Re: [PATCH v4 2/2] serial: fsl_linflexuart: add clock management

[Frank Li]

On Mon, Nov 11, 2024 at 01:29:21PM +0200, Ciprian Costea wrote:
> From: Ciprian Marian Costea <ciprianmarian.costea@xxxxxxxxxxx>
>
> Add optional clock 'ipg' and 'lin' support to NXP LINFlexD UART driver,
> which is used by S32G2 and S32G3 SoCs.
>
> LINFlex driver should perform clock management and not rely on a previous
> bootloader configuration.
>
> Clocking support is added as optional in order to not break existing
> support for S32V234 SoC. Therefore, there should be no impact if not
> providing LINFlexD clocks and continue to rely on a bootloader clock
> configuration and enablement.
>
> Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@xxxxxxxxxxx>
> ---
>  drivers/tty/serial/fsl_linflexuart.c | 82 +++++++++++++++++++++++-----
>  1 file changed, 68 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/tty/serial/fsl_linflexuart.c b/drivers/tty/serial/fsl_linflexuart.c
> index e972df4b188d..66b822f36d06 100644
> --- a/drivers/tty/serial/fsl_linflexuart.c
> +++ b/drivers/tty/serial/fsl_linflexuart.c
> @@ -3,9 +3,10 @@
>   * Freescale LINFlexD UART serial port driver
>   *
>   * Copyright 2012-2016 Freescale Semiconductor, Inc.
> - * Copyright 2017-2019 NXP
> + * Copyright 2017-2019, 2024 NXP
>   */
>
> +#include <linux/clk.h>
>  #include <linux/console.h>
>  #include <linux/io.h>
>  #include <linux/irq.h>
> @@ -120,9 +121,29 @@
>
>  #define PREINIT_DELAY			2000 /* us */
>
> +struct linflex_devtype_data {
> +	const char * const *clks_names;
> +	int n_clks;
> +};
> +
> +struct linflex_port {
> +	struct uart_port port;
> +	struct clk_bulk_data *clks;
> +	const struct linflex_devtype_data *devtype_data;
> +};
> +
> +static const char * const s32v234_clk_names[] = {
> +	"ipg", "lin",
> +};
> +
> +static const struct linflex_devtype_data s32v234_data = {
> +	.clks_names = s32v234_clk_names,
> +	.n_clks = ARRAY_SIZE(s32v234_clk_names),
> +};
> +
>  static const struct of_device_id linflex_dt_ids[] = {
>  	{
> -		.compatible = "fsl,s32v234-linflexuart",
> +		.compatible = "fsl,s32v234-linflexuart", .data = &s32v234_data,
>  	},
>  	{ /* sentinel */ }
>  };
> @@ -807,12 +828,13 @@ static struct uart_driver linflex_reg = {
>  static int linflex_probe(struct platform_device *pdev)
>  {
>  	struct device_node *np = pdev->dev.of_node;
> +	struct linflex_port *lfport;
>  	struct uart_port *sport;
>  	struct resource *res;
> -	int ret;
> +	int i, ret;
>
> -	sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
> -	if (!sport)
> +	lfport = devm_kzalloc(&pdev->dev, sizeof(*lfport), GFP_KERNEL);
> +	if (!lfport)
>  		return -ENOMEM;
>
>  	ret = of_alias_get_id(np, "serial");
> @@ -826,8 +848,14 @@ static int linflex_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  	}
>
> +	sport = &lfport->port;
>  	sport->line = ret;
>
> +	lfport->devtype_data = of_device_get_match_data(&pdev->dev);
> +	if (!lfport->devtype_data)
> +		return dev_err_probe(&pdev->dev, -ENODEV,
> +				"Failed to get linflexuart driver data\n");
> +
>  	sport->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
>  	if (IS_ERR(sport->membase))
>  		return PTR_ERR(sport->membase);
> @@ -844,37 +872,63 @@ static int linflex_probe(struct platform_device *pdev)
>  	sport->flags = UPF_BOOT_AUTOCONF;
>  	sport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE);
>
> -	linflex_ports[sport->line] = sport;
> +	lfport->clks = devm_kmalloc_array(&pdev->dev, lfport->devtype_data->n_clks,
> +				    sizeof(*lfport->clks), GFP_KERNEL);
> +	if (!lfport->clks)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < lfport->devtype_data->n_clks; i++)
> +		lfport->clks[i].id = lfport->devtype_data->clks_names[i];
> +
> +	ret = devm_clk_bulk_get_optional(&pdev->dev,
> +					 lfport->devtype_data->n_clks, lfport->clks);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret,
> +				"Failed to get linflexuart clocks\n");
> +
> +	ret = clk_bulk_prepare_enable(lfport->devtype_data->n_clks,
> +				      lfport->clks);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret,
> +				"Failed to enable linflexuart clocks\n");

devm_clk_bulk_get_all_enable() will be more simple. If use
clk_bulk_prepare_enable() here, you need add a customer action
devm_add_action_or_reset() otherwise if uart_add_one_port() failure,
all clocks will be enabled.

Frank

>
> -	platform_set_drvdata(pdev, sport);
> +	linflex_ports[sport->line] = sport;
> +	platform_set_drvdata(pdev, lfport);
>
>  	return uart_add_one_port(&linflex_reg, sport);
>  }
>
>  static void linflex_remove(struct platform_device *pdev)
>  {
> -	struct uart_port *sport = platform_get_drvdata(pdev);
> +	struct linflex_port *lfport = platform_get_drvdata(pdev);
>
> -	uart_remove_one_port(&linflex_reg, sport);
> +	uart_remove_one_port(&linflex_reg, &lfport->port);
>  }
>
>  #ifdef CONFIG_PM_SLEEP
>  static int linflex_suspend(struct device *dev)
>  {
> -	struct uart_port *sport = dev_get_drvdata(dev);
> +	struct linflex_port *lfport = dev_get_drvdata(dev);
> +
> +	uart_suspend_port(&linflex_reg, &lfport->port);
>
> -	uart_suspend_port(&linflex_reg, sport);
> +	clk_bulk_disable_unprepare(lfport->devtype_data->n_clks,
> +				   lfport->clks);
>
>  	return 0;
>  }
>
>  static int linflex_resume(struct device *dev)
>  {
> -	struct uart_port *sport = dev_get_drvdata(dev);
> +	struct linflex_port *lfport = dev_get_drvdata(dev);
> +	int ret;
>
> -	uart_resume_port(&linflex_reg, sport);
> +	ret = clk_bulk_prepare_enable(lfport->devtype_data->n_clks,
> +				      lfport->clks);
> +	if (ret)
> +		return ret;
>
> -	return 0;
> +	return uart_resume_port(&linflex_reg, &lfport->port);
>  }
>  #endif
>
> --
> 2.45.2
>