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From: Conor Dooley <conor@kernel.org>
To: linux-mmc@vger.kernel.org
Cc: conor@kernel.org, Conor Dooley <conor.dooley@microchip.com>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	cyril.jean@microchip.com, Mark Brown <broonie@kernel.org>,
	linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-spi@vger.kernel.org
Subject: [RFC v1 3/3] spi: microchip-core-qspi: set min_speed_hz during probe
Date: Wed, 12 Jun 2024 16:48:33 +0100	[thread overview]
Message-ID: <20240612-attach-distaste-5c32099c1a76@spud> (raw)
In-Reply-To: <20240612-brigade-shell-1f626e7e592f@spud>

From: Conor Dooley <conor.dooley@microchip.com>

The controller's minimum possible bus clock is 1/30 the rate of the
input clock. Naively set the minimum bus clock speed the controller
is capable of during probe, assuming that the rate will never reduce
further.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 drivers/spi/spi-microchip-core-qspi.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/spi/spi-microchip-core-qspi.c b/drivers/spi/spi-microchip-core-qspi.c
index 1b23a38c155c..a549911b2f66 100644
--- a/drivers/spi/spi-microchip-core-qspi.c
+++ b/drivers/spi/spi-microchip-core-qspi.c
@@ -763,6 +763,7 @@ static int mchp_coreqspi_probe(struct platform_device *pdev)
 	ctlr->transfer_one_message = mchp_coreqspi_transfer_one_message;
 	ctlr->num_chipselect = 2;
 	ctlr->use_gpio_descriptors = true;
+	ctlr->min_speed_hz = clk_get_rate(qspi->clk) / 30;
 
 	ret = devm_spi_register_controller(&pdev->dev, ctlr);
 	if (ret)
-- 
2.43.0


      parent reply	other threads:[~2024-06-12 15:49 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-06-12 15:48 [RFC v1 0/3] mmc-spi - support controllers incapable of getting as low as 400KHz Conor Dooley
2024-06-12 15:48 ` [RFC v1 1/3] mmc: mmc_spi: allow for spi controllers incapable of getting as low as 400k Conor Dooley
2024-06-20 12:50   ` Ulf Hansson
2024-06-20 14:12     ` Conor Dooley
2024-06-20 14:24       ` Ulf Hansson
2024-06-12 15:48 ` [RFC v1 2/3] spi: microchip-core-qspi: Add regular transfers Conor Dooley
2024-06-12 16:40   ` Mark Brown
2024-06-12 20:48     ` Conor Dooley
2024-06-19 11:18       ` Conor Dooley
2024-06-12 15:48 ` Conor Dooley [this message]

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