cregit-Linux how code gets into the kernel

Release 4.7 drivers/gpu/drm/tegra/dpaux.c

/*
 * Copyright (C) 2013 NVIDIA Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of_gpio.h>
#include <linux/platform_device.h>
#include <linux/reset.h>
#include <linux/regulator/consumer.h>
#include <linux/workqueue.h>

#include <drm/drm_dp_helper.h>
#include <drm/drm_panel.h>

#include "dpaux.h"
#include "drm.h"

static DEFINE_MUTEX(dpaux_lock);
static LIST_HEAD(dpaux_list);


struct tegra_dpaux {
	
struct drm_dp_aux aux;
	
struct device *dev;

	
void __iomem *regs;
	
int irq;

	
struct tegra_output *output;

	
struct reset_control *rst;
	
struct clk *clk_parent;
	
struct clk *clk;

	
struct regulator *vdd;

	
struct completion complete;
	
struct work_struct work;
	
struct list_head list;
};


static inline struct tegra_dpaux *to_dpaux(struct drm_dp_aux *aux) { return container_of(aux, struct tegra_dpaux, aux); }

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static inline struct tegra_dpaux *work_to_dpaux(struct work_struct *work) { return container_of(work, struct tegra_dpaux, work); }

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static inline u32 tegra_dpaux_readl(struct tegra_dpaux *dpaux, unsigned long offset) { return readl(dpaux->regs + (offset << 2)); }

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static inline void tegra_dpaux_writel(struct tegra_dpaux *dpaux, u32 value, unsigned long offset) { writel(value, dpaux->regs + (offset << 2)); }

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static void tegra_dpaux_write_fifo(struct tegra_dpaux *dpaux, const u8 *buffer, size_t size) { size_t i, j; for (i = 0; i < DIV_ROUND_UP(size, 4); i++) { size_t num = min_t(size_t, size - i * 4, 4); u32 value = 0; for (j = 0; j < num; j++) value |= buffer[i * 4 + j] << (j * 8); tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXDATA_WRITE(i)); } }

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static void tegra_dpaux_read_fifo(struct tegra_dpaux *dpaux, u8 *buffer, size_t size) { size_t i, j; for (i = 0; i < DIV_ROUND_UP(size, 4); i++) { size_t num = min_t(size_t, size - i * 4, 4); u32 value; value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXDATA_READ(i)); for (j = 0; j < num; j++) buffer[i * 4 + j] = value >> (j * 8); } }

