diff options
| -rw-r--r-- | drivers/net/can/mscan/mpc5xxx_can.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/drivers/net/can/mscan/mpc5xxx_can.c b/drivers/net/can/mscan/mpc5xxx_can.c index e59b3a392af6..f48f1297ff30 100644 --- a/drivers/net/can/mscan/mpc5xxx_can.c +++ b/drivers/net/can/mscan/mpc5xxx_can.c @@ -109,6 +109,177 @@ 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; + struct clk *clk_ipg; + + /* 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; + 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; + 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; + } + + /* the above clk_can item is used for the bitrate, access to + * the peripheral's register set needs the clk_ipg item + */ + clk_ipg = devm_clk_get(&ofdev->dev, "ipg"); + if (IS_ERR(clk_ipg)) + goto err_notavail_ipg; + if (clk_prepare_enable(clk_ipg)) + goto err_notavail_ipg; + priv = netdev_priv(dev_get_drvdata(&ofdev->dev)); + priv->clk_ipg = clk_ipg; + + /* return the determined clock source rate */ + return freq_calc; + +err_invalid: + dev_err(&ofdev->dev, "invalid clock source specification\n"); + /* clock source rate could not get determined */ + return 0; + +err_notavail: + dev_err(&ofdev->dev, "cannot acquire or setup bitrate clock source\n"); + /* clock source rate could not get determined */ + return 0; + +err_notavail_ipg: + dev_err(&ofdev->dev, "cannot acquire or setup register clock\n"); + /* clock source rate could not get determined */ + 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_ipg) + clk_disable_unprepare(priv->clk_ipg); +} + +#else /* COMMON_CLK */ + struct mpc512x_clockctl { u32 spmr; /* System PLL Mode Reg */ u32 sccr[2]; /* System Clk Ctrl Reg 1 & 2 */ @@ -239,12 +410,18 @@ 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 +563,13 @@ 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[] = { |