diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2009-09-08 20:55:21 -0400 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2009-09-08 20:55:21 -0400 |
| commit | bbb20089a3275a19e475dbc21320c3742e3ca423 (patch) | |
| tree | 216fdc1cbef450ca688135c5b8969169482d9a48 /arch/arm/plat-pxa/pwm.c | |
| parent | 3e48e656903e9fd8bc805c6a2c4264d7808d315b (diff) | |
| parent | 657a77fa7284d8ae28dfa48f1dc5d919bf5b2843 (diff) | |
Merge branch 'dmaengine' into async-tx-next
Conflicts:
crypto/async_tx/async_xor.c
drivers/dma/ioat/dma_v2.h
drivers/dma/ioat/pci.c
drivers/md/raid5.c
Diffstat (limited to 'arch/arm/plat-pxa/pwm.c')
| -rw-r--r-- | arch/arm/plat-pxa/pwm.c | 303 |
1 files changed, 303 insertions, 0 deletions
diff --git a/arch/arm/plat-pxa/pwm.c b/arch/arm/plat-pxa/pwm.c new file mode 100644 index 000000000000..a9eabdcfa163 --- /dev/null +++ b/arch/arm/plat-pxa/pwm.c | |||
| @@ -0,0 +1,303 @@ | |||
| 1 | /* | ||
| 2 | * linux/arch/arm/mach-pxa/pwm.c | ||
| 3 | * | ||
| 4 | * simple driver for PWM (Pulse Width Modulator) controller | ||
| 5 | * | ||
| 6 | * This program is free software; you can redistribute it and/or modify | ||
| 7 | * it under the terms of the GNU General Public License version 2 as | ||
| 8 | * published by the Free Software Foundation. | ||
| 9 | * | ||
| 10 | * 2008-02-13 initial version | ||
| 11 | * eric miao <eric.miao@marvell.com> | ||
| 12 | */ | ||
| 13 | |||
| 14 | #include <linux/module.h> | ||
| 15 | #include <linux/kernel.h> | ||
| 16 | #include <linux/platform_device.h> | ||
| 17 | #include <linux/err.h> | ||
| 18 | #include <linux/clk.h> | ||
| 19 | #include <linux/io.h> | ||
| 20 | #include <linux/pwm.h> | ||
| 21 | |||
| 22 | #include <asm/div64.h> | ||
| 23 | |||
| 24 | #define HAS_SECONDARY_PWM 0x10 | ||
| 25 | #define PWM_ID_BASE(d) ((d) & 0xf) | ||
| 26 | |||
| 27 | static const struct platform_device_id pwm_id_table[] = { | ||
| 28 | /* PWM has_secondary_pwm? */ | ||
| 29 | { "pxa25x-pwm", 0 }, | ||
| 30 | { "pxa27x-pwm", 0 | HAS_SECONDARY_PWM }, | ||
| 31 | { "pxa168-pwm", 1 }, | ||
| 32 | { "pxa910-pwm", 1 }, | ||
| 33 | { }, | ||
| 34 | }; | ||
| 35 | MODULE_DEVICE_TABLE(platform, pwm_id_table); | ||
| 36 | |||
| 37 | /* PWM registers and bits definitions */ | ||
| 38 | #define PWMCR (0x00) | ||
| 39 | #define PWMDCR (0x04) | ||
| 40 | #define PWMPCR (0x08) | ||
| 41 | |||
| 42 | #define PWMCR_SD (1 << 6) | ||
| 43 | #define PWMDCR_FD (1 << 10) | ||
| 44 | |||
| 45 | struct pwm_device { | ||
| 46 | struct list_head node; | ||
| 47 | struct pwm_device *secondary; | ||
| 48 | struct platform_device *pdev; | ||
| 49 | |||
| 50 | const char *label; | ||
| 51 | struct clk *clk; | ||
| 52 | int clk_enabled; | ||
| 53 | void __iomem *mmio_base; | ||
| 54 | |||
| 55 | unsigned int use_count; | ||
| 56 | unsigned int pwm_id; | ||
| 57 | }; | ||
| 58 | |||
| 59 | /* | ||
| 60 | * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE | ||
| 61 | * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE | ||
| 62 | */ | ||
| 63 | int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) | ||
| 64 | { | ||
| 65 | unsigned long long c; | ||
| 66 | unsigned long period_cycles, prescale, pv, dc; | ||
| 67 | |||
| 68 | if (pwm == NULL || period_ns == 0 || duty_ns > period_ns) | ||
| 69 | return -EINVAL; | ||
| 70 | |||
| 71 | c = clk_get_rate(pwm->clk); | ||
| 72 | c = c * period_ns; | ||
| 73 | do_div(c, 1000000000); | ||
| 74 | period_cycles = c; | ||
| 75 | |||
| 76 | if (period_cycles < 1) | ||
| 77 | period_cycles = 1; | ||
| 78 | prescale = (period_cycles - 1) / 1024; | ||
