From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ritesh Harjani Subject: [PATCH v6 08/14] mmc: sdhci-msm: Implement set_clock callback for sdhci-msm Date: Mon, 7 Nov 2016 16:54:31 +0530 Message-ID: <1478517877-23733-9-git-send-email-riteshh@codeaurora.org> References: <1478517877-23733-1-git-send-email-riteshh@codeaurora.org> Return-path: In-Reply-To: <1478517877-23733-1-git-send-email-riteshh@codeaurora.org> Sender: linux-clk-owner@vger.kernel.org To: ulf.hansson@linaro.org, linux-mmc@vger.kernel.org, adrian.hunter@intel.com, shawn.lin@rock-chips.com, sboyd@codeaurora.org Cc: devicetree@vger.kernel.org, linux-clk@vger.kernel.org, david.brown@linaro.org, andy.gross@linaro.org, linux-arm-msm@vger.kernel.org, georgi.djakov@linaro.org, alex.lemberg@sandisk.com, mateusz.nowak@intel.com, Yuliy.Izrailov@sandisk.com, asutoshd@codeaurora.org, kdorfman@codeaurora.org, david.griego@linaro.org, stummala@codeaurora.org, venkatg@codeaurora.org, rnayak@codeaurora.org, pramod.gurav@linaro.org, Ritesh Harjani List-Id: linux-arm-msm@vger.kernel.org sdhci-msm controller may have different clk-rates for each bus speed mode. Thus implement set_clock callback for sdhci-msm driver. Signed-off-by: Sahitya Tummala Signed-off-by: Ritesh Harjani --- drivers/mmc/host/sdhci-msm.c | 87 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 86 insertions(+), 1 deletion(-) diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c index fde2777..ff0915b 100644 --- a/drivers/mmc/host/sdhci-msm.c +++ b/drivers/mmc/host/sdhci-msm.c @@ -82,6 +82,7 @@ struct sdhci_msm_host { struct clk *clk; /* main SD/MMC bus clock */ struct clk *pclk; /* SDHC peripheral bus clock */ struct clk *bus_clk; /* SDHC bus voter clock */ + unsigned long clk_rate; struct mmc_host *mmc; bool use_14lpp_dll_reset; }; @@ -573,6 +574,90 @@ static unsigned int sdhci_msm_get_min_clock(struct sdhci_host *host) return SDHCI_MSM_MIN_CLOCK; } +/** + * __sdhci_msm_set_clock - sdhci_msm clock control. + * + * Description: + * Implement MSM version of sdhci_set_clock. + * This is required since MSM controller does not + * use internal divider and instead directly control + * the GCC clock as per HW recommendation. + **/ +void __sdhci_msm_set_clock(struct sdhci_host *host, unsigned int clock) +{ + u16 clk; + unsigned long timeout; + + /* + * Keep actual_clock as zero - + * - since there is no divider used so no need of having actual_clock. + * - MSM controller uses SDCLK for data timeout calculation. If + * actual_clock is zero, host->clock is taken for calculation. + */ + host->mmc->actual_clock = 0; + + sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL); + + if (clock == 0) + return; + + /* + * MSM controller do not use clock divider. + * Thus read SDHCI_CLOCK_CONTROL and only enable + * clock with no divider value programmed. + */ + clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL); + + clk |= SDHCI_CLOCK_INT_EN; + sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL); + + /* Wait max 20 ms */ + timeout = 20; + while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL)) + & SDHCI_CLOCK_INT_STABLE)) { + if (timeout == 0) { + pr_err("%s: Internal clock never stabilised\n", + mmc_hostname(host->mmc)); + return; + } + timeout--; + mdelay(1); + } + + clk |= SDHCI_CLOCK_CARD_EN; + sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL); +} + +/* sdhci_msm_set_clock - Called with (host->lock) spinlock held. */ +static void sdhci_msm_set_clock(struct sdhci_host *host, unsigned int clock) +{ + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); + struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host); + int rc; + + if (!clock) { + msm_host->clk_rate = clock; + goto out; + } + + spin_unlock_irq(&host->lock); + if (clock != msm_host->clk_rate) { + rc = clk_set_rate(msm_host->clk, clock); + if (rc) { + pr_err("%s: Failed to set clock at rate %u\n", + mmc_hostname(host->mmc), clock); + spin_lock_irq(&host->lock); + goto out; + } + msm_host->clk_rate = clock; + pr_debug("%s: Setting clock at rate %lu\n", + mmc_hostname(host->mmc), clk_get_rate(msm_host->clk)); + } + spin_lock_irq(&host->lock); +out: + __sdhci_msm_set_clock(host, clock); +} + static const struct of_device_id sdhci_msm_dt_match[] = { { .compatible = "qcom,sdhci-msm-v4" }, {}, @@ -583,7 +668,7 @@ static unsigned int sdhci_msm_get_min_clock(struct sdhci_host *host) static const struct sdhci_ops sdhci_msm_ops = { .platform_execute_tuning = sdhci_msm_execute_tuning, .reset = sdhci_reset, - .set_clock = sdhci_set_clock, + .set_clock = sdhci_msm_set_clock, .get_min_clock = sdhci_msm_get_min_clock, .get_max_clock = sdhci_msm_get_max_clock, .set_bus_width = sdhci_set_bus_width, -- The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.