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static ssize_t tegra_dpaux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) { unsigned long timeout = msecs_to_jiffies(250); struct tegra_dpaux *dpaux = to_dpaux(aux); unsigned long status; ssize_t ret = 0; u32 value; /* Tegra has 4x4 byte DP AUX transmit and receive FIFOs. */ if (msg->size > 16) return -EINVAL; /* * Allow zero-sized messages only for I2C, in which case they specify * address-only transactions. */ if (msg->size < 1) { switch (msg->request & ~DP_AUX_I2C_MOT) { case DP_AUX_I2C_WRITE_STATUS_UPDATE: case DP_AUX_I2C_WRITE: case DP_AUX_I2C_READ: value = DPAUX_DP_AUXCTL_CMD_ADDRESS_ONLY; break; default: return -EINVAL; } } else { /* For non-zero-sized messages, set the CMDLEN field. */ value = DPAUX_DP_AUXCTL_CMDLEN(msg->size - 1); } switch (msg->request & ~DP_AUX_I2C_MOT) { case DP_AUX_I2C_WRITE: if (msg->request & DP_AUX_I2C_MOT) value |= DPAUX_DP_AUXCTL_CMD_MOT_WR; else value |= DPAUX_DP_AUXCTL_CMD_I2C_WR; break; case DP_AUX_I2C_READ: if (msg->request & DP_AUX_I2C_MOT) value |= DPAUX_DP_AUXCTL_CMD_MOT_RD; else value |= DPAUX_DP_AUXCTL_CMD_I2C_RD; break; case DP_AUX_I2C_WRITE_STATUS_UPDATE: if (msg->request & DP_AUX_I2C_MOT) value |= DPAUX_DP_AUXCTL_CMD_MOT_RQ; else value |= DPAUX_DP_AUXCTL_CMD_I2C_RQ; break; case DP_AUX_NATIVE_WRITE: value |= DPAUX_DP_AUXCTL_CMD_AUX_WR; break; case DP_AUX_NATIVE_READ: value |= DPAUX_DP_AUXCTL_CMD_AUX_RD; break; default: return -EINVAL; } tegra_dpaux_writel(dpaux, msg->address, DPAUX_DP_AUXADDR); tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXCTL); if ((msg->request & DP_AUX_I2C_READ) == 0) { tegra_dpaux_write_fifo(dpaux, msg->buffer, msg->size); ret = msg->size; } /* start transaction */ value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXCTL); value |= DPAUX_DP_AUXCTL_TRANSACTREQ; tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXCTL); status = wait_for_completion_timeout(&dpaux->complete, timeout); if (!status) return -ETIMEDOUT; /* read status and clear errors */ value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXSTAT); tegra_dpaux_writel(dpaux, 0xf00, DPAUX_DP_AUXSTAT); if (value & DPAUX_DP_AUXSTAT_TIMEOUT_ERROR) return -ETIMEDOUT; if ((value & DPAUX_DP_AUXSTAT_RX_ERROR) || (value & DPAUX_DP_AUXSTAT_SINKSTAT_ERROR) || (value & DPAUX_DP_AUXSTAT_NO_STOP_ERROR)) return -EIO; switch ((value & DPAUX_DP_AUXSTAT_REPLY_TYPE_MASK) >> 16) { case 0x00: msg->reply = DP_AUX_NATIVE_REPLY_ACK; break; case 0x01: msg->reply = DP_AUX_NATIVE_REPLY_NACK; break; case 0x02: msg->reply = DP_AUX_NATIVE_REPLY_DEFER; break; case 0x04: msg->reply = DP_AUX_I2C_REPLY_NACK; break; case 0x08: msg->reply = DP_AUX_I2C_REPLY_DEFER; break; } if ((msg->size > 0) && (msg->reply == DP_AUX_NATIVE_REPLY_ACK)) { if (msg->request & DP_AUX_I2C_READ) { size_t count = value & DPAUX_DP_AUXSTAT_REPLY_MASK; if (WARN_ON(count != msg->size)) count = min_t(size_t, count, msg->size); tegra_dpaux_read_fifo(dpaux, msg->buffer, count); ret = count; } } return ret; }

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static void tegra_dpaux_hotplug(struct work_struct *work) { struct tegra_dpaux *dpaux = work_to_dpaux(work); if (dpaux->output) drm_helper_hpd_irq_event(dpaux->output->connector.dev); }

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static irqreturn_t tegra_dpaux_irq(int irq, void *data) { struct tegra_dpaux *dpaux = data; irqreturn_t ret = IRQ_HANDLED; u32 value; /* clear interrupts */ value = tegra_dpaux_readl(dpaux, DPAUX_INTR_AUX); tegra_dpaux_writel(dpaux, value, DPAUX_INTR_AUX); if (value & (DPAUX_INTR_PLUG_EVENT | DPAUX_INTR_UNPLUG_EVENT)) schedule_work(&dpaux->work); if (value & DPAUX_INTR_IRQ_EVENT) { /* TODO: handle this */ } if (value & DPAUX_INTR_AUX_DONE) complete(&dpaux->complete); return ret; }

