pwrseq_simple.c 4.1 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * Copyright (C) 2014 Linaro Ltd
  4. *
  5. * Author: Ulf Hansson <ulf.hansson@linaro.org>
  6. *
  7. * Simple MMC power sequence management
  8. */
  9. #include <linux/clk.h>
  10. #include <linux/init.h>
  11. #include <linux/kernel.h>
  12. #include <linux/platform_device.h>
  13. #include <linux/module.h>
  14. #include <linux/slab.h>
  15. #include <linux/device.h>
  16. #include <linux/err.h>
  17. #include <linux/gpio/consumer.h>
  18. #include <linux/delay.h>
  19. #include <linux/property.h>
  20. #include <linux/mmc/host.h>
  21. #include "pwrseq.h"
  22. struct mmc_pwrseq_simple {
  23. struct mmc_pwrseq pwrseq;
  24. bool clk_enabled;
  25. u32 post_power_on_delay_ms;
  26. u32 power_off_delay_us;
  27. struct clk *ext_clk;
  28. struct gpio_descs *reset_gpios;
  29. };
  30. #define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq)
  31. static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
  32. int value)
  33. {
  34. struct gpio_descs *reset_gpios = pwrseq->reset_gpios;
  35. if (!IS_ERR(reset_gpios)) {
  36. unsigned long *values;
  37. int nvalues = reset_gpios->ndescs;
  38. values = bitmap_alloc(nvalues, GFP_KERNEL);
  39. if (!values)
  40. return;
  41. if (value)
  42. bitmap_fill(values, nvalues);
  43. else
  44. bitmap_zero(values, nvalues);
  45. gpiod_set_array_value_cansleep(nvalues, reset_gpios->desc,
  46. reset_gpios->info, values);
  47. kfree(values);
  48. }
  49. }
  50. static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
  51. {
  52. struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
  53. if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) {
  54. clk_prepare_enable(pwrseq->ext_clk);
  55. pwrseq->clk_enabled = true;
  56. }
  57. mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
  58. }
  59. static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
  60. {
  61. struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
  62. mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
  63. if (pwrseq->post_power_on_delay_ms)
  64. msleep(pwrseq->post_power_on_delay_ms);
  65. }
  66. static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
  67. {
  68. struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
  69. mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
  70. if (pwrseq->power_off_delay_us)
  71. usleep_range(pwrseq->power_off_delay_us,
  72. 2 * pwrseq->power_off_delay_us);
  73. if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
  74. clk_disable_unprepare(pwrseq->ext_clk);
  75. pwrseq->clk_enabled = false;
  76. }
  77. }
  78. static const struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
  79. .pre_power_on = mmc_pwrseq_simple_pre_power_on,
  80. .post_power_on = mmc_pwrseq_simple_post_power_on,
  81. .power_off = mmc_pwrseq_simple_power_off,
  82. };
  83. static const struct of_device_id mmc_pwrseq_simple_of_match[] = {
  84. { .compatible = "mmc-pwrseq-simple",},
  85. {/* sentinel */},
  86. };
  87. MODULE_DEVICE_TABLE(of, mmc_pwrseq_simple_of_match);
  88. static int mmc_pwrseq_simple_probe(struct platform_device *pdev)
  89. {
  90. struct mmc_pwrseq_simple *pwrseq;
  91. struct device *dev = &pdev->dev;
  92. pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL);
  93. if (!pwrseq)
  94. return -ENOMEM;
  95. pwrseq->ext_clk = devm_clk_get(dev, "ext_clock");
  96. if (IS_ERR(pwrseq->ext_clk) && PTR_ERR(pwrseq->ext_clk) != -ENOENT)
  97. return PTR_ERR(pwrseq->ext_clk);
  98. pwrseq->reset_gpios = devm_gpiod_get_array(dev, "reset",
  99. GPIOD_OUT_HIGH);
  100. if (IS_ERR(pwrseq->reset_gpios) &&
  101. PTR_ERR(pwrseq->reset_gpios) != -ENOENT &&
  102. PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) {
  103. return PTR_ERR(pwrseq->reset_gpios);
  104. }
  105. device_property_read_u32(dev, "post-power-on-delay-ms",
  106. &pwrseq->post_power_on_delay_ms);
  107. device_property_read_u32(dev, "power-off-delay-us",
  108. &pwrseq->power_off_delay_us);
  109. pwrseq->pwrseq.dev = dev;
  110. pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
  111. pwrseq->pwrseq.owner = THIS_MODULE;
  112. platform_set_drvdata(pdev, pwrseq);
  113. return mmc_pwrseq_register(&pwrseq->pwrseq);
  114. }
  115. static int mmc_pwrseq_simple_remove(struct platform_device *pdev)
  116. {
  117. struct mmc_pwrseq_simple *pwrseq = platform_get_drvdata(pdev);
  118. mmc_pwrseq_unregister(&pwrseq->pwrseq);
  119. return 0;
  120. }
  121. static struct platform_driver mmc_pwrseq_simple_driver = {
  122. .probe = mmc_pwrseq_simple_probe,
  123. .remove = mmc_pwrseq_simple_remove,
  124. .driver = {
  125. .name = "pwrseq_simple",
  126. .of_match_table = mmc_pwrseq_simple_of_match,
  127. },
  128. };
  129. module_platform_driver(mmc_pwrseq_simple_driver);
  130. MODULE_LICENSE("GPL v2");