| 79 | pv = period_cycles / (prescale + 1) - 1; | ||
| 80 | |||
| 81 | if (prescale > 63) | ||
| 82 | return -EINVAL; | ||
| 83 | |||
| 84 | if (duty_ns == period_ns) | ||
| 85 | dc = PWMDCR_FD; | ||
| 86 | else | ||
| 87 | dc = (pv + 1) * duty_ns / period_ns; | ||
| 88 | |||
| 89 | /* NOTE: the clock to PWM has to be enabled first | ||
| 90 | * before writing to the registers | ||
| 91 | */ | ||
| 92 | clk_enable(pwm->clk); | ||
| 93 | __raw_writel(prescale, pwm->mmio_base + PWMCR); | ||
| 94 | __raw_writel(dc, pwm->mmio_base + PWMDCR); | ||
| 95 | __raw_writel(pv, pwm->mmio_base + PWMPCR); | ||
| 96 | clk_disable(pwm->clk); | ||
| 97 | |||
| 98 | return 0; | ||
| 99 | } | ||
| 100 | EXPORT_SYMBOL(pwm_config); | ||
| 101 | |||
| 102 | int pwm_enable(struct pwm_device *pwm) | ||
| 103 | { | ||
| 104 | int rc = 0; | ||
| 105 | |||
| 106 | if (!pwm->clk_enabled) { | ||
| 107 | rc = clk_enable(pwm->clk); | ||
| 108 | if (!rc) | ||
| 109 | pwm->clk_enabled = 1; | ||
| 110 | } | ||
| 111 | return rc; | ||
| 112 | } | ||
| 113 | EXPORT_SYMBOL(pwm_enable); | ||
| 114 | |||
| 115 | void pwm_disable(struct pwm_device *pwm) | ||
| 116 | { | ||
| 117 | if (pwm->clk_enabled) { | ||
| 118 | clk_disable(pwm->clk); | ||
| 119 | pwm->clk_enabled = 0; | ||
| 120 | } | ||
| 121 | } | ||
| 122 | EXPORT_SYMBOL(pwm_disable); | ||
| 123 | |||
| 124 | static DEFINE_MUTEX(pwm_lock); | ||
| 125 | static LIST_HEAD(pwm_list); | ||
| 126 | |||
| 127 | struct pwm_device *pwm_request(int pwm_id, const char *label) | ||
| 128 | { | ||
| 129 | struct pwm_device *pwm; | ||
| 130 | int found = 0; | ||
| 131 | |||
| 132 | mutex_lock(&pwm_lock); | ||
| 133 | |||
| 134 | list_for_each_entry(pwm, &pwm_list, node) { | ||
| 135 | if (pwm->pwm_id == pwm_id) { | ||
| 136 | found = 1; | ||
| 137 | break; | ||
| 138 | } | ||
| 139 | } | ||
| 140 | |||
| 141 | if (found) { | ||
| 142 | if (pwm->use_count == 0) { | ||
| 143 | pwm->use_count++; | ||
| 144 | pwm->label = label; | ||
| 145 | } else | ||
| 146 | pwm = ERR_PTR(-EBUSY); | ||
| 147 | } else | ||
| 148 | pwm = ERR_PTR(-ENOENT); | ||
| 149 | |||
| 150 | mutex_unlock(&pwm_lock); | ||
| 151 | return pwm; | ||
| 152 | } | ||
| 153 | EXPORT_SYMBOL(pwm_request); | ||
| 154 | |||
| 155 | void pwm_free(struct pwm_device *pwm) | ||
| 156 | { | ||
| 157 | mutex_lock(&pwm_lock); | ||
| 158 | |||
| 159 | if (pwm->use_count) { | ||
| 160 | pwm->use_count--; | ||
| 161 | pwm->label = NULL; | ||
| 162 | } else | ||
| 163 | pr_warning("PWM device already freed\n"); | ||
| 164 | |||
| 165 | mutex_unlock(&pwm_lock); | ||
| 166 | } | ||
| 167 | EXPORT_SYMBOL(pwm_free); | ||
| 168 | |||
| 169 | static inline void __add_pwm(struct pwm_device *pwm) | ||
| 170 | { | ||
| 171 | mutex_lock(&pwm_lock); | ||
| 172 | list_add_tail(&pwm->node, &pwm_list); | ||
| 173 | mutex_unlock(&pwm_lock); | ||
| 174 | } | ||
| 175 | |||
| 176 | static int __devinit pwm_probe(struct platform_device *pdev) | ||
| 177 | { | ||
| 178 | struct platform_device_id *id = platform_get_device_id(pdev); | ||
| 179 | struct pwm_device *pwm, *secondary = NULL; | ||
| 180 | struct resource *r; | ||
| 181 | int ret = 0; | ||
| 182 | |||
| 183 | pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); | ||
| 184 | if (pwm == NULL) { | ||
| 185 | dev_err(&pdev->dev, "failed to allocate memory\n"); | ||
| 186 | return -ENOMEM; | ||
| 187 | } | ||
| 188 | |||
| 189 | pwm->clk = clk_get(&pdev->dev, NULL); | ||
| 190 | if (IS_ERR(pwm->clk)) { | ||
| 191 | ret = PTR_ERR(pwm->clk); | ||
| 192 | goto err_free; | ||
| 193 | } | ||
