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>
53 	[RPI_FIRMWARE_PIXEL_BVB_CLK_ID]	= "pixel-bvb",
61 	struct rpi_firmware *firmware;  member
74  * Structure of the message passed to Raspberry Pi's firmware in order to
80  * use the firmware interface as the firmware ultimately takes care of
84  * For more information on the firmware interface check:
85  * https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface
93 static int raspberrypi_clock_property(struct rpi_firmware *firmware,  in raspberrypi_clock_property()  argument
98 		.id = cpu_to_le32(data->id),  in raspberrypi_clock_property()
104 	ret = rpi_firmware_property(firmware, tag, &msg, sizeof(msg));  in raspberrypi_clock_property()
117 	struct raspberrypi_clk *rpi = data->rpi;  in raspberrypi_fw_is_prepared()
121 	ret = raspberrypi_clock_property(rpi->firmware, data,  in raspberrypi_fw_is_prepared()
135 	struct raspberrypi_clk *rpi = data->rpi;  in raspberrypi_fw_get_rate()
139 	ret = raspberrypi_clock_property(rpi->firmware, data,  in raspberrypi_fw_get_rate()
152 	struct raspberrypi_clk *rpi = data->rpi;  in raspberrypi_fw_set_rate()
156 	ret = raspberrypi_clock_property(rpi->firmware, data,  in raspberrypi_fw_set_rate()
159 		dev_err_ratelimited(rpi->dev, "Failed to change %s frequency: %d",  in raspberrypi_fw_set_rate()
169 	 * The firmware will do the rounding but that isn't part of  in raspberrypi_fw_dumb_determine_rate()
170 	 * the interface with the firmware, so we just do our best  in raspberrypi_fw_dumb_determine_rate()
173 	req->rate = clamp(req->rate, req->min_rate, req->max_rate);  in raspberrypi_fw_dumb_determine_rate()
193 	data = devm_kzalloc(rpi->dev, sizeof(*data), GFP_KERNEL);  in raspberrypi_clk_register()
195 		return ERR_PTR(-ENOMEM);  in raspberrypi_clk_register()
196 	data->rpi = rpi;  in raspberrypi_clk_register()
197 	data->id = id;  in raspberrypi_clk_register()
199 	init.name = devm_kasprintf(rpi->dev, GFP_KERNEL,  in raspberrypi_clk_register()
200 				   "fw-clk-%s",  in raspberrypi_clk_register()
205 	data->hw.init = &init;  in raspberrypi_clk_register()
207 	ret = raspberrypi_clock_property(rpi->firmware, data,  in raspberrypi_clk_register()
211 		dev_err(rpi->dev, "Failed to get clock %d min freq: %d",  in raspberrypi_clk_register()
216 	ret = raspberrypi_clock_property(rpi->firmware, data,  in raspberrypi_clk_register()
220 		dev_err(rpi->dev, "Failed to get clock %d max freq: %d\n",  in raspberrypi_clk_register()
225 	ret = devm_clk_hw_register(rpi->dev, &data->hw);  in raspberrypi_clk_register()
229 	clk_hw_set_rate_range(&data->hw, min_rate, max_rate);  in raspberrypi_clk_register()
232 		ret = devm_clk_hw_register_clkdev(rpi->dev, &data->hw,  in raspberrypi_clk_register()
235 			dev_err(rpi->dev, "Failed to initialize clkdev\n");  in raspberrypi_clk_register()
240 	return &data->hw;  in raspberrypi_clk_register()
254 	clks = devm_kcalloc(rpi->dev,  in raspberrypi_discover_clocks()
258 		return -ENOMEM;  in raspberrypi_discover_clocks()
260 	ret = rpi_firmware_property(rpi->firmware, RPI_FIRMWARE_GET_CLOCKS,  in raspberrypi_discover_clocks()
266 	while (clks->id) {  in raspberrypi_discover_clocks()
269 		switch (clks->id) {  in raspberrypi_discover_clocks()
275 			hw = raspberrypi_clk_register(rpi, clks->parent,  in raspberrypi_discover_clocks()
276 						      clks->id);  in raspberrypi_discover_clocks()
280 			data->hws[clks->id] = hw;  in raspberrypi_discover_clocks()
281 			data->num = clks->id + 1;  in raspberrypi_discover_clocks()
297 	struct device *dev = &pdev->dev;  in raspberrypi_clk_probe()
298 	struct rpi_firmware *firmware;  in raspberrypi_clk_probe()  local
303 	 * We can be probed either through the an old-fashioned  in raspberrypi_clk_probe()
305 	 * child of the firmware node. Handle both cases.  in raspberrypi_clk_probe()
307 	if (dev->of_node)  in raspberrypi_clk_probe()
308 		firmware_node = of_get_parent(dev->of_node);  in raspberrypi_clk_probe()
311 							"raspberrypi,bcm2835-firmware");  in raspberrypi_clk_probe()
313 		dev_err(dev, "Missing firmware node\n");  in raspberrypi_clk_probe()
314 		return -ENOENT;  in raspberrypi_clk_probe()
317 	firmware = rpi_firmware_get(firmware_node);  in raspberrypi_clk_probe()
319 	if (!firmware)  in raspberrypi_clk_probe()
320 		return -EPROBE_DEFER;  in raspberrypi_clk_probe()
324 		return -ENOMEM;  in raspberrypi_clk_probe()
326 	rpi->dev = dev;  in raspberrypi_clk_probe()
327 	rpi->firmware = firmware;  in raspberrypi_clk_probe()
334 		return -ENOMEM;  in raspberrypi_clk_probe()
345 	rpi->cpufreq = platform_device_register_data(dev, "raspberrypi-cpufreq",  in raspberrypi_clk_probe()
346 						     -1, NULL, 0);  in raspberrypi_clk_probe()
355 	platform_device_unregister(rpi->cpufreq);  in raspberrypi_clk_remove()
361 	{ .compatible = "raspberrypi,firmware-clocks" },
368 		.name = "raspberrypi-clk",
377 MODULE_DESCRIPTION("Raspberry Pi firmware clock driver");
379 MODULE_ALIAS("platform:raspberrypi-clk");