1 // SPDX-License-Identifier: GPL-2.0-or-later
7  * Copyright (C) 2011 - 2021 Xilinx Inc.
14 #include <linux/clk-provider.h>
54  * @hw:	Clock hw struct
57  * @max_freq:	Maximum frequency for this device
58  * @fxtal:	Factory xtal frequency
59  * @n1:		Clock divider N1
60  * @hs_div:	Clock divider HSDIV
61  * @rfreq:	Clock multiplier RFREQ
62  * @frequency:	Current output frequency
74 	u64 frequency;  member
85  * si570_get_divs() - Read clock dividers from HW
92  * Retrieve clock dividers and multipliers from the HW.
101 	err = regmap_bulk_read(data->regmap, SI570_REG_HS_N1 + data->div_offset,  in si570_get_divs()
123  * si570_get_defaults() - Get default values
125  * @fout:	Factory frequency output
136 		regmap_write(data->regmap, SI570_REG_CONTROL,  in si570_get_defaults()
139 	err = si570_get_divs(data, &data->rfreq, &data->n1, &data->hs_div);  in si570_get_defaults()
147 	fdco = fout * data->n1 * data->hs_div;  in si570_get_defaults()
149 		data->fxtal = div64_u64(fdco << 24, data->rfreq >> 4);  in si570_get_defaults()
151 		data->fxtal = div64_u64(fdco << 28, data->rfreq);  in si570_get_defaults()
153 	data->frequency = fout;  in si570_get_defaults()
159  * si570_update_rfreq() - Update clock multiplier
167 	reg[0] = ((data->n1 - 1) << 6) |  in si570_update_rfreq()
168 		((data->rfreq >> 32) & RFREQ_37_32_MASK);  in si570_update_rfreq()
169 	reg[1] = (data->rfreq >> 24) & 0xff;  in si570_update_rfreq()
170 	reg[2] = (data->rfreq >> 16) & 0xff;  in si570_update_rfreq()
171 	reg[3] = (data->rfreq >> 8) & 0xff;  in si570_update_rfreq()
172 	reg[4] = data->rfreq & 0xff;  in si570_update_rfreq()
174 	return regmap_bulk_write(data->regmap, SI570_REG_N1_RFREQ0 +  in si570_update_rfreq()
175 			data->div_offset, reg, ARRAY_SIZE(reg));  in si570_update_rfreq()
179  * si570_calc_divs() - Caluclate clock dividers
180  * @frequency:	Target frequency
183  * @out_n1:	Clock divider N1 (output)
184  * @out_hs_div:	Clock divider HSDIV (output)
187  * Calculate the clock dividers (@out_hs_div, @out_n1) and clock multiplier
188  * (@out_rfreq) for a given target @frequency.
190 static int si570_calc_divs(unsigned long frequency, struct clk_si570 *data,  in si570_calc_divs()  argument
201 		n1 = div_u64(div_u64(FDCO_MIN, hs_div), frequency);  in si570_calc_divs()
205 			fdco = (u64)frequency * (u64)hs_div * (u64)n1;  in si570_calc_divs()
211 				*out_rfreq = div64_u64(fdco << 28, data->fxtal);  in si570_calc_divs()
219 		return -EINVAL;  in si570_calc_divs()
234 		dev_err(&data->i2c_client->dev, "unable to recalc rate\n");  in si570_recalc_rate()
235 		return data->frequency;  in si570_recalc_rate()
239 	rate = (data->fxtal * rfreq) >> 28;  in si570_recalc_rate()
255 	if (div64_u64(abs(rate - data->frequency) * 10000LL,  in si570_round_rate()
256 				data->frequency) < 35) {  in si570_round_rate()
257 		rfreq = div64_u64((data->rfreq * rate) +  in si570_round_rate()
258 				div64_u64(data->frequency, 2), data->frequency);  in si570_round_rate()
259 		n1 = data->n1;  in si570_round_rate()
260 		hs_div = data->hs_div;  in si570_round_rate()
265 			dev_err(&data->i2c_client->dev,  in si570_round_rate()
275  * si570_set_frequency() - Adjust output frequency
277  * @frequency:	Target frequency
280  * Update output frequency for big frequency changes (> 3,500 ppm).
