linux-kernel - Re: [PATCH 1/5] net: ethernet: stmmac: Add support for syscfg clock

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Date:   Thu, 3 Oct 2019 12:13:44 +0200
From:   Alexandre Torgue <alexandre.torgue@...com>
To:     Christophe Roullier <christophe.roullier@...com>,
        <robh@...nel.org>, <davem@...emloft.net>, <joabreu@...opsys.com>,
        <mark.rutland@....com>, <mcoquelin.stm32@...il.com>,
        <peppe.cavallaro@...com>
CC:     <linux-stm32@...md-mailman.stormreply.com>,
        <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>, <netdev@...r.kernel.org>,
        <andrew@...n.ch>
Subject: Re: [PATCH 1/5] net: ethernet: stmmac: Add support for syscfg clock

Hi,

On 9/20/19 7:38 AM, Christophe Roullier wrote:
> Add optional support for syscfg clock in dwmac-stm32.c
> Now Syscfg clock is activated automatically when syscfg
> registers are used
> 
> Signed-off-by: Christophe Roullier <christophe.roullier@...com>
> ---
>   .../net/ethernet/stmicro/stmmac/dwmac-stm32.c | 36 +++++++++++++------
>   1 file changed, 25 insertions(+), 11 deletions(-)

Acked-by: Alexandre TORGUE <alexandre.torgue@...com>

> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c
> index 4ef041bdf6a1..7e6619868cc1 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c
> @@ -152,23 +152,32 @@ static int stm32mp1_clk_prepare(struct stm32_dwmac *dwmac, bool prepare)
>   	int ret = 0;
>   
>   	if (prepare) {
> -		ret = clk_prepare_enable(dwmac->syscfg_clk);
> -		if (ret)
> -			return ret;
> -
> +		if (dwmac->syscfg_clk) {
> +			ret = clk_prepare_enable(dwmac->syscfg_clk);
> +			if (ret)
> +				return ret;
> +		}
>   		if (dwmac->clk_eth_ck) {
>   			ret = clk_prepare_enable(dwmac->clk_eth_ck);
>   			if (ret) {
> -				clk_disable_unprepare(dwmac->syscfg_clk);
> +				if (dwmac->syscfg_clk)
> +					goto unprepare_syscfg;
>   				return ret;
>   			}
>   		}
>   	} else {
> -		clk_disable_unprepare(dwmac->syscfg_clk);
> +		if (dwmac->syscfg_clk)
> +			clk_disable_unprepare(dwmac->syscfg_clk);
> +
>   		if (dwmac->clk_eth_ck)
>   			clk_disable_unprepare(dwmac->clk_eth_ck);
>   	}
>   	return ret;
> +
> +unprepare_syscfg:
> +	clk_disable_unprepare(dwmac->syscfg_clk);
> +
> +	return ret;
>   }
>   
>   static int stm32mp1_set_mode(struct plat_stmmacenet_data *plat_dat)
> @@ -296,7 +305,7 @@ static int stm32mp1_parse_data(struct stm32_dwmac *dwmac,
>   {
>   	struct platform_device *pdev = to_platform_device(dev);
>   	struct device_node *np = dev->of_node;
> -	int err = 0;
> +	int err;
>   
>   	/* Gigabit Ethernet 125MHz clock selection. */
>   	dwmac->eth_clk_sel_reg = of_property_read_bool(np, "st,eth-clk-sel");
> @@ -320,13 +329,17 @@ static int stm32mp1_parse_data(struct stm32_dwmac *dwmac,
>   		return PTR_ERR(dwmac->clk_ethstp);
>   	}
>   
> -	/*  Clock for sysconfig */
> +	/*  Optional Clock for sysconfig */
>   	dwmac->syscfg_clk = devm_clk_get(dev, "syscfg-clk");
>   	if (IS_ERR(dwmac->syscfg_clk)) {
> -		dev_err(dev, "No syscfg clock provided...\n");
> -		return PTR_ERR(dwmac->syscfg_clk);
> +		err = PTR_ERR(dwmac->syscfg_clk);
> +		if (err != -ENOENT)
> +			return err;
> +		dwmac->syscfg_clk = NULL;
>   	}
>   
> +	err = 0;
> +
>   	/* Get IRQ information early to have an ability to ask for deferred
>   	 * probe if needed before we went too far with resource allocation.
>   	 */
> @@ -436,7 +449,8 @@ static int stm32mp1_suspend(struct stm32_dwmac *dwmac)
>   		return ret;
>   
>   	clk_disable_unprepare(dwmac->clk_tx);
> -	clk_disable_unprepare(dwmac->syscfg_clk);
> +	if (dwmac->syscfg_clk)
> +		clk_disable_unprepare(dwmac->syscfg_clk);
>   	if (dwmac->clk_eth_ck)
>   		clk_disable_unprepare(dwmac->clk_eth_ck);
>   
>