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