drivers/clk/nxp/clk-lpc18xx-ccu.c

   1 /*
   2  * Clk driver for NXP LPC18xx/LPC43xx Clock Control Unit (CCU)
   3  *
   4  * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
   5  *
   6  * This file is licensed under the terms of the GNU General Public
   7  * License version 2. This program is licensed "as is" without any
   8  * warranty of any kind, whether express or implied.
   9  */
  10
  11 #include <linux/clk.h>
  12 #include <linux/clk-provider.h>
  13 #include <linux/io.h>
  14 #include <linux/kernel.h>
  15 #include <linux/of.h>
  16 #include <linux/of_address.h>
  17 #include <linux/slab.h>
  18 #include <linux/string.h>
  19
  20 #include <dt-bindings/clock/lpc18xx-ccu.h>
  21
  22 /* Bit defines for CCU branch configuration register */
  23 #define LPC18XX_CCU_RUN         BIT(0)
  24 #define LPC18XX_CCU_AUTO        BIT(1)
  25 #define LPC18XX_CCU_DIV         BIT(5)
  26 #define LPC18XX_CCU_DIVSTAT     BIT(27)
  27
  28 /* CCU branch feature bits */
  29 #define CCU_BRANCH_IS_BUS       BIT(0)
  30 #define CCU_BRANCH_HAVE_DIV2    BIT(1)
  31
  32 struct lpc18xx_branch_clk_data {
  33         const char **name;
  34         int num;
  35 };
  36
  37 struct lpc18xx_clk_branch {
  38         const char *base_name;
  39         const char *name;
  40         u16 offset;
  41         u16 flags;
  42         struct clk *clk;
  43         struct clk_gate gate;
  44 };
  45
  46 static struct lpc18xx_clk_branch clk_branches[] = {
  47         {"base_apb3_clk", "apb3_bus",           CLK_APB3_BUS,           CCU_BRANCH_IS_BUS},
  48         {"base_apb3_clk", "apb3_i2c1",          CLK_APB3_I2C1,          0},
  49         {"base_apb3_clk", "apb3_dac",           CLK_APB3_DAC,           0},
  50         {"base_apb3_clk", "apb3_adc0",          CLK_APB3_ADC0,          0},
  51         {"base_apb3_clk", "apb3_adc1",          CLK_APB3_ADC1,          0},
  52         {"base_apb3_clk", "apb3_can0",          CLK_APB3_CAN0,          0},
  53
  54         {"base_apb1_clk", "apb1_bus",           CLK_APB1_BUS,           CCU_BRANCH_IS_BUS},
  55         {"base_apb1_clk", "apb1_mc_pwm",        CLK_APB1_MOTOCON_PWM,   0},
  56         {"base_apb1_clk", "apb1_i2c0",          CLK_APB1_I2C0,          0},
  57         {"base_apb1_clk", "apb1_i2s",           CLK_APB1_I2S,           0},
  58         {"base_apb1_clk", "apb1_can1",          CLK_APB1_CAN1,          0},
  59
  60         {"base_spifi_clk", "spifi",             CLK_SPIFI,              0},
  61
  62         {"base_cpu_clk", "cpu_bus",             CLK_CPU_BUS,            CCU_BRANCH_IS_BUS},
  63         {"base_cpu_clk", "cpu_spifi",           CLK_CPU_SPIFI,          0},
  64         {"base_cpu_clk", "cpu_gpio",            CLK_CPU_GPIO,           0},
  65         {"base_cpu_clk", "cpu_lcd",             CLK_CPU_LCD,            0},
  66         {"base_cpu_clk", "cpu_ethernet",        CLK_CPU_ETHERNET,       0},
  67         {"base_cpu_clk", "cpu_usb0",            CLK_CPU_USB0,           0},
  68         {"base_cpu_clk", "cpu_emc",             CLK_CPU_EMC,            0},
