1 // SPDX-License-Identifier: GPL-2.0
3  * RTC driver for the interal RTC block in the Amlogic Meson6, Meson8,
6  * The RTC is split in to two parts, the AHB front end and a simple serial
19 #include <linux/nvmem-provider.h>
25 #include <linux/rtc.h>
46 /* rtc registers accessed via rtc-serial interface */
70 	.name		= "peripheral-registers",
77 /* RTC front-end serialiser controls */
79 static void meson_rtc_sclk_pulse(struct meson_rtc *rtc)  in meson_rtc_sclk_pulse()  argument
82 	regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SCLK, 0);  in meson_rtc_sclk_pulse()
84 	regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SCLK,  in meson_rtc_sclk_pulse()
88 static void meson_rtc_send_bit(struct meson_rtc *rtc, unsigned int bit)  in meson_rtc_send_bit()  argument
90 	regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SDI,  in meson_rtc_send_bit()
92 	meson_rtc_sclk_pulse(rtc);  in meson_rtc_send_bit()
95 static void meson_rtc_send_bits(struct meson_rtc *rtc, u32 data,  in meson_rtc_send_bits()  argument
98 	u32 bit = 1 << (nr - 1);  in meson_rtc_send_bits()
101 		meson_rtc_send_bit(rtc, data & bit);  in meson_rtc_send_bits()
106 static void meson_rtc_set_dir(struct meson_rtc *rtc, u32 mode)  in meson_rtc_set_dir()  argument
108 	regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SEN, 0);  in meson_rtc_set_dir()
109 	regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SDI, 0);  in meson_rtc_set_dir()
110 	meson_rtc_send_bit(rtc, mode);  in meson_rtc_set_dir()
111 	regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SDI, 0);  in meson_rtc_set_dir()
114 static u32 meson_rtc_get_data(struct meson_rtc *rtc)  in meson_rtc_get_data()  argument
120 		meson_rtc_sclk_pulse(rtc);  in meson_rtc_get_data()
123 		regmap_read(rtc->peripheral, RTC_ADDR1, &tmp);  in meson_rtc_get_data()
130 static int meson_rtc_get_bus(struct meson_rtc *rtc)  in meson_rtc_get_bus()  argument
137 	regmap_update_bits(rtc->peripheral, RTC_ADDR0, val, 0);  in meson_rtc_get_bus()
141 		if (!regmap_read_poll_timeout(rtc->peripheral, RTC_ADDR1, val,  in meson_rtc_get_bus()
146 		dev_warn(rtc->dev, "failed to get bus, resetting RTC\n");  in meson_rtc_get_bus()
148 		ret = reset_control_reset(rtc->reset);  in meson_rtc_get_bus()
153 	dev_err(rtc->dev, "bus is not ready\n");  in meson_rtc_get_bus()
154 	return -ETIMEDOUT;  in meson_rtc_get_bus()
160 	struct meson_rtc *rtc = context;  in meson_rtc_serial_bus_reg_read()  local
163 	ret = meson_rtc_get_bus(rtc);  in meson_rtc_serial_bus_reg_read()
167 	regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SEN,  in meson_rtc_serial_bus_reg_read()
169 	meson_rtc_send_bits(rtc, reg, RTC_ADDR_BITS);  in meson_rtc_serial_bus_reg_read()
170 	meson_rtc_set_dir(rtc, 0);  in meson_rtc_serial_bus_reg_read()
171 	*data = meson_rtc_get_data(rtc);  in meson_rtc_serial_bus_reg_read()
179 	struct meson_rtc *rtc = context;  in meson_rtc_serial_bus_reg_write()  local
182 	ret = meson_rtc_get_bus(rtc);  in meson_rtc_serial_bus_reg_write()
186 	regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SEN,  in meson_rtc_serial_bus_reg_write()
188 	meson_rtc_send_bits(rtc, data, RTC_DATA_BITS);  in meson_rtc_serial_bus_reg_write()
189 	meson_rtc_send_bits(rtc, reg, RTC_ADDR_BITS);  in meson_rtc_serial_bus_reg_write()
190 	meson_rtc_set_dir(rtc, 1);  in meson_rtc_serial_bus_reg_write()
201 	.name		= "serial-registers",
