[PATCH v3 1/2] can: mcp251xfd: mcp251xfd_probe(): try to get crystal clock rate from property

[Marc Kleine-Budde <mkl@pengutronix.de>]

From: 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>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
v3: - only read clock-frequency property if no clk is found
    - add error handling to device_property_read_u32()
v2: new patch    

 drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index 47c3f408a799..c8f8bdfc1bfb 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -2883,11 +2883,19 @@ 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);
+	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 (clk) {
+		freq = clk_get_rate(clk);
+	} else {
+		err = device_property_read_u32(&spi->dev, "clock-frequency",
+					       &freq);
+		if (err)
+			return dev_err_probe(&spi->dev, err,
+					     "Failed to get clock-frequency!\n");
+	}
 
 	/* Sanity check */
 	if (freq < MCP251XFD_SYSCLOCK_HZ_MIN ||
-- 
2.30.2