[PATCH v3 27/31] net: can: mscan: add common clock support for mpc512x
Marc Kleine-Budde
mkl at pengutronix.de
Mon Jul 22 09:04:52 EDT 2013
On 07/22/2013 02:14 PM, Gerhard Sittig wrote:
> implement a .get_clock() callback for the MPC512x platform which uses
> the common clock infrastructure (eliminating direct access to the clock
> control registers from within the CAN network driver), and provide the
> corresponding .put_clock() callback to release resources after use
>
> keep the previous implementation of MPC512x support in place during
> migration, since common clock support is optional
>
> this change is neutral to the MPC5200 platform
>
> Signed-off-by: Gerhard Sittig <gsi at denx.de>
> ---
> drivers/net/can/mscan/mpc5xxx_can.c | 169 +++++++++++++++++++++++++++++++++++
> 1 file changed, 169 insertions(+)
>
> diff --git a/drivers/net/can/mscan/mpc5xxx_can.c b/drivers/net/can/mscan/mpc5xxx_can.c
> index e59b3a3..4897929 100644
> --- a/drivers/net/can/mscan/mpc5xxx_can.c
> +++ b/drivers/net/can/mscan/mpc5xxx_can.c
> @@ -109,6 +109,167 @@ static u32 mpc52xx_can_get_clock(struct platform_device *ofdev,
> #endif /* CONFIG_PPC_MPC52xx */
>
> #ifdef CONFIG_PPC_MPC512x
> +
> +#if IS_ENABLED(CONFIG_COMMON_CLK)
> +
> +static u32 mpc512x_can_get_clock(struct platform_device *ofdev,
> + const char *clock_source, int *mscan_clksrc)
> +{
> + struct device_node *np;
> + u32 clockdiv;
> + enum {
> + CLK_FROM_AUTO,
> + CLK_FROM_IPS,
> + CLK_FROM_SYS,
> + CLK_FROM_REF,
> + } clk_from;
> + struct clk *clk_in, *clk_can;
> + unsigned long freq_calc;
> + struct mscan_priv *priv;
> +
> + /* the caller passed in the clock source spec that was read from
> + * the device tree, get the optional clock divider as well
> + */
> + np = ofdev->dev.of_node;
> + clockdiv = 1;
> + of_property_read_u32(np, "fsl,mscan-clock-divider", &clockdiv);
> + dev_dbg(&ofdev->dev, "device tree specs: clk src[%s] div[%d]\n",
> + clock_source ? clock_source : "<NULL>", clockdiv);
> +
> + /* when clock-source is 'ip', the CANCTL1[CLKSRC] bit needs to
> + * get set, and the 'ips' clock is the input to the MSCAN
> + * component
> + *
> + * for clock-source values of 'ref' or 'sys' the CANCTL1[CLKSRC]
> + * bit needs to get cleared, an optional clock-divider may have
> + * been specified (the default value is 1), the appropriate
> + * MSCAN related MCLK is the input to the MSCAN component
> + *
> + * in the absence of a clock-source spec, first an optimal clock
> + * gets determined based on the 'sys' clock, if that fails the
> + * 'ref' clock is used
> + */
> + clk_from = CLK_FROM_AUTO;
> + if (clock_source) {
> + /* interpret the device tree's spec for the clock source */
> + if (!strcmp(clock_source, "ip"))
> + clk_from = CLK_FROM_IPS;
> + else if (!strcmp(clock_source, "sys"))
> + clk_from = CLK_FROM_SYS;
> + else if (!strcmp(clock_source, "ref"))
> + clk_from = CLK_FROM_REF;
> + else
> + goto err_invalid;
> + dev_dbg(&ofdev->dev, "got a clk source spec[%d]\n", clk_from);
> + }
> + if (clk_from == CLK_FROM_AUTO) {
> + /* no spec so far, try the 'sys' clock; round to the
> + * next MHz and see if we can get a multiple of 16MHz
> + */
> + dev_dbg(&ofdev->dev, "no clk source spec, trying SYS\n");
> + clk_in = devm_clk_get(&ofdev->dev, "sys");
> + if (IS_ERR(clk_in))
> + goto err_notavail;
> + freq_calc = clk_get_rate(clk_in);
> + freq_calc += 499999;
> + freq_calc /= 1000000;
> + freq_calc *= 1000000;
> + if ((freq_calc % 16000000) == 0) {
> + clk_from = CLK_FROM_SYS;
> + clockdiv = freq_calc / 16000000;
> + dev_dbg(&ofdev->dev,
> + "clk fit, sys[%lu] div[%d] freq[%lu]\n",
> + freq_calc, clockdiv, freq_calc / clockdiv);
> + }
> + }
> + if (clk_from == CLK_FROM_AUTO) {
> + /* no spec so far, use the 'ref' clock */
> + dev_dbg(&ofdev->dev, "no clk source spec, trying REF\n");
> + clk_in = devm_clk_get(&ofdev->dev, "ref");
> + if (IS_ERR(clk_in))
> + goto err_notavail;
> + clk_from = CLK_FROM_REF;
> + freq_calc = clk_get_rate(clk_in);
> + dev_dbg(&ofdev->dev,
> + "clk fit, ref[%lu] (no div) freq[%lu]\n",
> + freq_calc, freq_calc);
> + }
> +
> + /* select IPS or MCLK as the MSCAN input (returned to the caller),
> + * setup the MCLK mux source and rate if applicable, apply the
> + * optionally specified or derived above divider, and determine
> + * the actual resulting clock rate to return to the caller
> + */
> + switch (clk_from) {
> + case CLK_FROM_IPS:
> + clk_can = devm_clk_get(&ofdev->dev, "ips");
> + if (IS_ERR(clk_can))
> + goto err_notavail;
> + if (clk_prepare(clk_can)) {
I would just call prepare_enable in the main mscan driver, then we don't
need a special "clock is prepared but not enabled" contract.
