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Tue, 9 Jul 2019 20:09:06 +0000 Received: from AM0PR06MB4066.eurprd06.prod.outlook.com ([fe80::141f:c11a:799e:97f9]) by AM0PR06MB4066.eurprd06.prod.outlook.com ([fe80::141f:c11a:799e:97f9%7]) with mapi id 15.20.2052.019; Tue, 9 Jul 2019 20:09:06 +0000 From: Melin Tomas To: "linux@roeck-us.net" , "wim@linux-watchdog.org" CC: "linux-watchdog@vger.kernel.org" , Melin Tomas Subject: [PATCH v3 4/4] watchdog: cadence_wdt: Support all available prescaler values Thread-Topic: [PATCH v3 4/4] watchdog: cadence_wdt: Support all available prescaler values Thread-Index: AQHVNpIpwwoCbUKMfU6U33+0Mj8DZw== Date: Tue, 9 Jul 2019 20:09:06 +0000 Message-ID: <20190709200801.42313-5-tomas.melin@vaisala.com> References: <20190709200801.42313-1-tomas.melin@vaisala.com> In-Reply-To: <20190709200801.42313-1-tomas.melin@vaisala.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-clientproxiedby: HE1PR0902CA0006.eurprd09.prod.outlook.com (2603:10a6:3:e5::16) To AM0PR06MB4066.eurprd06.prod.outlook.com (2603:10a6:208:b8::17) authentication-results: spf=none (sender IP is ) smtp.mailfrom=tomas.melin@vaisala.com; 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received-spf: None (protection.outlook.com: vaisala.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: uluAqRLv24aSQwt79Q+8XUJ5velDrZGjnfY61iLeahd0Ntu/hnoaPLkz5u9veVitBbcxjE54GgOsOfliutXLWAw1U/meSv1YlaDGGWzTZoPazmk3hXBExNoGrys+5h51W9dLP08F0gLwFhodXUz4QWp8uik1DA2fze4pS79cfuaPxjalXtGkdsHeJb8zrS7NMVVfj1yzX4RdOERImP4ka58Bh19tnlt4rBZ/b5Dh1RhhIfl2p7r7Zd4FKqRheFNnZnqvlnjQwOPC9AqvjvVlnCInVHGqT/i30Q1NLvs0fzW9cMJKdcse0RtRQh7ho2wz3yWl6lF7XUZN/29g+qStijB+BtFeL0DZbQOD6nv9QFd8Xmnn6kO552IoErLDheIIEVEcTdc3N41PtUsjuS67Z0bYkAvx0yAMOPpUBTX3agw= MIME-Version: 1.0 X-OriginatorOrg: vaisala.com X-MS-Exchange-CrossTenant-Network-Message-Id: 4a568963-74c9-45b3-0159-08d704a94bf7 X-MS-Exchange-CrossTenant-originalarrivaltime: 09 Jul 2019 20:09:06.8066 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 6d7393e0-41f5-4c2e-9b12-4c2be5da5c57 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: tomas.melin@vaisala.com X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM0PR06MB3890 Sender: linux-watchdog-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Cadence watchdog HW supports prescaler values of 8, 64, 512 and 4096. Add support to select prescaler values of 8 and 64 for lower input clock frequencies. Prescaler value is selected to keep timeout resolution of 1 second. For clock frequencies below 32kHz, 1 second resolution does no longer hold, thereby returning an error. Signed-off-by: Tomas Melin --- drivers/watchdog/cadence_wdt.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/drivers/watchdog/cadence_wdt.c b/drivers/watchdog/cadence_wdt.c index 0bdb275d904a..037faf557f9d 100644 --- a/drivers/watchdog/cadence_wdt.c +++ b/drivers/watchdog/cadence_wdt.c @@ -33,16 +33,17 @@ #define CDNS_WDT_COUNTER_VALUE_DIVISOR 0x1000 /* Clock prescaler value and selection */ +#define CDNS_WDT_PRESCALE_8 8 #define CDNS_WDT_PRESCALE_64 64 #define CDNS_WDT_PRESCALE_512 512 #define CDNS_WDT_PRESCALE_4096 4096 +#define CDNS_WDT_PRESCALE_SELECT_8 0 #define CDNS_WDT_PRESCALE_SELECT_64 1 #define CDNS_WDT_PRESCALE_SELECT_512 2 #define CDNS_WDT_PRESCALE_SELECT_4096 3 -/* Input clock frequency */ -#define CDNS_WDT_CLK_10MHZ 10000000 -#define CDNS_WDT_CLK_75MHZ 75000000 +/* Base input clock frequency */ +#define CDNS_WDT_CLK_32KHZ 32768 /* Counter maximum value */ #define CDNS_WDT_COUNTER_MAX 0xFFF @@ -318,10 +319,18 @@ static int cdns_wdt_probe(struct platform_device *pdev) return ret; clock_f = clk_get_rate(wdt->clk); - if (clock_f == 0) { - dev_err(dev, "invalid clock frequency, (f=%lu)\n", clock_f); + if (clock_f < CDNS_WDT_CLK_32KHZ) { + dev_err(dev, + "cannot find suitable clock prescaler, (f=%lu)\n", + clock_f); return -EINVAL; - } else if (clock_f <= CDNS_WDT_CLK_75MHZ) { + } else if (clock_f <= CDNS_WDT_CLK_32KHZ * CDNS_WDT_PRESCALE_8) { + wdt->prescaler = CDNS_WDT_PRESCALE_8; + wdt->ctrl_clksel = CDNS_WDT_PRESCALE_SELECT_8; + } else if (clock_f <= CDNS_WDT_CLK_32KHZ * CDNS_WDT_PRESCALE_64) { + wdt->prescaler = CDNS_WDT_PRESCALE_64; + wdt->ctrl_clksel = CDNS_WDT_PRESCALE_SELECT_64; + } else if (clock_f <= CDNS_WDT_CLK_32KHZ * CDNS_WDT_PRESCALE_512) { wdt->prescaler = CDNS_WDT_PRESCALE_512; wdt->ctrl_clksel = CDNS_WDT_PRESCALE_SELECT_512; } else {