1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Clk driver for NXP LPC18xx/LPC43xx Clock Control Unit (CCU)
4  *
5  * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
6  */
7 
8 #include <linux/clk.h>
9 #include <linux/clk-provider.h>
10 #include <linux/io.h>
11 #include <linux/kernel.h>
12 #include <linux/of.h>
13 #include <linux/of_address.h>
14 #include <linux/slab.h>
15 #include <linux/string.h>
16 
17 #include <dt-bindings/clock/lpc18xx-ccu.h>
18 
19 /* Bit defines for CCU branch configuration register */
20 #define LPC18XX_CCU_RUN		BIT(0)
21 #define LPC18XX_CCU_AUTO	BIT(1)
22 #define LPC18XX_CCU_DIV		BIT(5)
23 #define LPC18XX_CCU_DIVSTAT	BIT(27)
24 
25 /* CCU branch feature bits */
26 #define CCU_BRANCH_IS_BUS	BIT(0)
27 #define CCU_BRANCH_HAVE_DIV2	BIT(1)
28 
29 struct lpc18xx_branch_clk_data {
30 	const char **name;
31 	int num;
32 };
33 
34 struct lpc18xx_clk_branch {
35 	const char *base_name;
36 	const char *name;
37 	u16 offset;
38 	u16 flags;
39 	struct clk *clk;
40 	struct clk_gate gate;
41 };
42 
43 static struct lpc18xx_clk_branch clk_branches[] = {
44 	{"base_apb3_clk", "apb3_bus",		CLK_APB3_BUS,		CCU_BRANCH_IS_BUS},
45 	{"base_apb3_clk", "apb3_i2c1",		CLK_APB3_I2C1,		0},
46 	{"base_apb3_clk", "apb3_dac",		CLK_APB3_DAC,		0},
47 	{"base_apb3_clk", "apb3_adc0",		CLK_APB3_ADC0,		0},
48 	{"base_apb3_clk", "apb3_adc1",		CLK_APB3_ADC1,		0},
49 	{"base_apb3_clk", "apb3_can0",		CLK_APB3_CAN0,		0},
50 
51 	{"base_apb1_clk", "apb1_bus",		CLK_APB1_BUS,		CCU_BRANCH_IS_BUS},
52 	{"base_apb1_clk", "apb1_mc_pwm",	CLK_APB1_MOTOCON_PWM,	0},
53 	{"base_apb1_clk", "apb1_i2c0",		CLK_APB1_I2C0,		0},
54 	{"base_apb1_clk", "apb1_i2s",		CLK_APB1_I2S,		0},
55 	{"base_apb1_clk", "apb1_can1",		CLK_APB1_CAN1,		0},
56 
57 	{"base_spifi_clk", "spifi",		CLK_SPIFI,		0},
58 
59 	{"base_cpu_clk", "cpu_bus",		CLK_CPU_BUS,		CCU_BRANCH_IS_BUS},
60 	{"base_cpu_clk", "cpu_spifi",		CLK_CPU_SPIFI,		0},
61 	{"base_cpu_clk", "cpu_gpio",		CLK_CPU_GPIO,		0},
62 	{"base_cpu_clk", "cpu_lcd",		CLK_CPU_LCD,		0},
63 	{"base_cpu_clk", "cpu_ethernet",	CLK_CPU_ETHERNET,	0},
64 	{"base_cpu_clk", "cpu_usb0",		CLK_CPU_USB0,		0},
65 	{"base_cpu_clk", "cpu_emc",		CLK_CPU_EMC,		0},
66 	{"base_cpu_clk", "cpu_sdio",		CLK_CPU_SDIO,		0},
67 	{"base_cpu_clk", "cpu_dma",		CLK_CPU_DMA,		0},
