > - return ret; > - } > - ret = clk_prepare_enable(atmel_port->clk); > - if (ret) { > - clk_put(atmel_port->clk); > - atmel_port->clk = NULL; > - return ret; > - } > - port->uartclk = clk_get_rate(atmel_port->clk); > - clk_disable_unprepare(atmel_port->clk); > - /* only enable clock when USART is in use */ > - } > + port->uartclk = clk_get_rate(atmel_port->clk); > > /* > * Use TXEMPTY for interrupt when rs485 or ISO7816 else TXRDY or > @@ -2640,10 +2623,6 @@ static int __init atmel_console_setup(struct console *co, char *options) > return -ENODEV; > } > > - ret = clk_prepare_enable(atmel_ports[co->index].clk); > - if (ret) > - return ret; > - Now, "int ret;" is unused, you can remove it.
> atmel_uart_writel(port, ATMEL_US_IDR, -1); > atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX); > atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN); > @@ -2889,14 +2868,23 @@ static int atmel_serial_probe(struct platform_device *pdev) > atomic_set(&atmel_port->tasklet_shutdown, 0); > spin_lock_init(&atmel_port->lock_suspended); > > + atmel_port->clk = devm_clk_get(&pdev->dev, "usart"); > + if (IS_ERR(atmel_port->clk)) { > + ret = PTR_ERR(atmel_port->clk); > + goto err; > + } > + ret = clk_prepare_enable(atmel_port->clk); > + if (ret) > + goto err; > + > ret = atmel_init_port(atmel_port, pdev); > if (ret) > - goto err_clear_bit; > + goto err_clk_disable_unprepare; > > atmel_port->gpios = mctrl_gpio_init(&atmel_port->uart, 0); > if (IS_ERR(atmel_port->gpios)) { > ret = PTR_ERR(atmel_port->gpios); > - goto err_clear_bit; > + goto err_clk_disable_unprepare; > } > > if (!atmel_use_pdc_rx(&atmel_port->uart)) { > @@ -2905,7 +2893,7 @@ static int atmel_serial_probe(struct platform_device *pdev) > sizeof(struct atmel_uart_char), > GFP_KERNEL); > if (!data) > - goto err_alloc_ring; > + goto err_clk_disable_unprepare; > atmel_port->rx_ring.buf = data; > } > > @@ -2915,26 +2903,9 @@ static int atmel_serial_probe(struct platform_device *pdev) > if (ret) > goto err_add_port; > > -#ifdef CONFIG_SERIAL_ATMEL_CONSOLE > - if (uart_console(&atmel_port->uart) > - && ATMEL_CONSOLE_DEVICE->flags & CON_ENABLED) { > - /* > - * The serial core enabled the clock for us, so undo > - * the clk_prepare_enable() in atmel_console_setup() > - */ > - clk_disable_unprepare(atmel_port->clk); > - } > -#endif > - > device_init_wakeup(&pdev->dev, 1); > platform_set_drvdata(pdev, atmel_port); > > - /* > - * The peripheral clock has been disabled by atmel_init_port(): > - * enable it before accessing I/O registers > - */ > - clk_prepare_enable(atmel_port->clk); > - > if (rs485_enabled) { > atmel_uart_writel(&atmel_port->uart, ATMEL_US_MR, > ATMEL_US_USMODE_NORMAL); > @@ -2958,12 +2929,8 @@ static int atmel_serial_probe(struct platform_device *pdev) > err_add_port: > kfree(atmel_port->rx_ring.buf); > atmel_port->rx_ring.buf = NULL; > -err_alloc_ring: > - if (!uart_console(&atmel_port->uart)) { > - clk_put(atmel_port->clk); > - atmel_port->clk = NULL; > - } > -err_clear_bit: > +err_clk_disable_unprepare: > + clk_disable_unprepare(atmel_port->clk); > clear_bit(atmel_port->uart.line, atmel_ports_in_use); > err: > return ret; > @@ -2997,8 +2964,6 @@ static int atmel_serial_remove(struct platform_device *pdev) > > clear_bit(port->line, atmel_ports_in_use); > > - clk_put(atmel_port->clk); > - atmel_port->clk = NULL; > pdev->dev.of_node = NULL; > > return ret; Thanks !
Regards, Richard
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