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