68 	{"base_cpu_clk", "cpu_core",		CLK_CPU_CORE,		0},
69 	{"base_cpu_clk", "cpu_sct",		CLK_CPU_SCT,		0},
70 	{"base_cpu_clk", "cpu_usb1",		CLK_CPU_USB1,		0},
71 	{"base_cpu_clk", "cpu_emcdiv",		CLK_CPU_EMCDIV,		CCU_BRANCH_HAVE_DIV2},
72 	{"base_cpu_clk", "cpu_flasha",		CLK_CPU_FLASHA,		CCU_BRANCH_HAVE_DIV2},
73 	{"base_cpu_clk", "cpu_flashb",		CLK_CPU_FLASHB,		CCU_BRANCH_HAVE_DIV2},
74 	{"base_cpu_clk", "cpu_m0app",		CLK_CPU_M0APP,		CCU_BRANCH_HAVE_DIV2},
75 	{"base_cpu_clk", "cpu_adchs",		CLK_CPU_ADCHS,		CCU_BRANCH_HAVE_DIV2},
76 	{"base_cpu_clk", "cpu_eeprom",		CLK_CPU_EEPROM,		CCU_BRANCH_HAVE_DIV2},
77 	{"base_cpu_clk", "cpu_wwdt",		CLK_CPU_WWDT,		0},
78 	{"base_cpu_clk", "cpu_uart0",		CLK_CPU_UART0,		0},
79 	{"base_cpu_clk", "cpu_uart1",		CLK_CPU_UART1,		0},
80 	{"base_cpu_clk", "cpu_ssp0",		CLK_CPU_SSP0,		0},
81 	{"base_cpu_clk", "cpu_timer0",		CLK_CPU_TIMER0,		0},
82 	{"base_cpu_clk", "cpu_timer1",		CLK_CPU_TIMER1,		0},
83 	{"base_cpu_clk", "cpu_scu",		CLK_CPU_SCU,		0},
84 	{"base_cpu_clk", "cpu_creg",		CLK_CPU_CREG,		0},
85 	{"base_cpu_clk", "cpu_ritimer",		CLK_CPU_RITIMER,	0},
86 	{"base_cpu_clk", "cpu_uart2",		CLK_CPU_UART2,		0},
87 	{"base_cpu_clk", "cpu_uart3",		CLK_CPU_UART3,		0},
88 	{"base_cpu_clk", "cpu_timer2",		CLK_CPU_TIMER2,		0},
89 	{"base_cpu_clk", "cpu_timer3",		CLK_CPU_TIMER3,		0},
90 	{"base_cpu_clk", "cpu_ssp1",		CLK_CPU_SSP1,		0},
91 	{"base_cpu_clk", "cpu_qei",		CLK_CPU_QEI,		0},
92 
93 	{"base_periph_clk", "periph_bus",	CLK_PERIPH_BUS,		CCU_BRANCH_IS_BUS},
94 	{"base_periph_clk", "periph_core",	CLK_PERIPH_CORE,	0},
95 	{"base_periph_clk", "periph_sgpio",	CLK_PERIPH_SGPIO,	0},
96 
97 	{"base_usb0_clk",  "usb0",		CLK_USB0,		0},
98 	{"base_usb1_clk",  "usb1",		CLK_USB1,		0},
99 	{"base_spi_clk",   "spi",		CLK_SPI,		0},
100 	{"base_adchs_clk", "adchs",		CLK_ADCHS,		0},
101 
102 	{"base_audio_clk", "audio",		CLK_AUDIO,		0},
103 	{"base_uart3_clk", "apb2_uart3",	CLK_APB2_UART3,		0},
104 	{"base_uart2_clk", "apb2_uart2",	CLK_APB2_UART2,		0},
105 	{"base_uart1_clk", "apb0_uart1",	CLK_APB0_UART1,		0},
106 	{"base_uart0_clk", "apb0_uart0",	CLK_APB0_UART0,		0},
107 	{"base_ssp1_clk",  "apb2_ssp1",		CLK_APB2_SSP1,		0},
108 	{"base_ssp0_clk",  "apb0_ssp0",		CLK_APB0_SSP0,		0},
109 	{"base_sdio_clk",  "sdio",		CLK_SDIO,		0},
