From patchwork Tue Nov 24 13:47:40 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ludovic Desroches X-Patchwork-Id: 7691191 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 12F569F2E9 for ; Tue, 24 Nov 2015 13:50:17 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 31F6220839 for ; Tue, 24 Nov 2015 13:50:16 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 567CD2082B for ; Tue, 24 Nov 2015 13:50:15 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1a1Dws-0005fq-2Q; Tue, 24 Nov 2015 13:47:58 +0000 Received: from eusmtp01.atmel.com ([212.144.249.242]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1a1Dwo-0005aE-Mt for linux-arm-kernel@lists.infradead.org; Tue, 24 Nov 2015 13:47:55 +0000 Received: from ibiza.corp.atmel.com (10.161.101.13) by eusmtp01.atmel.com (10.161.101.30) with Microsoft SMTP Server id 14.3.235.1; Tue, 24 Nov 2015 14:47:29 +0100 From: Ludovic Desroches To: , , , Subject: [PATCH 1/3] i2c: at91: add setting HOLD field of TWIHS_CWGR via DT Date: Tue, 24 Nov 2015 14:47:40 +0100 Message-ID: <1448372862-11912-1-git-send-email-ludovic.desroches@atmel.com> X-Mailer: git-send-email 2.5.0 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20151124_054755_151307_C5332F94 X-CRM114-Status: GOOD ( 10.65 ) X-Spam-Score: -4.8 (----) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Wenyou Yang , Ludovic Desroches , linux-i2c@vger.kernel.org, cyrille.pichen@atmel.com, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.8 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Wenyou Yang Add the HOLD field management. Some i2c devices need a longer data hold time than the one given in the i2c bus specification. Since this value depends on the i2c device connected to the bus, add a DT property to configure it: "atmel,twd-hold-cycles". Signed-off-by: Wenyou Yang Signed-off-by: Ludovic Desroches --- drivers/i2c/busses/i2c-at91.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c index 10835d1..b3595ea 100644 --- a/drivers/i2c/busses/i2c-at91.c +++ b/drivers/i2c/busses/i2c-at91.c @@ -64,6 +64,7 @@ #define AT91_TWI_IADR 0x000c /* Internal Address Register */ #define AT91_TWI_CWGR 0x0010 /* Clock Waveform Generator Reg */ +#define AT91_TWI_CWGR_HOLD(x) (((x) & 0x1f) << 24) #define AT91_TWI_SR 0x0020 /* Status Register */ #define AT91_TWI_TXCOMP BIT(0) /* Transmission Complete */ @@ -185,7 +186,8 @@ static void at91_init_twi_bus(struct at91_twi_dev *dev) * Calculate symmetric clock as stated in datasheet: * twi_clk = F_MAIN / (2 * (cdiv * (1 << ckdiv) + offset)) */ -static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk) +static void at91_calc_twi_clock(struct at91_twi_dev *dev, + int twi_clk, u32 twd_hold) { int ckdiv, cdiv, div; struct at91_twi_pdata *pdata = dev->pdata; @@ -204,7 +206,9 @@ static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk) cdiv = 255; } - dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv; + dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv + | AT91_TWI_CWGR_HOLD(twd_hold); + dev_dbg(dev->dev, "cdiv %d ckdiv %d\n", cdiv, ckdiv); } @@ -994,6 +998,7 @@ static int at91_twi_probe(struct platform_device *pdev) int rc; u32 phy_addr; u32 bus_clk_rate; + u32 twd_hold_cycles = 0; dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL); if (!dev) @@ -1050,7 +1055,10 @@ static int at91_twi_probe(struct platform_device *pdev) if (rc) bus_clk_rate = DEFAULT_TWI_CLK_HZ; - at91_calc_twi_clock(dev, bus_clk_rate); + of_property_read_u32(dev->dev->of_node, "atmel,twd-hold-cycles", + &twd_hold_cycles); + + at91_calc_twi_clock(dev, bus_clk_rate, twd_hold_cycles); at91_init_twi_bus(dev); snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");