Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755575AbbKRKMe (ORCPT ); Wed, 18 Nov 2015 05:12:34 -0500 Received: from eusmtp01.atmel.com ([212.144.249.243]:38196 "EHLO eusmtp01.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932429AbbKRKKI (ORCPT ); Wed, 18 Nov 2015 05:10:08 -0500 From: Wenyou Yang To: Wolfgang Grandegger , Marc Kleine-Budde CC: , , , Nicolas Ferre , Wenyou Yang Subject: [PATCH 2/2] can: m_can: Add CAN clock generated by UPLLCK support Date: Wed, 18 Nov 2015 18:04:09 +0800 Message-ID: <1447841049-5010-3-git-send-email-wenyou.yang@atmel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1447841049-5010-1-git-send-email-wenyou.yang@atmel.com> References: <1447841049-5010-1-git-send-email-wenyou.yang@atmel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2053 Lines: 63 As said SAMA5D2 datasheet, it is recommended to use the CAN clock at frequencies of 20, 40 or 80 MHz. To achieve these frequencies, PMC GCK3 must select the UPLLCK(480 MHz) as source clock and divide by 24, 12 or 6. In this patch the CAN clock at 20 MHz. As it is configured through DT, it doesn't affect the M_CAN without configuring CAN clock and its generated clock. Signed-off-by: Wenyou Yang --- drivers/net/can/m_can/m_can.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index fd1caa0..2ca47db 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -269,6 +269,8 @@ enum m_can_mram_cfg { #define TX_BUF_XTD BIT(30) #define TX_BUF_RTR BIT(29) +#define AT91_CAN_CLK_FREQ 20000000 + /* address offset and element number for each FIFO/Buffer in the Message RAM */ struct mram_cfg { u16 off; @@ -1188,7 +1190,7 @@ static int m_can_plat_probe(struct platform_device *pdev) struct m_can_priv *priv; struct resource *res; void __iomem *addr; - struct clk *hclk, *cclk; + struct clk *hclk, *cclk, *upll_clk; int irq, ret; hclk = devm_clk_get(&pdev->dev, "hclk"); @@ -1198,6 +1200,18 @@ static int m_can_plat_probe(struct platform_device *pdev) return -ENODEV; } + upll_clk = devm_clk_get(&pdev->dev, "upllclk"); + if (!IS_ERR(upll_clk)) { + ret = clk_set_parent(cclk, upll_clk); + if (!ret) { + ret = clk_set_rate(cclk, AT91_CAN_CLK_FREQ); + if (ret) { + dev_err(&pdev->dev, "failed to set gck\n"); + return -ENODEV; + } + } + } + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "m_can"); addr = devm_ioremap_resource(&pdev->dev, res); irq = platform_get_irq_byname(pdev, "int0"); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/