1 files changed, 155 insertions, 118 deletions

diff --git a/drivers/net/can/mscan/mpc5xxx_can.c b/drivers/net/can/mscan/mpc5xxx_can.c
index e59b3a392af6..44725296f72a 100644
--- a/drivers/net/can/mscan/mpc5xxx_can.c
+++ b/drivers/net/can/mscan/mpc5xxx_can.c
@@ -16,8 +16,7 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
 #include <linux/kernel.h>
@@ -109,135 +108,170 @@ static u32 mpc52xx_can_get_clock(struct platform_device *ofdev,
 #endif /* CONFIG_PPC_MPC52xx */
 
 #ifdef CONFIG_PPC_MPC512x
-struct mpc512x_clockctl {
-	u32 spmr;		/* System PLL Mode Reg */
-	u32 sccr[2];		/* System Clk Ctrl Reg 1 & 2 */
-	u32 scfr1;		/* System Clk Freq Reg 1 */
-	u32 scfr2;		/* System Clk Freq Reg 2 */
-	u32 reserved;
-	u32 bcr;		/* Bread Crumb Reg */
-	u32 pccr[12];		/* PSC Clk Ctrl Reg 0-11 */
-	u32 spccr;		/* SPDIF Clk Ctrl Reg */
-	u32 cccr;		/* CFM Clk Ctrl Reg */
-	u32 dccr;		/* DIU Clk Cnfg Reg */
-	u32 mccr[4];		/* MSCAN Clk Ctrl Reg 1-3 */
-};
-
-static struct of_device_id mpc512x_clock_ids[] = {
-	{ .compatible = "fsl,mpc5121-clock", },
-	{}
-};
-
 static u32 mpc512x_can_get_clock(struct platform_device *ofdev,
-				 const char *clock_name, int *mscan_clksrc)
+				 const char *clock_source, int *mscan_clksrc)
 {
-	struct mpc512x_clockctl __iomem *clockctl;
-	struct device_node *np_clock;
-	struct clk *sys_clk, *ref_clk;
-	int plen, clockidx, clocksrc = -1;
-	u32 sys_freq, val, clockdiv = 1, freq = 0;
-	const u32 *pval;
-
-	np_clock = of_find_matching_node(NULL, mpc512x_clock_ids);
-	if (!np_clock) {
-		dev_err(&ofdev->dev, "couldn't find clock node\n");
-		return 0;
-	}
-	clockctl = of_iomap(np_clock, 0);
-	if (!clockctl) {
-		dev_err(&ofdev->dev, "couldn't map clock registers\n");
-		goto exit_put;
-	}
+	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;
 
-	/* Determine the MSCAN device index from the peripheral's
-	 * physical address. Register address offsets against the
-	 * IMMR base are:  0x1300, 0x1380, 0x2300, 0x2380
+	/* the caller passed in the clock source spec that was read from
+	 * the device tree, get the optional clock divider as well
 	 */
-	pval = of_get_property(ofdev->dev.of_node, "reg", &plen);
-	BUG_ON(!pval || plen < sizeof(*pval));
-	clockidx = (*pval & 0x80) ? 1 : 0;
-	if (*pval & 0x2000)
-		clockidx += 2;
+	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);
+	}
 
-	/*
-	 * Clock source and divider selection: 3 different clock sources
-	 * can be selected: "ip", "ref" or "sys". For the latter two, a
-	 * clock divider can be defined as well. If the clock source is
-	 * not specified by the device tree, we first try to find an
-	 * optimal CAN source clock based on the system clock. If that
-	 * is not posslible, the reference clock will be used.
+	/* 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
 	 */
-	if (clock_name && !strcmp(clock_name, "ip")) {
+	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;
-		freq = mpc5xxx_get_bus_frequency(ofdev->dev.of_node);
-	} else {
+		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;
-
-		pval = of_get_property(ofdev->dev.of_node,
-				       "fsl,mscan-clock-divider", &plen);
-		if (pval && plen == sizeof(*pval))
-			clockdiv = *pval;
-		if (!clockdiv)
-			clockdiv = 1;
-
-		if (!clock_name || !strcmp(clock_name, "sys")) {
-			sys_clk = devm_clk_get(&ofdev->dev, "sys_clk");
-			if (IS_ERR(sys_clk)) {
-				dev_err(&ofdev->dev, "couldn't get sys_clk\n");
-				goto exit_unmap;
-			}
-			/* Get and round up/down sys clock rate */
-			sys_freq = 1000000 *
-				((clk_get_rate(sys_clk) + 499999) / 1000000);
-
-			if (!clock_name) {
-				/* A multiple of 16 MHz would be optimal */
-				if ((sys_freq % 16000000) == 0) {
-					clocksrc = 0;
-					clockdiv = sys_freq / 16000000;
-					freq = sys_freq / clockdiv;
-				}
-			} else {
-				clocksrc = 0;
-				freq = sys_freq / clockdiv;
-			}
-		}
-
-		if (clocksrc < 0) {
-			ref_clk = devm_clk_get(&ofdev->dev, "ref_clk");
-			if (IS_ERR(ref_clk)) {
-				dev_err(&ofdev->dev, "couldn't get ref_clk\n");
-				goto exit_unmap;
-			}
-			clocksrc = 1;
-			freq = clk_get_rate(ref_clk) / clockdiv;
-		}
+		dev_dbg(&ofdev->dev, "clk from MCLK, clksrc[%d] freq[%lu]\n",
+			*mscan_clksrc, freq_calc);
+		break;
+	default:
+		goto err_invalid;
 	}
 
-	/* Disable clock */
-	out_be32(&clockctl->mccr[clockidx], 0x0);
-	if (clocksrc >= 0) {
-		/* Set source and divider */
-		val = (clocksrc << 14) | ((clockdiv - 1) << 17);
-		out_be32(&clockctl->mccr[clockidx], val);
-		/* Enable clock */
-		out_be32(&clockctl->mccr[clockidx], val | 0x10000);
-	}
+	/* 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;
 
-	/* Enable MSCAN clock domain */
-	val = in_be32(&clockctl->sccr[1]);
-	if (!(val & (1 << 25)))
-		out_be32(&clockctl->sccr[1], val | (1 << 25));
+err_notavail:
+	dev_err(&ofdev->dev, "cannot acquire or setup bitrate clock source\n");
+	/* clock source rate could not get determined */
+	return 0;
 
-	dev_dbg(&ofdev->dev, "using '%s' with frequency divider %d\n",
-		*mscan_clksrc == MSCAN_CLKSRC_IPS ? "ips_clk" :
-		clocksrc == 1 ? "ref_clk" : "sys_clk", clockdiv);
+err_notavail_ipg:
+	dev_err(&ofdev->dev, "cannot acquire or setup register clock\n");
+	/* clock source rate could not get determined */
+	return 0;
+}
 
-exit_unmap:
-	iounmap(clockctl);
-exit_put:
-	of_node_put(np_clock);
-	return freq;
+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 /* !CONFIG_PPC_MPC512x */
 static u32 mpc512x_can_get_clock(struct platform_device *ofdev,
@@ -245,6 +279,7 @@ static u32 mpc512x_can_get_clock(struct platform_device *ofdev,
 {
 	return 0;
 }
+#define mpc512x_can_put_clock NULL
 #endif /* CONFIG_PPC_MPC512x */
 
 static const struct of_device_id mpc5xxx_can_table[];
@@ -386,11 +421,13 @@ 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[] = {