[PATCH v2 1/2] can: mcp251xfd: Try to get crystal clock rate from property

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

In some configurations, mainly ACPI-based, the clock frequency of the device
is supplied by very well established 'clock-frequency' property. Hence, try
to get it from the property at last if no other providers are available.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
v2: new patch
 drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index e0ae00e34c7b..e42f87c3f2ec 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -2856,7 +2856,7 @@ static int mcp251xfd_probe(struct spi_device *spi)
 	struct gpio_desc *rx_int;
 	struct regulator *reg_vdd, *reg_xceiver;
 	struct clk *clk;
-	u32 freq;
+	u32 freq, rate;
 	int err;
 
 	if (!spi->irq)
@@ -2883,11 +2883,16 @@ static int mcp251xfd_probe(struct spi_device *spi)
 		return dev_err_probe(&spi->dev, PTR_ERR(reg_xceiver),
 				     "Failed to get Transceiver regulator!\n");
 
-	clk = devm_clk_get(&spi->dev, NULL);
+	/* Always ask for fixed clock rate from a property. */
+	device_property_read_u32(&spi->dev, "clock-frequency", &rate);
+
+	clk = devm_clk_get_optional(&spi->dev, NULL);
 	if (IS_ERR(clk))
 		return dev_err_probe(&spi->dev, PTR_ERR(clk),
 				     "Failed to get Oscillator (clock)!\n");
 	freq = clk_get_rate(clk);
+	if (freq == 0)
+		freq = rate;
 
 	/* Sanity check */
 	if (freq < MCP251XFD_SYSCLOCK_HZ_MIN ||
-- 
2.30.2