110 };
111 
lpc18xx_ccu_branch_clk_get(struct of_phandle_args * clkspec,void * data)112 static struct clk *lpc18xx_ccu_branch_clk_get(struct of_phandle_args *clkspec,
113 					      void *data)
114 {
115 	struct lpc18xx_branch_clk_data *clk_data = data;
116 	unsigned int offset = clkspec->args[0];
117 	int i, j;
118 
119 	for (i = 0; i < ARRAY_SIZE(clk_branches); i++) {
120 		if (clk_branches[i].offset != offset)
121 			continue;
122 
123 		for (j = 0; j < clk_data->num; j++) {
124 			if (!strcmp(clk_branches[i].base_name, clk_data->name[j]))
125 				return clk_branches[i].clk;
126 		}
127 	}
128 
129 	pr_err("%s: invalid clock offset %d\n", __func__, offset);
130 
131 	return ERR_PTR(-EINVAL);
132 }
133 
lpc18xx_ccu_gate_endisable(struct clk_hw * hw,bool enable)134 static int lpc18xx_ccu_gate_endisable(struct clk_hw *hw, bool enable)
135 {
136 	struct clk_gate *gate = to_clk_gate(hw);
137 	u32 val;
138 
139 	/*
140 	 * Divider field is write only, so divider stat field must
141 	 * be read so divider field can be set accordingly.
142 	 */
143 	val = readl(gate->reg);
144 	if (val & LPC18XX_CCU_DIVSTAT)
145 		val |= LPC18XX_CCU_DIV;
146 
147 	if (enable) {
148 		val |= LPC18XX_CCU_RUN;
149 	} else {
150 		/*
151 		 * To safely disable a branch clock a squence of two separate
152 		 * writes must be used. First write should set the AUTO bit
153 		 * and the next write should clear the RUN bit.
154 		 */
155 		val |= LPC18XX_CCU_AUTO;
156 		writel(val, gate->reg);
157 
158 		val &= ~LPC18XX_CCU_RUN;
159 	}
160 
161 	writel(val, gate->reg);
162 
163 	return 0;
164 }
165 
lpc18xx_ccu_gate_enable(struct clk_hw * hw)166 static int lpc18xx_ccu_gate_enable(struct clk_hw *hw)
167 {
168 	return lpc18xx_ccu_gate_endisable(hw, true);
169 }
170 
lpc18xx_ccu_gate_disable(struct clk_hw * hw)171 static void lpc18xx_ccu_gate_disable(struct clk_hw *hw)
172 {
173 	lpc18xx_ccu_gate_endisable(hw, false);
174 }
175 
lpc18xx_ccu_gate_is_enabled(struct clk_hw * hw)176 static int lpc18xx_ccu_gate_is_enabled(struct clk_hw *hw)
177 {
178 	const struct clk_hw *parent;
179 
180 	/*
181 	 * The branch clock registers are only accessible
182 	 * if the base (parent) clock is enabled. Register
183 	 * access with a disabled base clock will hang the
184 	 * system.