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static int tegra_dpaux_probe(struct platform_device *pdev) { struct tegra_dpaux *dpaux; struct resource *regs; u32 value; int err; dpaux = devm_kzalloc(&pdev->dev, sizeof(*dpaux), GFP_KERNEL); if (!dpaux) return -ENOMEM; INIT_WORK(&dpaux->work, tegra_dpaux_hotplug); init_completion(&dpaux->complete); INIT_LIST_HEAD(&dpaux->list); dpaux->dev = &pdev->dev; regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); dpaux->regs = devm_ioremap_resource(&pdev->dev, regs); if (IS_ERR(dpaux->regs)) return PTR_ERR(dpaux->regs); dpaux->irq = platform_get_irq(pdev, 0); if (dpaux->irq < 0) { dev_err(&pdev->dev, "failed to get IRQ\n"); return -ENXIO; } dpaux->rst = devm_reset_control_get(&pdev->dev, "dpaux"); if (IS_ERR(dpaux->rst)) { dev_err(&pdev->dev, "failed to get reset control: %ld\n", PTR_ERR(dpaux->rst)); return PTR_ERR(dpaux->rst); } dpaux->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(dpaux->clk)) { dev_err(&pdev->dev, "failed to get module clock: %ld\n", PTR_ERR(dpaux->clk)); return PTR_ERR(dpaux->clk); } err = clk_prepare_enable(dpaux->clk); if (err < 0) { dev_err(&pdev->dev, "failed to enable module clock: %d\n", err); return err; } reset_control_deassert(dpaux->rst); dpaux->clk_parent = devm_clk_get(&pdev->dev, "parent"); if (IS_ERR(dpaux->clk_parent)) { dev_err(&pdev->dev, "failed to get parent clock: %ld\n", PTR_ERR(dpaux->clk_parent)); return PTR_ERR(dpaux->clk_parent); } err = clk_prepare_enable(dpaux->clk_parent); if (err < 0) { dev_err(&pdev->dev, "failed to enable parent clock: %d\n", err); return err; } err = clk_set_rate(dpaux->clk_parent, 270000000); if (err < 0) { dev_err(&pdev->dev, "failed to set clock to 270 MHz: %d\n", err); return err; } dpaux->vdd = devm_regulator_get(&pdev->dev, "vdd"); if (IS_ERR(dpaux->vdd)) { dev_err(&pdev->dev, "failed to get VDD supply: %ld\n", PTR_ERR(dpaux->vdd)); return PTR_ERR(dpaux->vdd); } err = devm_request_irq(dpaux->dev, dpaux->irq, tegra_dpaux_irq, 0, dev_name(dpaux->dev), dpaux); if (err < 0) { dev_err(dpaux->dev, "failed to request IRQ#%u: %d\n", dpaux->irq, err); return err; } disable_irq(dpaux->irq); dpaux->aux.transfer = tegra_dpaux_transfer; dpaux->aux.dev = &pdev->dev; err = drm_dp_aux_register(&dpaux->aux); if (err < 0) return err; /* * Assume that by default the DPAUX/I2C pads will be used for HDMI, * so power them up and configure them in I2C mode. * * The DPAUX code paths reconfigure the pads in AUX mode, but there * is no possibility to perform the I2C mode configuration in the * HDMI path. */ value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE); value &= ~DPAUX_HYBRID_SPARE_PAD_POWER_DOWN; tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE); value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_PADCTL); value = DPAUX_HYBRID_PADCTL_I2C_SDA_INPUT_RCV | DPAUX_HYBRID_PADCTL_I2C_SCL_INPUT_RCV | DPAUX_HYBRID_PADCTL_MODE_I2C; tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_PADCTL); /* enable and clear all interrupts */ value = DPAUX_INTR_AUX_DONE | DPAUX_INTR_IRQ_EVENT | DPAUX_INTR_UNPLUG_EVENT | DPAUX_INTR_PLUG_EVENT; tegra_dpaux_writel(dpaux, value, DPAUX_INTR_EN_AUX); tegra_dpaux_writel(dpaux, value, DPAUX_INTR_AUX); mutex_lock(&dpaux_lock); list_add_tail(&dpaux->list, &dpaux_list); mutex_unlock(&dpaux_lock); platform_set_drvdata(pdev, dpaux); return 0; }

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static int tegra_dpaux_remove(struct platform_device *pdev) { struct tegra_dpaux *dpaux = platform_get_drvdata(pdev); u32 value; /* make sure pads are powered down when not in use */ value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE); value |= DPAUX_HYBRID_SPARE_PAD_POWER_DOWN; tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE); drm_dp_aux_unregister(&dpaux->aux); mutex_lock(&dpaux_lock); list_del(&dpaux->list); mutex_unlock(&dpaux_lock); cancel_work_sync(&dpaux->work); clk_disable_unprepare(dpaux->clk_parent); reset_control_assert(dpaux->rst); clk_disable_unprepare(dpaux->clk); return 0; }

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static const struct of_device_id tegra_dpaux_of_match[] = { { .compatible = "nvidia,tegra210-dpaux", }, { .compatible = "nvidia,tegra124-dpaux", }, { }, }; MODULE_DEVICE_TABLE(of, tegra_dpaux_of_match); struct platform_driver tegra_dpaux_driver = { .driver = { .name = "tegra-dpaux", .of_match_table = tegra_dpaux_of_match, }, .probe = tegra_dpaux_probe, .remove = tegra_dpaux_remove, };
struct drm_dp_aux *drm_dp_aux_find_by_of_node(struct device_node *np) { struct tegra_dpaux *dpaux; mutex_lock(&dpaux_lock); list_for_each_entry(dpaux, &dpaux_list, list) if (np == dpaux->dev->of_node) { mutex_unlock(&dpaux_lock); return &dpaux->aux; } mutex_unlock(&dpaux_lock); return NULL; }

