[U-Boot] [PATCH v6 2/2] DW SPI: Get clock value from Device Tree

[Marek Vasut]

On 12/11/2017 05:18 PM, Eugeniy Paltsev wrote:
> Add option to set spi controller clock frequency via device tree
> using standard clock bindings.
> 
> Define dw_spi_get_clk function as 'weak' as some targets
> (like SOCFPGA_GEN5 and SOCFPGA_ARRIA10) fon't use standard clock API
> and implement dw_spi_get_clk their own way in their clock manager.
> 
> Get rid of clock_manager.h include as we don't use
> cm_get_spi_controller_clk_hz function anymore. (we use redefined
> dw_spi_get_clk in SOCFPGA clock managers instead)
> 
> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev at synopsys.com>
> ---
>  drivers/spi/designware_spi.c | 43 +++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 41 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/spi/designware_spi.c b/drivers/spi/designware_spi.c
> index 5aa507b..a037376 100644
> --- a/drivers/spi/designware_spi.c
> +++ b/drivers/spi/designware_spi.c
> @@ -11,6 +11,7 @@
>   */
>  
>  #include <common.h>
> +#include <clk.h>
>  #include <dm.h>
>  #include <errno.h>
>  #include <malloc.h>
> @@ -18,7 +19,6 @@
>  #include <fdtdec.h>
>  #include <linux/compat.h>
>  #include <asm/io.h>
> -#include <asm/arch/clock_manager.h>
>  
>  DECLARE_GLOBAL_DATA_PTR;
>  
> @@ -94,6 +94,8 @@ struct dw_spi_priv {
>  	void __iomem *regs;
>  	unsigned int freq;		/* Default frequency */
>  	unsigned int mode;
> +	struct clk clk;
> +	unsigned long bus_clk_rate;
>  
>  	int bits_per_word;
>  	u8 cs;			/* chip select pin */
> @@ -176,14 +178,51 @@ static void spi_hw_init(struct dw_spi_priv *priv)
>  	debug("%s: fifo_len=%d\n", __func__, priv->fifo_len);
>  }
>  
> +/*
> + * We define dw_spi_get_clk function as 'weak' as some targets
> + * (like SOCFPGA_GEN5 and SOCFPGA_ARRIA10) fon't use standard clock API
> + * and implement dw_spi_get_clk their own way in their clock manager.
> + */
> +__weak int dw_spi_get_clk(struct udevice *bus, ulong *rate)
> +{
> +	struct dw_spi_priv *priv = dev_get_priv(bus);
> +	int ret;
> +
> +	ret = clk_get_by_index(bus, 0, &priv->clk);
> +	if (ret)
> +		return -EINVAL;

if (ret)
 return ret;

> +	ret = clk_enable(&priv->clk);
> +	if (ret && ret != -ENOSYS && ret != -ENOSYS && ret != -ENOTSUPP)

You have ENOSYS twice in there, but you can do just if (ret) return ret
again.

> +		return ret;
> +
> +	*rate = clk_get_rate(&priv->clk);
> +	if (!*rate) {
> +		clk_disable(&priv->clk);

You didn't do clk_free() here, just implement a failpath (ie. goto
err_rate).

> +		return -EINVAL;
> +	}
> +
> +	debug("%s: get spi controller clk via device tree: %lu Hz\n",
> +	      __func__, *rate);
> +
> +	clk_free(&priv->clk);

If anyone accesses priv->clk outside of this function, the code will
crash, so remove this.

> +	return 0;

err_rate:
 clk_free() ...

> +}
> +
>  static int dw_spi_probe(struct udevice *bus)
>  {
>  	struct dw_spi_platdata *plat = dev_get_platdata(bus);
>  	struct dw_spi_priv *priv = dev_get_priv(bus);
> +	int ret;
>  
>  	priv->regs = plat->regs;
>  	priv->freq = plat->frequency;
>  
> +	ret = dw_spi_get_clk(bus, &priv->bus_clk_rate);
> +	if (ret)
> +		return ret;
> +
>  	/* Currently only bits_per_word == 8 supported */
>  	priv->bits_per_word = 8;
>  
> @@ -369,7 +408,7 @@ static int dw_spi_set_speed(struct udevice *bus, uint speed)
>  	spi_enable_chip(priv, 0);
>  
>  	/* clk_div doesn't support odd number */
> -	clk_div = cm_get_spi_controller_clk_hz() / speed;
> +	clk_div = priv->bus_clk_rate / speed;
>  	clk_div = (clk_div + 1) & 0xfffe;
>  	dw_writel(priv, DW_SPI_BAUDR, clk_div);
>  
> 


-- 
Best regards,
Marek Vasut