282 static int si570_set_frequency(struct clk_si570 *data, unsigned long frequency)  in si570_set_frequency()  argument
286 	err = si570_calc_divs(frequency, data, &data->rfreq, &data->n1,  in si570_set_frequency()
287 			&data->hs_div);  in si570_set_frequency()
292 	 * The DCO reg should be accessed with a read-modify-write operation  in si570_set_frequency()
295 	regmap_write(data->regmap, SI570_REG_FREEZE_DCO, SI570_FREEZE_DCO);  in si570_set_frequency()
296 	regmap_write(data->regmap, SI570_REG_HS_N1 + data->div_offset,  in si570_set_frequency()
297 			((data->hs_div - HS_DIV_OFFSET) << HS_DIV_SHIFT) |  in si570_set_frequency()
298 			(((data->n1 - 1) >> 2) & N1_6_2_MASK));  in si570_set_frequency()
300 	regmap_write(data->regmap, SI570_REG_FREEZE_DCO, 0);  in si570_set_frequency()
301 	regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_NEWFREQ);  in si570_set_frequency()
303 	/* Applying a new frequency can take up to 10ms */  in si570_set_frequency()
310  * si570_set_frequency_small() - Adjust output frequency
312  * @frequency:	Target frequency
315  * Update output frequency for small frequency changes (< 3,500 ppm).
318 				     unsigned long frequency)  in si570_set_frequency_small()  argument
321 	 * This is a re-implementation of DIV_ROUND_CLOSEST  in si570_set_frequency_small()
325 	data->rfreq = div64_u64((data->rfreq * frequency) +  in si570_set_frequency_small()
326 			div_u64(data->frequency, 2), data->frequency);  in si570_set_frequency_small()
327 	regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_FREEZE_M);  in si570_set_frequency_small()
329 	regmap_write(data->regmap, SI570_REG_CONTROL, 0);  in si570_set_frequency_small()
331 	/* Applying a new frequency (small change) can take up to 100us */  in si570_set_frequency_small()
341 	struct i2c_client *client = data->i2c_client;  in si570_set_rate()
344 	if (rate < SI570_MIN_FREQ || rate > data->max_freq) {  in si570_set_rate()
345 		dev_err(&client->dev,  in si570_set_rate()
346 			"requested frequency %lu Hz is out of range\n", rate);  in si570_set_rate()
347 		return -EINVAL;  in si570_set_rate()
350 	if (div64_u64(abs(rate - data->frequency) * 10000LL,  in si570_set_rate()
351 				data->frequency) < 35)  in si570_set_rate()
359 	data->frequency = rate;  in si570_set_rate()
418 	enum clk_si570_variant variant = id->driver_data;  in si570_probe()
420 	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);  in si570_probe()
422 		return -ENOMEM;  in si570_probe()
427 	data->hw.init = &init;  in si570_probe()
428 	data->i2c_client = client;  in si570_probe()
431 		err = of_property_read_u32(client->dev.of_node,  in si570_probe()
432 				"temperature-stability", &stability);  in si570_probe()
434 			dev_err(&client->dev,  in si570_probe()
435 				  "'temperature-stability' property missing\n");  in si570_probe()
440 			data->div_offset = SI570_DIV_OFFSET_7PPM;  in si570_probe()
442 		data->max_freq = SI570_MAX_FREQ;  in si570_probe()
444 		data->max_freq = SI598_MAX_FREQ;  in si570_probe()
447 	if (of_property_read_string(client->dev.of_node, "clock-output-names",  in si570_probe()
449 		init.name = client->dev.of_node->name;  in si570_probe()
451 	err = of_property_read_u32(client->dev.of_node, "factory-fout",  in si570_probe()
454 		dev_err(&client->dev, "'factory-fout' property missing\n");  in si570_probe()
458 	skip_recall = of_property_read_bool(client->dev.of_node,  in si570_probe()
459 					    "silabs,skip-recall");  in si570_probe()
461 	data->regmap = devm_regmap_init_i2c(client, &si570_regmap_config);  in si570_probe()
462 	if (IS_ERR(data->regmap)) {  in si570_probe()
463 		dev_err(&client->dev, "failed to allocate register map\n");  in si570_probe()
464 		return PTR_ERR(data->regmap);  in si570_probe()
472 	err = devm_clk_hw_register(&client->dev, &data->hw);  in si570_probe()
474 		dev_err(&client->dev, "clock registration failed\n");  in si570_probe()
477 	err = of_clk_add_hw_provider(client->dev.of_node, of_clk_hw_simple_get,  in si570_probe()
478 				     &data->hw);  in si570_probe()
480 		dev_err(&client->dev, "unable to add clk provider\n");  in si570_probe()
484 	/* Read the requested initial output frequency from device tree */  in si570_probe()
485 	if (!of_property_read_u32(client->dev.of_node, "clock-frequency",  in si570_probe()
487 		err = clk_set_rate(data->hw.clk, initial_fout);  in si570_probe()
489 			of_clk_del_provider(client->dev.of_node);  in si570_probe()
495 	dev_info(&client->dev, "registered, current frequency %llu Hz\n",  in si570_probe()
496 			data->frequency);  in si570_probe()
503 	of_clk_del_provider(client->dev.of_node);  in si570_remove()