1 // SPDX-License-Identifier: GPL-2.0+
3  * Raspberry Pi driver for firmware controlled clocks
5  * Even though clk-bcm2835 provides an interface to the hardware registers for
6  * the system clocks we've had to factor out 'pllb' as the firmware 'owns' it.
8  * over-temperature and under-voltage protections provided by the firmware.
14 #include <linux/clk-provider.h>
19 #include <soc/bcm2835/raspberrypi-firmware.h>
35 	[RPI_FIRMWARE_PIXEL_BVB_CLK_ID]	= "pixel-bvb",
47 	struct rpi_firmware *firmware;  member
99 		 * HDMI connector, the firmware will skip the HSM
150  * Structure of the message passed to Raspberry Pi's firmware in order to
156  * use the firmware interface as the firmware ultimately takes care of
160  * For more information on the firmware interface check:
161  * https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface
169 static int raspberrypi_clock_property(struct rpi_firmware *firmware,  in raspberrypi_clock_property()  argument
174 		.id = cpu_to_le32(data->id),  in raspberrypi_clock_property()
179 	ret = rpi_firmware_property(firmware, tag, &msg, sizeof(msg));  in raspberrypi_clock_property()
191 	struct raspberrypi_clk *rpi = data->rpi;  in raspberrypi_fw_is_prepared()
195 	ret = raspberrypi_clock_property(rpi->firmware, data,  in raspberrypi_fw_is_prepared()
208 	struct raspberrypi_clk *rpi = data->rpi;  in raspberrypi_fw_get_rate()
212 	ret = raspberrypi_clock_property(rpi->firmware, data,  in raspberrypi_fw_get_rate()
224 	struct raspberrypi_clk *rpi = data->rpi;  in raspberrypi_fw_set_rate()
228 	ret = raspberrypi_clock_property(rpi->firmware, data,  in raspberrypi_fw_set_rate()
231 		dev_err_ratelimited(rpi->dev, "Failed to change %s frequency: %d\n",  in raspberrypi_fw_set_rate()
241 	struct raspberrypi_clk_variant *variant = data->variant;  in raspberrypi_fw_dumb_determine_rate()
244 	 * The firmware will do the rounding but that isn't part of  in raspberrypi_fw_dumb_determine_rate()
245 	 * the interface with the firmware, so we just do our best  in raspberrypi_fw_dumb_determine_rate()
249 	req->rate = clamp(req->rate, req->min_rate, req->max_rate);  in raspberrypi_fw_dumb_determine_rate()
256 	if (variant->minimize && req->min_rate > 0)  in raspberrypi_fw_dumb_determine_rate()
257 		req->rate = req->min_rate;  in raspberrypi_fw_dumb_determine_rate()
279 	data = devm_kzalloc(rpi->dev, sizeof(*data), GFP_KERNEL);  in raspberrypi_clk_register()
281 		return ERR_PTR(-ENOMEM);  in raspberrypi_clk_register()
282 	data->rpi = rpi;  in raspberrypi_clk_register()
283 	data->id = id;  in raspberrypi_clk_register()
284 	data->variant = variant;  in raspberrypi_clk_register()
286 	init.name = devm_kasprintf(rpi->dev, GFP_KERNEL,  in raspberrypi_clk_register()
287 				   "fw-clk-%s",  in raspberrypi_clk_register()
292 	data->hw.init = &init;  in raspberrypi_clk_register()
294 	ret = raspberrypi_clock_property(rpi->firmware, data,  in raspberrypi_clk_register()
298 		dev_err(rpi->dev, "Failed to get clock %d min freq: %d\n",  in raspberrypi_clk_register()
303 	ret = raspberrypi_clock_property(rpi->firmware, data,  in raspberrypi_clk_register()
307 		dev_err(rpi->dev, "Failed to get clock %d max freq: %d\n",  in raspberrypi_clk_register()
312 	ret = devm_clk_hw_register(rpi->dev, &data->hw);  in raspberrypi_clk_register()
316 	clk_hw_set_rate_range(&data->hw, min_rate, max_rate);  in raspberrypi_clk_register()