  69         {"base_cpu_clk", "cpu_sdio",            CLK_CPU_SDIO,           0},
  70         {"base_cpu_clk", "cpu_dma",             CLK_CPU_DMA,            0},
  71         {"base_cpu_clk", "cpu_core",            CLK_CPU_CORE,           0},
  72         {"base_cpu_clk", "cpu_sct",             CLK_CPU_SCT,            0},
  73         {"base_cpu_clk", "cpu_usb1",            CLK_CPU_USB1,           0},
  74         {"base_cpu_clk", "cpu_emcdiv",          CLK_CPU_EMCDIV,         CCU_BRANCH_HAVE_DIV2},
  75         {"base_cpu_clk", "cpu_flasha",          CLK_CPU_FLASHA,         CCU_BRANCH_HAVE_DIV2},
  76         {"base_cpu_clk", "cpu_flashb",          CLK_CPU_FLASHB,         CCU_BRANCH_HAVE_DIV2},
  77         {"base_cpu_clk", "cpu_m0app",           CLK_CPU_M0APP,          CCU_BRANCH_HAVE_DIV2},
  78         {"base_cpu_clk", "cpu_adchs",           CLK_CPU_ADCHS,          CCU_BRANCH_HAVE_DIV2},
  79         {"base_cpu_clk", "cpu_eeprom",          CLK_CPU_EEPROM,         CCU_BRANCH_HAVE_DIV2},
  80         {"base_cpu_clk", "cpu_wwdt",            CLK_CPU_WWDT,           0},
  81         {"base_cpu_clk", "cpu_uart0",           CLK_CPU_UART0,          0},
  82         {"base_cpu_clk", "cpu_uart1",           CLK_CPU_UART1,          0},
  83         {"base_cpu_clk", "cpu_ssp0",            CLK_CPU_SSP0,           0},
  84         {"base_cpu_clk", "cpu_timer0",          CLK_CPU_TIMER0,         0},
  85         {"base_cpu_clk", "cpu_timer1",          CLK_CPU_TIMER1,         0},
  86         {"base_cpu_clk", "cpu_scu",             CLK_CPU_SCU,            0},
  87         {"base_cpu_clk", "cpu_creg",            CLK_CPU_CREG,           0},
  88         {"base_cpu_clk", "cpu_ritimer",         CLK_CPU_RITIMER,        0},
  89         {"base_cpu_clk", "cpu_uart2",           CLK_CPU_UART2,          0},
  90         {"base_cpu_clk", "cpu_uart3",           CLK_CPU_UART3,          0},
  91         {"base_cpu_clk", "cpu_timer2",          CLK_CPU_TIMER2,         0},
  92         {"base_cpu_clk", "cpu_timer3",          CLK_CPU_TIMER3,         0},
  93         {"base_cpu_clk", "cpu_ssp1",            CLK_CPU_SSP1,           0},
  94         {"base_cpu_clk", "cpu_qei",             CLK_CPU_QEI,            0},
  95
  96         {"base_periph_clk", "periph_bus",       CLK_PERIPH_BUS,         CCU_BRANCH_IS_BUS},
  97         {"base_periph_clk", "periph_core",      CLK_PERIPH_CORE,        0},
  98         {"base_periph_clk", "periph_sgpio",     CLK_PERIPH_SGPIO,       0},
  99
 100         {"base_usb0_clk",  "usb0",              CLK_USB0,               0},
 101         {"base_usb1_clk",  "usb1",              CLK_USB1,               0},
 102         {"base_spi_clk",   "spi",               CLK_SPI,                0},
 103         {"base_adchs_clk", "adchs",             CLK_ADCHS,              0},
 104
 105         {"base_audio_clk", "audio",             CLK_AUDIO,              0},
 106         {"base_uart3_clk", "apb2_uart3",        CLK_APB2_UART3,         0},