185 	 */
186 	parent = clk_hw_get_parent(hw);
187 	if (!parent)
188 		return 0;
189 
190 	if (!clk_hw_is_enabled(parent))
191 		return 0;
192 
193 	return clk_gate_ops.is_enabled(hw);
194 }
195 
196 static const struct clk_ops lpc18xx_ccu_gate_ops = {
197 	.enable		= lpc18xx_ccu_gate_enable,
198 	.disable	= lpc18xx_ccu_gate_disable,
199 	.is_enabled	= lpc18xx_ccu_gate_is_enabled,
200 };
201 
lpc18xx_ccu_register_branch_gate_div(struct lpc18xx_clk_branch * branch,void __iomem * reg_base,const char * parent)202 static void lpc18xx_ccu_register_branch_gate_div(struct lpc18xx_clk_branch *branch,
203 						 void __iomem *reg_base,
204 						 const char *parent)
205 {
206 	const struct clk_ops *div_ops = NULL;
207 	struct clk_divider *div = NULL;
208 	struct clk_hw *div_hw = NULL;
209 
210 	if (branch->flags & CCU_BRANCH_HAVE_DIV2) {
211 		div = kzalloc(sizeof(*div), GFP_KERNEL);
212 		if (!div)
213 			return;
214 
215 		div->reg = branch->offset + reg_base;
216 		div->flags = CLK_DIVIDER_READ_ONLY;
217 		div->shift = 27;
218 		div->width = 1;
219 
220 		div_hw = &div->hw;
221 		div_ops = &clk_divider_ro_ops;
222 	}
223 
224 	branch->gate.reg = branch->offset + reg_base;
225 	branch->gate.bit_idx = 0;
226 
227 	branch->clk = clk_register_composite(NULL, branch->name, &parent, 1,
228 					     NULL, NULL,
229 					     div_hw, div_ops,
230 					     &branch->gate.hw, &lpc18xx_ccu_gate_ops, 0);
231 	if (IS_ERR(branch->clk)) {
232 		kfree(div);
233 		pr_warn("%s: failed to register %s\n", __func__, branch->name);
234 		return;
235 	}
236 
237 	/* Grab essential branch clocks for CPU and SDRAM */
238 	switch (branch->offset) {
239 	case CLK_CPU_EMC:
240 	case CLK_CPU_CORE:
241 	case CLK_CPU_CREG:
242 	case CLK_CPU_EMCDIV:
243 		clk_prepare_enable(branch->clk);
244 	}
245 }
246 
lpc18xx_ccu_register_branch_clks(void __iomem * reg_base,const char * base_name)247 static void lpc18xx_ccu_register_branch_clks(void __iomem *reg_base,
248 					     const char *base_name)
249 {
250 	const char *parent = base_name;
251 	int i;
252 
253 	for (i = 0; i < ARRAY_SIZE(clk_branches); i++) {
254 		if (strcmp(clk_branches[i].base_name, base_name))
255 			continue;
256 
257 		lpc18xx_ccu_register_branch_gate_div(&clk_branches[i], reg_base,
258 						     parent);
259 
260 		if (clk_branches[i].flags & CCU_BRANCH_IS_BUS)
261 			parent = clk_branches[i].name;
262 	}
263 }
264 
lpc18xx_ccu_init(struct device_node * np)265 static void __init lpc18xx_ccu_init(struct device_node *np)
266 {
267 	struct lpc18xx_branch_clk_data *clk_data;
268 	void __iomem *reg_base;
269 	int i, ret;
270 
271 	reg_base = of_iomap(np, 0);
272 	if (!reg_base) {
273 		pr_warn("%s: failed to map address range\n", __func__);
274 		return;
275 	}
276 
277 	clk_data = kzalloc(sizeof(*clk_data), GFP_KERNEL);
278 	if (!clk_data) {
279 		iounmap(reg_base);
280 		return;
281 	}
282 
283 	clk_data->num = of_property_count_strings(np, "clock-names");
284 	clk_data->name = kcalloc(clk_data->num, sizeof(char *), GFP_KERNEL);
285 	if (!clk_data->name) {
286 		iounmap(reg_base);
287 		kfree(clk_data);
288 		return;
289 	}
290 
291 	for (i = 0; i < clk_data->num; i++) {
292 		ret = of_property_read_string_index(np, "clock-names", i,
293 						    &clk_data->name[i]);
294 		if (ret) {
295 			pr_warn("%s: failed to get clock name at idx %d\n",
296 				__func__, i);
297 			continue;
298 		}
299 
300 		lpc18xx_ccu_register_branch_clks(reg_base, clk_data->name[i]);
301 	}
302 
303 	of_clk_add_provider(np, lpc18xx_ccu_branch_clk_get, clk_data);
304 }
305 CLK_OF_DECLARE(lpc18xx_ccu, "nxp,lpc1850-ccu", lpc18xx_ccu_init);
306