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int drm_dp_aux_attach(struct drm_dp_aux *aux, struct tegra_output *output) { struct tegra_dpaux *dpaux = to_dpaux(aux); unsigned long timeout; int err; output->connector.polled = DRM_CONNECTOR_POLL_HPD; dpaux->output = output; err = regulator_enable(dpaux->vdd); if (err < 0) return err; timeout = jiffies + msecs_to_jiffies(250); while (time_before(jiffies, timeout)) { enum drm_connector_status status; status = drm_dp_aux_detect(aux); if (status == connector_status_connected) { enable_irq(dpaux->irq); return 0; } usleep_range(1000, 2000); } return -ETIMEDOUT; }

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int drm_dp_aux_detach(struct drm_dp_aux *aux) { struct tegra_dpaux *dpaux = to_dpaux(aux); unsigned long timeout; int err; disable_irq(dpaux->irq); err = regulator_disable(dpaux->vdd); if (err < 0) return err; timeout = jiffies + msecs_to_jiffies(250); while (time_before(jiffies, timeout)) { enum drm_connector_status status; status = drm_dp_aux_detect(aux); if (status == connector_status_disconnected) { dpaux->output = NULL; return 0; } usleep_range(1000, 2000); } return -ETIMEDOUT; }

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enum drm_connector_status drm_dp_aux_detect(struct drm_dp_aux *aux) { struct tegra_dpaux *dpaux = to_dpaux(aux); u32 value; value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXSTAT); if (value & DPAUX_DP_AUXSTAT_HPD_STATUS) return connector_status_connected; return connector_status_disconnected; }

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int drm_dp_aux_enable(struct drm_dp_aux *aux) { struct tegra_dpaux *dpaux = to_dpaux(aux); u32 value; value = DPAUX_HYBRID_PADCTL_AUX_CMH(2) | DPAUX_HYBRID_PADCTL_AUX_DRVZ(4) | DPAUX_HYBRID_PADCTL_AUX_DRVI(0x18) | DPAUX_HYBRID_PADCTL_AUX_INPUT_RCV | DPAUX_HYBRID_PADCTL_MODE_AUX; tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_PADCTL); value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE); value &= ~DPAUX_HYBRID_SPARE_PAD_POWER_DOWN; tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE); return 0; }

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int drm_dp_aux_disable(struct drm_dp_aux *aux) { struct tegra_dpaux *dpaux = to_dpaux(aux); u32 value; value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE); value |= DPAUX_HYBRID_SPARE_PAD_POWER_DOWN; tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE); return 0; }

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int drm_dp_aux_prepare(struct drm_dp_aux *aux, u8 encoding) { int err; err = drm_dp_dpcd_writeb(aux, DP_MAIN_LINK_CHANNEL_CODING_SET, encoding); if (err < 0) return err; return 0; }

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int drm_dp_aux_train(struct drm_dp_aux *aux, struct drm_dp_link *link, u8 pattern) { u8 tp = pattern & DP_TRAINING_PATTERN_MASK; u8 status[DP_LINK_STATUS_SIZE], values[4]; unsigned int i; int err; err = drm_dp_dpcd_writeb(aux, DP_TRAINING_PATTERN_SET, pattern); if (err < 0) return err; if (tp == DP_TRAINING_PATTERN_DISABLE) return 0; for (i = 0; i < link->num_lanes; i++) values[i] = DP_TRAIN_MAX_PRE_EMPHASIS_REACHED | DP_TRAIN_PRE_EMPH_LEVEL_0 | DP_TRAIN_MAX_SWING_REACHED | DP_TRAIN_VOLTAGE_SWING_LEVEL_0; err = drm_dp_dpcd_write(aux, DP_TRAINING_LANE0_SET, values, link->num_lanes); if (err < 0) return err; usleep_range(500, 1000); err = drm_dp_dpcd_read_link_status(aux, status); if (err < 0) return err; switch (tp) { case DP_TRAINING_PATTERN_1: if (!drm_dp_clock_recovery_ok(status, link->num_lanes)) return -EAGAIN; break; case DP_TRAINING_PATTERN_2: if (!drm_dp_channel_eq_ok(status, link->num_lanes)) return -EAGAIN; break; default: dev_err(aux->dev, "unsupported training pattern %u\n", tp); return -EINVAL; } err = drm_dp_dpcd_writeb(aux, DP_EDP_CONFIGURATION_SET, 0); if (err < 0) return err; return 0; }

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