diff options
Diffstat (limited to 'kernel/drivers/mmc/host/sdhci-of-at91.c')
| -rw-r--r-- | kernel/drivers/mmc/host/sdhci-of-at91.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/kernel/drivers/mmc/host/sdhci-of-at91.c b/kernel/drivers/mmc/host/sdhci-of-at91.c new file mode 100644 index 000000000..06d0b50df --- /dev/null +++ b/kernel/drivers/mmc/host/sdhci-of-at91.c @@ -0,0 +1,191 @@ +/* + * Atmel SDMMC controller driver. + * + * Copyright (C) 2015 Atmel, + * 2015 Ludovic Desroches <ludovic.desroches@atmel.com> + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/mmc/host.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> + +#include "sdhci-pltfm.h" + +#define SDMMC_CACR 0x230 +#define SDMMC_CACR_CAPWREN BIT(0) +#define SDMMC_CACR_KEY (0x46 << 8) + +struct sdhci_at91_priv { + struct clk *hclock; + struct clk *gck; + struct clk *mainck; +}; + +static const struct sdhci_ops sdhci_at91_sama5d2_ops = { + .set_clock = sdhci_set_clock, + .set_bus_width = sdhci_set_bus_width, + .reset = sdhci_reset, + .set_uhs_signaling = sdhci_set_uhs_signaling, +}; + +static const struct sdhci_pltfm_data soc_data_sama5d2 = { + .ops = &sdhci_at91_sama5d2_ops, + .quirks2 = SDHCI_QUIRK2_NEED_DELAY_AFTER_INT_CLK_RST, +}; + +static const struct of_device_id sdhci_at91_dt_match[] = { + { .compatible = "atmel,sama5d2-sdhci", .data = &soc_data_sama5d2 }, + {} +}; + +static int sdhci_at91_probe(struct platform_device *pdev) +{ + const struct of_device_id *match; + const struct sdhci_pltfm_data *soc_data; + struct sdhci_host *host; + struct sdhci_pltfm_host *pltfm_host; + struct sdhci_at91_priv *priv; + unsigned int caps0, caps1; + unsigned int clk_base, clk_mul; + unsigned int gck_rate, real_gck_rate; + int ret; + + match = of_match_device(sdhci_at91_dt_match, &pdev->dev); + if (!match) + return -EINVAL; + soc_data = match->data; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) { + dev_err(&pdev->dev, "unable to allocate private data\n"); + return -ENOMEM; + } + + priv->mainck = devm_clk_get(&pdev->dev, "baseclk"); + if (IS_ERR(priv->mainck)) { + dev_err(&pdev->dev, "failed to get baseclk\n"); + return PTR_ERR(priv->mainck); + } + + priv->hclock = devm_clk_get(&pdev->dev, "hclock"); + if (IS_ERR(priv->hclock)) { + dev_err(&pdev->dev, "failed to get hclock\n"); + return PTR_ERR(priv->hclock); + } + + priv->gck = devm_clk_get(&pdev->dev, "multclk"); + if (IS_ERR(priv->gck)) { + dev_err(&pdev->dev, "failed to get multclk\n"); + return PTR_ERR(priv->gck); + } + + host = sdhci_pltfm_init(pdev, soc_data, 0); + if (IS_ERR(host)) + return PTR_ERR(host); + + /* + * The mult clock is provided by as a generated clock by the PMC + * controller. In order to set the rate of gck, we have to get the + * base clock rate and the clock mult from capabilities. + */ + clk_prepare_enable(priv->hclock); + caps0 = readl(host->ioaddr + SDHCI_CAPABILITIES); + caps1 = readl(host->ioaddr + SDHCI_CAPABILITIES_1); + clk_base = (caps0 & SDHCI_CLOCK_V3_BASE_MASK) >> SDHCI_CLOCK_BASE_SHIFT; + clk_mul = (caps1 & SDHCI_CLOCK_MUL_MASK) >> SDHCI_CLOCK_MUL_SHIFT; + gck_rate = clk_base * 1000000 * (clk_mul + 1); + ret = clk_set_rate(priv->gck, gck_rate); + if (ret < 0) { + dev_err(&pdev->dev, "failed to set gck"); + goto hclock_disable_unprepare; + } + /* + * We need to check if we have the requested rate for gck because in + * some cases this rate could be not supported. If it happens, the rate + * is the closest one gck can provide. We have to update the value + * of clk mul. + */ + real_gck_rate = clk_get_rate(priv->gck); + if (real_gck_rate != gck_rate) { + clk_mul = real_gck_rate / (clk_base * 1000000) - 1; + caps1 &= (~SDHCI_CLOCK_MUL_MASK); + caps1 |= ((clk_mul << SDHCI_CLOCK_MUL_SHIFT) & SDHCI_CLOCK_MUL_MASK); + /* Set capabilities in r/w mode. */ + writel(SDMMC_CACR_KEY | SDMMC_CACR_CAPWREN, host->ioaddr + SDMMC_CACR); + writel(caps1, host->ioaddr + SDHCI_CAPABILITIES_1); + /* Set capabilities in ro mode. */ + writel(0, host->ioaddr + SDMMC_CACR); + dev_info(&pdev->dev, "update clk mul to %u as gck rate is %u Hz\n", + clk_mul, real_gck_rate); + } + + clk_prepare_enable(priv->mainck); + clk_prepare_enable(priv->gck); + + pltfm_host = sdhci_priv(host); + pltfm_host->priv = priv; + + ret = mmc_of_parse(host->mmc); + if (ret) + goto clocks_disable_unprepare; + + sdhci_get_of_property(pdev); + + ret = sdhci_add_host(host); + if (ret) + goto clocks_disable_unprepare; + + return 0; + +clocks_disable_unprepare: + clk_disable_unprepare(priv->gck); + clk_disable_unprepare(priv->mainck); +hclock_disable_unprepare: + clk_disable_unprepare(priv->hclock); + sdhci_pltfm_free(pdev); + return ret; +} + +static int sdhci_at91_remove(struct platform_device *pdev) +{ + struct sdhci_host *host = platform_get_drvdata(pdev); + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); + struct sdhci_at91_priv *priv = pltfm_host->priv; + + sdhci_pltfm_unregister(pdev); + + clk_disable_unprepare(priv->gck); + clk_disable_unprepare(priv->hclock); + clk_disable_unprepare(priv->mainck); + + return 0; +} + +static struct platform_driver sdhci_at91_driver = { + .driver = { + .name = "sdhci-at91", + .of_match_table = sdhci_at91_dt_match, + .pm = SDHCI_PLTFM_PMOPS, + }, + .probe = sdhci_at91_probe, + .remove = sdhci_at91_remove, +}; + +module_platform_driver(sdhci_at91_driver); + +MODULE_DESCRIPTION("SDHCI driver for at91"); +MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@atmel.com>"); +MODULE_LICENSE("GPL v2"); |