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X-Envelope-From: akhilesh@ee.iitb.ac.in X-Qmail-Scanner-Mime-Attachments: | X-Qmail-Scanner-Zip-Files: | Received: from unknown (HELO ldns2.iitb.ac.in) (10.200.1.25) by ldns2.iitb.ac.in with SMTP; 19 Aug 2025 16:17:30 +0530 Received: from bhairav.ee.iitb.ac.in (bhairav.ee.iitb.ac.in [10.107.1.1]) by ldns2.iitb.ac.in (Postfix) with ESMTP id 40ABB3414EC; Tue, 19 Aug 2025 16:17:30 +0530 (IST) Received: from bhairav-test.ee.iitb.ac.in (bhairav.ee.iitb.ac.in [10.107.1.1]) (Authenticated sender: akhilesh) by bhairav.ee.iitb.ac.in (Postfix) with ESMTPSA id 56F831E81492; Tue, 19 Aug 2025 16:17:29 +0530 (IST) Date: Tue, 19 Aug 2025 16:17:23 +0530 From: Akhilesh Patil To: alexandre.belloni@bootlin.com, mturquette@baylibre.com, sboyd@kernel.org Cc: linux-rtc@vger.kernel.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, akhileshpatilvnit@gmail.com, skhan@linuxfoundation.org Subject: [PATCH 1/1] rtc: ds1307: add support for clock provider in ds1307 Message-ID: <6b44b47567e418a7bc3f68b626e287b8106641f3.1755599808.git.akhilesh@ee.iitb.ac.in> References: Precedence: bulk X-Mailing-List: linux-rtc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Add support for square-wave output for ds1307 rtc via common clock framework clock provider. tested on TI am62x SK board using ds1307 RTC hardware module. Signed-off-by: Akhilesh Patil --- drivers/rtc/rtc-ds1307.c | 139 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 137 insertions(+), 2 deletions(-) diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c index 7205c59ff729..dd99b9a3836d 100644 --- a/drivers/rtc/rtc-ds1307.c +++ b/drivers/rtc/rtc-ds1307.c @@ -1658,18 +1658,153 @@ static int ds3231_clks_register(struct ds1307 *ds1307) return 0; } +/* ds1307 RTC clock output support */ +static unsigned long ds1307_clk_rates[] = { + 1, + 4096, + 8192, + 32768, +}; + +static unsigned long ds1307_clk_sqw_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + int ret; + unsigned int rate_id; + struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw); + + ret = regmap_read(ds1307->regmap, DS1307_REG_CONTROL, &rate_id); + if (ret) + return ret; + + rate_id &= (DS1307_BIT_RS1 | DS1307_BIT_RS0); + + return ds1307_clk_rates[rate_id]; +} + +static int ds1307_clk_sqw_determine_rate(struct clk_hw *hw, + struct clk_rate_request *req) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(ds1307_clk_rates); i++) { + if (req->rate <= ds1307_clk_rates[i]) { + req->rate = ds1307_clk_rates[i]; + return 0; + } + } + + /* Default rate 1Hz */ + req->rate = ds1307_clk_rates[0]; + + return 0; +} + +static int ds1307_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + int id, ret; + struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw); + + for (id = 0; id < ARRAY_SIZE(ds1307_clk_rates); id++) { + if (ds1307_clk_rates[id] == rate) + break; + } + + if (id >= ARRAY_SIZE(ds1307_clk_rates)) + return -EINVAL; + + ret = regmap_update_bits(ds1307->regmap, DS1307_REG_CONTROL, + DS1307_BIT_RS0 | DS1307_BIT_RS1, id); + + return ret; +} + +static int ds1307_clk_sqw_prepare(struct clk_hw *hw) +{ + int ret; + struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw); + + ret = regmap_update_bits(ds1307->regmap, DS1307_REG_CONTROL, + DS1307_BIT_SQWE, DS1307_BIT_SQWE); + + return ret; +} + +static void ds1307_clk_sqw_unprepare(struct clk_hw *hw) +{ + struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw); + + regmap_update_bits(ds1307->regmap, DS1307_REG_CONTROL, + DS1307_BIT_SQWE, ~DS1307_BIT_SQWE); +} + +static int ds1307_clk_sqw_is_prepared(struct clk_hw *hw) +{ + int ret; + struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw); + unsigned int status; + + ret = regmap_read(ds1307->regmap, DS1307_REG_CONTROL, &status); + if (ret) + return ret; + + return !!(status & DS1307_BIT_SQWE); +} + +static const struct clk_ops ds1307_clk_sqw_ops = { + .prepare = ds1307_clk_sqw_prepare, + .unprepare = ds1307_clk_sqw_unprepare, + .is_prepared = ds1307_clk_sqw_is_prepared, + .recalc_rate = ds1307_clk_sqw_recalc_rate, + .set_rate = ds1307_clk_sqw_set_rate, + .determine_rate = ds1307_clk_sqw_determine_rate, +}; + +static int rtc_ds1307_clks_register(struct ds1307 *ds1307) +{ + struct device_node *node = ds1307->dev->of_node; + struct clk *clk; + struct clk_init_data init = {0}; + + init.name = "ds1307_clk_sqw"; + init.ops = &ds1307_clk_sqw_ops; + + ds1307->clks[0].init = &init; + + /* Register the clock with CCF */ + clk = devm_clk_register(ds1307->dev, &ds1307->clks[0]); + if (IS_ERR(clk)) + return PTR_ERR(clk); + + if (node) + of_clk_add_provider(node, of_clk_src_simple_get, clk); + + return 0; +} + static void ds1307_clks_register(struct ds1307 *ds1307) { int ret; - if (ds1307->type != ds_3231) + switch (ds1307->type) { + case ds_3231: + ret = ds3231_clks_register(ds1307); + break; + + case ds_1307: + ret = rtc_ds1307_clks_register(ds1307); + break; + + default: return; + } - ret = ds3231_clks_register(ds1307); if (ret) { dev_warn(ds1307->dev, "unable to register clock device %d\n", ret); } + } #else