| 194 | pwm->clk_enabled = 0; | ||
| 195 | |||
| 196 | pwm->use_count = 0; | ||
| 197 | pwm->pwm_id = PWM_ID_BASE(id->driver_data) + pdev->id; | ||
| 198 | pwm->pdev = pdev; | ||
| 199 | |||
| 200 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); | ||
| 201 | if (r == NULL) { | ||
| 202 | dev_err(&pdev->dev, "no memory resource defined\n"); | ||
| 203 | ret = -ENODEV; | ||
| 204 | goto err_free_clk; | ||
| 205 | } | ||
| 206 | |||
| 207 | r = request_mem_region(r->start, r->end - r->start + 1, pdev->name); | ||
| 208 | if (r == NULL) { | ||
| 209 | dev_err(&pdev->dev, "failed to request memory resource\n"); | ||
| 210 | ret = -EBUSY; | ||
| 211 | goto err_free_clk; | ||
| 212 | } | ||
| 213 | |||
| 214 | pwm->mmio_base = ioremap(r->start, r->end - r->start + 1); | ||
| 215 | if (pwm->mmio_base == NULL) { | ||
| 216 | dev_err(&pdev->dev, "failed to ioremap() registers\n"); | ||
| 217 | ret = -ENODEV; | ||
| 218 | goto err_free_mem; | ||
| 219 | } | ||
| 220 | |||
| 221 | if (id->driver_data & HAS_SECONDARY_PWM) { | ||
| 222 | secondary = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); | ||
| 223 | if (secondary == NULL) { | ||
| 224 | ret = -ENOMEM; | ||
| 225 | goto err_free_mem; | ||
| 226 | } | ||
| 227 | |||
| 228 | *secondary = *pwm; | ||
| 229 | pwm->secondary = secondary; | ||
| 230 | |||
| 231 | /* registers for the second PWM has offset of 0x10 */ | ||
| 232 | secondary->mmio_base = pwm->mmio_base + 0x10; | ||
| 233 | secondary->pwm_id = pdev->id + 2; | ||
| 234 | } | ||
| 235 | |||
| 236 | __add_pwm(pwm); | ||
| 237 | if (secondary) | ||
| 238 | __add_pwm(secondary); | ||
| 239 | |||
| 240 | platform_set_drvdata(pdev, pwm); | ||
| 241 | return 0; | ||
| 242 | |||
| 243 | err_free_mem: | ||
| 244 | release_mem_region(r->start, r->end - r->start + 1); | ||
| 245 | err_free_clk: | ||
| 246 | clk_put(pwm->clk); | ||
| 247 | err_free: | ||
| 248 | kfree(pwm); | ||
| 249 | return ret; | ||
| 250 | } | ||
| 251 | |||
| 252 | static int __devexit pwm_remove(struct platform_device *pdev) | ||
| 253 | { | ||
| 254 | struct pwm_device *pwm; | ||
| 255 | struct resource *r; | ||
| 256 | |||
| 257 | pwm = platform_get_drvdata(pdev); | ||
| 258 | if (pwm == NULL) | ||
| 259 | return -ENODEV; | ||
| 260 | |||
| 261 | mutex_lock(&pwm_lock); | ||
| 262 | |||
| 263 | if (pwm->secondary) { | ||
| 264 | list_del(&pwm->secondary->node); | ||
| 265 | kfree(pwm->secondary); | ||
| 266 | } | ||
| 267 | |||
| 268 | list_del(&pwm->node); | ||
| 269 | mutex_unlock(&pwm_lock); | ||
| 270 | |||
| 271 | iounmap(pwm->mmio_base); | ||
| 272 | |||
| 273 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); | ||
| 274 | release_mem_region(r->start, r->end - r->start + 1); | ||
| 275 | |||
| 276 | clk_put(pwm->clk); | ||
| 277 | kfree(pwm); | ||
| 278 | return 0; | ||
| 279 | } | ||
| 280 | |||
| 281 | static struct platform_driver pwm_driver = { | ||
| 282 | .driver = { | ||
| 283 | .name = "pxa25x-pwm", | ||
| 284 | .owner = THIS_MODULE, | ||
| 285 | }, | ||
| 286 | .probe = pwm_probe, | ||
| 287 | .remove = __devexit_p(pwm_remove), | ||
| 288 | .id_table = pwm_id_table, | ||
| 289 | }; | ||
| 290 | |||
| 291 | static int __init pwm_init(void) | ||
| 292 | { | ||
| 293 | return platform_driver_register(&pwm_driver); | ||
| 294 | } | ||
| 295 | arch_initcall(pwm_init); | ||
| 296 | |||
| 297 | static void __exit pwm_exit(void) | ||
| 298 | { | ||
| 299 | platform_driver_unregister(&pwm_driver); | ||
| 300 | } | ||
| 301 | module_exit(pwm_exit); | ||
| 302 | |||
| 303 | MODULE_LICENSE("GPL v2"); | ||