209 static int meson_rtc_write_static(struct meson_rtc *rtc, u32 data)  in meson_rtc_write_static()  argument
213 	regmap_write(rtc->peripheral, RTC_REG4,  in meson_rtc_write_static()
218 	regmap_update_bits(rtc->peripheral, RTC_ADDR0,  in meson_rtc_write_static()
222 	return regmap_read_poll_timeout(rtc->peripheral, RTC_REG4, tmp,  in meson_rtc_write_static()
227 /* RTC interface layer functions */
231 	struct meson_rtc *rtc = dev_get_drvdata(dev);  in meson_rtc_gettime()  local
235 	ret = regmap_read(rtc->serial, RTC_COUNTER, &time);  in meson_rtc_gettime()
244 	struct meson_rtc *rtc = dev_get_drvdata(dev);  in meson_rtc_settime()  local
246 	return regmap_write(rtc->serial, RTC_COUNTER, rtc_tm_to_time64(tm));  in meson_rtc_settime()
259 	struct meson_rtc *rtc = context;  in meson_rtc_regmem_read()  local
265 	return regmap_bulk_read(rtc->serial, read_offset, buf, read_size);  in meson_rtc_regmem_read()
271 	struct meson_rtc *rtc = context;  in meson_rtc_regmem_write()  local
277 	return regmap_bulk_write(rtc->serial, write_offset, buf, write_size);  in meson_rtc_regmem_write()
283 		.name = "meson-rtc-regmem",  in meson_rtc_probe()
291 	struct device *dev = &pdev->dev;  in meson_rtc_probe()
292 	struct meson_rtc *rtc;  in meson_rtc_probe()  local
298 	rtc = devm_kzalloc(dev, sizeof(struct meson_rtc), GFP_KERNEL);  in meson_rtc_probe()
299 	if (!rtc)  in meson_rtc_probe()
300 		return -ENOMEM;  in meson_rtc_probe()
306 	platform_set_drvdata(pdev, rtc);  in meson_rtc_probe()
308 	rtc->dev = dev;  in meson_rtc_probe()
310 	rtc_dev->ops = &meson_rtc_ops;  in meson_rtc_probe()
311 	rtc_dev->range_max = U32_MAX;  in meson_rtc_probe()
317 	rtc->peripheral = devm_regmap_init_mmio(dev, base,  in meson_rtc_probe()
319 	if (IS_ERR(rtc->peripheral)) {  in meson_rtc_probe()
321 		return PTR_ERR(rtc->peripheral);  in meson_rtc_probe()
324 	rtc->reset = devm_reset_control_get(dev, NULL);  in meson_rtc_probe()
325 	if (IS_ERR(rtc->reset)) {  in meson_rtc_probe()
327 		return PTR_ERR(rtc->reset);  in meson_rtc_probe()
330 	rtc->vdd = devm_regulator_get(dev, "vdd");  in meson_rtc_probe()
331 	if (IS_ERR(rtc->vdd)) {  in meson_rtc_probe()
332 		dev_err(dev, "failed to get the vdd-supply\n");  in meson_rtc_probe()
333 		return PTR_ERR(rtc->vdd);  in meson_rtc_probe()
336 	ret = regulator_enable(rtc->vdd);  in meson_rtc_probe()
338 		dev_err(dev, "failed to enable vdd-supply\n");  in meson_rtc_probe()
342 	ret = meson_rtc_write_static(rtc, MESON_STATIC_DEFAULT);  in meson_rtc_probe()
348 	rtc->serial = devm_regmap_init(dev, &meson_rtc_serial_bus, rtc,  in meson_rtc_probe()
350 	if (IS_ERR(rtc->serial)) {  in meson_rtc_probe()
352 		ret = PTR_ERR(rtc->serial);  in meson_rtc_probe()
357 	 * check if we can read RTC counter, if not then the RTC is probably  in meson_rtc_probe()
360 	ret = regmap_read(rtc->serial, RTC_COUNTER, &tm);  in meson_rtc_probe()
362 		dev_err(dev, "cannot read RTC counter, RTC not functional\n");  in meson_rtc_probe()
366 	meson_rtc_nvmem_config.priv = rtc;  in meson_rtc_probe()
378 	regulator_disable(rtc->vdd);  in meson_rtc_probe()
383 	{ .compatible = "amlogic,meson6-rtc", },
384 	{ .compatible = "amlogic,meson8-rtc", },
385 	{ .compatible = "amlogic,meson8b-rtc", },
386 	{ .compatible = "amlogic,meson8m2-rtc", },
394 		.name		= "meson-rtc",
400 MODULE_DESCRIPTION("Amlogic Meson RTC Driver");
404 MODULE_ALIAS("platform:meson-rtc");