pwm-ep93xx.c 5.4 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221
  1. // SPDX-License-Identifier: GPL-2.0-or-later
  2. /*
  3. * PWM framework driver for Cirrus Logic EP93xx
  4. *
  5. * Copyright (c) 2009 Matthieu Crapet <mcrapet@gmail.com>
  6. * Copyright (c) 2009, 2013 H Hartley Sweeten <hsweeten@visionengravers.com>
  7. *
  8. * EP9301/02 have only one channel:
  9. * platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)
  10. *
  11. * EP9307 has only one channel:
  12. * platform device ep93xx-pwm.0 - PWMOUT
  13. *
  14. * EP9312/15 have two channels:
  15. * platform device ep93xx-pwm.0 - PWMOUT
  16. * platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)
  17. */
  18. #include <linux/module.h>
  19. #include <linux/platform_device.h>
  20. #include <linux/slab.h>
  21. #include <linux/clk.h>
  22. #include <linux/err.h>
  23. #include <linux/io.h>
  24. #include <linux/pwm.h>
  25. #include <asm/div64.h>
  26. #include <linux/soc/cirrus/ep93xx.h> /* for ep93xx_pwm_{acquire,release}_gpio() */
  27. #define EP93XX_PWMx_TERM_COUNT 0x00
  28. #define EP93XX_PWMx_DUTY_CYCLE 0x04
  29. #define EP93XX_PWMx_ENABLE 0x08
  30. #define EP93XX_PWMx_INVERT 0x0c
  31. struct ep93xx_pwm {
  32. void __iomem *base;
  33. struct clk *clk;
  34. struct pwm_chip chip;
  35. };
  36. static inline struct ep93xx_pwm *to_ep93xx_pwm(struct pwm_chip *chip)
  37. {
  38. return container_of(chip, struct ep93xx_pwm, chip);
  39. }
  40. static int ep93xx_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  41. {
  42. struct platform_device *pdev = to_platform_device(chip->dev);
  43. return ep93xx_pwm_acquire_gpio(pdev);
  44. }
  45. static void ep93xx_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
  46. {
  47. struct platform_device *pdev = to_platform_device(chip->dev);
  48. ep93xx_pwm_release_gpio(pdev);
  49. }
  50. static int ep93xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  51. int duty_ns, int period_ns)
  52. {
  53. struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
  54. void __iomem *base = ep93xx_pwm->base;
  55. unsigned long long c;
  56. unsigned long period_cycles;
  57. unsigned long duty_cycles;
  58. unsigned long term;
  59. int ret = 0;
  60. /*
  61. * The clock needs to be enabled to access the PWM registers.
  62. * Configuration can be changed at any time.
  63. */
  64. if (!pwm_is_enabled(pwm)) {
  65. ret = clk_enable(ep93xx_pwm->clk);
  66. if (ret)
  67. return ret;
  68. }
  69. c = clk_get_rate(ep93xx_pwm->clk);
  70. c *= period_ns;
  71. do_div(c, 1000000000);
  72. period_cycles = c;
  73. c = period_cycles;
  74. c *= duty_ns;
  75. do_div(c, period_ns);
  76. duty_cycles = c;
  77. if (period_cycles < 0x10000 && duty_cycles < 0x10000) {
  78. term = readw(base + EP93XX_PWMx_TERM_COUNT);
  79. /* Order is important if PWM is running */
  80. if (period_cycles > term) {
  81. writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
  82. writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
  83. } else {
  84. writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
  85. writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
  86. }
  87. } else {
  88. ret = -EINVAL;
  89. }
  90. if (!pwm_is_enabled(pwm))
  91. clk_disable(ep93xx_pwm->clk);
  92. return ret;
  93. }
  94. static int ep93xx_pwm_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
  95. enum pwm_polarity polarity)
  96. {
  97. struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
  98. int ret;
  99. /*
  100. * The clock needs to be enabled to access the PWM registers.
  101. * Polarity can only be changed when the PWM is disabled.
  102. */
  103. ret = clk_enable(ep93xx_pwm->clk);
  104. if (ret)
  105. return ret;
  106. if (polarity == PWM_POLARITY_INVERSED)
  107. writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT);
  108. else
  109. writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT);
  110. clk_disable(ep93xx_pwm->clk);
  111. return 0;
  112. }
  113. static int ep93xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
  114. {
  115. struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
  116. int ret;
  117. ret = clk_enable(ep93xx_pwm->clk);
  118. if (ret)
  119. return ret;
  120. writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
  121. return 0;
  122. }
  123. static void ep93xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
  124. {
  125. struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
  126. writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
  127. clk_disable(ep93xx_pwm->clk);
  128. }
  129. static const struct pwm_ops ep93xx_pwm_ops = {
  130. .request = ep93xx_pwm_request,
  131. .free = ep93xx_pwm_free,
  132. .config = ep93xx_pwm_config,
  133. .set_polarity = ep93xx_pwm_polarity,
  134. .enable = ep93xx_pwm_enable,
  135. .disable = ep93xx_pwm_disable,
  136. .owner = THIS_MODULE,
  137. };
  138. static int ep93xx_pwm_probe(struct platform_device *pdev)
  139. {
  140. struct ep93xx_pwm *ep93xx_pwm;
  141. struct resource *res;
  142. int ret;
  143. ep93xx_pwm = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_pwm), GFP_KERNEL);
  144. if (!ep93xx_pwm)
  145. return -ENOMEM;
  146. res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  147. ep93xx_pwm->base = devm_ioremap_resource(&pdev->dev, res);
  148. if (IS_ERR(ep93xx_pwm->base))
  149. return PTR_ERR(ep93xx_pwm->base);
  150. ep93xx_pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk");
  151. if (IS_ERR(ep93xx_pwm->clk))
  152. return PTR_ERR(ep93xx_pwm->clk);
  153. ep93xx_pwm->chip.dev = &pdev->dev;
  154. ep93xx_pwm->chip.ops = &ep93xx_pwm_ops;
  155. ep93xx_pwm->chip.base = -1;
  156. ep93xx_pwm->chip.npwm = 1;
  157. ret = pwmchip_add(&ep93xx_pwm->chip);
  158. if (ret < 0)
  159. return ret;
  160. platform_set_drvdata(pdev, ep93xx_pwm);
  161. return 0;
  162. }
  163. static int ep93xx_pwm_remove(struct platform_device *pdev)
  164. {
  165. struct ep93xx_pwm *ep93xx_pwm = platform_get_drvdata(pdev);
  166. return pwmchip_remove(&ep93xx_pwm->chip);
  167. }
  168. static struct platform_driver ep93xx_pwm_driver = {
  169. .driver = {
  170. .name = "ep93xx-pwm",
  171. },
  172. .probe = ep93xx_pwm_probe,
  173. .remove = ep93xx_pwm_remove,
  174. };
  175. module_platform_driver(ep93xx_pwm_driver);
  176. MODULE_DESCRIPTION("Cirrus Logic EP93xx PWM driver");
  177. MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>");
  178. MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
  179. MODULE_ALIAS("platform:ep93xx-pwm");
  180. MODULE_LICENSE("GPL");