> + devm_clk_put(&ofdev->dev, clk_can);
not needed, as this driver instance will fail, doesn't it?
> + goto err_notavail;
> + }
> + priv = netdev_priv(dev_get_drvdata(&ofdev->dev));
> + priv->clk_can = clk_can;
> + freq_calc = clk_get_rate(clk_can);
> + *mscan_clksrc = MSCAN_CLKSRC_IPS;
> + dev_dbg(&ofdev->dev, "clk from IPS, clksrc[%d] freq[%lu]\n",
> + *mscan_clksrc, freq_calc);
> + break;
> + case CLK_FROM_SYS:
> + case CLK_FROM_REF:
> + clk_can = devm_clk_get(&ofdev->dev, "mclk");
> + if (IS_ERR(clk_can))
> + goto err_notavail;
> + if (clk_prepare(clk_can)) {
> + devm_clk_put(&ofdev->dev, clk_can);
same here
> + goto err_notavail;
> + }
> + priv = netdev_priv(dev_get_drvdata(&ofdev->dev));
> + priv->clk_can = clk_can;
> + if (clk_from == CLK_FROM_SYS)
> + clk_in = devm_clk_get(&ofdev->dev, "sys");
> + if (clk_from == CLK_FROM_REF)
> + clk_in = devm_clk_get(&ofdev->dev, "ref");
> + if (IS_ERR(clk_in))
> + goto err_notavail;
> + clk_set_parent(clk_can, clk_in);
> + freq_calc = clk_get_rate(clk_in);
> + freq_calc /= clockdiv;
> + clk_set_rate(clk_can, freq_calc);
> + freq_calc = clk_get_rate(clk_can);
> + *mscan_clksrc = MSCAN_CLKSRC_BUS;
> + dev_dbg(&ofdev->dev, "clk from MCLK, clksrc[%d] freq[%lu]\n",
> + *mscan_clksrc, freq_calc);
> + break;
> + default:
> + goto err_invalid;
> + }
> +
> + return freq_calc;
> +
> +err_invalid:
> + dev_err(&ofdev->dev, "invalid clock source specification\n");
> + return 0;
return 0 in case of error? Please add a comment what this 0 means here.
> +
> +err_notavail:
> + dev_err(&ofdev->dev, "cannot acquire or setup clock source\n");
> + return 0;
> +}
> +
> +static void mpc512x_can_put_clock(struct platform_device *ofdev)
> +{
> + struct mscan_priv *priv;
> +
> + priv = netdev_priv(dev_get_drvdata(&ofdev->dev));
> + if (priv->clk_can) {
> + clk_unprepare(priv->clk_can);
> + devm_clk_put(&ofdev->dev, priv->clk_can);
devm_clk_put can be removed, it's called automatically.
> + }
> +}
> +
> +#else /* COMMON_CLK */
> +
> struct mpc512x_clockctl {
> u32 spmr; /* System PLL Mode Reg */
> u32 sccr[2]; /* System Clk Ctrl Reg 1 & 2 */
> @@ -239,12 +400,18 @@ exit_put:
> of_node_put(np_clock);
> return freq;
> }
> +
> +#define mpc512x_can_put_clock NULL
> +
> +#endif /* COMMON_CLK */
> +
> #else /* !CONFIG_PPC_MPC512x */
> static u32 mpc512x_can_get_clock(struct platform_device *ofdev,
> const char *clock_name, int *mscan_clksrc)
> {
> return 0;
> }
> +#define mpc512x_can_put_clock NULL
> #endif /* CONFIG_PPC_MPC512x */
>
> static const struct of_device_id mpc5xxx_can_table[];
> @@ -386,11 +553,13 @@ static int mpc5xxx_can_resume(struct platform_device *ofdev)
> static const struct mpc5xxx_can_data mpc5200_can_data = {
> .type = MSCAN_TYPE_MPC5200,
> .get_clock = mpc52xx_can_get_clock,
> + /* .put_clock not applicable */
> };
>
> static const struct mpc5xxx_can_data mpc5121_can_data = {
> .type = MSCAN_TYPE_MPC5121,
> .get_clock = mpc512x_can_get_clock,
> + .put_clock = mpc512x_can_put_clock,
> };
>
> static const struct of_device_id mpc5xxx_can_table[] = {
>
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
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