 107         {"base_uart2_clk", "apb2_uart2",        CLK_APB2_UART2,         0},
 108         {"base_uart1_clk", "apb0_uart1",        CLK_APB0_UART1,         0},
 109         {"base_uart0_clk", "apb0_uart0",        CLK_APB0_UART0,         0},
 110         {"base_ssp1_clk",  "apb2_ssp1",         CLK_APB2_SSP1,          0},
 111         {"base_ssp0_clk",  "apb0_ssp0",         CLK_APB0_SSP0,          0},
 112         {"base_sdio_clk",  "sdio",              CLK_SDIO,               0},
 113 };
 114
 115 static struct clk *lpc18xx_ccu_branch_clk_get(struct of_phandle_args *clkspec,
 116                                               void *data)
 117 {
 118         struct lpc18xx_branch_clk_data *clk_data = data;
 119         unsigned int offset = clkspec->args[0];
 120         int i, j;
 121
 122         for (i = 0; i < ARRAY_SIZE(clk_branches); i++) {
 123                 if (clk_branches[i].offset != offset)
 124                         continue;
 125
 126                 for (j = 0; j < clk_data->num; j++) {
 127                         if (!strcmp(clk_branches[i].base_name, clk_data->name[j]))
 128                                 return clk_branches[i].clk;
 129                 }
 130         }
 131
 132         pr_err("%s: invalid clock offset %d\n", __func__, offset);
 133
 134         return ERR_PTR(-EINVAL);
 135 }
 136
 137 static int lpc18xx_ccu_gate_endisable(struct clk_hw *hw, bool enable)
 138 {
 139         struct clk_gate *gate = to_clk_gate(hw);
 140         u32 val;
 141
 142         /*
 143          * Divider field is write only, so divider stat field must
 144          * be read so divider field can be set accordingly.
 145          */
 146         val = readl(gate->reg);
 147         if (val & LPC18XX_CCU_DIVSTAT)
 148                 val |= LPC18XX_CCU_DIV;
 149
 150         if (enable) {
 151                 val |= LPC18XX_CCU_RUN;
 152         } else {
 153                 /*
 154                  * To safely disable a branch clock a squence of two separate
 155                  * writes must be used. First write should set the AUTO bit
 156                  * and the next write should clear the RUN bit.
 157                  */
 158                 val |= LPC18XX_CCU_AUTO;
 159                 writel(val, gate->reg);
 160
 161                 val &= ~LPC18XX_CCU_RUN;
 162         }
 163
 164         writel(val, gate->reg);
 165
 166         return 0;
 167 }
 168
 169 static int lpc18xx_ccu_gate_enable(struct clk_hw *hw)
 170 {
 171         return lpc18xx_ccu_gate_endisable(hw, true);
 172 }
 173
 174 static void lpc18xx_ccu_gate_disable(struct clk_hw *hw)
 175 {
 176         lpc18xx_ccu_gate_endisable(hw, false);
 177 }
 178
 179 static int lpc18xx_ccu_gate_is_enabled(struct clk_hw *hw)
 180 {
 181         const struct clk_hw *parent;
 182
 183         /*
 184          * The branch clock registers are only accessible
 185          * if the base (parent) clock is enabled. Register
 186          * access with a disabled base clock will hang the
 187          * system.