318 	if (variant->clkdev) {  in raspberrypi_clk_register()
319 		ret = devm_clk_hw_register_clkdev(rpi->dev, &data->hw,  in raspberrypi_clk_register()
320 						  NULL, variant->clkdev);  in raspberrypi_clk_register()
322 			dev_err(rpi->dev, "Failed to initialize clkdev\n");  in raspberrypi_clk_register()
327 	if (variant->min_rate) {  in raspberrypi_clk_register()
330 		clk_hw_set_rate_range(&data->hw, variant->min_rate, max_rate);  in raspberrypi_clk_register()
332 		rate = raspberrypi_fw_get_rate(&data->hw, 0);  in raspberrypi_clk_register()
333 		if (rate < variant->min_rate) {  in raspberrypi_clk_register()
334 			ret = raspberrypi_fw_set_rate(&data->hw, variant->min_rate, 0);  in raspberrypi_clk_register()
340 	return &data->hw;  in raspberrypi_clk_register()
355 	 * The firmware doesn't guarantee that the last element of  in raspberrypi_discover_clocks()
359 	clks = devm_kcalloc(rpi->dev,  in raspberrypi_discover_clocks()
363 		return -ENOMEM;  in raspberrypi_discover_clocks()
365 	ret = rpi_firmware_property(rpi->firmware, RPI_FIRMWARE_GET_CLOCKS,  in raspberrypi_discover_clocks()
371 	while (clks->id) {  in raspberrypi_discover_clocks()
374 		if (clks->id >= RPI_FIRMWARE_NUM_CLK_ID) {  in raspberrypi_discover_clocks()
375 			dev_err(rpi->dev, "Unknown clock id: %u (max: %u)\n",  in raspberrypi_discover_clocks()
376 					   clks->id, RPI_FIRMWARE_NUM_CLK_ID - 1);  in raspberrypi_discover_clocks()
377 			return -EINVAL;  in raspberrypi_discover_clocks()
380 		variant = &raspberrypi_clk_variants[clks->id];  in raspberrypi_discover_clocks()
381 		if (variant->export) {  in raspberrypi_discover_clocks()
384 			hw = raspberrypi_clk_register(rpi, clks->parent,  in raspberrypi_discover_clocks()
385 						      clks->id, variant);  in raspberrypi_discover_clocks()
389 			data->num = clks->id + 1;  in raspberrypi_discover_clocks()
390 			data->hws[clks->id] = hw;  in raspberrypi_discover_clocks()
403 	struct device *dev = &pdev->dev;  in raspberrypi_clk_probe()
404 	struct rpi_firmware *firmware;  in raspberrypi_clk_probe()  local
409 	 * We can be probed either through the an old-fashioned  in raspberrypi_clk_probe()
411 	 * child of the firmware node. Handle both cases.  in raspberrypi_clk_probe()
413 	if (dev->of_node)  in raspberrypi_clk_probe()
414 		firmware_node = of_get_parent(dev->of_node);  in raspberrypi_clk_probe()
417 							"raspberrypi,bcm2835-firmware");  in raspberrypi_clk_probe()
419 		dev_err(dev, "Missing firmware node\n");  in raspberrypi_clk_probe()
420 		return -ENOENT;  in raspberrypi_clk_probe()
423 	firmware = devm_rpi_firmware_get(&pdev->dev, firmware_node);  in raspberrypi_clk_probe()
425 	if (!firmware)  in raspberrypi_clk_probe()
426 		return -EPROBE_DEFER;  in raspberrypi_clk_probe()
430 		return -ENOMEM;  in raspberrypi_clk_probe()
432 	rpi->dev = dev;  in raspberrypi_clk_probe()
433 	rpi->firmware = firmware;  in raspberrypi_clk_probe()
440 		return -ENOMEM;  in raspberrypi_clk_probe()
451 	rpi->cpufreq = platform_device_register_data(dev, "raspberrypi-cpufreq",  in raspberrypi_clk_probe()
452 						     -1, NULL, 0);  in raspberrypi_clk_probe()
461 	platform_device_unregister(rpi->cpufreq);  in raspberrypi_clk_remove()
465 	{ .compatible = "raspberrypi,firmware-clocks" },
472 		.name = "raspberrypi-clk",
481 MODULE_DESCRIPTION("Raspberry Pi firmware clock driver");
483 MODULE_ALIAS("platform:raspberrypi-clk");