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

Marek Vasut
2017-12-11T16:21:54Z

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@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