 188          */
 189         parent = clk_hw_get_parent(hw);
 190         if (!parent)
 191                 return 0;
 192
 193         if (!clk_hw_is_enabled(parent))
 194                 return 0;
 195
 196         return clk_gate_ops.is_enabled(hw);
 197 }
 198
 199 static const struct clk_ops lpc18xx_ccu_gate_ops = {
 200         .enable         = lpc18xx_ccu_gate_enable,
 201         .disable        = lpc18xx_ccu_gate_disable,
 202         .is_enabled     = lpc18xx_ccu_gate_is_enabled,
 203 };
 204
 205 static void lpc18xx_ccu_register_branch_gate_div(struct lpc18xx_clk_branch *branch,
 206                                                  void __iomem *reg_base,
 207                                                  const char *parent)
 208 {
 209         const struct clk_ops *div_ops = NULL;
 210         struct clk_divider *div = NULL;
 211         struct clk_hw *div_hw = NULL;
 212
 213         if (branch->flags & CCU_BRANCH_HAVE_DIV2) {
 214                 div = kzalloc(sizeof(*div), GFP_KERNEL);
 215                 if (!div)
 216                         return;
 217
 218                 div->reg = branch->offset + reg_base;
 219                 div->flags = CLK_DIVIDER_READ_ONLY;
 220                 div->shift = 27;
 221                 div->width = 1;
 222
 223                 div_hw = &div->hw;
 224                 div_ops = &clk_divider_ro_ops;
 225         }
 226
 227         branch->gate.reg = branch->offset + reg_base;
 228         branch->gate.bit_idx = 0;
 229
 230         branch->clk = clk_register_composite(NULL, branch->name, &parent, 1,
 231                                              NULL, NULL,
 232                                              div_hw, div_ops,
 233                                              &branch->gate.hw, &lpc18xx_ccu_gate_ops, 0);
 234         if (IS_ERR(branch->clk)) {
 235                 kfree(div);
 236                 pr_warn("%s: failed to register %s\n", __func__, branch->name);
 237                 return;
 238         }
 239
 240         /* Grab essential branch clocks for CPU and SDRAM */
 241         switch (branch->offset) {
 242         case CLK_CPU_EMC:
 243         case CLK_CPU_CORE:
 244         case CLK_CPU_CREG:
 245         case CLK_CPU_EMCDIV:
 246                 clk_prepare_enable(branch->clk);
 247         }
 248 }
 249
 250 static void lpc18xx_ccu_register_branch_clks(void __iomem *reg_base,
 251                                              const char *base_name)
 252 {
 253         const char *parent = base_name;
 254         int i;
 255
 256         for (i = 0; i < ARRAY_SIZE(clk_branches); i++) {
 257                 if (strcmp(clk_branches[i].base_name, base_name))
 258                         continue;
 259
 260                 lpc18xx_ccu_register_branch_gate_div(&clk_branches[i], reg_base,
 261                                                      parent);
 262
 263                 if (clk_branches[i].flags & CCU_BRANCH_IS_BUS)
 264                         parent = clk_branches[i].name;
 265         }
 266 }
 267
 268 static void __init lpc18xx_ccu_init(struct device_node *np)
 269 {
 270         struct lpc18xx_branch_clk_data *clk_data;
 271         void __iomem *reg_base;
 272         int i, ret;
 273
 274         reg_base = of_iomap(np, 0);
 275         if (!reg_base) {
 276                 pr_warn("%s: failed to map address range\n", __func__);
 277                 return;
 278         }
 279
 280         clk_data = kzalloc(sizeof(*clk_data), GFP_KERNEL);
 281         if (!clk_data) {
 282                 iounmap(reg_base);
 283                 return;
 284         }
 285
 286         clk_data->num = of_property_count_strings(np, "clock-names");
 287         clk_data->name = kcalloc(clk_data->num, sizeof(char *), GFP_KERNEL);
 288         if (!clk_data->name) {
 289                 iounmap(reg_base);
 290                 kfree(clk_data);
 291                 return;
 292         }
 293
 294         for (i = 0; i < clk_data->num; i++) {
 295                 ret = of_property_read_string_index(np, "clock-names", i,
 296                                                     &clk_data->name[i]);
 297                 if (ret) {
 298                         pr_warn("%s: failed to get clock name at idx %d\n",
 299                                 __func__, i);
 300                         continue;
 301                 }
 302
 303                 lpc18xx_ccu_register_branch_clks(reg_base, clk_data->name[i]);
 304         }
 305
 306         of_clk_add_provider(np, lpc18xx_ccu_branch_clk_get, clk_data);
 307 }
 308 CLK_OF_DECLARE(lpc18xx_ccu, "nxp,lpc1850-ccu", lpc18xx_ccu_init);